Improving flow and noise performances of centrifugal pump in dishwasher through impeller design optimization

Noise and performance are critical factors in the customer's selection of dishwashers. The centrifugal pump, which circulates water for washing dishes, dominantly influences the performance and noise of a dishwasher. This study aims to improve the performance and reduce the noise of a centrifugal pump by modifying its impeller design. Priorly, the flow and noise characteristics of the target pump were experimentally characterized. Then, the flow performance of the pump was predicted using a virtual pump performance tester based on the computational fluid dynamics techniques to solve the three-dimensional unsteady incompressible Reynolds Averaged Navier-Stokes equations. The noise radiation generated by the impeller was predicted using the Ffowcs Williams-Hawkings equation. The results were validated by comparing the predicted with the measured. The Response Surface Method, where the blade inlet and outlet angles at the hub and shroud locations were used as design variables, was applied to improve the flow and noise performance of the pump. The optimized impeller design increased the pump flow rate by 17.5% and reduced the flow noise level by 3.5 dB at the same flow rate, as per the fan law predictions.