TY - JOUR
TI - Numerical investigation of natural gas direct injection properties and mixture formation in a spark ignition engine
AU - Yadollahi Bijan
AU - Boroomand Masoud
JN - Thermal Science
PY - 2014
VL - 18
IS - 1
SP - 39
EP - 52
PT - Article
AB - In this study, a numerical model has been developed in AVL FIRE software to  perform investigation of Direct Natural Gas Injection into the cylinder of  Spark Ignition Internal Combustion Engines. In this regard two main parts  have been taken into consideration, aiming to convert an MPFI gasoline engine  to direct injection NG engine. In the first part of study multi-dimensional  numerical simulation of transient injection process, mixing and flow field  have been performed via three different validation cases in order to assure  the numerical model validity of results. Adaption of such a modeling was  found to be a challenging task because of required computational effort and  numerical instabilities. In all cases present results were found to have  excellent agreement with experimental and numerical results from literature.  In the second part, using the moving mesh capability the validated model has  been applied to methane Injection into the cylinder of a Direct Injection  engine. Five different piston head shapes along with two injector types have  been taken into consideration in investigations. A centrally mounted injector  location has been adapted to all cases. The effects of injection parameters,  combustion chamber geometry, injector type and engine RPM have been studied  on mixing of air-fuel inside cylinder. Based on the results, suitable  geometrical configuration for a NG DI Engine has been discussed.