This calculator helps estimate the pressure drop in a pipe system based on flow rate and pipe diameter. Understanding pressure drop is crucial in fluid dynamics for designing efficient piping systems, ensuring adequate delivery pressure, and preventing energy loss.
function calculatePressureDrop() {
var flowRateLPM = parseFloat(document.getElementById("flowRate").value);
var diameterMM = parseFloat(document.getElementById("diameter").value);
var fluidViscosityCP = parseFloat(document.getElementById("fluidViscosity").value);
var pipeLengthM = parseFloat(document.getElementById("pipeLength").value);
var resultDiv = document.getElementById("result");
if (isNaN(flowRateLPM) || isNaN(diameterMM) || isNaN(fluidViscosityCP) || isNaN(pipeLengthM) ||
flowRateLPM <= 0 || diameterMM <= 0 || fluidViscosityCP <= 0 || pipeLengthM <= 0) {
resultDiv.innerHTML = "Please enter valid positive numbers for all fields.";
return;
}
// Convert units to SI for calculation
// Flow Rate: L/min to m^3/s
var flowRateM3S = flowRateLPM / 60000;
// Diameter: mm to m
var diameterM = diameterMM / 1000;
// Viscosity: cP to Pa.s
var fluidViscosityPaS = fluidViscosityCP / 1000;
// Calculate cross-sectional area of the pipe (m^2)
var areaM2 = Math.PI * Math.pow(diameterM / 2, 2);
// Calculate fluid velocity (m/s)
var velocityMS = flowRateM3S / areaM2;
// Calculate Reynolds number (dimensionless)
// Re = (density * velocity * diameter) / viscosity
// Assuming water density (approx 1000 kg/m^3) for simplicity. For other fluids, density would be another input.
var fluidDensityKGM3 = 1000;
var reynoldsNumber = (fluidDensityKGM3 * velocityMS * diameterM) / fluidViscosityPaS;
var frictionFactor;
// Calculate friction factor using Colebrook equation approximation (Haaland equation)
// This is an approximation and more complex calculations might be needed for high accuracy
if (reynoldsNumber < 2300) {
// Laminar flow
frictionFactor = 64 / reynoldsNumber;
} else if (reynoldsNumber < 4000) {
// Transition flow – simplified approach, highly variable
// For simplicity, we'll blend between laminar and turbulent or use a turbulent approximation
frictionFactor = 0.025; // A common approximation for transition/mild turbulent
} else {
// Turbulent flow
var term1 = -1.8 * Math.log10((0.000001 / diameterM) / 3.7 + Math.pow(10, 6.9 / reynoldsNumber));
frictionFactor = Math.pow(term1, -2);
}
// Calculate pressure drop using Darcy-Weisbach equation (Pa)
// deltaP = f * (L/D) * (rho * v^2 / 2)
var pressureDropPa = frictionFactor * (pipeLengthM / diameterM) * (fluidDensityKGM3 * Math.pow(velocityMS, 2) / 2);
// Convert pressure drop to a more common unit like kPa
var pressureDropKPa = pressureDropPa / 1000;
resultDiv.innerHTML = "