Abstract
The internal flow of the mini pumps for washing machines is complex due to its compact structure and it normally adopts the upper drainage method. Due to decline in liquid level at the end of drainage (empty discharge period), the pump experiences water-air multiphase flow condition and produces unsteady flow. This unstable flow not only results in the deterioration of pump energy performance, but also induces larger vibration and noise, which in turn, reduce the working capability of pumps and disturb the people living environment. Therefore, with the aim of exploring the internal flow features and noise characteristics of drainage pumps during empty discharge period, the energy performance test was processed under pure water condition as well as under different air void fraction and part load conditions. Moreover, the internal flow field is calculated based on (both k-epsilon and k-omega) turbulence model and Euler non-uniform stream model under pure water, and different inlet air content for part load conditions, respectively. All the experimental conditions for test and boundary conditions for simulation are provided. The overall and local results of internal flow field and gas phase distribution are obtained and analyzed. In addition, the research results can provide a theoretical recommendation for designing the lower noise mini pumps.