MODELLING OF TURBULENCE PREMIXED COMBUSTION RELEVANT TO SPARK IGNITION ENGINE

The identification on the nature of Spark Ignition (SI) engine combustion shows that the engine flames can be classified as turbulence premixed type. It consists of complex phenomena such as reaction, diffusion, volume expansion and in general involves complicated geometries, complex physics, heat transfer, and fluid flow. Because of the above factors, the need of models to simulate these combustion processes is highly demanded to evaluate the performance of different designs, perform parametric studies
and virtual prototype each design before actual fabrication. Computer simulations were carried out using an in-house Reynolds averaged Navier-Stokes equations (RANS)
Computational Fluid Dynamics (CFD) code being developed at Loughborough University, known as Turbulence Reactance Flow 2-Dimension (TRF2D). Since the code is still in the development stage, comparison of its capability were asessed with experimental results that use mounted obstacles to allow the build-up of turbulence
creating complex interaction and challenging problem for numerical modelling. Results were d iscussed based on the structure of flame propagation, flame location and the
pressure time history within the combustion chamber. By using the standard turbulence model, the code shows a good correlation with the experimental results but the flame
propagation failed to reproduce the recirculation phenomena that took place in the combustion chamber. It is confirmed that the calculated flame is ahead of the
experimental and there is an over prediction on the pressure as the calculated pressure peak much higher than it should be with a difference of 0.05 bar. The identification of the approach applied was also discovered to be in the region of SI engine reaction.