A Numerical Study on Correlation of Chemiluminescent Species and Heat Release Distributions Using Large Eddy Simulation 2018-32-0066
In recent years, there has been an increasing demand for improved advance internal combustion engines in terms of exhaust emissions and engines efficiency. This fact suggests a need for more accurate predictions of thermal conditions, in particular, the gas temperatures inside the combustion chamber. Better thermal predictions would help to control the level of emissions of motor vehicles.
In the present study, a mixed timescale subgrid model of large eddy simulation (LES) is applied to simulate the turbulence approach in diesel engine combustion. The combustion model uses the direct integration approach with an explicit Ordinary Differential Equation (ODE) solver called ERENA, and additionally parallelized by OpenMP. The Diesel oil surrogate mechanism was used which was developed at Chalmers University of Technology, consisting of 70 species and 309 reactions. Additional reactions for the production and consumption of OH*, CO2* and CH* species are added from recent kinetic studies. Collisional quenching and spontaneous emission are responsible for the de-excitation of excited state radical. The soot mass production within a computation cell is determined from a phenomenological soot formation model developed by Waseda University. The model is combined with the LES code mentioned above, including the following important steps: particle inception in which naphthalene grows irreversibly to form soot, surface growth with the addition of C2H2, surface oxidation with OH radical and O2 attack, and particle coagulation.
We investigated the correlation of the excited chemical species and heat release distributions in the later part of diesel spray combustion by using the large eddy simulation. The results show that it is possible to predict heat release regions from the excited radical species concentrations.
Beini ZHOU, Takayuki Adachi, Jin Kusaka
SAE/JSAE Small Engine Technology Conference