Study on characteristics of vortex structures and irreversible losses in the centrifugal pump

Abstract

The development of flow control methods in the centrifugal pump relies on further understanding of the characteristics of vortex structures and their irreversible losses. In this paper, the detached eddy simulation is conducted on a model centrifugal pump, which shows a good agreement with the experiment. Combining with three generations of vortex identification methods (vorticity, Q criterion, omega and Liutex methods) and entropy production analysis, the results show omega and Liutex methods are highly recommended to analyze the vortex structures. Vorticity is the key factor to promote the energy dissipation, and the irreversible losses of vortex areas can be lower than their surroundings when there exists smaller vorticity or higher rotation strength. Concerning the pressure pulsation induced by vortex shedding, it is unreasonable to analyze this unsteady process via vortex structures identified by iso-surface because of the restriction of the threshold. In comparison, the change of integral length is more related to the pressure pulsation.