چكيده به لاتين
Wankel is a rotary internal combustion (IC) engine. The engine has been considered in the air and car industries for its high power-to-weight ratios, as well as low-noise and intrinsic balance. Overheating of the rotor of this rotary engine is due to the rotor being located in a closed chamber; and direct contact with combustion gases can be mentioned from its defects solved by applying a cooling system. Two types of cooling systems are employed for the rotor, a cooling system with lubricating oil and a cooling system with air-fuel mixture. The rotor’s cool air system is very practical due to its low production costs and lack of additional weight on the engine.
No research has so far focused on the cooling system of the Wankel engine’s rotor. Hence, in order to recognize the heat transfer behavior in the cooling system runners of the Wankel engine’s rotor, first the flow and heat transfer have been simulated inside a pipe that all of its geometric and functional parameters are in accordance with the cooling system runners of the rotor. Then, using the results obtained from this section, the cooling system of the Wankel motor’s rotor has been simulated by the ANSYS FLUENT Software and the Reynolds Stress Turbulence Model at the rotor’s maximum rotational velocity of 3000 rpm, with oscillating thermal boundary conditions. In addition, all the thermodynamic properties of the air fluid have been considered variable with temperature. The results of the first section indicate that increasing the rotational velocity, the rotation-axis distance from the pipe’s axis, the oscillation and the flow Reynolds number enhance the heat transfer. Nevertheless, by increasing the Reynolds number to more than 50,000, the heat transfer is not affected by the increased rotational velocity and the rotation-axis distance from the pipe’s axis, anymore. Moreover, the oscillation of the input flow for the average Reynolds numbers more than 15,000 relatively reduces the heat transfer compared to the stable condition. The simulation of the cooling system of Wankel engine’s rotor indicates that the constant thermal boundary condition can be used for the rotor's parts. It is also noteworthy that the Nusselt number is the average cooling system of the Wankel engine’s rotor in the range of 572 to 586, indicating the good efficiency and proper operation of this type of cooling system for the rotor. With obtaining the average temperature of the rotor in the range of 551 K, this value can be further used in the present study to develop the Wankel engine performance and the lubrication system of the output shaft, and proceed to develop this engine.
