Abstract：In order to reveal the internal flow characteristics of electrical submersible pumps during operation, the energy characteristics and flow features of electrical submersible pumps under different flow conditions were studied by using numerical simulation combined with the entropy production theory. Variation rules and inter-stage differences of volume-averaged entropy production rate, three different types of entropy production and total entropy production, vortex core shape, as well as wall entropy production distribution in the main flow passage components with the growth of flow rate were compared and analyzed. The results show that the entropy production in the diffuser of the impeller at each stage decreases first and then increases with the growth of the flow rate, and the entropy production in the diffuser part is the largest. The entropy generation of velocity pulsation is much higher than the entropy production caused by the wall effect and time averaged process, which accounts for the vast majority of the total entropy production which is an important factor leading to energy loss. In the case of large flow rate condition, the energy loss of the flow passage components shows a clear trend of increasing in steps as the number of stages rises. The number and scale of vortex core in impellers and diffusers decreases and then increases with the growth of flow rate, which is consistent with the variation law of entropy production loss with the rise of flow rate. Based on the dimensionless turbulent dissipation coefficient of entropy production, the location of backflow in the flow-passage components can be determined intuitively. The results from this study can serve as a reference for the optimal design of electrical submersible pumps.
