Cavitation performance prediction of engine cooling water pump based on CFD

Li Wei,Shi Weidong,Zhang Hua,Pei Bing,Lu Weigang(Research Center of Fluid Machinery Engineering and Technology,Jiangsu University,Zhenjiang,Jiangsu 212013,China)

engine cooling water pump;cavitation performance;three-dimensional turbulent flow;critical NPSH;performance prediction

The three-dimensional turbulent flow in an engine cooling water pump with the impeller,which has ever been severely damaged in operation,was simulated employing the time-averaged N-S equations,the standard k-ε turbulence model and multiphase flow model by CFX software.The characteristics and cavitation performance were predicted and the reasons for the impeller damage were clarified by observing the flow variable distributions in the impeller of the pump.The numerical simulation results indicat that the critical NPSH of the pump is about 10.7 m at 85 ℃,and a serious cavitation occurs under zero gauge pressure,it is suggested that cavitation causes the impeller damage.The experimental head of the pump is 6.1 m at the design flow rate of 285 L/min,it is well below the numerical simulation head under room temperature,thus a serious cavitation has occurred in the real operating conditions;such a conclusion based on the predicted results is basically consistent with the experimental observations.The numerical results provide a theoretical basis for improving the cavitation performance or preventing from or mitigating cavitation in an engine cooling water pump.It offers a fast and precise computational method for simulating and identifying cavitation damage in engine cooling water pumps as well.