Pump Head Calculator
Interactive pump curves with TDH, NPSHa, and power calculations
About this Simulator
Interactive pump curve visualization showing pump head curve, system curve, and operating point. Adjust parameters to see how changes affect pump performance, TDH, and NPSHa in real-time.
Physics & Formulas
Total Differential Head (TDH):
$$TDH = (HLL - LLL) + (P_d - P_s) + h_{f,discharge} + h_{f,suction}$$
NPSHa:
$$NPSH_a = P_{atm} + P_s + LLL - P_{vapor} - h_{f,suction} - h_{eye}$$
Brake Horsepower:
$$BHP = \frac{Q \times TDH \times SG}{274 \times \eta_{pump}}$$
How to Use
- Adjust Flow Rate to move the operating point along the curves
- Change HLL and LLL to modify static head (elevation difference)
- Adjust Discharge Pressure to add system pressure requirement
- Modify friction losses to see effect on system curve steepness
- Watch the pump curve (cyan) and system curve (red) intersection
- Monitor NPSHa to ensure adequate suction conditions
Frequently Asked Questions
What do the curves represent?
The cyan Pump Curve shows head vs flow for the pump (drops as flow increases). The red System Curve shows head required by the system (rises as flow increases due to friction). Where they intersect is the Operating Point.
What is NPSHa and why is it shown?
NPSHa (Net Positive Suction Head Available) is the pressure available at pump suction above vapor pressure. It must exceed NPSHr (required by pump) to prevent cavitation. The yellow dashed line shows current NPSHa.
How do I increase flow rate?
To increase flow: reduce system resistance (lower discharge pressure or friction losses), or select a pump with higher head at desired flow. The operating point will shift right along the pump curve.
What does the efficiency curve show?
The purple dashed efficiency curve shows pump efficiency vs flow. Pumps are most efficient at their Best Efficiency Point (BEP). Operating far from BEP wastes energy and can damage the pump.
