Application of entropy production theory for energy losses and other investigation in pumps and turbines: A review

Numerical investigation of energy loss mechanism of mixed-flow pump under stall condition

Energy loss mechanism due to tip leakage flow of axial flow pump as turbine under various operating conditions

Diagnosis of internal energy characteristics of mixed-flow pump within stall region based on entropy production analysis model

Effect of blade thickness on rotating stall of mixed-flow pump using entropy generation analysis

Energy characteristics of mixed-flow pump under different tip clearances based on entropy production analysis

In order to better understand the flow characteristics of mixed-flow pump with non-uniform tip clearance, a test rig is established and the flow fields of various cross section in impeller are studied based on particle image velocimetry technology. The velocity vector distributions of three cross sections, e.g., impeller blade inlet, middle and outlet, were measured. The influences of flow rate and eccentricity on the flow fields of mixed-flow pump with non-uniform tip clearance were analyzed, and the relative velocity distribution of different positions at the same cross section is quantitatively discussed. The results show that the external characteristics have been greatly affected by the eccentricity of impeller. There is a significant negative correlation between eccentricity and efficiency. The maximum head and efficiency drop of eccentric impeller reach 11% and 20% separately. With the increase in eccentricity, the secondary flow phenomenon increases, such as backflow and vortex flow in impeller flow passage. Vortex structure is easily formed in the end wall region, which will give rise to backflow and even blocks the flow passage near impeller hub. The energy loss increases continuously in this process which is the main reason for the significant drop in efficiency. The research results are instructive for revealing the flow characteristics of flow fields of mixed-flow pump with non-uniform tip clearance.

Zhenyu Yang

Papers

Energy characteristics of mixed-flow pump under different tip clearances based on entropy production analysis

Particle image velocimetry measurement of flow fields in a mixed-flow pump with non-uniform tip clearance