1. What Is Pump Discharge Pressure?

Pump discharge pressure is the total pressure at the outlet of a pump, calculated as the sum of the pressure required to overcome the static head and the suction pressure. It is a critical parameter in pump selection and system design.

2. How Does The Calculator Work?

The calculator uses the discharge pressure equation:

Where:

• \( P_d \) — Discharge pressure (Pa)
• \( \rho \) — Fluid density (kg/m³)
• \( g \) — Gravitational acceleration (9.81 m/s²)
• \( H \) — Total head (m)
• \( P_s \) — Suction pressure (Pa)

Explanation: The equation calculates the total pressure required at the pump discharge by combining the pressure needed to lift the fluid against gravity (ρgH) with the existing suction pressure.

3. Importance Of Discharge Pressure Calculation

Details: Accurate discharge pressure calculation is essential for proper pump selection, system design, energy efficiency optimization, and preventing cavitation or system failure.

4. Using The Calculator

Tips: Enter fluid density in kg/m³, total head in meters, and suction pressure in Pascals. All values must be positive (suction pressure can be zero for systems starting from atmospheric pressure).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between head and pressure?
A: Head is the height a pump can lift fluid, measured in meters, while pressure is the force per unit area, measured in Pascals. They are related through fluid density.

Q2: Why is suction pressure included in the calculation?
A: Suction pressure represents the pressure already available at the pump inlet, which contributes to the total discharge pressure output.

Q3: What are typical fluid densities used in calculations?
A: Water at 20°C is 998 kg/m³, seawater is about 1025 kg/m³, and various oils range from 800-950 kg/m³ depending on type and temperature.

Q4: How does temperature affect the calculation?
A: Temperature affects fluid density - warmer fluids are less dense, requiring less pressure for the same head. Always use density at operating temperature.

Q5: When should friction losses be considered?
A: This basic equation calculates theoretical discharge pressure. For practical applications, add pressure losses due to pipe friction, fittings, and valves to the total head.