| { |
| "topics": { |
| "Heat Transfer": [ |
| { |
| "question": "Asteelsphereofradius 0.1 mat 400 Kisimmersedinoilat 300k. IftheCanterofthespherereaches 350Kin 20 min, howlongwillittakefora 0.05mradiussteelspheretoreachthesametemperature (atthecentre) underidenticalcondition? Assumethattheconvectiveheattransfercoefficientisinfinitelylarge.", |
| "options": [ |
| "5 min", |
| "10 min", |
| "20 min", |
| "40 min 2001 - IITKanpurQ . 5 Heattransferbynaturalconvectionisenhancedinsystemswith" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Ifthebafflespacinginashellandtubeheatexchangeincreases, thentheReynoldsnumberoftheshellsidefluid", |
| "options": [ |
| "Remainsunchanged", |
| "Increases", |
| "Increasesordecreasesdependingonnumberofshellspasses", |
| "Decreases" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "AcompositewallconsistsoftwoplatesAandBplacedinseriesnormaltotheflowofheat. ThethermalconductivitiesareandandthespecificheatcapacitiesareandforplatesAandBrespectively. PlateBhastwicethethicknessofplateA. Atsteadystate, thetemperaturedifferenceacrossplateAisgreaterthanthatacrossplateB, when", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "1000 kgofliquidatinawell - stirredvesselhastobeheatedtousingimmersedcoilscarryingcondensingsteamat . Theareaofthesteamcoilsisandoverallheattransfercoefficienttotheliquidis . Assumingnegligibleheatlosstosurroundingandspecificheatcapacityoftheliquidtobethetimetakenfortheliquidtoreachdesiredtemperaturewillbe", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A 10 cmdiametersteampipe, carryingsteam, atiscoveredwithinsulation(Conductivity . Itlosesheattothesurroundingsat . Assumeaheattransfercoefficientofforthetransferfromsurfacetothesurroundings. Neglectwallresistanceofthepipeandfilmresistanceofsteam. Iftheinsulationthickness 2 cm, therateofheatlossfromthisinsulatedpipewillbe", |
| "options": [ |
| "greaterthanthatoftheun - insulatedsteampipe", |
| "lessthanthatoftheun - insulatedsteampipe", |
| "Equaltotheoftheun - insulatedsteampipe", |
| "lessthanthestempipewith 5 cminsulation 2003 - IITMadras" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Theunitofresistancetoheattransferare", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Adiluteaqueoussolutionistobeconcentratedinanevaporatorsystem. Highpressuresteamisavailable. Multipleeffectevaporatorsystemisemployedbecause", |
| "options": [ |
| "Totalheattransferareaofalltheeffectsislessthanthatinasingleeffectevaporatorsystem", |
| "Totalamountofvaporproducedperkgoffeedsteaminamulti - effectsystemismuchhigherthaninasingleeffect", |
| "Boilingpointelevationinasingleeffectsystemmuchhigherthanthatinanyeffectinamultieffectsystem", |
| "Heattransfercoefficientinasingleeffectismuchlowerthanthatinanyeffectinamultieffectsystem" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Threesolidobjectsofthematerialandofequalmasses - asphere, acylinder (length = diameter ) andacubeareatinitial. Thesearedroppedinaquenchingbathcontainingalargevolumeofcoolingoileachattainingthebathtemperatureeventually. Thetimerequiredfor 90% changeoftemperatureissmallestfor", |
| "options": [ |
| "Cube", |
| "Cylinder", |
| "Sphere", |
| "Equalforallthethree" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Foragivenambientairtemperaturewithincreaseinthethicknessofinsulationofahotcylindricalpipe, therateofheatlossfromthesurfacewould", |
| "options": [ |
| "Decrease", |
| "Firstdecreaseandthenincrease", |
| "Increase", |
| "Firstincreaseandthendecrease" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Airistobeheatedbycondensingsteam. Theheatexchangersareavailable (i) Ashellandtubeheatexchanger, and (ii) Afinnedtubeheatexchanger. Tubesideheattransferareaisequalinbothcases. Therecommendedarrangementis", |
| "options": [ |
| "Finnedtubeheatexchangerwithairinsideandsteamoutside", |
| "Finnedtubeheatexchangewithairoutsideandsteaminside", |
| "Shellandtubeheatexchangerwithairinsidetubesandsteamonshellside", |
| "Shellandtubeheatexchangerwithaironshellsideandsteaminsidetubes" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "ratethetubesideheattransfercoefficientforturbulentflowconditionsisproportionalto", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Steamistobecondensedinashellandtubeheatexchanger 5 mlongwithashelldiameterof 1 m. Coolingwateristobeusedforremovingtheheat. Heattransfercoefficientforthecoolingwaterweatherofshellsideortubesideissame. Thebestarrangementis", |
| "options": [ |
| "Verticalheatexchangerwithsteamontubeside", |
| "Verticalheatexchangerwithsteamonshellside", |
| "Horizontalheatexchangerwithsteamontubeside", |
| "Horizontalheatexchangerwithsteamonshellside" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Theinnerwallofafurnaceisatatemperatureof . Thecompositewallismadeoftwosubstances, 10 and 20 cmthickwiththermalconductivitiesof 0.05 and 0.1 respectively. Theambientairisatandtheheattransfercoefficientbetweentheoutersurfaceofwallandairis . Therateofheatlossflowtheoutersurfaceinis", |
| "options": [ |
| "167.4", |
| "167.5", |
| "172.5", |
| "175" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Aprocesssteamofdiluteaqueoussolutionflowingattherateofistobeheated. Steamcondensateatisavailableforheatingpurpose, alsoatarateof 1 0 kg/s. A 1 - 1 shellandtubeheatexchangerisavailableforheatingpurpose, alsoatarateofA 1 - 1 shellandtubeheatexchangerisavailable . Thebestarrangementis", |
| "options": [ |
| "Counterflowwithprocessstreamonshellside", |
| "Counterflowwithprocessstreamontubeside", |
| "Parallelflowwithprocessstreamonshellside", |
| "Parallelflowwithprocessstreamontubeside 2004 - IITDelhi" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Foranidealblackbody,", |
| "options": [ |
| "Absorptivity", |
| "Reflectivity", |
| "Emissivity 0", |
| "transmissivity" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Inforces - convection, theNusseltnumberNuisafunctionof", |
| "options": [ |
| "ReandPr", |
| "ReandGr", |
| "PrandGr", |
| "ReandSc" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Hotwaterentersthetubesideofaco - currentshellandtubeheatexchangeratandleavesat . Coldoilofdensityandspecificheatofentersat . Thelogmeantemperaturedifferenceinisapproximately", |
| "options": [ |
| "32", |
| "37", |
| "45", |
| "50" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Itisdesiredtoconcentratea 20% saltsolution (20 kgofsaltin 100 kgofsolution) toa 30 % saltsolutioninanevaporator. Considerafeedof 300 kg/minat . Theboilingpointofthesolutionis , thelatentheatofvaporizationis 2100 kJ/kg, andthespecificheatofthesolutionis 4 kJ / (kg - K). Therateatwhichheathastobesupplied (inkJ /min) totheevaporatoris", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Ametalballofradius 0. 1 matauniformtemperatureofisleftinairat . Thedensityandthespecificheatofthemetalareand 0.4 kJ /g - K) respectively. Theheattransfercoefficientis . Neglectingthetemperaturegradientinsidetheball , thetimetaken (inhour) fortheballtocooltois", |
| "options": [ |
| "555", |
| "57.5", |
| "0.55", |
| "0.15" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Theleftfaceofaonedimensionalslabofthickness 0.2 mismaintainedatandtherightfaceisexposedtoairat . Thethermalconductivityoftheslabis 1.2 W /(m - K) andtheheattransfercoefficientfromtherightfaceis 10 . Atsteadystate , thetemperatureoftherightfaceinis", |
| "options": [ |
| "75.2", |
| "11.2", |
| "63.8", |
| "48.7 2005 - IITBombay" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Infilmtypecondensationofliquidalongaverticaltube, thethicknessofthecondensateLayerincreasestowardsthebottom. Thisimpliesthatthelocalheattransfercoefficient", |
| "options": [ |
| "Increasesfromtoptobottom", |
| "Decreasesfromtoptobottom", |
| "Remainsconstantfromtoptobottom", |
| "Firstincreasesandthendecreasesfromtoptobottom" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Bafflesareusedinheatexchangersinorderto", |
| "options": [ |
| "Promotevibrationintheheatexchanger", |
| "Promotecrossflowandturbulenceintheshellsidefluid", |
| "Preventshellexpansionduetothermaleffects" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Anelectricallyheatedelementissubmergedinapoolofwateratitssaturationtemperature. Asthetemperatureoftheelementincreases, themaximumheattransfercoefficientisobserved", |
| "options": [ |
| "Inthefreeconvectionregime", |
| "Betweenthenucleateboilingandpartialnucleateboilingmixedwithunstablefilmboilingregimes", |
| "Intheincipientnucleateboilingregime", |
| "InthestablefilmboilingregimewithoutsignificantradiationeffectsCommonDataforQuestions" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Whatistheoverallheattransfercoefficientin", |
| "options": [ |
| "1", |
| "4.04", |
| "9.07", |
| "10" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Whatisthetimerequiredforthetemperatureoftheliquidtoreducetoaftertheheaterisswitchedoff, assuminglumpedheatsystemanalysisisvalid?", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Fluidflowsinanannulusofinnerdiameter 0.8 mandouterdiameter 1 m. Heatistransferredtothefluidfrominnertubesurfaceoftheannulus . Whatistheequivalentdiameterforheattransferinmeter?", |
| "options": [ |
| "0.45", |
| "", |
| "0 .64", |
| "0.90" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Acounter - currentflowdoublepipeheatexchangerisusedtoheatwaterflowingat 1 kg/sfromto .Oilisusedforheatinganditstemperaturechangefromto . Theoverallheattransfercoefficientis . Ifitisreplacedbya 1 - 2 shellandtubeheatexchangerwithcounter - currentflowconfigurationwithwaterflowinginshellandoilflowinginthetube, whatistheexcessarearequiredwithrespecttothedoublepipeheatexchanger? Thecorrectionfactor, forLMTD ( LogMeanTemperatureDifference), basedontheabovedoublepipeheatexchangeris 0.5 Theheattransfercoefficientremainsunchanged, andthesameinletandoutletconditionsaremaintained.", |
| "options": [ |
| "Zero", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Asemi - infiniteslaboccupyingtheregionandisataninitialtemperature . Attime , thesurfaceofthe, slabatisbroughtintocontactwithaheatbathatatemperature . Thetemperatureofthe, slabrisesaccordingtotheequationwherexispositionandtistime. Theheatfluxatthesurfaceisproportionalto", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Considertheflowofagaswithdensityviscosity , specificheatandthermalconductivity , inapipeofdiametermandlengthmandassumetheviscositydoesnotchangewithtemperature. TheNusseltnumberforapipewith ( L/D) ratiogreaterthan 10 andReynoldsnumbergreaterthan 20000 isgivenby . WhiletheNusseltnumberforalaminarflowforReynoldsnumberlessthan 210 0 and (RePrD / L ) < 10 is . Ifthegasflowsthroughthepipewithanaveragevelocityof 0.1 m/ s, theheattransfercoefficientis", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Acirculartubeofouterdiameter 5 cmandinnerdiameter 4 cmisusedtoconveyhotfluid. Theinnersurfaceofthewallofthetubeisatatemperatureofwhiletheoutersurfaceofthewallofthetubeisat . Whatistherateofheattransportacrossthetubewallpermeterlengthofthetubeatsteadystate, ifthethermalconductivityofthetubewallis", |
| "options": [ |
| "13823 W /m", |
| "15487 W /m", |
| "17279 W /m", |
| "27646W /m" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "AblackbodyatahighertemperaturetransfersenergybyradiationtoablackbodyatalowertemperatureInitially , andthenetratofenergytransferis 25 W . Aftersometime, whenand , whatisthenetrateofenergytransfer ?", |
| "options": [ |
| "", |
| "", |
| "13.89 W", |
| "11.01 W 2006 - IITKharagpur" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Astagnantliquidfilmof 0.4 mmthicknessisheldbetweentwoparallelplates. Thetopplateismaintainedatandthebottomplateismaintainedat . Ifthethermalconductivityoftheliquidis 0.14 W /(m - K), thenthesteadystateflux (inassumingone - dimensionalheattransfer, is", |
| "options": [ |
| "3.5", |
| "350", |
| "3500", |
| "7000" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Afluidflowsthroughacylindricalpipeunderfullydeveloped, steadystatelaminarflowconditions. Thetubewallismaintainedatconstanttemperature. Assumingconstantphysicalpropertiesandnegligibleviscousheatdissipation, thegoverningequationforthetemperatureprofileis (z - axildirection; r - radialdirection)", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Aprocessfluidhastobecooledfromtousingbrineina 2 - 4 shellandtubeheatexchangershowbelow. Thebrineentersatandleavesat . Theoverallheattransfercoefficientis . Thedesignheatloadis 30 kW . Thebrineflowsonthetubesideandtheprocessfluidontheshellside. Theheattransferareainis", |
| "options": [ |
| "1.1", |
| "7.77", |
| "6.59", |
| "7.53" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Aninsulatedcylindricalpipeof 0.2 mdiameterhassurfacetemperatureof . Itisexposedtoblackbodysurroundingsat . Theemissivityandabsorptivityoftheinsulationsurfaceare 0.96 and 0.93 respectively. Theconvectiveheattransfercoefficientoutsidetheinsulationsurfaceis . . TheStefanBoltzmannconstantis . Thesurroundingfluidmaybeassumedtobetransparent. Findthepercentagecontributionfromradiationtothetotalheattransferratetothesurroundings.", |
| "options": [ |
| "30.9", |
| "50.0", |
| "57.6", |
| "68.4" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Onedimensionalsteadystateheat - transferoccursfromaflatverticalwalloflength 0.1mintotheadjacentfluid. Theheatfluxintothisfluidis . Thewallthermalconductivityis 1.73 W /(m - K). IftheheattransfercoefficientisandtheNusseltnumberbasedonthewalllengthis 20, thenthemagnitudeofthetemperaturegradientatthewallonthefluidside ( inK/m ) is", |
| "options": [ |
| "0.7", |
| "12.14", |
| "120", |
| "140 CommonDataforQuestions" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Themassflowrateofthecondensatethroughanyaxialpositionxperunitwidthoftheplateisgivenby", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Differentiatewithrespecttotogetthedifferentialincreaseincondensatemassdmwithfilmthicknessi.e. . Thenobtainassumingheatfluxthroughthefilmtobeduetoconductionbaseonalineartemperatureprofilebetweenthevaporandliquid. Hencedetermine . Here, isliquidviscosity, isthermalconductivityandislatentheatofcondensation. isthevapourtemperatureandisthewalltemperature", |
| "options": [ |
| "", |
| "", |
| "", |
| "2007 - IITKanpur" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "TheGrashofNumberis", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "InadoublepipeheatexchangertheIDandODoftheinnerpipeare 4 cmand 5 cmrespectively. TheIDoftheouterpipeis 10 cmwithawallthicknessof 1 cm. Thentheequivalentdiameters (incm ) oftheannulforheathealtransferandpressuredroprespectivelyare", |
| "options": [ |
| "15, 5", |
| "21, 6", |
| "6, 19", |
| "15, 21" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "ThefollowinglistofoptionsP , Q, RandSaresomeoftheimportantinthedesignofashellandtubeheatexchanger. (P) Squarepitchpermitsthe - useofmoretubesingivenshelldiameter. (Q) Thetubesideclearanceshouldnotbelessthanone - fourthofthetubediameter. (R) Bafflespacinginnotgreater - thanthediameteroftheshellorlessthanone - fifthoftheshelldiameter . (S) Thepressuredroponthetubesideislessthan 10 psi. Pickoutthecorrectcombinationoftruestatementsfromthefollowing.", |
| "options": [ |
| "P ,QandR", |
| "Q, RandS", |
| "R , SandP", |
| "P, Q, RandS" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Consideraliquidstoredinacontainerexposedtoitssaturatedvaporatconstanttemperature . Thebottomsurfaceofthecontainerismaintainedataconstanttemperaturewhileitssidewallsareinsulated. Thethermalconductivityisoftheliquid, itslatentheatofvaporizationanddensityareknown. Assumingalineartemperaturedistributionintheliquid, theexpressionforthegrowthoftheliquidlayerasafunctionoftimetisgivenby", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Ahotfluidenteringawell - stirredvesseliscooledbyfeedingcoldwaterthroughajacketaroundthevessel. Assumethejacketiswell - mixed. Forthefollowingdata: Massflow - rateofthefluidMassflow - rateofcoldwaterSpecificheatofoilSpecificheatofcoldwaterTheinletandexittemperaturesofthehotfluidareandrespectively, InlettemperatureofcoldwaterTheoverallheattransferefficientisTheheattransferareain , is", |
| "options": [ |
| "1.82", |
| "2.1", |
| "3", |
| "4.26" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Waterentersathinwalledtube ( ) ataninlettemperatureofandmassflowrate 0.015 kg/s. Thetubewallismaintainedataconstanttemperatureof . Giventhefollowingdataforwater, DensityViscositySpecificheatInsiderheattransfercoefficientTheoutletofwaterinis", |
| "options": [ |
| "28", |
| "37", |
| "62", |
| "96" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "ThecompositewallofanovenconsistsofthreematerialsA,BandC . Understeadystateoperatingconditions, theoutersurfacetemperatureis , theinnersurfacetemperatureisandtheovenairtemperatureis . Forthefollowingdata : ThermalconductivitiesandThickness , andInner - wallheattransfercoefficient , ThethermalconductivityinW /(m - K) ofthematerialB , iscalculatedas", |
| "options": [ |
| "35", |
| "", |
| "0.66", |
| "0.03" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Forthetwolongconcentriccylinderswithsurfaceareasandtheviewfactorisgivenby", |
| "options": [ |
| "Zero", |
| "1", |
| "", |
| "2008 IIScBangalore" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Transientthree - dimensionalheatconductionisgovernedbyoneofthefollowingdifferentialequations ( thermaldiffusivity, thermalconductivityandvolumetricrateofheatgeneration)", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Duringthetransientconvectivecoolingofasolidobject, Biotnumberindicates", |
| "options": [ |
| "Uniformtemperaturethroughouttheobject", |
| "Negligibleconvectionatthesurfaceoftheobject", |
| "Significantthermalresistancewithintheobject", |
| "Significanttemperaturegradientwithintheobject" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "ThePrandtlnumberofafluidistheratioof", |
| "options": [ |
| "thermaldiffusivitytomomentumdiffusivity", |
| "momentumdiffusivitytothermaldiffusivity", |
| "conductiveresistancetoconvectiveresistance", |
| "thermaldiffusivitytokinematicviscosityCommonDataforQuestions" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Whichoneofthefollowingstatementsaboutbafflesinashellandtubeheatexchangerisfalse? Baffles", |
| "options": [ |
| "Actasasupporttothetubebundle", |
| "Reducethepressuredropontheshell - side", |
| "Altertheshell - sideflowpattern", |
| "Helpinincreasingtheshell - sideheattransfercoefficient" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "TheratioofNusseltnumbertoBiotnumberis", |
| "options": [ |
| "Conductiveresistanceoffluid/ conductiveresistanceofsolid", |
| "Conductiveresistanceoffluid/ conductiveresistanceoffluid", |
| "Conductiveresistanceofsolid/ conductiveresistanceoffluid", |
| "UnityCommonDataforQuestions" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Infilmtypecondensationoveraverticaltube, localheattransfercoefficientis", |
| "options": [ |
| "Inverselyproportionaltolocalfilmthickness", |
| "Directlyproportionaltolocalfilmthickness", |
| "Equaltolocalfilmthickness", |
| "Independentoflocalfilmthickness" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Considertwoblackbodieswithsurfaces (area ) and (area ). Theyexchangeheatonlybyradiation , 40 % oftheenergyemittedbyisreceivedby . Thefractionofenergyemittedbythatisreceivedbyis", |
| "options": [ |
| "0.05", |
| "0.1", |
| "0.4", |
| "0.6" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Forheattransferacrossasolid - fluidinterface, whichoneofthefollowingstatementsisNOTtruewhentheBiotnumberisverysmallcomparedto 1?", |
| "options": [ |
| "Conductionresistanceinthesolidisverysmallcomparedtoconvectionresistanceinthefluid", |
| "Temperatureprofilewithinthesolidisnearlyuniform", |
| "Temperaturedropinthefluidissignificant", |
| "TemperaturedropintheSolidissignificant" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "AsolidspherewithinitialtemperatureTiisimmersedinalargethermalreservoiroftemperatureTo . Thespherereachesasteadytemperatureafteracertaintimet 1 . Iftheradiusofthesphereisdoubled, thetimerequiredtoreachsteady - statewillbe", |
| "options": [ |
| "", |
| "", |
| "2t 1", |
| "4t 1" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Aholeofareaisopenedonthesurfaceoflargesphericalcavitywhoseinsidetemperatureismaintainedat . ThevalueofStefanBoltzmannconstantis . Assumingblackbodyradiation, therateatwhichtheenergyisemitted (inW ) bythecavitythroughthehole, upto 3 digitsafterthedecimalpoint , is", |
| "options": [ |
| "5.13", |
| "5.67", |
| "5.35", |
| "5.79" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Inapoolboilingexperiment, thefollowingphenomenawereobserved. P . NaturalconvectionQ. FilmboilingR. TransitionboilingS. NucleateboilingWhatwasthecorrectsequenceoftheiroccurrence ?", |
| "options": [ |
| "P, Q, R, S", |
| "S, R , Q, P", |
| "Q, R, P , S", |
| "P, S , R,Q" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Theeffectivenessofaheatexchangerinthe - NTUmethodisdefinedas", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Steameconomyofamultipleeffectevaporatorsystemisdefinedas", |
| "options": [ |
| "Kilogramofsteamusedperhour", |
| "Kilogramofsteamconsumedinalltheeffectsforeachkilogramofsteamfed", |
| "Kilogramofsteamusedinalltheeffectsforeachkilogramofwatervaporizedperhour", |
| "Kilogramofwatervaporizedfromalltheeffectsforeachkilogramofsteamfedtothefirsteffect" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Inacompletelyopaquemedium, if 50% oftheincidentmonochromaticradiationisabsorbed, thenwhichofthefollowingstatementsareCORRECT? (P) 50%oftheincidentradiationisreflected (Q) 25%oftheincidentradiationisreflected (R) 25%oftheincidentradiationistransmitted (S) Noincidentradiationistransmitted", |
| "options": [ |
| "PandSonly", |
| "QandRonly", |
| "PandQonly", |
| "RandSonly" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Twoinfinitelylargeparallelplates ( IandII ) areheldattemperaturesandrespectively, andplacedatadistance 2dapartinvacuum. Aninfinitelylargeflatradiationshield ( III) isplacedinparallelinwithandwithouttheshieldis :", |
| "options": [ |
| "0.5", |
| "0.75", |
| "0.25", |
| "0" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "MatchthedimensionlessnumbersinGroup - 1 withtherationinGroup - 2 Group - 1 (P) Biotnumber (Q) Schmidtnumber (R) GrashofnumberGroup - 2 ( I) ( II) ( III)", |
| "options": [ |
| "P - II, Q - I, R - III", |
| "P - I, Q - III, R - II", |
| "P - III, Q - I, R - II", |
| "P - II, Q - III, R - I" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Steamatiscondensingonaverticalsteelplate. Thecondensateflowislaminar. TheaverageNusseltnumbersareand , whentheplatetemperaturesareandrespectively. Assumethephysicalpropertiesofthefluidandsteeltoremainconstantwithinthetemperaturerangeofinterest. UsingNusseltequationsforfilm - typecondensation, whatisthevalueoftheratio", |
| "options": [ |
| "0.5", |
| "0.84", |
| "1.19", |
| "1.41" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Theone - dimensionalunsteadyheatconductionequationisWhereT - temperaturet - timer - radialposition, k - thermalconductivity, densityandspecificheat. Forthecylindricalco - ordinatesystem, thevalueofanntheaboveequationis", |
| "options": [ |
| "0", |
| "1", |
| "2", |
| "3" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Segmentalbafflesina 2 - 4 shellandtubeheatexchanger", |
| "options": [ |
| "Changetheflowpatternofthetubesidefluidandincreasetheoverallheattransfercoefficient", |
| "Increasetheheattransfercoefficientintheshellsideandsupportthetubes", |
| "Helptoreducethethermalexpansionofthetubesandincreasetheheattransfercoefficientinthetubeside", |
| "Increasethenumberofpassesintheshellsideandincreasetheheattransfercoefficientinthetubeside" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Economyofevaporatorsusedforconcentratingsugarcanejuiceis", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Considerthetwocountercurrentheatexchangerdesignsforheatingacoldstreamfromto , asshowninfigure. Thehotprocessstreamisavailableat . Theinletstreamconditionsandoverallheattransfercoefficientsareidenticalinboththedesigns. TheheattransferareainDesignIIarerespectivelyandIfheatlossesareneglected, andif 7 oththedesignsarefeasible, whichofthefollowingstatementsholdstrue:", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Prandtlnumbersignifiestheratioof", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Poolboilingequipmentoperatingaboveambienttemperatureisusuallydesignedtooperate", |
| "options": [ |
| "Farabovethecriticalheatflux", |
| "Nearthecriticalheatflux", |
| "FarabovetheLeidenfrostpoint", |
| "NeartheLeidenfrostpoint" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Ratioofmomentumdiffusivitytothermaldiffusivityis", |
| "options": [ |
| "Pecletnumber", |
| "Nusseltnumber", |
| "Reynoldsnumber", |
| "Prandtlnumber" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Leidenfrostphenomenaistruefor", |
| "options": [ |
| "Condensationofvaporonacoldsurface", |
| "Themeltingoffrost", |
| "Theexchangeofheatbetweentwosolids", |
| "Filmboilingevaporationofliquiddropletsfallingonaveryhotsurface" |
| ], |
| "answer": null, |
| "explanation": "" |
| } |
| ] |
| }, |
| "all": [ |
| { |
| "question": "A steel sphere o f radius 0.1 m at 400 K is im mersed in oil at 300k. If th e C anter of the sphe re r eac hes 350K in 20 mi n, how long will it take for a 0.05m radius steel sphere to reach the same temperatur e (at the centre) unde r identical conditi on? Assume th at t he conve cti ve he at t ransfe r coe fficient i s i nfini tel y lar ge.", |
| "options": [ |
| "5 mi n", |
| "10 min", |
| "20 mi n", |
| "40 min 2001 - IIT Kanpur Q . 5 Heat t ransf er b y n atural c onvecti on is enhanc ed in s ystems wit h" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "If the ba ffle spacin g in a shell and tube heat exchan ge incr eases, then the R e ynolds number of the shell side fluid", |
| "options": [ |
| "Remains unch an ged", |
| "Incr eases", |
| "Incr eases o r dec reas e s dependin g on number o f shell s passes", |
| "De cr eases" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A compos it e w all consi sts of two pl ates A and B plac ed in s eries nor mal to the flow of he at. The th ermal conducti vit ies are and and the specific h eat c apac it ies are and for plates A and B r espe cti vel y. P late B has twice the thi ckness of plate A. At ste ad y state, the temp eratur e differ ence across plate A is gre ater than that across plate B, when", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "1000 kg o f li quid at in a well - sti rr ed vessel h as to be heat ed to using im mersed coil s c arr yin g condensin g steam at . The area of the steam coi ls is and overall heat transfer coe fficient to the li quid is . Assumi ng negli gibl e heat loss to surrounding and specific he at c apacit y o f the li quid to be the tim e taken for the liq uid t o reach desir ed temp eratur e will be", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A 10 cm diameter steam pi pe, carr yin g steam, at is covered with insul ati on(Conducti vit y . It loses he at to the surro undings at . Assume a heat transf er co efficient o f for the transf er from su rfa ce to t h e sur ro undings. Ne glect w all resis tanc e o f the pipe and film resis t ance o f steam. If the insu lation thi ckness 2 cm, th e rate of h eat loss from thi s ins ulated pipe wil l be", |
| "options": [ |
| "gr eate r than that of the u n - insul ated steam pi pe", |
| "less than that of the un - in sulated st eam pi pe", |
| "Equal t o the of the un - insul ated steam pi pe", |
| "less t han the stem pi pe with 5 cm ins ulation 2003 - IIT Madras" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The unit of resis tanc e to heat t ransf er a re", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A dil ute aqu eous solut ion is to be conc entrated in an evapo rator s yst e m. High pressu re ste am is avail able. Mul ti ple effect ev apor ator s ystem i s emplo yed b ec ause", |
| "options": [ |
| "Total heat t ransf er a rea o f all the eff ects i s less t ha n that in a single e ffe ct e vaporator s ystem", |
| "Total amount of v apor produced p er k g of fe ed steam in a mul ti - eff ect s ystem is much hi gher than in a single e ffe ct", |
| "Boil ing point el evati on in a single e ffe ct s yst e m much higher th an that in an y eff ect i n a mul ti ef fect s ystem", |
| "Heat t ransf er coef ficient in a single e ffe ct i s much lower than that in an y e f fect i n a mul ti eff ect s ys tem" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Three soli d objects of th e material and o f equ al masses - a sphe re, a c yli nder (len gth = di ameter ) a nd a cube ar e at ini ti al. These ar e drop ped in a qu enchin g b ath containing a la r ge volum e of cooli ng oil ea ch att a ini ng the bath t emperatu re ev e ntuall y. The ti me r equire d for 90% ch an ge of t emperatur e is s ma ll est for", |
| "options": [ |
| "C ube", |
| "C yli nder", |
| "Sphere", |
| "Equal fo r all the thre e" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "For a given ambi ent air t emperatur e with i nc re ase in t he thi ckness of insula ti on of a hot c yli ndrical p ipe, the r ate of heat l oss from t he sur f ace would", |
| "options": [ |
| "Decr ease", |
| "First dec reas e and then i ncreas e", |
| "Incr ease", |
| "First i ncre ase and th en d ecre ase" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Air is to be heated b y co ndensing ste am. The he at ex changers ar e av ail able (i) A shell and tube heat ex changer, and (ii) A finned tube he at ex cha nge r. Tube side heat t r ansfe r ar ea is equal i n both cas es. The re comm ended a rran gem ent i s", |
| "options": [ |
| "Finned tube he at ex chan ge r wit h air insi de and st eam out side", |
| "Finned tube he at ex chan ge with air outsi de and st eam i nside", |
| "S hell and tube heat ex cha nge r wit h air insi de tubes and st eam on s hell side", |
| "Shell and tube he at e x changer with air on shel l si de and st eam i nside tubes" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "rate the tube side h eat t ra nsfer co effici ent for turb ulent flow condit ions i s proporti onal t o", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "S team is to be condense d in a shell and tube he a t ex change r 5 m long with a shell diameter of 1 m. C ooli ng water is to be us ed fo r r e movi ng the h eat. Heat t ra nsfer coef ficient fo r the c ooli ng w ater weath er of s hell side or tube side is same. The be st arran gem ent i s", |
| "options": [ |
| "Vertical he at ex chan ger wit h st eam on t ube side", |
| "Vertical he at ex chan ger with s team on s hell side", |
| "Horiz ontal heat ex change r wit h st eam on t ube side", |
| "Horiz ontal heat ex change r wit h st eam on s hell side" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The inner wall of a furn ace is at a temper ature o f . The compos it e w all is made of two subst anc e s, 10 and 20 cm thi ck with th ermal condu cti vit ies of 0.05 and 0.1 respecti vel y. Th e ambi ent ai r is at and the heat tr ansfer coe fficient betwe en the oute r surfa ce of w all and air is . The rate of heat l oss flow the outer s urfac e in is", |
| "options": [ |
| "167.4", |
| "167.5", |
| "172.5", |
| "175" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A proc ess steam o f dil ute aqueous solut ion flowing at the rate o f is to be heated. S team condens ate a t is avail able for h eati n g p urpose, also at a r ate of 1 0 kg/s. A 1 - 1 shell and t ube he at ex chan ge r is av ail able for heati n g purpos e, als o at a rate o f A 1 - 1 s hell and tube heat ex ch anger is avail abl e . The best arran gement is", |
| "options": [ |
| "C ounter flow with proces s st ream on s hell side", |
| "Counte r flow with pr ocess st ream on t ube side", |
| "P arall el flow wit h proc e ss st ream on s hell side", |
| "Par all el flow wit h pr ocess st ream on t ube side 2004 - IIT Delhi" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "For an id eal bl ack bod y,", |
| "options": [ |
| "Absorpti vit y", |
| "R eflecti vit y", |
| "Emi ssi vit y 0", |
| "transmi ssi vit y" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "In forc es - conv ecti on, the Nusselt number Nu is a f uncti on of", |
| "options": [ |
| "R e and P r", |
| "Re and Gr", |
| "Pr and Gr", |
| "R e and S c" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Hot water enters the tube side of a co - cur rent shell and tube heat ex chan ger at and leaves at . C old oil of densit y and specific he at of enters at . The log mean temper ature diff er e nce in is approx im atel y", |
| "options": [ |
| "32", |
| "37", |
| "45", |
| "50" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "It is desired to conc entrat e a 20% salt solut ion (20 kg of salt in 100 kg of s olut ion) to a 30 % sa lt solut ion in an evaporato r. C onsi der a fe ed of 300 kg/m in at . The boil ing point of the solut ion is , the latent heat of vaporiz ati on is 2100 kJ/kg, and the spe cific he at of the solut ion is 4 kJ / (kg - K). The rate at which h e at has to be suppl ied (in kJ /mi n) to t he evapor ator is", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A metal b all of radius 0. 1 m at a unifo rm tempe ra ture of is left in air at . Th e densit y and the speci fic heat of the met al a re an d 0.4 kJ /g - K) r especti ve l y. Th e h eat tr ansfer co e fficient is . Ne glecti n g the tempe ratu re gradi ent i nside the ball , the tim e taken (in hour) for the ball to cool to is", |
| "options": [ |
| "555", |
| "57.5", |
| "0.55", |
| "0.15" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The left fa ce o f a one di mensional slab of t hickn ess 0.2 m is maintain ed a t and the ri ght fa ce is ex posed to air at . The thermal cond ucti vit y of the slab is 1.2 W /(m - K) and the he at tra nsfer coef ficient f rom the right face is 10 . At st ead y state , the temperatur e of the right fa ce in is", |
| "options": [ |
| "75.2", |
| "11.2", |
| "63.8", |
| "48.7 2005 - IIT B o mbay" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "In film t ype condensatio n of liqui d along a v ertic al t ube, the thickness of t he condensat e La ye r inc reas es towards t he bott om. Thi s im pli es that t he local heat t r ansfe r coeffi cient", |
| "options": [ |
| "In cre ases f rom top t o bott om", |
| "Dec reas es from t op t o bott om", |
| "R emains const ant from t op to bot tom", |
| "First i ncre ases and then d ecre ases f rom top t o b ott om" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Baf fles ar e used in he at e x changers in o rder to", |
| "options": [ |
| "P romote vibrati on in t he heat ex chan ger", |
| "P romote cross flow and t urbulence in t he sh ell side flui d", |
| "P revent shell ex pa nsion due to t hermal ef fects" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "An electric all y he ated el ement is subm erged in a pool of water at it s saturati on temperature. As the temperature of the element i nc reas es, the max im um heat t ransfer coe fficient i s obse rved", |
| "options": [ |
| "In the fre e conv ecti on re gim e", |
| "Betw een the nu cleat e boil ing and partial nu cle ate boili ng mi x ed with uns table fil m boi li ng re gi mes", |
| "In the incipi ent nucle ate boili ng r e gim e", |
| "In the stabl e fil m boi li ng re gim e without si gnificant radi ati on effe cts Com mo n Data fo r Questio ns" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "W hat i s the overall heat t ransfe r coe fficient i n", |
| "options": [ |
| "1", |
| "4.04", |
| "9.07", |
| "10" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "W hat is the ti me required for the temperature of the li quid to reduce to a fter the heate r is switched off, assum ing lum ped he at s ystem anal ysis is vali d?", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Flui d flows in an annulus of inne r diamet er 0.8 m and oute r diamete r 1 m. Heat is transf err ed to the fluid f rom inner tube surf ace o f the annulus . W hat i s the equivalent di ameter fo r he at t ransfe r in meter?", |
| "options": [ |
| "0.45", |
| "", |
| "0 .64", |
| "0.90" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A counter - cu rrent flow d ouble pipe heat ex changer is used to heat water flowing at 1 kg/s from to .Oil is used for h eati n g a nd it s temperatur e ch an ge from to . The ove rall he at transf er co effi cient is . If it is repl aced b y a 1 - 2 shell and tube h eat ex changer with counte r - cu rre nt flow con fi gurati on with water flowin g in s hell and oil flowing in t he tube, what is the ex c ess are a requir ed with r espect to the double pipe heat ex chan ger? The corr ecti on facto r, fo r LMTD ( Lo g Mean Te mperature Dif fer enc e), b ased on the above doubl e pipe heat ex changer is 0.5 The heat transfer co effi cient re mains unchanged, and the same inl et and outl et condit ions are maintained.", |
| "options": [ |
| "Ze ro", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A semi - infini te slab occup yin g the re gion and is at an ini ti al temperature . At time , the surfac e of the, slab at is brought int o contact with a heat bath at a te mperature . The temper ature of the, slab rises a ccord ing to the equati on where x is posi ti on and t is ti me. The heat flux at t he surfac e is proporti onal t o", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "C onsi der the flow of a ga s with densit y viscosit y , specific h eat and thermal conducti vit y , in a pipe of diameter m and length m and assum e the viscosit y does not ch ange with temperature. T he Nusselt nu mber for a pipe with ( L/D) rati o gre ater than 10 and R e ynolds number gr eater than 20000 is give n b y . W hile the Nusselt number for a laminar flow for R e ynolds number less than 210 0 and (Re P r D / L ) < 10 is . If the gas flows through th e pipe w it h an avera ge velocit y of 0.1 m/ s, the heat t ransfe r coeffi cient is", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A circula r tube o f outer d iameter 5 cm and inne r d iameter 4 cm is used to c onve y hot fluid. The inn e r surfa ce o f the wall of the tube is at a temperatur e of while the outer surf ace o f the wa ll of the tube is at . W hat is the rate of heat transport across the tube wall per meter length of the tube at stead y state, if the thermal conducti vit y of the tub e wall is", |
| "options": [ |
| "13823 W /m", |
| "15487 W /m", |
| "17279 W /m", |
| "27646W /m" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A black bod y at a high er temperature transfe rs en er g y b y radiation to a black bod y at a lower te mperature Init iall y , and the net r a t of ener g y t ransf er is 25 W . After some ti me, when and , what i s the net r ate of ener g y tr ansfe r ?", |
| "options": [ |
| "", |
| "", |
| "13.89 W", |
| "11.01 W 2006 - IIT Kharag pur" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A stagnant li quid film of 0.4 mm thi ckness is held between two parall el plates. The top plate is maint ained at and the bott om plate is maintained at . If the th ermal condu cti vit y of the li quid is 0.14 W /(m - K), then the stead y state flux (in assum ing one - dim en sional heat t ransf er, is", |
| "options": [ |
| "3.5", |
| "350", |
| "3500", |
| "7000" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A fluid flows throu gh a c yli ndric al pipe unde r fu ll y develop ed, stead y sta te laminar flow condit io ns. The tube wall is maintained at const ant temperature. Assu mi ng const ant ph ysi cal properties and ne gli gibl e viscous heat diss ipation, t he governin g equ ati on for the temp er ature profil e is (z - ax il directi on; r - radi al di recti on)", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A process fluid has to be cooled from to using brine in a 2 - 4 shell and tube heat ex change r show below. The brin e enters a t and leaves at . The over all heat transf er coef ficie nt is . The design h eat load is 30 k W . The brine flows on t he tube side and the pro cess fluid on the sh ell side. The h eat transfer are a in is", |
| "options": [ |
| "1.1", |
| "7.77", |
| "6.59", |
| "7.53" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "An insul ated c yli ndric al pipe of 0.2 m diameter has surfac e temper ature o f . It is ex posed to black bod y surroundings at . The emi ssi vit y and absorptivi t y of the insul ati on surface are 0.96 and 0.93 respe cti vel y. The conv ecti ve he at tr ansfer coe fficient outsi de the insul ati on sur f a ce is . . The S tefan Bolt z mann const ant i s . The surroundin g flui d ma y b e assum ed to be tr an sparent. Find t he per centa ge contr ibut ion from radiation t o the total heat t ransf er r ate to t he surroundings.", |
| "options": [ |
| "30.9", |
| "50.0", |
| "57.6", |
| "68.4" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "One dim ension al stead y state heat - transf er occu rs from a flat vertical wall of length 0.1m int o the adjacent flu id. The heat flux int o thi s fluid is . The wall the rma l conducti vit y is 1.73 W /(m - K). If th e heat tr ans fer coeffi cient is and the Nu sselt number based on t he wall len gth is 20, then the magnit ude o f the te mperatur e gradient at t he wall on the flui d si de ( in K/m ) is", |
| "options": [ |
| "0.7", |
| "12.14", |
| "120", |
| "140 Com mo n Data fo r Questio ns" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The mass flow r ate of the condensate through an y ax ial posi ti on x per unitwidth of the plate is giv e n b y", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Differ enti ate with respect to to get the diffe renti al increas e in condensat e mass dm with film thickness i.e. . Then obtain assum ing he at flux through the film to be due to conducti on base on a li ne a r temperatur e profil e bet ween the vapo r and li quid. Hence dete rmine . Here, is li quid viscosity, is thermal conducti vit y an d is latent heat of condensation. is the vapour temperatur e and is the wall temperatur e", |
| "options": [ |
| "", |
| "", |
| "", |
| "2007 - IIT Kanpur" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The Grasho f Number is", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "In a double pipe he at ex changer the ID and O D of the inner pipe are 4 cm and 5 cm respecti vel y. T he ID of the outer pipe is 10 cm with a wall thi ckn ess of 1 cm. Then the equivalent dia meters (in cm ) of the an nul for he at heal t ransf er and p ressur e drop resp ecti vel y a re", |
| "options": [ |
| "15, 5", |
| "21, 6", |
| "6, 19", |
| "15, 21" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The following li st of opti ons P , Q, R and S are some of the im portant in the design of a shell and tube heat ex changer. (P) S quare pit ch permits the - use of more tubes in give n shell diameter. (Q) The tube sidecle aran ce s hould not be less than one - fourth of th e tube diam eter. (R) Baf fle spa cing in not gr e ater - than th e diameter o f the shell or less t han one - fifth of the shell diameter . (S) The pressur e drop on the tube side is less than 10 psi. P ick out the corre ct com bination of true statemen ts from t he foll owing.", |
| "options": [ |
| "P ,Q and R", |
| "Q, R and S", |
| "R , S and P", |
| "P, Q, R and S" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "C onsi der a li quid stored in a containe r ex posed t o it s saturated v apor at c onst ant temperatur e . The bott om surfac e of the containe r is maintained at a const ant temperature while it s side wall s are insul ated. The thermal conducti vit y is of the li quid, it s latent heat of vaporiz ati on and den sit y are known. Assumi n g a li near temperatu re dist ributi on in the li quid, the ex pressi on for the growth of the li quid la ye r as a f uncti on of ti me t is given b y", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A hot fluid entering a w ell - sti rred vessel is cooled b y f eedin g cold wate r through a ja cket aroun d the vessel. Assume the jacket i s well - mi x ed. For the foll owing dat a: Mass flow - rat e of the flui d Mass flow - rat e of cold w ater S pecific heat o f oil S pecific heat o f cold wat er The inl et and ex it temperatures of the hot flui d a re and respe cti vel y, Inlet temp eratur e of cold water The over all heat t ransf er efficient i s The heat t r ansfer ar ea in , is", |
| "options": [ |
| "1.82", |
| "2.1", |
| "3", |
| "4.26" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "W ater enters a thi n wall ed tube ( ) at an inl et temperatur e of and mass flow rate 0.015 kg/s. The tube wall is m aint ained at a const ant t em peratur e of . Given the fo ll owing data fo r wat er, Densit y Viscosit y S pecific heat Inside r heat t r ansfe r coe f ficient The outl et of wate r in is", |
| "options": [ |
| "28", |
| "37", |
| "62", |
| "96" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The compos it e w all of a n oven consi sts of three materials A,B and C . Un der stead y state op erati n g condit ions, the outer su rfa ce t emperatur e is , the inner s urfac e temp eratur e is a nd the oven air temperatur e is . For the f oll owing data : Thermal condu cti vit ies and Th ickness , and Inn er - w all heat t ransf er co effi cient , The thermal condu cti vit y in W /(m - K) of the mater ial B , is calculated as", |
| "options": [ |
| "35", |
| "", |
| "0.66", |
| "0.03" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "For the two lon g con cent ric c yli nders wit h surf ac e areas and the view facto r is given b y", |
| "options": [ |
| "Ze ro", |
| "1", |
| "", |
| "2008 IIScB anga lore" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Transient thre e - dim ensio nal heat conducti on is governed b y one o f the f oll owing diff erenti al equ ati ons ( thermal diffusivi t y, ther mal conducti vit y and volum etric rate o f heat gene rati on)", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "During th e transient conv ecti ve cooli n g of a sol id object, Biot number indi cates", |
| "options": [ |
| "Uniform temperatu re thr oughout t he obje ct", |
| "Ne gli gibl e convecti on at the surfac e of the obj ect", |
| "S ignificant t herm al resis tance withi n the obje ct", |
| "S ignificant t empe rature gradient withi n the object" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The P randtl number of a fluid i s the rati o of", |
| "options": [ |
| "thermal diffusivi t y to m o mentum di ffusivi t y", |
| "mom entum diffusivi t y to thermal diffusivi t y", |
| "conducti ve resis tan ce to convecti ve r esis tance", |
| "thermal diffusivi t y to ki n ematic viscosit y Com mo n Data fo r Questio ns" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "W hich one of the foll owing statements about baffl es in a shell and tube he a t ex change r is f alse? Baf fles", |
| "options": [ |
| "Act as a support to t he tu be bundle", |
| "R educe the pr essure d rop on the shell - side", |
| "Alter the shell - side flow patt ern", |
| "Help i n increas in g the sh ell - side heat t rans fer coef ficient" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The rati o of Nuss elt number to Biot number is", |
| "options": [ |
| "C onducti ve resis tance o f fluid/ conducti ve resis tan ce of solid", |
| "C onducti ve resis tance o f fluid/ conducti ve resis tan ce of flui d", |
| "C onducti ve resis tance o f soli d/ conducti ve resis tan ce of flui d", |
| "Unit y Com mo n Data fo r Questio ns" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "In film t ype condensatio n over a ve rtical t ube, loc al heat t ransf er coef ficien t i s", |
| "options": [ |
| "Inv ersel y propo rtional t o local fil m t hickness", |
| "Directl y proporti onal t o l ocal fil m t hickness", |
| "Equal t o local fil m t hickness", |
| "Ind ependent o f local fil m thi ckness" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "C onsi der two black bodies with surfaces (ar ea ) and (area ). The y ex chan ge he at onl y b y radiation , 40 % of the ener g y emi tt ed b y is rec eived b y . The fracti on of ener g y emi tt ed b y that is receiv ed b y is", |
| "options": [ |
| "0.05", |
| "0.1", |
| "0.4", |
| "0.6" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "For heat transf er ac ross a soli d - fluid interface, whi ch one of the following statements is NOT true when the Biot number is ver y small co mpared to 1?", |
| "options": [ |
| "C onducti on resis tance in the soli d is v er y small co mpared to conve cti on res ist ance in t he flui d", |
| "Temperatur e profil e withi n the soli d is n earl y unif orm", |
| "Temper ature drop in the fl uid i s si gnificant", |
| "Temperatur e drop in t he S oli d is s ignificant" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A soli d sphere with ini ti al temperature T i is im mersed in a large thermal res ervoir of temper ature T o . The sphere reach es a stead y tempe ra ture after a cert ain ti me t 1 . If the radius of the sp here is doubled, the ti me required to reach st ead y - stat e will be", |
| "options": [ |
| "", |
| "", |
| "2t 1", |
| "4t 1" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "A hole of area is opened on the surface of lar ge spherical c avit y whose insi de temperatur e is maintained at . The value o f S tefan B olt z mann const ant is . A ssum ing black bod y radi ati on, the rate at which the en er g y is emi tt ed (in W ) b y the cavit y throu gh the hole, up to 3 digit s after the de cim al point , is", |
| "options": [ |
| "5.13", |
| "5.67", |
| "5.35", |
| "5.79" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "In a pool boi li ng ex perim ent, t he foll owing ph eno mena wer e observ ed. P . Natural conv ecti on Q. Fil m boi li ng R. Transit ion boi li ng S. Nucleate boili n g W hat was the corr ect seq uence of th eir oc curr ence ?", |
| "options": [ |
| "P, Q, R, S", |
| "S, R , Q, P", |
| "Q, R, P , S", |
| "P, S , R,Q" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The eff ecti ven ess of a h e at ex changer in the - NTU method is defined as", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "S team econom y of a mul ti ple effe ct evapor ator s ystem i s defined as", |
| "options": [ |
| "Kilogram o f steam used per hour", |
| "Kilogram o f steam consu med in all the effe cts for each kil o gram o f steam f ed", |
| "Kilogram o f steam used i n all the eff ects for each kil ogram of water v apori z ed per hour", |
| "Kilogram o f wate r vapori z ed from all t he eff ects f or each kil o gr am of stea m fed to t he first ef fect" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "In a compl etel y opaque medium, if 50% of the incident mo nochromatic ra diation is absorbed, then which of the following statements a re C ORR ECT? (P) 50%of the incident r adia ti on is reflected (Q) 25%of the incident r adia ti on is reflected (R) 25%of the incident r adia ti on is transmi tt ed (S) No incident r adiation i s transmi tt ed", |
| "options": [ |
| "P and S onl y", |
| "Q and R onl y", |
| "P and Q onl y", |
| "R and S onl y" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Two infini tel y l ar ge pa r all el plates ( I and II ) a r e held at temperatures a nd respecti vel y, and placed at a dist ance 2d apart in v acuum. An inf ini tel y lar ge fl at radi ati on shield ( III) is plac ed i n parall el in with an d without the shield is :", |
| "options": [ |
| "0.5", |
| "0.75", |
| "0.25", |
| "0" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Match the dimensionl ess num bers in Grou p - 1 wit h the rati on in Grou p - 2 Grou p - 1 (P) Biot number (Q) S chmi dt num ber (R) Grashof numbe r Grou p - 2 ( I) ( II) ( III)", |
| "options": [ |
| "P - II, Q - I, R - III", |
| "P - I, Q - III, R - II", |
| "P - III, Q - I, R - II", |
| "P - II, Q - III, R - I" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "S team at is condensing on a vertical steel plate. The condensate flow is laminar. The ave ra ge N usselt numbers are and , when the plate temperatures ar e and respecti vel y. Assu me the ph ysi cal properties of the fluid a nd steel to remain const ant withi n the temperat ure r an ge of int erest. U sing Nusselt equati ons for fil m - t ype c ondensation, what i s the value of the r ati o", |
| "options": [ |
| "0.5", |
| "0.84", |
| "1.19", |
| "1.41" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "The one - dim ension al uns tead y heat conducti on eq uati on is W here T - tempe rature t - t im e r - radial posi ti on, k - t hermal conducti vit y, densit y and specific he at. Fo r the c yli ndric al co - o rdinate s ystem, t he value of an n th e above equati on is", |
| "options": [ |
| "0", |
| "1", |
| "2", |
| "3" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "S egmental b affles in a 2 - 4 shell and tube heat ex c hanger", |
| "options": [ |
| "C han ge th e flow patt ern of the tube side fluid and incr e ase the ov erall h eat t ransf er co effi cient", |
| "In cre ase th e h eat t rans fer coeffi cient in the shell side and support the tubes", |
| "Help t o reduc e the therm al ex pansion of the tubes and incre ase the h eat t ran sfe r co effici ent i n the tube side", |
| "In cre ase the numbe r of p asses in t he shell si de an d increas e the he at t ransf er coe fficient i n the tube side" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "E conom y o f evapo rators usedfor con centr ati ng su ga rcan e jui ce is", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "C onsi der the two countercurrent he at ex changer d esigns for h eati ng a cold stream from to , as shown in figur e. The hot proc ess stream is av ail able at . The inl et stre am con dit ions and overall he at transfe r coeffi cients ar e identical in bot h the designs. The heat t ransf er a rea in D esi gn II ar e resp ecti vel y and If heat l osses are n e glect ed, and if 7 oth t he desi gn s are f easibl e, which o f the foll owing stat ements hol ds t rue:", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "P randtl number signifies the rati o of", |
| "options": [ |
| "", |
| "", |
| "", |
| "" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "P ool boi li ng equipm ent operati n g above ambi ent t emperatur e is us uall y d es igned to ope rate", |
| "options": [ |
| "F ar above the critical he a t flux", |
| "Near the critical he at flux", |
| "F ar above the Le iden f ro st poi nt", |
| "Near the Leiden f rost point" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "R ati o of m omentum di ffusivi t y to t he rmal diffusi vit y is", |
| "options": [ |
| "P eclet number", |
| "Nusselt number", |
| "R e ynolds number", |
| "P randtl number" |
| ], |
| "answer": null, |
| "explanation": "" |
| }, |
| { |
| "question": "Leid en frost ph enom ena is t rue for", |
| "options": [ |
| "C ondensation of vapor o n a cold su rfa ce", |
| "The melti ng of frost", |
| "The ex chan ge of h eat bet ween two sol ids", |
| "Fil m boi li ng evapor ati on of li quid droplets fall ing on a ver y hot s urf ac e" |
| ], |
| "answer": null, |
| "explanation": "" |
| } |
| ] |
| } |
