Controlling Corner Stall Separation With Plasma Actuators in a Compressor Cascade

Abstract

This paper presents a numerical and experimental assessment of a plasma actuation concept for controlling corner stall separation in a highly loaded compressor cascade. CFD simulations were first carried out to assess actuator effectiveness and determine the best actuation parameters. Subsequently, experiments were performed to demonstrate the concept and confirmed the CFD tool validity at a Reynolds number of 1.5 × 105. Finally, the validated CFD tool was used to simulate the concept at higher velocities, beyond the experimental capability of existing plasma actuators. These results were used to obtain a preliminary scaling law that would allow approximation of the plasma actuation requirements at realistic operating conditions. Several configurations were examined, but the most effective setup was found to be when plasma actuators were mounted upstream of the separation point on both the suction surface and the endwall. Most of the improvement in total pressure loss stemmed from the suction surface actuator. Comparison with experimental data showed that the CFD simulations could capture the flow features and the effect of plasma actuation reasonably well. Simulations at higher flow velocities indicated that the required plasma actuator strength scales approximately with the square of the Reynolds number.

Control of Corner Separation with Plasma Actuation in a High-Speed Compressor Cascade

“…This finding is in accordance with the results of Akcayoz et al [22], which point out that, compared with the endwall plasma actuation, the plasma actuation on the blade suction surface contributes the most to the improvement in the total pressure loss of the compressor cascade. However, this paper finds that, through suppressing the development of the PV, the endwall plasma actuation is more efficient in reducing the flow blockage and improving the static pressure rise of the high-speed compressor cascade.…”

“…Based on their findings, they concluded that increasing the actuation voltage can enhance the control effect of plasma actuation, but, from an energetic point of view, the plasma actuation with lower voltage is more efficient [21]. In 2016, Akcayoz et al [22] published their studies on the plasma control of the compressor corner separation. They evaluated the effects of plasma actuations placed on the blade suction surface and the endwall respectively by suppressing the corner separation in a low-speed highly loaded compressor cascade with both numerical and experimental methods and found that the plasma actuators mounted upstream of the separation on both the suction surface and the endwall were most effective in suppressing the corner separation, while most of the improvement in total pressure loss stemmed from the suction surface actuator.…”

Numerical Assessment of Virtual Control Surfaces for Load Alleviation on Compressor Blades

“…Notice that the k-ω SST Menter model is used in other numerical works dealing with turbomachinery cascades. Akcayoz et al [14] used the same solver and the same modeling to perform RANS computations on a compressor cascade equipped with plasma actuators, employed to control corner stall separations. Keerthi et al [2] used Ansys CFX R to carry out fully turbulent RANS computations closed with the k-ω SST Menter model on a linear cascade featuring blades oscillating in pitch.…”

“…Consistently with the assessments of Ref. [14] and with the experiments of Ref. [38], a force per unit span of 300 mN/m is used in this work.…”

“…It was shown that properly tuned plasma actuation allows for an effective reduction of pressure losses on highly loaded compressor blades. Akcayoz et al [14] performed numerical and experimental assessments of plasma actuators to control corner stall separation on a heavily loaded blade cascade. In this work, realistic operation conditions were simulated.…”