Defining Total Dynamic Head
Why is total dynamic head relevant when assessing pump performance in the field? Total dynamic head is the total amount of pressure when water is flowing in a system, taking into account vertical rise and friction loss. Total dynamic head is represented on the performance curve by the difference between the suction pressure and the discharge pressure.
Why Calculate Total Dynamic Head
Calculating total dynamic head can help centrifugal pump operators understand the proper sizing and scale for a pumping application. This measurement also assists operators in determining the health and performance of the pump in the field, as without knowing the pressure the pump is operating against, users cannot accurately anticipate wear, maintenance or productivity.
Comparing Discharge & Total Differential Pressure
Griswold® advises against solely measuring discharge pressure to analyze pump operation, as this number does not accurately represent total differential pressure and can lead to false assumptions about pump performance.
In the below Centrifugal Pump Minute video, James Farley, Griswold Product Manager, uses the Griswold Test Lab to demonstrate the dramatic difference between discharge pressure and total dynamic head. In his example, the discharge pressure gauge reads a measurement of 20.6 psi. However, according to the differential pressure gauge, the pump is actually performing at 33.2 psi. By simulating a field performance test in the lab, James illustrates just how operators can accurately determine the differential pressure their pump is operating against.
Interested in learning more about pump operation and performance? Check out our other blog posts and Centrifugal Pump Minute videos here.