Abstract: The calculation models of combustion and turbulent flow are established for a spark-ignition rotary engine in order to realize dynamic simulation of operating process of natural gas-fueled rotary engine. The evolution processes of flow and temperature fields and the propagation process of flame in cylinder are obtained by numerical simulation, and the effects of different ignition advance angles on the flame propagation are analyzed under the same ignition. The results show that the eddy in cylinder can largely accelerate the flame propagation speed. When the spark plug begins to ignite, it is best to be located at the transition region between eddy zone and unidirectional flow. With the motion of rotor, the eddy is extruded and disappears because the volume of combustion chamber decreases. The ignition advance angle should be appropriately increased for making full use of the eddy action time under the constant eddy disappearance moment condition. Under the computational conditions, when the ignition advance angle is 47°, the combustion efficiency and the peak pressure in the cylinder are the highest, and the lower NO_x exhaust is also taken into consideration. This study provides some theoretical guidance for the determination of best ignition advance angles under different working conditions.

Key words: engineering thermophysics, natural gas-fueledrotary engine, ignition advance angle, combustion process, two-dimension dynamic simulation