This calculator helps you estimate the pressure drop in a pipe due to fluid flow. Pressure drop is a crucial factor in fluid dynamics, affecting pump selection, system efficiency, and the overall performance of piping systems. Several factors contribute to pressure loss, including flow rate, fluid viscosity, pipe diameter, pipe length, and the roughness of the pipe's inner surface.
The calculation below uses a simplified approach based on the Darcy-Weisbach equation, which is a common method for calculating pressure loss in pipes. For more complex scenarios, consider consulting specialized fluid dynamics software or an engineer.
function calculatePressureDrop() {
var flowRate = parseFloat(document.getElementById("flowRate").value);
var fluidViscosity = parseFloat(document.getElementById("fluidViscosity").value);
var pipeDiameter = parseFloat(document.getElementById("pipeDiameter").value);
var pipeLength = parseFloat(document.getElementById("pipeLength").value);
var fluidDensity = parseFloat(document.getElementById("fluidDensity").value);
var pipeRoughness = parseFloat(document.getElementById("pipeRoughness").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// Basic validation for input values
if (isNaN(flowRate) || isNaN(fluidViscosity) || isNaN(pipeDiameter) || isNaN(pipeLength) || isNaN(fluidDensity) || isNaN(pipeRoughness)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
// — Unit Conversions (Example: assuming common units, adjust as needed) —
// Assuming flowRate is in L/min, viscosity in cP, diameter in mm, length in m, density in kg/m³, roughness in mm
// Convert L/min to m³/s
var flowRate_m3_s = flowRate * (1 / 60) * (1 / 1000);
// Convert cP to Pa·s
var fluidViscosity_Pa_s = fluidViscosity * 0.001;
// Convert mm diameter to m
var pipeDiameter_m = pipeDiameter / 1000;
// Convert mm roughness to m
var pipeRoughness_m = pipeRoughness / 1000;
// — Calculations —
// 1. Calculate Flow Velocity (v = Q / A)
var pipeArea = Math.PI * Math.pow(pipeDiameter_m / 2, 2);
var velocity = flowRate_m3_s / pipeArea;
// 2. Calculate Reynolds Number (Re = ρvD / μ)
var reynoldsNumber = (fluidDensity * velocity * pipeDiameter_m) / fluidViscosity_Pa_s;
// 3. Calculate Friction Factor (f)
var frictionFactor;
if (reynoldsNumber < 2300) { // Laminar Flow
frictionFactor = 64 / reynoldsNumber;
} else { // Turbulent Flow – Using Colebrook-White equation (implicit, requires iteration or approximation)
// For simplicity, we'll use an explicit approximation like Haaland equation
// Haaland equation for turbulent flow: 1/√f ≈ -1.8 * log[ (ε/D/3.7)^1.11 + 6.9/Re ]
var term1 = Math.pow((pipeRoughness_m / pipeDiameter_m) / 3.7, 1.11);
var term2 = 6.9 / reynoldsNumber;
frictionFactor = 1 / Math.pow(-1.8 * (Math.log10(term1 + term2)), 2);
}
// 4. Calculate Pressure Drop (ΔP = f * (L/D) * (ρv²/2))
var pressureDrop_Pa = frictionFactor * (pipeLength / pipeDiameter_m) * (fluidDensity * Math.pow(velocity, 2) / 2);
// Convert pressure drop from Pascals to a more common unit like kPa or psi if needed
var pressureDrop_kPa = pressureDrop_Pa / 1000;
var pressureDrop_psi = pressureDrop_Pa * 0.000145038; // 1 Pa = 0.000145038 psi
// Display the results
resultDiv.innerHTML = "