Pressure Calculator From Flow Rate

Orifice Flow Equation:

\[ P = \left( \frac{Q}{C_d A} \right)^2 \times \frac{\rho}{2} \]

Flow Rate (Q):

m³/s

Discharge Coefficient (C_d):

Area (A):

m²

Density (ρ):

kg/m³

Pressure (P):

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1. What is the Orifice Flow Equation?

The orifice flow equation calculates pressure drop across an orifice based on flow rate, discharge coefficient, area, and fluid density. It's commonly used in fluid mechanics for flow measurement and pressure loss calculations in piping systems.

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

\[ P = \left( \frac{Q}{C_d A} \right)^2 \times \frac{\rho}{2} \]

Where:

\( P \) — Pressure (Pascal)
\( Q \) — Flow rate (m³/s)
\( C_d \) — Discharge coefficient (dimensionless)
\( A \) — Orifice area (m²)
\( \rho \) — Fluid density (kg/m³)

Explanation: The equation calculates the pressure required to achieve a specific flow rate through an orifice, accounting for energy losses through the discharge coefficient.

3. Importance of Pressure Calculation

Details: Accurate pressure calculation is essential for designing piping systems, selecting pumps, sizing control valves, and ensuring proper flow conditions in industrial processes and hydraulic systems.

4. Using the Calculator

Tips: Enter flow rate in m³/s, discharge coefficient (typically 0.6-0.65 for sharp-edged orifices), area in m², and fluid density in kg/m³. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient value?
A: For sharp-edged orifices, C_d is typically 0.61-0.63. The value depends on orifice geometry and Reynolds number.

Q2: Can this calculator be used for gases?
A: Yes, but for compressible fluids like gases, additional compressibility factors may be needed for accurate results at high pressure drops.

Q3: What are common applications of this equation?
A: Flow measurement using orifice plates, pressure drop calculations in piping systems, pump sizing, and hydraulic system design.

Q4: How accurate is this calculation?
A: Accuracy depends on correct discharge coefficient selection and assumptions of steady, incompressible flow. Real-world factors like turbulence and viscosity may affect results.

Q5: What units should I use for the inputs?
A: Use SI units: flow rate in m³/s, area in m², density in kg/m³. The result will be in Pascals (Pa).