Experimental study and numerical simulation of internal flow dissipation mechanism of an axial-flow pump under different design parameters

This research uses CFD (computational fluid dynamics) to simulate an axial-flow pump and analyzes its internal flow dissipation. The results show that under different operating conditions, with increasing tip cascade density, the pump head gradually increases. With increasing tip cascade density, the pump efficiency gradually decreases under small discharge conditions, and the high-efficiency zone of the axial-flow pump gradually narrows when the pump is operated under large discharge conditions. Under the design operating conditions, the highest efficiency of the axial-flow pump reaches 86.15%. The total entropy generation of the impeller, guide vane, and outlet pipe decreases and then increases with increasing discharge. Meanwhile, the total entropy generation of the impeller is 3.37 W/K, which is the largest among different over-water flow components, accounting for 47%. The turbulence entropy generation (EGTD) ratios of the impeller, guide vane and outlet pipe are 42%, 59%, and 65% under the design operating conditions, respectively. Finally, the results of numerical simulation are reliable as verified by a model test. The research results have implications for improving the efficiency of axial-flow pumps.