app.py

import streamlit as st
import math
import numpy as np
import plotly.graph_objects as go

# Title and description
st.title("🚀 Pipe Size Suggestion App")
st.markdown("""
#### Enter the required flow rate and permissible velocity to get the suggested pipe diameter.

**Formula Used:**
- **Q = A × V**

Where:
- Q = Flow rate (m³/s)
- A = Cross-sectional Area (m²)
- V = Velocity (m/s)
""")

# Input fields with stylish layout
st.sidebar.header("Input Parameters")
flow_rate = st.sidebar.number_input("Flow Rate (m³/s)", min_value=0.0, step=0.01, format="%.4f")
velocity = st.sidebar.number_input("Permissible Velocity (m/s)", min_value=0.01, step=0.01, format="%.2f")

if st.sidebar.button("Calculate Pipe Size"):
    if velocity > 0:
        area = flow_rate / velocity  # m^2
        diameter = math.sqrt((4 * area) / math.pi)  # m
        diameter_mm = diameter * 1000  # mm

        st.success(f"\U0001F4A1 Suggested Pipe Diameter: **{diameter_mm:.2f} mm**")

        # Create a 3D pipe visualization
        theta = np.linspace(0, 2 * np.pi, 50)
        z = np.linspace(0, 3, 50)
        theta_grid, z_grid = np.meshgrid(theta, z)

        x_grid = (diameter / 2) * np.cos(theta_grid)
        y_grid = (diameter / 2) * np.sin(theta_grid)

        fig = go.Figure(data=[go.Surface(x=x_grid, y=y_grid, z=z_grid, colorscale='Blues', opacity=0.8)])

        fig.update_layout(
            title=f"3D Pipe Visualization ({diameter_mm:.1f} mm Diameter)",
            scene=dict(
                xaxis_title='X (m)',
                yaxis_title='Y (m)',
                zaxis_title='Length (m)',
                aspectratio=dict(x=1, y=1, z=2)
            ),
            margin=dict(l=0, r=0, t=50, b=0)
        )

        st.plotly_chart(fig, use_container_width=True)
    else:
        st.error("Velocity must be greater than 0.")