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A detailed chemistry-based CFD model (GTEA, General Transport Equation Analysis) is developed to simulate the diesel spray, combustion and emission process. The numerical model incorporates an improved droplet tracking model, the Hybrid breakup model that consider the influence of turbulence inside the nozzle, the reaction mechanism of n-decane coupled with a reduced NOx mechanism, a phenomenological soot model, a modified dynamic mesh model, a spray/wall impingement model, and other improved sub models in the GTEA codes. The model is first applied to predict the diesel spray process. The computational results demonstrate that the model is capable of predicting satisfactory fuel spray process, and the improved agreement is attributed to the ability of the new Hybrid breakup model to account for the effects of turbulence inside the nozzle, which enhance the spray process.

Turbocharger is an important part of the turbocharged diesel engine. Due to the increase of mass flow rate and pressure ratio, aerodynamic noise of turbocharger has become more apparent. And turbocharger noise becomes one of the major noise sources of the main engine system of the ship. In the paper, the aerodynamic noise is predicted by using Computational fluid mechanics (CFD) and indirect boundary element method (IBEM) based on Lighthill acoustic analogy theory. Unsteady viscous flow in the centrifugal Compressor is simulated with finite volume method using the single stator and rotor blade passages and the characteristic of compressor is agreed well with the experimental value. The flow field characteristics and frequency spectrum of the fluctuating pressure are analyzed which agree well with the theoretical value. Dipole is the main noise source in compressor and the datum of pressure fluctuation at rotor blade are extracted.