Simulation of Combustion in a DI-Diesel Engine with Application of a Moving Grid 2000-01-1888
This paper focuses on the initial stage of internal combustion, auto-ignition. The fuel used for simulation of a DI-diesel engine in this study is n-heptane. The condensed model based on formulations for n-heptane [1], iso-octane and a mixture of fuels [2]. The engine simulated is a 1.9 liter VW research engine.
CFD simulations have to be done fast, if the user wants to experiment with the simulation. For a rapid simulation of the kinetic in a reacting turbulent flow, only a couple of active species can be calculated. An additional way to decrease the solution time is to keep the number of elements small.
In this paper a model describes the reactive processes in the gas phase of a diesel engine, using the RIF-model (RIF: Representative Interactive Flamelets) [3] with a flexible discretisation by the method of lines and a dynamic adaptive grid technique [4].
The other possibility is just to focus on the ignition process by using a condensed model. At a minimum one step describes the low temperature ignition, while the other step describes the high temperature ignition and its dependence on the pressure. The results of the simulation are compared with experiments [5]. The program package used to solve the reaction kinetic is the ODE-solver DASSL [8].
The simulated ignition delay time and the relevant temperature are entered interactively into the three-dimensional flow simulation program KIVA3V [9].
With such a detailed description of the kinetics the ignition process can be better understood and simulated. The model provides a good foundation for simulating a reactive turbulent flow field [10].
