Effects of the foam metal casing treatment on aerodynamic stability and aerocoustic noise in an axial flow compressor

Abstract This paper concerns the stability improvement and noise reduction of an axial compressor caused by the foam metal casing treatment (FMCT). Three FMCTs with different PPI (pores per inch), 20, 35, and 50, are tested experimentally. Two installation locations of foam metal in casing are considered and investigated. At location 1, it is found that the FMCT improves the stall margin by 5.4%~8.7% and the attenuation of compressor noise is up to 5 dB. At location 2, the stall margin is extended by 22.2%~37.1% but increasing the noise mostly. Besides, foam metal at location 1 causes less efficiency loss than that in location 2. Based on the analysis in near-casing pressure distribution, spanwise performance comparison and stall inception, the mechanism of the FMCT for enhancing compressor stability is also discussed.

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Design and experimental investigations of a new type of casing treatment for an axial flow compressor

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1243/09576509jpe139 ◽

2006 ◽

Vol 220 (3) ◽

pp. 207-215 ◽

Cited By ~ 1

Author(s):

I Zhu ◽

W Chu ◽

X Lu

Keyword(s):

Axial Flow ◽

Experimental Investigations ◽

Casing Treatment ◽

Axial Flow Compressor ◽

New Type ◽

Flow Compressor

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Numerical Investigations of the Coupled Flow Through a Subsonic Compressor Rotor and Axial Skewed Slot

Journal of Turbomachinery ◽

10.1115/1.2948959 ◽

2008 ◽

Vol 131 (1) ◽

Cited By ~ 16

Author(s):

Xingen Lu ◽

Wuli Chu ◽

Junqiang Zhu ◽

Yangfeng Zhang

Keyword(s):

Axial Flow ◽

Tip Clearance ◽

Stall Margin ◽

Tip Clearance Flow ◽

Casing Treatment ◽

Axial Flow Compressor ◽

Compressor Rotor ◽

Clearance Flow ◽

Flow Through ◽

Flow Compressor

In order to advance the understanding of the fundamental mechanisms of axial skewed slot casing treatment and their effects on the subsonic axial-flow compressor flow field, the coupled unsteady flow through a subsonic compressor rotor and the axial skewed slot was simulated with a state-of-the-art multiblock flow solver. The computational results were first compared with available measured data, that showed the numerical procedure calculates the overall effect of the axial skewed slot correctly. Then, the numerically obtained flow fields were interrogated to identify the physical mechanism responsible for improvement in stall margin of a modern subsonic axial-flow compressor rotor due to the discrete skewed slots. It was found that the axial skewed slot casing treatment can increase the stall margin of subsonic compressor by repositioning of the tip clearance flow trajectory further toward the trailing of the blade passage and retarding the movement of the incoming∕tip clearance flow interface toward the rotor leading edge plane.

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Experimental Investigation on the Effect of Porosity of Bend Skewed Casing Treatment on a Single Stage Transonic Axial Flow Compressor

Volume 2A: Turbomachinery ◽

10.1115/gt2014-26102 ◽

2014 ◽

Cited By ~ 1

Author(s):

Dilipkumar B. Alone ◽

Subramani Satish Kumar ◽

Shobhavathy Thimmaiah ◽

Janaki Rami Reddy Mudipalli ◽

A. M. Pradeep ◽

...

Keyword(s):

Experimental Investigation ◽

Axial Flow ◽

Compressor Stage ◽

Casing Treatment ◽

Operating Range ◽

Axial Flow Compressor ◽

Transonic Compressor ◽

Stable Operating ◽

Flow Compressor ◽

Casing Treatments

A bend skewed casing treatment was designed, to study the influence of one of its geometrical parameter porosity on the stable performance of single stage transonic axial flow compressor. The compressor was designed for the stage total-to-total pressure ratio of 1.35, corrected mass flow rate of 22 kg/s at corrected design speed of 12930 RPM. Bend skewed casing treatment has an axial inlet segment till 50% of the total length and rear segment that is skewed by 45° in the direction of the rotor tip section stagger. Both the sections were oriented at a skew angle of 45° to the radial plane such that the flow exiting the slot is in counter-clockwise direction to that of the rotor direction. The casing treatment slot width was equal to the maximum thickness of the rotor blades. Three casing treatment configurations were identified for the current experimental investigation. All the treatment geometries considered for the experimental research have lower porosities than reported in the open literatures. The effect of the porosity parameter on the performance of transonic compressor stage was evaluated at two axial coverages of 20% and 40% relative to the rotor tip axial chord. Performance maps were obtained for the solid casing and casing treatment with three different porosities. Comparative studies were carried out and experimental results showed a maximum of 65% improvement in the stable operating range of the compressor for one of the treatment configurations. It was also observed that the stable operating range of the compressor increases with an increase in the casing treatment porosity. All the casing treatment configurations showed that the compressor stall occurs at lower mass flows as compared to the solid casing. Compressor stage peak efficiency shows significant degradations with increase in the porosity as compared to solid casing. Detailed blade element performances were also obtained using calibrated multi-hole aerodynamic probe. Comparative variations of flow parameters like absolute flow angle, Mach number were studied at full flow and near stall conditions for the solid casing and casing treatment configurations. Hot wire measurements show very high fluctuation in the inlet axial velocity in the presence of solid casing as compared to casing treatments. Experimental investigation revealed that the porosity of the casing treatments has strong influence on the transonic compressor stage performance.

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The Effects on Stability, Performance, and Tip Leakage Flow of Recirculating Casing Treatment in a Subsonic Axial Flow Compressor

Volume 2A: Turbomachinery ◽

10.1115/gt2016-56756 ◽

2016 ◽

Cited By ~ 2

Author(s):

Wei Wang ◽

Wuli Chu ◽

Haoguang Zhang ◽

Yanhui Wu

Keyword(s):

Axial Flow ◽

Leakage Flow ◽

Tip Leakage Flow ◽

Tip Leakage Vortex ◽

Stall Inception ◽

Casing Treatment ◽

Tip Leakage ◽

Axial Flow Compressor ◽

Overall Performance ◽

Flow Compressor

Recirculating casing treatment (RCT) was studied in a subsonic axial flow compressor experimentally and numerically. The RCT was parameterized with the injector throat height and circumferential coverage percentage (ccp) to investigate its influence on compressor stability and on the overall performance in the experimentation. The injector throat height varied from 2 to 6 times the height of the rotor tip clearance, and the ccp ranged from 8.3% to 25% of the casing perimeter. Various RCT configurations were achieved with a modular design procedure. The rotor casing was instrumented with fast-response pressure transducers to detect the stall inception, rotational speed of stall cells, and pressure flow fields. Whole-passage unsteady simulations were also implemented for the RCT and solid casing to understand the flow details. Results indicate that both the compressor stability and overall performance can be improved through RCT with appropriate geometrical parameters. The effect of injector throat height on the stability depends on the choice of ccp, i.e., interaction effect exists. In general, the RCT with a moderate injector throat height and a large circumferential coverage is the optimal choice. Phase-locked pattern of the casing wall pressure reveals a weakened tip leakage vortex under the effect of RCT compared with the solid casing. The numerical results show that the RCT has a substantial effect on tip blockage even when the blade passages break away from the domain of RCT. The reduction of tip blockage induced by the tip leakage vortex is the main reason for the extension of stable operation range. The unsteadiness of double-leakage flow is detected both in the experiment and in numerical simulations. The pressure fluctuations caused by double-leakage flow are depressed with RCT. This observation indicates reduced losses related with the double-leakage flow. Although the stall inception is not changed by implementing RCT, the stall pattern is altered. The stall with two cells is detected in RCT compared with the solid casing with only one stall cell.

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Aerodynamic behavior of a transonic axial flow compressor stage with self-recirculating casing treatment

Aerospace Science and Technology ◽

10.1016/j.ast.2021.106587 ◽

2021 ◽

pp. 106587

Author(s):

S Satish Kumar ◽

Dilipkumar Bhanudasji Alone ◽

Shobhavathy M Thimmaiah ◽

Janaki Rami Reddy Mudipalli ◽

Lakshya Kumar ◽

...

Keyword(s):

Axial Flow ◽

Compressor Stage ◽

Casing Treatment ◽

Axial Flow Compressor ◽

Flow Compressor

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

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650916673266 ◽

2016 ◽

Vol 230 (8) ◽

pp. 805-818 ◽

Cited By ~ 2

Author(s):

Wei Wang ◽

Wuli Chu ◽

Haoguang Zhang ◽

Yanhui Wu

Keyword(s):

Axial Flow ◽

Operating Conditions ◽

Geometrical Parameters ◽

Flow Angle ◽

Casing Treatment ◽

Axial Flow Compressor ◽

Blade Tip ◽

Overall Performance ◽

Flow Compressor ◽

Casing Treatments

Parametric studies of recirculating casing treatment were experimentally performed in a subsonic axial flow compressor. The recirculating casing treatment was parameterized with injector throat height, injection position, and circumferential coverage percentage. Eighteen recirculating casing treatments were tested to study the effects on compressor stability and on the compressor overall performance at three blade speeds. The profiles of recirculating casing treatment were optimized to minimize the losses generated by air recirculation. In the experiment, the stalling mass flow rate, total pressure ratio, and adiabatic efficiency of the compressor were measured to study the steady-state effects on the compressor performance of recirculating casing treatments, and static pressure disturbances on the casing wall were monitored to study the influence on stall dynamics. Results indicate that both the compressor stability and overall performance can be improved through recirculating casing treatment with appropriate geometrical parameters for all the test speeds. The influence on stall margin of one geometric parameter often depends on the choice of others, i.e. the interaction effects exist. In general, the recirculating casing treatment with a moderate injector throat and a large circumferential coverage is the optimal choice to enhance compressor stability. The injector of recirculating casing treatment should be placed upstream of the blade tip leading edge and the injector throat height should be lower than four times the rotor tip gap for the benefits of compressor efficiency. At 71% speed, the blade tip loading is decreased through recirculating casing treatment at the operating condition of near peak efficiency and increased near stall. Moreover, the outlet absolute flow angle is reduced in the tip region and enhanced at lower blade spans for both operating conditions. The stall inceptions are not changed with the implementation of recirculating casing treatment for all the test speeds, but the stall patterns are altered at 33% and 53% speeds, i.e. the stall with two cells is detected in the recirculating casing treatment compared with the solid casing with only one stall cell.

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