(1-16) Numerical Prediction of Mixture Formation and Combustion Processes in Premixed Compression Ignition Engines((NCS-1)Novel Combustion Systems 1-Homogeneous Charge, Premixed Charge Compression Ignition Engines)

Abstract

In order to numerically predict the mixture formation and combustion processes in premixed compression ignition engines, submodels for fuel sprays (solid-cone and hollow-cone sprays), ignition and combustion were investigated. As an ignition model, the Livengood-Wu's model and the Schreiber's reduced kinetic model were examined. As a combustion model, the Reitz's model was employed. These submodels were incorporated into the authors' GTT code, and the mixture formation and combustion processes in the two types of premixed compression ignition engines (side-injection and central-injection engines) were numerically analyzed using this code. The validity of the submodels was confirmed by comparing the calculated results with the experimental ones. Figure I shows the mixture formation process in the side-injection engine. It has been found that using the Livengood-Wu's model the curves of heat release rate in the main combustion period in the test engines have been predicted reasonably well with the appropriate model constants. It has been also found that using the Schreiber's reduced kinetic model the curves of heat release rate in both periods of low-temperature oxidation and main combustion for two cases in the side-injection engine have been predicted considerably well with the appropriate parameters for the reaction rate constants. Figure II shows an example of the comparison between the experimental result of the heat release rate in the side-injection engine and the calculated result of the heat release rate using the Schreiber's model and the Reitz's model.