Pressure Versus Flow Rate Calculator

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 Versus Flow Rate Calculator?

Definition: This calculator determines fluid velocity and volumetric flow rate based on pressure difference, fluid density, and pipe cross-sectional area.

Purpose: It helps engineers and technicians analyze fluid systems by relating pressure changes to flow characteristics.

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:

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

Explanation: The first equation calculates velocity from pressure difference (converted to psf) and density. The second converts velocity to flow rate in gallons per minute.

3. Importance of Pressure-Flow Calculations

Details: Understanding this relationship is crucial for designing piping systems, selecting pumps, and troubleshooting flow issues.

4. Using the Calculator

Tips: Enter pressure values (P₁ and P₂), fluid density (default 62.4 lb/ft³ for water), and pipe cross-sectional area. All values must be > 0 except P₂ which can equal P₁.

5. Frequently Asked Questions (FAQ)

Q1: What does the 144 factor represent?
A: It 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 GPM (gallons per minute), as 1 ft³/s = 448.83 GPM.

Q3: What's a typical fluid density?
A: Water at 60°F is 62.4 lb/ft³. For other fluids: gasoline ~42, oil ~55, seawater ~64 lb/ft³.

Q4: How do I find cross-sectional area?
A: For round pipes: \( A = \pi \times (D/2)^2 \) where D is diameter in feet.

Q5: Does this account for friction losses?
A: No, this is ideal flow. For real systems, include friction factors and minor losses.