Large Eddy Simulation of Diesel Spray Using OpenFOAM

Abstract

The objective of this study is to develop LES analysis method for the prediction of diesel spray and combustion using OpenFOAM. In order to achieve reduction of emission and improvement of thermal efficiency in the diesel engine, it is necessary to quantitatively clarify the phenomenon from the fuel injection to the combustion process in the diesel engine cylinder. It is effective to use LES (Large Eddy Simulation) because LES is able to calculate the unsteady behavior such as the turbulent fluctuation and the turbulent vortex. However, the computational time increases because the grid refinement is necessary. Thus, it is effective to use parallel computing to reduce the computational time. So, OpenFOAM is valid. OpenFOAM supports parallel computing. And OpenFOAM is written in C++. Therefore, the extension that incorporated submodels is easy compared to KIVA. In this study, WAVE-MTAB model, which is breakup model, is incorporated to OpenFOAM, because the accuracy of the LES analysis using OpenFOAM is modified. LES analysis of non-evaporative spray is conducted by using OpenFOAM. As a result, because the degrees of freedom in MTAB model are changed from 6 to 12 and computational domain which is equivalent to the constant volume size using the experiment is applied, the good agreement is obtained between computational and experimental results.