Pressure vs Flow Rate Calculator

Pressure vs Flow Rate Formulas:

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

Inlet Pressure (P₁):

psi

Outlet 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 vs Flow Rate Calculator?

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

Purpose: It helps engineers and technicians analyze fluid systems by showing the relationship between pressure drop and flow rate.

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)
\( P_1 \) — Inlet pressure (psi)
\( P_2 \) — Outlet 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 using Bernoulli's principle. The second converts velocity to flow rate.

3. Importance of Pressure-Flow Relationship

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 > P₂), fluid density (default 62.4 lb/ft³ for water), and cross-sectional area. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What units does this calculator use?
A: US customary units - psi for pressure, lb/ft³ for density, ft² for area, ft/s for velocity, and GPM for flow rate.

Q2: What's a typical fluid density?
A: Water at 60°F is 62.4 lb/ft³. Oil ranges 50-58 lb/ft³. Check specific gravity for other fluids.

Q3: How accurate are these calculations?
A: They provide theoretical values. Real systems have friction losses not accounted for here.

Q4: What if P₂ > P₁?
A: The calculator will return NaN (Not a Number) since you can't have negative velocity.

Q5: Why multiply by 448.83?
A: This converts ft³/s to gallons per minute (GPM).