Study On Numerical Simulation Of Combustion In Diesel Rotary Engine

The diesel rotary engine was studied in this paper. Firstly, the flow and combustion process in rotary engine was analyzed in detail. Two-dimension physical and mathematics models of combustion process in rotary engine were established by means of appropriate simplification. Secondly, the flow and combustion process in rotary engine has been numerically calculated on the platform of CFD software FLUENT6.2 by compiling with user defined program, the results were analyzed and certified by using results of reference. At last, combustion chamber of P52 series rotary engine was optimized by using the certified model, and the influences of load, speed, and injection angle of advance on the combustion process in rotary engine has also been investigated individually.The main conclusions and innovations of the paper:(1)Geometry model of rotary engine was established by means of multiple-point, the dynamics mesh model of rotary engine was established by compiling with the user defined program, it was obtainable that the meshes in dynamics zone were updated during the rotor was rotating.(2) Physical parameters of 2# diesel data were added in the FLUENT fuel data lib; The flow and combustion process in 218 series rotary engine was numerically calculated, and compared with result of reference, the results of this paper indicated the computational model of rotary engine was reliable.(3)The results about the optimization of recess geometry of P52 rotary engine indicated: when rotor recess was placed in the middle of rotor surface and deepened shallowly, better combustion efficiency and performance but lower NO emission can be drawn.(4) The results about the effect of operating parameters on combustion process of rotary engine indicated: The mean chamber pressure and mean chamber temperature raised with increase of load, and the area of combustion zone enlarged. As for the temperature peek in the rotary engine, raised with the increase of load below the specified load, but the amplitude of the peek increase will fall above the specified load; For the lower speed, the combustion zone will mainly concentrate on the center of chamber. With increase of speed, the temperature peek fall, the area of combustion zone also reduced, and mainly focused on the narrow zone near the housing. When injection was advanced, both mean chamber pressure and mean chamber temperature increased, but too early injection resulted in the increase of NO; Retarded injection caused combustion to start too late, and reduced expansion work. Reduction in expansion work leaded to the decrease of engine power output.