I would like to ask how to draw the performance curve of a centrifugal pump

Support yourself first; if you ask everyone to share their thoughts, it will definitely earn you extra points

This post was last edited by wuchangjian on 2010-3-22 at 13:29. The head and shaft power (current) corresponding to the measurements are determined, and then the efficiency is calculated. The measured points are marked on a coordinate graph, and after connecting them smoothly, the performance curve is obtained. The method for measuring the net positive suction head is relatively complex; only the common methods will be described here: adjust the flow rate to a certain value, then create a vacuum at the inlet until cavitation occurs (the head drops by 5% suddenly). Record the inlet pressure at that point, and repeat this process for several different flow rates in order to draw the net positive suction head curve. The horizontal axis represents flow rate, while the vertical axes represent head, shaft power, efficiency, and net positive suction head. Introduction to the drawing method: At least 5 points should be measured based on the experimental records. By changing the flow rate, the corresponding head and shaft power (current) are measured, and efficiency is calculated. The measured points are plotted on a coordinate graph, and then connected smoothly to form the performance curve. The methods for measuring the net positive suction head are relatively complex; only the common methods will be discussed here: adjust the flow rate to a certain value, then create a vacuum at the inlet until cavitation occurs (the head drops by 5% suddenly). Record the inlet pressure at that point, and repeat this process for several different flow rates, so as to draw a curve representing the net positive suction head

The introduction on the 2nd floor is too comprehensive. Many modern pump testing stations can now record data online and generate performance curves directly. Of course, this is generally referred to as the pump’s factory-tested hydraulic report.

To be precise, the performance curve is not drawn manually; it is an essential part of the factory testing process for centrifugal pumps, and it is created based on data measured by computers. Even in the absence of automated devices, it is still necessary to measure data at multiple points before drawing the curve. This information can be found in professional books, and referring to those sources will suffice

In fact, the performance curve of a pump consists of two parts: theoretical values and actual values； The theoretical values are provided in the manuals and samples, indicating the performance that the pump of this model must achieve ； The actual values are determined during the factory testing, and they are recorded in the fluid performance test report issued at the time of production; all parameters should not show any negative deviations, while positive deviations must not exceed 5%. Therefore, the theoretical value should be the statistical average of the actual values.

But then how can the performance curve of the pipeline be drawn after the flow rate changes?