| Oil pump is a core part in lubrication system of engine; excellent performance oilpump can save energy and reduce engine vibration and noise., According to research, thevariable oil pump can reduce fuel consumption of engine by0.5%to2%. Cavitationexistting in the oil pump generally not only affects the efficiency of pump but also impactsof the safety and the reliability, which results in performance changed, material erosion andstructural damage. In addition, cavitation can cause vibration and noise, affectting theNVH performance of the car, so the cavitation research has important significance.In this paper, the CFD analysis and vibration and noise analysis of oil pump which areused to analysis the pump during the variable gear pump development process have beenresearched and the cavitation characteristics of variable gear pump, the simulation methodof noise caused by flow in pump and test analysis of vibration and noise have been mainlyresearched. CFD model of variable gear pump was established Pumplinx professional CFDanalysis software and the CFD analysis method is described detailly. In order to verify thecorrectness of the model and analysis method, the pump outlet flow is measured thoughcomprehensive test of pump performance and the measured result compare with thesimulated result, which show that the calculated and experimental results are basically thesame. Then the cavitation characteristics of variable gear pump are analysised based on themodel. The study finds that the cavitation of variable cavitation gear pump occurs mainlyin the gear meshing which is the basically same as traditional gear pump. In addition, theinfluence of inlet pressure, outlet pressure and unload grooves on cavitaion of gear pumpare researched, which finds that reasonable unload grooves can not only improve cavitationof pump but also reduce the pressure fluctuations in gear pump that is in favour of reducingvibration and noise of gear pump.Pumplinx software has powerful features but it can not combine with other analysissoftwares to caculate together. In this paper, the problem that Pumplinx software can not combine with the acoustic calculation software Actran to simulation together. The soundpropagation of gear pump is analyzed by Actran using the Lighthill acoustic analogymethod to change the flow field inside the pump into the sound source of information.After the calculation of the sound propagation, different contour results and SPL resultssuch as the spectrum characteristics are analyzed. In addition, the influence of cavitationon the oil pump noise is rescheared, which finds that cavitation affectes the noise in entirefrequency domain, especially has a greater impact on broadband noise of gear pump, and itdoes not affect the discrete noise of gear pump.The vibration and noise of varable gear pump is tested using B&K PULSE test system,and by this way, NVH characteristics of the varable gear pump is analyzed on differentcondition including high-pressure conditions, the low-pressure conditions, startingconditions and cavitation conditions. Through the analysis of the cavitation condition,study finds that cavitation effects the vibration in the2KHz~16KHz range and hasgreater effect on vibration in the8KHz~14KHz. Besides, the comparation measuredsound pressure though experiment with Actran calculated sound pressure finds that theresults from Pumplinx and Actran calculated together is in good agreement withexperiment. This method can be used to calculate the noise of pump caused by flow, whichis important for the oil pump design. |
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