Calculate Flow Rate from Pressure – Cost Calculator

Flow Rate Calculator

Pressure Difference (Pa):

Flow Resistance (Pa·s/m³):

Understanding Flow Rate and Pressure

In fluid dynamics, the flow rate of a fluid through a system is often directly related to the pressure difference driving that flow and inversely related to the resistance the fluid encounters. This relationship is fundamental to understanding how fluids move through pipes, channels, or porous media.

The Relationship: Hagen-Poiseuille Law (Simplified Analogy

While the exact physics can be complex and depend on whether the flow is laminar or turbulent, a simplified analogy often used for understanding the basic relationship between pressure and flow rate is derived from principles similar to Ohm's Law in electrical circuits or the Hagen-Poiseuille equation for laminar flow in pipes.

In this context, we can consider:

Pressure Difference (ΔP): This is the driving force. It's the difference in pressure between two points in the system. A larger pressure difference will generally lead to a higher flow rate. It is measured in Pascals (Pa).
Flow Resistance (R): This represents how difficult it is for the fluid to flow. Factors like the viscosity of the fluid, the length and diameter of the pipe, and any obstructions contribute to resistance. Higher resistance will impede flow, leading to a lower flow rate for a given pressure difference. It is measured in Pascal-seconds per cubic meter (Pa·s/m³).
Flow Rate (Q): This is the volume of fluid passing a point per unit of time. It is measured in cubic meters per second (m³/s).

The Formula

The relationship can be expressed by the formula:
Flow Rate (Q) = Pressure Difference (ΔP) / Flow Resistance (R)

How to Use the Calculator

To use this calculator, you need to provide two key pieces of information:

Pressure Difference: Enter the pressure difference in Pascals (Pa) across the section of the system you are analyzing.
Flow Resistance: Enter the flow resistance in Pascal-seconds per cubic meter (Pa·s/m³) that the fluid encounters.

Clicking the "Calculate Flow Rate" button will then provide you with the estimated flow rate in cubic meters per second (m³/s).

Example Calculation

Let's say you have a system where the pressure difference across a certain section is 1000 Pa, and the estimated flow resistance of that section is 500 Pa·s/m³.
Using the formula:
Q = 1000 Pa / 500 Pa·s/m³ = 2 m³/s
Therefore, the flow rate through this system would be 2 cubic meters per second.