Impact of the grooves on the enhancement of heat transfer in an annular space of a rotor-stator

Abstract

This work concerns a numerical study of heat transfer by convection in an annulo-cylindrical space of an axial air flow between a rotor rotating at constant angular velocity and a fixed stator. We used the Fluent software to simulate the thermal influence on the groove. We propose to study four geometric configurations of the rotor and stator. The first is to take the surfaces of the rotor and the stator as smooth. In the second configuration, the stator wall is grooved along the cylinder and the rotor is smooth. For the third, it is considered that the rotor and the stator are provided with grooves of the same geometrical shape as regards the last case; it is only on the rotor that the same types of grooves are considered. The numerical results obtained in rotational flow for different rotational speeds of the rotor and for different air injection rates through grooves of different depth values have shown that the presence of grooves enhances the heat transfer at as speed increases. In the presence of an axial flow of air, the results obtained in a turbulent flow show that the case of the grooved rotor is interesting from the thermal point of view with respect to the others (smooth, grooved stator, and grooved rotor-stator). This numerical study is based on the use of an SST (Shear-Stress-Transport) type turbulence model to evaluate heat exchanges in the various rotor-stator configurations.