Parametric Investigation of Circumferential Grooves on Compressor Rotor Performance

Abstract

This paper presents numerical and experimental investigations about grooved casing treatment with the help of a high-speed small-scale compressor rotor. First, the numerical investigation seeks to offer a contribution of understanding the working mechanism by which circumferential grooves improve stall margin. It is found that stall margin gain due to the presence of circumferential grooves arises from the suction-injection effect and the near-tip unloading effect. Based on that, the philosophy of design of experiment is then set up. Finally, parametric studies are carried out through systematical experiments. It is found that the orthogonal experiment and the factorial analyses are successful in identifying the “best casing configuration” in terms of stall margin improvement. However, the ineffectiveness of the deduction from simulations suggests that the secondary flow circulations on stall margin gain should not be neglected, and the overall contribution of each groove to stall margin gain depends on its unloading effect and the compound effect of suction-injection. Further numerical investigation will focus on how to set up quantitative criteria to evaluate the compound effect of suction-injection and the unloading effect on stall margin gain respectively in each groove.

Experimental study of self-recirculating casing treatment in a subsonic axial flow compressor

“…The compressor has been applied to various kinds of casing treatments to test their effects on compressor stability for its tip-critical nature. 4,37 Figure 7 shows the test facility and instrumentation for both the steady-state and dynamic measurements. The shaft speed of a 250 kW DC motor was accelerated by a gearbox up to 15,200 r/min.…”

“…33%, 53%, and 71% of the design speed. The tested facility and measurement method are discussed in detail in Lu et al, 4 Wang et al, 35 and Wu et al 37 Results and discussion Effect on compressor stability…”

Visualization and Time-Resolved Particle Image Velocimetry Measurements of the Flow in the Tip Region of a Subsonic Compressor Rotor

“…Indeed, numerous attempts have been made to develop tip flow control strategies. They have ranged from active methods, e.g., real-time control of the IGV stagger angle [24] and momentum injection into the casing endwall boundary layer upstream of the rotor [25,26] to passive techniques, such as endwall casing treatments [27,28]. Although it has been established that casing treatments do extend the stall margin, insufficient understanding of the flow mechanisms involved has hindered the ability to, for instance, optimize the location and geometry of grooves.…”

Study on casing treatment and stator matching on multistage fan

“…Several other groups have attempted to explain the effectiveness of circumferential grooves. From the stable flow point of view, Muller [11] and Wu et al [13] suggested that the circumferential grooves delay the overflow at the leading edge of blade tips, thereby enlarging the stall margin. Zhao et al [15] studied the unstable flow effects of the circumferential grooves on the leakage flow at blade tips.…”

“…Furthermore, Muller [11] and Raba and Hah [12] suggested that the leading edge of the blade is the best position. Wu Anhui [13] and Bennington [14] reported that the stability extension achieved through circumferential groove treatments decreases as the groove width increases. In addition, Bailey [9] and Bennington [14] reported that the stability extension effect increases with increasing groove depth.…”