Numerical investigation of fluid flow in a rotor–stator cavity with curved rotor disk

In this research, by presenting a new idea of creating a curved surface on rotor disk wall, its effects on flow structure and the performance parameters of rotor–stator cavity is investigated. The fluid enters the cavity axially through a hole provided at the center of the stator and eventually leaves the cavity radially through the clearance between the rotor and shroud. By varying the geometrical parameters of elliptical bumps on rotor disks, their effects on the flow structure and on the performance parameters of rotor–stator cavity are evaluated. The geometrical parameters of elliptical bumps include the semi major axis of elliptical bump (half of bump length), semi minor axis of elliptical bump (bump thickness), and the distance between the center of elliptical bump and the system’s rotation axis. The governing equations for the steady, three-dimensional, turbulent, and compressible flow, including the continuity, momentum, and energy equations, in the Cartesian coordinate system have been solved using a commercial finite-volume-based software (Ansys CFX). The numerical results have been validated by means of experimental results, and there has been a good match between the results obtained from the two methods. As the distance between the bump and rotation axis increases, more energy is imparted to the fluid and the total pressure at cavity outflow and the moment applied to rotor increase. Furthermore, the enlarging of bump’s curvature leads to the increase of tangential flow velocity over the bump and the reduction of static pressure at the inlet. With the reduction of static pressure, the mass flow rate of fluid in the cavity increases.