Abstract
The interaction between impeller and volute produces a complex and unsteady water flow. It involves the interference of the non-uniform flow (such as the impeller’s jet wake and a secondary flow). In this paper, the transient flow in a new type of dishwasher pump is investigated numerically. In addition, pressure measurements are used to validate the numerical method, and the simulation results agree well with the experiment. Three schemes, 0 rpm (revolutions per minute)/30 rpm/60 rpm, of volute speeds are investigated. Multiple monitoring points are set at different positions of the new dishwasher pump to record pressure-pulse signals. In addition, frequency signals are obtained using a Fast Fourier Transform, which is then used to analyze the effect of the volute tongue and the outflow of the impeller. The radial force on the principal axis is recorded, and the schemes with different rotation speeds of volute are compared. The results show that the volute speed has only a small effect on the pump performance. In addition, the speed of the volute mainly affects the flow field in the transition section located between impeller and volute. The difference of the flow field in the impeller depends on the relative position between the impeller and the volute. The time domain curve for the pressure pulse is periodic, and there is a deviation between the peak for the schemes in the outflow region. In the frequency domain, the characteristic frequency equals the blade passing frequency. In the outflow region, the effect of the volute speeds increases with increasing volute speed. For the radial force, the rotating volute strengthens the fluctuation of the radial force, which affects the operational stability of the pump. The shape of the vector distribution is most regular for the 30 rpm scheme, which indicates that the stability of the pump is the highest. This paper can be used to improve both the control and selection of volute speeds.
Highlights
Electric dishwashers are commonly used in private households as well as commercially
Researchers have already carried out several detailed and Numerical Analysis of Dishwasher Pump systematic studies of the key parts of dishwashers (Dedoussis and Giannatsis, 2004; Santori et al, 2013; Pérez-Mohedano et al, 2015; Minde, 2016; Pérez-Mohedano et al, 2017), and their results indicate that the water-movement analysis plays a very important role in performance studies
The tongue and outlet of the double volute were still one, and the structure of a twin volute is clearly different from a double volute
Summary
Electric dishwashers are commonly used in private households as well as commercially. Due to their relatively complex pipe-systems, conventional dishwashers can accumulate dirt and often suffer from substantial flow-reduction speeds and poor spray-power. The application of computational fluid dynamics (CFD) is commonly used to study and improve dishwashers. The new type of dishwasher pump, which is described in this paper, uses an open cleaning concept to enable cleaning without pipelines in the water tank. Driven by the rotating impeller, the fluid flows into the volute and generates a speed torque that causes the volute to rotate. Thanks to the combination of volute flow channel with pipeline spray, the cleaning system has no pipeline, which shortens the cleaning time and saves both water and electricity
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