3-D CFD analysis of the combustion process in a DI diesel engine using a flamelet model

摘要

A 3-dimensional numerical study has been conducted investigating the combustion process in a VW 1.9l TDI diesel engine. Simulations were performed modeling the spray injection of a 5-hole diesel injector in a pressure chamber. A graphical methodology was utilized to match the spray resulting from the widely used Discrete Droplet Spray model to pressure chamber spray images. Satisfactory agreement has been obtained regarding the simulated and experimental spray penetration and cone angles. Thereafter, the combustion process in the engine was simulated. Using engine measurements to initialize the combustion chamber conditions, the compression stroke, the spray injection and the combustion simulation was performed. The novel RTZF two-zone flamelet combustion model was used for the combustion simulation and was tested for partial load operating conditions. An objective analysis of the model is presented including the results of a numerical parameter study. A comparison of numerical and experimental engine results was found to be encouraging and show potential for the further development and implementation of the combustion model.