Modeling with finite volume the combustion in direct injection natural gas engine using non-premixed combustion model

Abstract

A gas engine is an internal combustion engine which runs on a gas fuel, such as coal gas, producer gas, biogas, landfill gas or natural gas. Generally the term gas engine refers to a heavy-duty industrial engine capable of running continuously at full load for periods approaching a high fraction of 8,760 hours per year. Unlike a gasoline automobile engine, which is lightweight, high-revving and typically runs for no more than 4,000 hours in its entire life. Typical power ranges from 10 kW (13 hp) to 4,000 kW (5,364 hp). In this paper one describe the simulation process of non-premixed combustion in a direct injection natural gas engine. Direct injection natural gas engines are used in many heavy duty vehicles. Similar to diesel engines, high thermal efficiency and power density is maintained in such direct injection natural gas engines. In such engines, natural gas is injected directly into the combustion chamber. Then the gas mixes with the high pressure air in the combustion chamber and combustion occurs. Due to the non-premixed nature of the combustion occurring in such engines, non-premixed combustion model of ANSYS FLUENT 13 can be used to simulate the combustion process. The CFD modeling of fuel injection and, combustion were performed to simulate these phenomena and processes in a compressed natural gas direct injection engine. The details of the engine geometry chosen for the calculations were given along with and explanation for the modeling choice. The simulation can be used for further optimization studies as combustion chamber geometry, injection timing and duration, compression ratios and piston geometry in order to increase the efficiency of the combustion process.