A Fundamental Criterion for the Application of Rotor Casing Treatment

Abstract

An experimental investigation has been carried out on the influence of grooved casing treatment on the stall margin of a compressor rotor. Tests were conducted with two rotor builds having different solidities (but all other parameters identical) so that one of the rotors exhibited a wall, or casing, type of stall, while the other showed a blade stall. It was found that the casing treatment, when compared to the solid casing, was very effective in increasing the stall margin of the wall stall configuration, whereas there was little or no change in the stall point of the blade stall configuration. Detailed relative frame measurements of the rotor exit flow field were also taken as part of the program. These showed that in a wall stall situation, the use of casing treatment produced a substantial decrease in the relative total pressure defect, compared with the solid casing, while this was not true for the blade stall type of blading. The results of the experiments, both in overall measurements and in the detailed relative frame traverses, support the hypothesis that casing treatment is effective only in a situation in which a wall stall exists.

Numerical Study on the Effect of Single Shallow Circumferential Groove Casing Treatment on the Flow Field and the Stability of a Transonic Compressor

“…Moore et al (1971) examined some casing treatment configurations and found that the circumferential groove could improve the stall margin and the peak efficiency of an axial-flow compressor rotor. Greitzer et al (1979) supposed the hypothesis that the casing treatment is effective only in a situation in which a wall stall exists. Crook et al (1993) numerically explored the effect of the grooved casing in suppressing the stall and identified two principal effects: suction of the high blockage fluid at the rear of the passage and energizing of the tip leakage flow.…”

Development of New Casing Treatment Configuration

“…This construction is characterized by great simplicity. Greitzer, E.M. et al have presented (5) the main conclusions of casing treatment (in the form of grooves and slots) use. Among these are the next: -The use of a grooved casing can provide substantial improvement in compressor stall range over a smooth wall casing (baseline).…”

Current Problems in Turbomachinery Fluid Dynamics.

“…This procedure has been used in the past in other investigations (see Ref. 25 for a notable example), however the additional pressure drop associated with the radial profile generator, which will be a screen or combination of screens, is high enough so that we will use the auxiliary fan, which was brought under AFOSR funding, in combination with the compressor. The radial profiles of D-factor and static pressure rise divided by inlet dynamic pressure, AP/Q for this case are shown in Fig.…”