Pressure to Flow Rate

Flow Rate Formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Initial Pressure (P₁):

psi

Final Pressure (P₂):

psi

Fluid Density (ρ):

lb/ft³

Cross-Sectional Area (A):

ft²

Velocity (V): ft/s

Flow Rate (Q): GPM

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1. What is a Pressure to Flow Rate Calculator?

Definition: This calculator converts pressure difference to flow rate using fluid dynamics principles.

Purpose: It helps engineers and technicians determine fluid flow rates in pipes and channels based on pressure measurements.

2. How Does the Calculator Work?

The calculator uses these formulas:

\[ V = \sqrt{\frac{2 \times (P_1 - P_2) \times 144}{\rho}} \] \[ Q = V \times A \times 448.83 \]

Where:

\( V \) — Velocity (ft/s)
\( P_1 \) — Initial pressure (psi)
\( P_2 \) — Final pressure (psi)
\( \rho \) — Fluid density (lb/ft³)
\( Q \) — Flow rate (GPM)
\( A \) — Cross-sectional area (ft²)

Explanation: The pressure difference is converted to velocity, which is then multiplied by area and a conversion factor to get flow rate.

3. Importance of Pressure-Flow Calculations

Details: Accurate flow rate estimation is crucial for system design, pump sizing, and process control in fluid systems.

4. Using the Calculator

Tips: Enter pressure values (psi), fluid density (default 62.4 lb/ft³ for water), and cross-sectional area. All values must be > 0 except P₂ which can be 0.

5. Frequently Asked Questions (FAQ)

Q1: What's the 144 factor in the formula?
A: This converts psi to psf (pounds per square foot) since 1 psi = 144 psf.

Q2: Why 448.83 in the flow rate formula?
A: This converts ft³/s to gallons per minute (GPM) - 1 ft³/s = 448.83 GPM.

Q3: What density should I use for other fluids?
A: Use 62.4 for water, ~49 for gasoline, ~58 for diesel, etc. Check fluid property tables.

Q4: How do I find cross-sectional area?
A: For round pipes: A = π × (diameter/2)². Convert diameter to feet first.

Q5: Does this account for friction losses?
A: No, this is for ideal flow. For real systems, consider additional factors like pipe roughness.