CFD Simulation of Natural Gas Combustion in a Spark Ignition Engine
Natural gas gains popularity as primary fuel in Automobiles because of its low emission characteristics as compared to petrol and diesel powered vehicles. A clear understanding of evolution of in-cylinder pressure and temperature, as a function crank angle, resulting from the combustion of natural gas is a requisite before it is being used in internal combustion engines and, also, for future development of natural gas powered engines. Keeping this in view, in this study, numerical simulation of combustion of natural gas in an idealized spark ignition engine during the period from closure of inlet valve to opening of exhaust valve was carried out and the results were reported. The numerical simulations were carried using the commercial computational fluid dynamic software package ANSYS Fluent 16. The evolution of in-cylinder pressure and temperature resulting from the combustion process at different ignition timing, varying from 6 to 180 before Top Dead Centre (bTDC), was predicted numerically. Among the various ignition timing set to initiate combustion, the peak pressure and temperature was found to occur when the ignition timing was set at 100 bTDC. The numerically simulated flow and thermal fields at different time instances are presented and discussed.
Keywords - Combustion, Natural Gas, Numerical Simulation, Ignition Timing