Fluid-sound coupling simulation and experimental validation for noise characteristics of a variable displacement external gear pump

The oil pump is an important part of vehicle engine, whose noise and vibration characteristics affect the engine performance significantly. The noises generated by both the pressure and flow fluctuations are the main contributors to the oil pump noise. Based on the computational fluid dynamics (CFD) method and the Lighthill’s acoustic analogy (LAA) algorithm, a hybrid simulation technique for noise analysis of an external gear pump, so-called the CFD-LAA method, is presented in this paper. The fluid pressure and velocity distributions of the flow field are firstly calculated by using a CFD model. The noises generated by flow field are simulated and their sound pressure spectra are obtained by using an LAA-based finite element (FE) model. The methodology addresses a numerical noise simulation method which combined the CFD and FE models. Experimental verifications suggest that the CFD-LAA method is effective and feasible for sound field simulation of the external gear pump. Furthermore, the noise characteristics of the gear pump under typical operating conditions are calculated and discussed. The technique presented in this paper can be regarded as a useful tool for optimization design of gear pumps in vehicle engineering.