Numerical Simulation and PIV Measurement on the Internal Flow in a Centrifugal Mini Pump at Low Flow Rate Conditions

This paper reports on the internal flow of a centrifugal mini pump working at the low flow rate operating conditions. The RNG $\kappa-\varepsilon$ turbulence model was employed to simulate the three-dimensional turbulent flow in the pump. To examine and certify the simulation results, a transparent acrylic centrifugal mini pump model which is suitable for PIV measurement has been developed. The tongue region and the passages region between blades were investigated using PIV. In order to eliminate the effect of refraction on the area closed to the wall and increase the measurement accuracy, the fluorescent particles were scatted into the working fluid with the tracing particles. It is found from the calculation and PIV measurement results that there is a large area of recirculation flow near the tongue at low flow rate operating conditions. The computationally predicted water head using the $\kappa-\varepsilon$ turbulence model at low flow rate operating conditions are in very good agreement with the experimentally measured water head and the mean velocity distributions at investigation area obtained by PIV and calculation showed a satisfactory agreement as well. Meanwhile, the results of PIV measurements show that the flow status in one passage is different to another. And for capturing the internal flow detail information, the $\kappa-\varepsilon$ turbulence model is not very suitable.