NUMERICAL INVESTIGATIONS OF AFC METHODS ON HIGHLY LOADED COMPRESSOR CASCADE

In the design of aircraft propulsion systems, particular attention is given to improving efficiency, to increasing the payload and to reducing noise and pollutants. Today, active and passive boundary layer control systems are studied and widely used to increase external aerodynamics efficiency. Particularly, those systems appear to be effective for the control of separation of flow stream, to reduce pressure losses and to improve efficiency and performance of engine. In this work a CFD analysis is applied to investigate the increase of pressure rise by suppression of boundary layer separation into a highly-loaded subsonic compressor stator cascade, by different active flow control techniques: pulsed jet, synthetic jet and plasma actuator. In literature, several works have investigated the use of these actuators on airfoil, but only few studies have compared their performance. Active flow control devices are installed at two different locations: end walls near the leading edge (with the aim to control secondary flow structures) and blade suction side (to reduce the flow separation at the trailing edge of the blade). The best actuators configuration appeared to be the combined forcing at side wall and suction side. Concerning pulsed/synthetic jet actuators, a suction/blowing type boundary condition is used, imposing a prescribed sinusoidal velocity depending on velocity amplitude, jet frequency and jet angle. Concerning plasma actuation, the effect is modeled into numerical flow solvers by adding the paraelectric plasma body force into momentum equation. The plasma, generated by Dielectric Barrier Discharge, acts as a momentum source to boundary layer allowing it to remain attached throughout a larger portion of blade.