Pipe Pressure Drop Calculator

import math

def pipe_pressure_drop(flow_m3_per_s, d_mm, length_m, eps_mm, rho, mu):
    """
    Calculates pressure drop in pipe using Darcy-Weisbach & Swamee-Jain equations.
    """
    d_m = d_mm / 1000.0
    area = math.pi * (d_m ** 2) / 4.0
    velocity = flow_m3_per_s / area
    
    # Reynolds Number
    Re = (rho * velocity * d_m) / mu
    
    # Friction Factor
    if Re < 2000:
        f = 64.0 / Re
    else:
        rel_roughness = eps_mm / d_mm
        denom = math.log10((rel_roughness / 3.7) + (5.74 / (Re ** 0.9)))
        f = 0.25 / (denom ** 2)
        
    # Pressure Drop
    dp_pa = f * (length_m / d_m) * (rho * (velocity ** 2) / 2.0)
    dp_bar = dp_pa / 100000.0
    head_loss_m = dp_pa / (rho * 9.80665)
    
    return velocity, Re, f, dp_pa, dp_bar, head_loss_m

# Inputs
Q = 5.0000e-3 # m³/s
D = 50 # mm
L = 50 # m
eps = 0.045 # mm
rho = 998 # kg/m³
mu = 0.001002 # Pa.s

v, Re, f, dp, dp_bar, h_loss = pipe_pressure_drop(Q, D, L, eps, rho, mu)
print(f"Velocity: {v:.2f} m/s")
print(f"Reynolds Number: {Re:.0f}")
print(f"Friction Factor: {f:.4f}")
print(f"Pressure Drop: {dp:.1f} Pa ({dp_bar:.3f} bar)")
print(f"Head Loss: {h_loss:.2f} m")

function [v, Re, f, dp_bar, h_loss] = pipe_pressure_drop(Q, D_mm, L_m, eps_mm, rho, mu)
    d_m = D_mm / 1000;
    area = pi * (d_m^2) / 4;
    v = Q / area;
    Re = (rho * v * d_m) / mu;
    
    if Re < 2000
        f = 64 / Re;
    else
        f = 0.25 / (log10((eps_mm/D_mm)/3.7 + 5.74/(Re^0.9)))^2;
    end
    
    dp_pa = f * (L_m / d_m) * (rho * v^2 / 2);
    dp_bar = dp_pa / 1e5;
    h_loss = dp_pa / (rho * 9.80665);
end

% Example
Q = 5.0000e-3;
[v, Re, f, dp_bar, h_loss] = pipe_pressure_drop(Q, 50, 50, 0.045, 998, 0.001002);
fprintf('Pressure Drop: %.3f bar\n', dp_bar);