Numerical Simulation Of Atomization And Combustion Based On Supersonic Inlet-channel Diesel Spray

Burning-quality of the internal combustion engine affect it's dynamic, economical and emission performance directly. It is most important to the combustion effect that if the fuel atomization is good or not. Good atomization is the precondition to increase the combustion efficiency, so it is important to the energy conservation and the purification.The classical fuel atomization is done by the direct cylinder spray, and the studies of the manners are most the high pressure spray and high pressure electric control spray. Some tentative studies toward the premixing are completed in this paper. A Laval tube was used to give supersonic. The Laval tube can be added to the inlet duct and the inlet channel.In the condition of supersonic spray, the mixture was proportioned better than the classical mix manner at the ignition point. When excess air coefficient was defined the number one, it could avoid the condition of producing the NO_x. At the present time, many studies are performed for the environmental problem. High pressure electronic control spray is the most popular manner to solve the diesel emission problem but it needs high technology and high cost.Double w piston was selected in this paper. The STAR-CD software was used to establish the modeling, plot the grid, define the moving grid, and enact the parameters. The flow vector graph and the fuel oil atomization of the inlet and compress stoke were gained at any time or position. After analysis, the fuel oil could be atomized well by supersonic flow and the Sauter average diameters obtained from the supersonic spray were less than those from the cylinder direct spray. The combustion statuses were different because of the different spray ways. The mixture was proportioned well by supersonic in the cylinder and the combustion could be completed. In the other side, the temperature of the cylinder direct spray was high enough to the compression-ignition but a lot of carbons or NO_x could appear because of the uneven mixture distribution and the high partial temperature.In general, the new supersonic spray manner presented in this study could be regard as an optimized method to the HCCI theory. This method could offer an effective reference to the diesel combustion and emission problem.