A numerical study of the effects of injection velocity on stability improvement in high-speed compressors

Khaleghi, Hossein; Boroomand, Masoud; Teixeira, Joao A.; Tousi, Abolghasem M.

doi:10.1243/09576509jpe443

Cited by 26 publications

(9 citation statements)

References 34 publications

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“…The numerical simulations for the smooth casing were validated against the experimental data in the previous publications of the present authors [36,39]. Results showed a satisfactory prediction of the compressor overall performance and flow characteristics.…”

Section: Resultsmentioning

confidence: 67%

Parametric Study of Injection Angle Effects on Stability Enhancement of Transonic Axial Compressors

Khaleghi

Teixeira

Tousi

et al. 2008

Journal of Propulsion and Power

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An effective approach in suppressing stall is mass injection upstream of the tip of an axial flow compressor. Developing reliable injection systems for high pressure ratio compressors requires an understanding of the effects of injection parameters, for example, injection angle, on the compressor stability and performance. This paper reports on a numerical investigation of injection angle on the operability of a high-speed compressor rotor. The injection port is set to be choked for all of the injection cases. Simulations indicate that injection angle has a significant impact on stability improvement. Maximum range extension is obtained when an injection yaw angle equal to 30 deg is applied. At this injection angle, the stalling mass flow coefficient was reduced by 17.4% by using an injected mass flow equivalent to 1.55% of the baseline annulus flow. Results also indicate that the best injection case creates an incidence angle of about 0 deg over the tip of the blade and adds the highest momentum in the relative frame of reference.Nomenclature A = area a = annulus adb = adiabatic amb = ambient DF = diffusion factor in = blade inlet j = jet out = blade outlet P 0 = total pressure rel = relative frame of reference T 0 = total temperature t = tip U, V = velocity x = axial component y = nondimensional wall distance = efficiency = tangential component = momentum = density = solidity = flow coefficient

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Section: Resultsmentioning

confidence: 67%

Parametric Study of Injection Angle Effects on Stability Enhancement of Transonic Axial Compressors

Khaleghi

Teixeira

Tousi

et al. 2008

Journal of Propulsion and Power

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“…The improvement of stability was attributed to the decline in incidence and blade loading at the rotor tip. The unloading effect of tip injection was confirmed by Kefalakis et al 8 in their experimental study and by Cassina et al 9 and Khaleghi et al 10,11 in their independent parametric studies.…”

Section: Introductionmentioning

confidence: 67%

“…The stabilizing effect of tip injection can be briefly summarized as the unloading effect, [7][8][9][10][11] the action on TLF or endwall blockage, [12][13][14][15][16][17] and the unsteady effect. [20][21][22][23][24] However, it is difficult to evaluate the influence on compressor efficiency accurately for the tip injection with external air source.…”

Section: Introductionmentioning

confidence: 99%

Mechanism study of performance enhancement in a subsonic axial flow compressor with recirculating casing treatment

Wang

Chu

Zhang

2017

Proceedings of the Institution of Mechanical Engineers, Part G:

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The improvements in both compressor efficiency and stability have been observed in a subsonic axial flow compressor with recirculating casing treatment. The study aims to understand the underlying flow mechanisms of the beneficial effect on the compressor efficiency of recirculating casing treatment. The recirculating casing treatment was investigated experimentally and numerically. In the experiment, static pressure fluctuations over the rotor tip were measured with fast-response pressure transducers. Whole-passage time-accurate simulations were also implemented to help in understanding the flow details. The unsteadiness of double-leakage flow and its effect on the loss generated at the rotor tip were discussed in detail for the solid casing. The effect of recirculating casing treatment on the double-leakage flow related loss was subsequently investigated. The results indicate that the double leakage flow is a main loss source in the rotor tip region. The double-leakage flow is completely unsteady, which induces a cyclical fluctuation of the amount of loss generated in the rotor tip region for the solid casing. With the recirculating casing treatment installed, the high-energy jet created in recirculating loops changes the unsteady characteristics of double-leakage flow by getting it diffused over the rotor tip gap along the chordwise direction, which results in the loss fluctuation that is dominated by the high-energy jet rather than the unsteadiness of double-leakage flow. The double-leakage flow is also pushed downstream by the jet and the amount is reduced when it passes through the recirculating loops. The effect of recirculating casing treatment on the double-leakage flow is primarily responsible for the improvement in the compressor efficiency.

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“…The positions and areas of bleeding and injecting were numerically studied by Hathaway 21 to build an optimal RCT, which provided significant improvements in stall margin with no penalty on the compressor efficiency. The benefit on the compressor efficiency at the off-design operating conditions was also numerically identified by Yang et al 22 Parametric studies on the effects of injection mass flow rate, velocity, yaw and pitch angles, and axial gap distance were performed numerically by Cassina et al 23 and Khaleghi et al, 24,25 and experimentally by Roy et al 26,27 Weichert et al 28 proposed a self-regulating casing treatment to reduce the penalty on compressor efficiency. In their studies, the recirculated flow was minimized at the compressor design condition and maximized near stall.…”

Section: Introductionmentioning

confidence: 96%

“…17,20,25,29 The injection velocity should be maximized by choking the injectors. 20,[23][24][25]32 Partly covering the annulus is adequate, although the optimal coverage is different for different compressors. 16,17,32,33 Nevertheless, the optimal options of some other parameters are still in dispute, such as injection yaw angle, i.e.…”

Section: Introductionmentioning

confidence: 99%

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

Wang

Chu

Zhang

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part A:

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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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A numerical study of the effects of injection velocity on stability improvement in high-speed compressors

Cited by 26 publications

References 34 publications

Parametric Study of Injection Angle Effects on Stability Enhancement of Transonic Axial Compressors

Parametric Study of Injection Angle Effects on Stability Enhancement of Transonic Axial Compressors

Mechanism study of performance enhancement in a subsonic axial flow compressor with recirculating casing treatment

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

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