Water Pressure vs Flow Rate Calculator

Flow Rate Formulas:

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

Inlet Pressure (P₁):

psi

Outlet Pressure (P₂):

psi

Water 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 Water Pressure vs Flow Rate Calculator?

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

Purpose: It helps engineers, plumbers, and irrigation specialists understand the relationship between pressure and flow in hydraulic systems.

2. How Does the Calculator Work?

The calculator uses two formulas:

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

Where:

\( V \) — Water velocity (feet per second)
\( P_1 \) — Inlet pressure (psi)
\( P_2 \) — Outlet pressure (psi)
\( \rho \) — Water density (pounds per cubic foot, typically 62.4)
\( Q \) — Flow rate (gallons per minute)
\( A \) — Cross-sectional area (square feet)

Explanation: The first equation calculates velocity from pressure difference, then the second converts this to volumetric flow rate.

3. Importance of Pressure-Flow Calculations

Details: Understanding this relationship is crucial for designing efficient piping systems, irrigation systems, and industrial fluid processes.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is there a 144 in the formula?
A: This converts psi (lb/in²) to lb/ft² (1 ft² = 144 in²).

Q2: What's the 448.83 conversion factor?
A: This converts ft³/s to gallons per minute (1 ft³/s = 448.83 GPM).

Q3: When would water density change?
A: Density varies slightly with temperature and significantly if dealing with other fluids.

Q4: How do I calculate pipe cross-sectional area?
A: For circular pipes: \( A = \pi \times (diameter/2)^2 \) (convert diameter to feet).

Q5: Does this account for friction losses?
A: No, this is theoretical maximum flow. Real systems will have lower flow due to friction.