Prediction of in-cylinder flow in DI diesel engine with RNG k -ε model

In a four stroke CI engine the fluid motion inside the engine cylinder plays an important role in proper combustion and emission characteristics of the engines. The KIVA code generally is used for such predictions, which solves three-dimensional unsteady turbulent flow equations and capable of predicting the behaviour of fluid flow in four-stroke DI diesel engine. In this work, the RNG k-ε turbulent model, which has the capability of predicting the fluidflow in four stroke DI diesel engines in a much better way was used in place of standard k-ε model. A hemi-spherical bowl-in -piston was considered to carryout the analysis. Global variables like pressure, turbulent kinetic energy during compression and expansion stroke and pollution formation, namely, CO, HC were predicted with both the turbulence models. The theoretical predictions were compared with the available experimental results in the literature and from the comparisons it was seen that the predictive capabilities of RNG k-ε turbulent model is better than the standard k-ε model. The results obtained with RNG k-ε turbulence model were found to be closer to the experimental results.