NACH OBEN

Centrifugal pump test bench

Contact: Dr.-Ing. Maximilian Paßmann, Artem Tukalov

At the centrifugal pump test stand of the HSM, the effects of cavitation on pump and system behavior, as well as the general performance of pumps in various operating conditions, are investigated. For this purpose, H/Q characteristic curves (head H versus flow rate Q) are created, and NPSH measurements (Net Positive Suction Head) are conducted. Additionally, measurements of pressure waves are used to capture the pressure level when cavitation occurs. The location of cavitation can be determined through endoscopic examinations and the dye injection method. The test stand is also used in education for conducting student laboratory experiments.

The schematic layout of the test stand is illustrated in Figure 1. Two single-stage, radial centrifugal pumps from Wilo SE can be examined, classified as low-speed pumps due to their low specific speed nq. A flow measurement device (MID) and a throttle valve enable the determination and adjustment of the flow rate. Using the vacuum pump, the pressure level can be reduced, thus inducing cavitation in the pumps.


Experimental focus:
  • Creation of H/Q characteristics
  • NPSH measurements characteristics
  • Performance measurements
  • Pressure level at onset of cavitation (NPSHi) using optical and acoustic methods
  • Location of cavitation (endoscope) and erosion (paint removal method)

Available measurement technology:

Stationary Measurement Technology:

  • High-precision pressure measurement (measurement uncertainty δp = 0.04% (FS))
  • Magnetic inductive flow measurement
  • Data acquisition: National Instruments DAQ system

Time-resolved Measurement Technology:

  • Piezoresistive pressure transmitters from Keller AG with a cutoff frequency of fmax = 5 kHz.
  • Data acquisition: imc CRONOSflex (base unit with additional expansion modules)

Technical data:


Publications on topic (selected):

Limbach, P. & Skoda, R. (2017). Numerical and Experimental Analysis of Cavitating Flow in a Low Specific Speed Centrifugal Pump With Different Surface Roughness. J. Fluids Eng. 2017, 139(10):101201-101201-8. DOI: 10.1115/1.4036673

Limbach, P., Müller, T., Blume, M. & Skoda, R. (2016). Numerical and experimental investigation of the cavitating flow in a low specific speed centrifugal pump and assessment of the influence of surface roughness on head prediction. Proc. 16th Int. Symp. Transport Phenomena and Dynamics of Rotating Machinery, ISROMAC 16, Honolulu, Hawaii, USA, April 10-15, 2016.


Fig 1: Centrifugal pump test bench at HSM
Fig 1: Centrifugal pump test bench at HSM
Fig 2: Representative measurement data of the radial pump BL 32/220-1.5/4 (□<sub>q</sub> = 12): (a) Head H as a function of the flow rate Q for two pump speeds n; (b) NPSH measurement for two flow rates Q.
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Fig 2: Representative measurement data of the radial pump BL 32/220-1.5/4 (□q = 12): (a) Head H as a function of the flow rate Q for two pump speeds n; (b) NPSH measurement for two flow rates Q.