This calculator helps you estimate the flow rate of a fluid through a pipe or system based on the pressure difference and the resistance to flow. It's particularly useful in fluid dynamics, plumbing, and various engineering applications.
Understanding Flow Rate, Pressure, and Resistance
Flow Rate (Q): This is the volume of fluid that passes through a given point per unit of time. It's commonly measured in units like liters per minute (LPM), gallons per minute (GPM), or cubic meters per second (m³/s).
Pressure Difference (ΔP): This is the difference in pressure between two points in the system. A higher pressure difference generally drives a higher flow rate. It's typically measured in Pascals (Pa), pounds per square inch (psi), or bar.
Resistance to Flow (R): This represents how much the system impedes the fluid's movement. It depends on factors like pipe diameter, length, roughness, and the fluid's viscosity. A higher resistance leads to a lower flow rate for a given pressure difference. In many simplified scenarios, we might use a resistance factor derived from known properties or empirical data. For this calculator, we'll assume a direct relationship or a factor that encapsulates this resistance. A common way to express this relationship in simple terms, especially when dealing with laminar flow or specific pipe characteristics, can be approximated by relating it to the pipe's characteristics and fluid properties. For a more general approach, especially for turbulent flow, the Darcy-Weisbach equation is often used, but for a simplified calculator, we might use a direct resistance value or a factor derived from it.
The fundamental relationship, often derived from concepts like Ohm's law for fluids (where pressure difference is like voltage, flow rate is like current, and resistance is like electrical resistance), is:
Flow Rate (Q) = Pressure Difference (ΔP) / Resistance (R)
In practical terms, we often have more information about the system's geometry and fluid properties. For instance, Poiseuille's Law describes laminar flow in a cylindrical pipe:
Q = (π * ΔP * r⁴) / (8 * η * L)
where:
Q = Flow rate
ΔP = Pressure difference
r = Radius of the pipe
η (eta) = Dynamic viscosity of the fluid
L = Length of the pipe
This calculator uses a simplified approach where you input the pressure difference and a direct resistance factor. If you need a more precise calculation based on fluid properties and pipe dimensions, you would need a more complex model incorporating Poiseuille's Law or Darcy-Weisbach.
function calculateFlowRate() {
var pressureDifference = parseFloat(document.getElementById("pressureDifference").value);
var resistanceFactor = parseFloat(document.getElementById("resistanceFactor").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(pressureDifference) || isNaN(resistanceFactor)) {
resultDiv.innerHTML = "Please enter valid numbers for all fields.";
return;
}
if (resistanceFactor <= 0) {
resultDiv.innerHTML = "Resistance factor must be greater than zero.";
return;
}
var flowRate = pressureDifference / resistanceFactor;
// Displaying result with appropriate units.
// Assuming pressureDifference is in Pascals (Pa) and resistanceFactor is in Pa/(m³/s)
// The resulting flowRate will be in cubic meters per second (m³/s)
resultDiv.innerHTML = "