Designing a Low-Cost Series, Parallel, and Single Centrifugal Pumps Exercise for an Upper-Level Undergraduate Laboratory

A four-hour long laboratory exercise has been developed for demonstrating the performance of centrifugal pumps in single, series, and parallel configurations by deploying a low-cost tabletop setup with the help of an existing water bench facility. The framework of the setup consists of two identical small-scale centrifugal pumps connected through a systematic layout featuring three ball valves to allow simple switching between the four configurations. A differential pressure transducer is connected across the inlet and the outlet of the setup to allow direct measurement of head rise of each pump configuration at different flow rates that are controlled by a throttle valve in the outlet. A Coriolis force mass flowmeter, connected to a constant head reservoir in the water bench, measures the flow rate from the reservoir through the setup. A DC power supply runs the pumps and reports the current and voltage. Without being allowed to disassemble the setups, students develop an experimental procedure to assess the performance of the pumps through measurements of the pump head and pump efficiency as a function of the flowrate. Students test hypotheses about the pump head and flowrates for the various configurations, assessing how the total pump head and total flowrate sum for series and parallel combinations of pumps. Similar assessments are made of the efficiency of the pump configurations. Evaluation surveys are taken by students and laboratory teaching assistants to examine the effectiveness of the learning outcomes of the lab exercise. A full description of the setup will be given, as well as a complete bill of materials and budget, which will be critically compared against some commercially available setups.