Numerical investigation of three-dimensional separation control in an axial compressor cascade

Abstract

The aerodynamic performances of three-dimensional compressor cascade are mainly influenced by secondary flow effects, such as the cross flow on the side wall and the corner separation at the wall-blade junction. Often, these secondary flows can produce a blockage and losses in the blade passage. A numerical study of active flow control using blowing technique in a linear compressor cascade has been carried out, in order to eliminate the 3D boundary layer stall and enhance the aerodynamic performance. The numerical simulation is performed using steady and incompressible RANS (Reynolds averaged Navier-Stokes) equations with Realizable k-ε turbulence model. Good agreement is found between numerical results and experimental data, in particular pressure coefficient (CP) and total pressure loss coefficient (). A detailed flow topology analysis is mentioned and gave the flow structure and the separation zone behavior. It was found that the blowing slot should be located upstream the dual nature critical point which represents the origin of separation. Furthermore, three suction slot configurations are used to control the separation, whereas one configuration on the suction side of the blade and two configurations are on the endwall. The first endwall slot is located parallel to the suction side of the blade and the second one is located perpendicular to the axial chord of the blade. Results indicate that the removal of the corner separation was not achieved using the slots on the blade suction side and on the endwall parallel to the suction side. Contrariwise, the perpendicular endwall slot was found to be most effective and the 3D separation is completely disappeared.

Effect of optimal slot location on the performance of cascades of blades

“…To simulate the B.L. phenomena with precision, the k-ε renormalization group (RNG) theory, which has been widely tested in other research studies on compressor cascade, 30,41,46,51 was employed. The standard k-ε model, proposed by Launder and Spalding, 52 neglects the B.L.…”

“…In the active approach, a low momentum area around the blade's surfaces is triggered with the aid of external auxiliary facilities, while in the passive techniques, no external equipment is exploited to accelerate the mainstream flow. Although the active flow control methods such as plasma actuator, [24][25][26] aspiration of boundary layer, 2,27,28 and flow injection 29,30 are more robust in the production of a high momentum jet for purposes of separated B.L. elimination, required additional facilities limit their application.…”

Characterization of the Performance of a Turbocharger Centrifugal Compressor by Component Loss Contributions

“…Using CFD some researchers focused on modifying the loss model coefficients to improve 1D models [19] or modifying the performance of the component through the complete map of the compressor [20][21][22][23][24].…”

A quasi-one-dimensional model for the centrifugal compressors performance simulations

“…They stack duct and bladed elements, connected through physical variables and relationships. The impeller analysis often relies on the jetwake model [4][5], but it has proved to be less accurate than the meanline computations using correlations [6]. In this paper, the current program resulting from the extension of an axial compressor and turbine model [7][8], is developed to model the stationary, transient and dynamic simulation operation of a centrifugal compressor.…”