关键词: 动力机械工程, 柴油机, 供油提前角, 燃烧模拟, STAR-CD

Abstract:

In order to understand the details of the diesel engine combustion process, the combustion of a turbocharged and intercooled diesel engine was simulated with the commercialized computational fluid dynamics software STARCD. To define the initial conditions of the simulation, such as pressures, temperatures,etc., the diesel engine was tested on a dynamometer testbed under different fuel supply advance angles to get its smoke and NOx emission behaviors. The combustion processes were simulated under the testing conditions. The simulation results show that a fuel spray tip is formed during the fuel injection process, and the spray tail breaks off from the main spray towards the end of injection. The unburned fuel impinges on the combustion chamber wall, then a part of which moves up into the clearance space between the piston top and the cylinder head bottom, and the majority of the impinged fuel moves down along the ωtype chamber wall to form a tumble flow. The ignition always occurs in the outer region of the fuel spray, the combustion goes on there, so the temperatures there are high.

Key words: power machinery and engineering, diesel engine, fuel supply advance angle, combustion simulation, STAR-CD