Unsteady Measurements of Periodic Effects in a Transonic Compressor With Casing Treatments

Brandstetter, Christoph; Wartzek, Fabian; Werner, Jan; Schiffer, Heinz-Peter; Heinichen, Frank

doi:10.1115/1.4032185

Cited by 25 publications

(12 citation statements)

References 11 publications

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“…This is especially the case for high circumferential Mach numbers. Similar effects were reported by Brandstetter [6] in his experiments with an axial compressor. This paper presents:…”

Section: Introductionsupporting

confidence: 89%

“…While early attempts to design CTs were based on analytic considerations and test experiences, the progress in 3D CFD and optimization techniques enables new improvement possibilities. Good examples are the published CT simulation and test results by Streit [5] and Brandstetter [6]. The effect of the herein developed and investigated CT is limited to the blade tip region and it is supposed to only act if the rotor is highly throttled close to its operation limit.…”

Section: Introductionmentioning

confidence: 97%

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A Casing Treatment with Axial Grooves for Centrifugal Compressors

Leichtfuß

Bühler

Schiffer

et al. 2019

IJTPP

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This paper provides an investigation of a casing treatment (CT) approach for pressure ratio improvements of centrifugal compressors between peak efficiency and surge. Results were experimentally verified for a variety of automotive turbocharger compressors and analyzed with 3D CFD. The CT design is an adaptation from an axial high-pressure compressor, which was successfully applied and intensively investigated in recent years. The aerodynamic working principle of the applied CT design and the achievable improvements are shown and described. The demand of operating range for automotive applications typically dictates high inlet shroud to outlet radius ratio (high trim) and past experiences indicate that a recirculation zone is formed in the inducer for those centrifugal compressors. This recirculation at the inlet shroud causes losses, a massive blockage and induces a co-rotating swirl at the inlet of the impeller. The result is a reduced pressure ratio, often leading to flat speed lines between the onset of recirculation and surge. This paper provides an understanding of inducer recirculation, its impacts and suggests countermeasures. The CT design for centrifugal compressors only influences flow locally at the inducer and prevents recirculation. It differs substantially in design and functionality from the classical bleed slot system commonly used to increase operating range. An experimental and CFD comparison between these designs is presented. While the classical bleed slot system often provides a massive increase in operating range, it often fails to increase the pressure ratio between onset of inducer recirculation and surge. In contrast, the CT design achieves a gain in pressure ratio near surge.

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“…This is especially the case for high circumferential Mach numbers. Similar effects were reported by Brandstetter [6] in his experiments with an axial compressor. This paper presents:…”

Section: Introductionsupporting

confidence: 89%

Section: Introductionmentioning

confidence: 97%

A Casing Treatment with Axial Grooves for Centrifugal Compressors

Leichtfuß

Bühler

Schiffer

et al. 2019

IJTPP

Self Cite

View full text Add to dashboard Cite

show abstract

“…Owing to the outstanding capacity of improving the compressor stability, the emphasis is laid on the application and exploration of axial slots [3][4][5][6][7][8] and axial skew slots [9][10][11][12][13][14][15][16] in most of the slot CT investigations. Wilke and Kau 3 performed a numerical investigation of axial slot CT on a transonic axial flow compressor, where the result shows that at 88% design speed, axial slot obtains the 6.5% decrease for the stall mass flow rate with the 5% decrease for the maximum efficiency.…”

Section: Introductionmentioning

confidence: 99%

Mechanism investigation of enhancing the stability of an axial flow rotor by blade angle slots

Zhang

Liu

Wang

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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This paper seeks to reveal the mechanisms of enhancing the stability of a subsonic axial flow rotor by applying blade angle slots casing treatment (BSCT). When blade angle slots are applied, there is about 9% stall margin improvement for the experiment and about 8% stall margin improvement for the calculation, but the decrease in the rotor maximum efficiency is about 11% for the experiment and the calculation. The compared results between smooth wall and blade angle slots indicate that the backflow in the rotor top passage is weakened by the injected and sucked flows formed inside the slots of BSCT. Moreover, the injected flows inside the slots interfere with the flows in the rotor passage upstream, and this interference leads to large flow losses. Therefore, the rotor efficiency for blade angle slots is much lower than that for smooth wall. To confirm that the structural optimization of blade angle slots can effectively improve the compressor stability with small efficiency losses, optimized blade angle slots casing treatment (BSCT1) was designed according to the past experience of slot casing treatment. The calculated result shows that the optimized blade angle slots generate about 59% stall margin improvement, and the compressor maximum efficiency with the optimized blade angle slots is about 0.05% more than that for smooth wall. The flow field analyses show that the strong sucked flows formed inside the slots for BSCT1 can prevent the backflow, which exists in the rotor top passage for BSCT, from appearing. In addition, the level of interference of the flows in the rotor passage upstream for BSCT1 is much lower than that for BSCT, and the corresponding losses with BSCT1 become lower. Therefore, the rotor with BSCT1 has a larger stable operating range and better efficiencies than that with BSCT.

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“…Casing treatment is found to be an effective passive control method for the instability occurring in the rotor tip since the 1950s. The researchers tested a mass of geometries on different test rigs in the past decades (Bailey and Voit, 1970;Koch, 1970;Brandstetter et al, 2015). The experimental results showed that the casing treatment extended the stall margin but at the cost of efficiency loss.…”

Section: Introductionmentioning

confidence: 99%

Momentum Transportation Analysis in Axial-slot Casing Treatment for Axial Compressors

Feng¹,

Zhu²,

Teng³

et al. 2019

Proceedings of Global Power &Amp; Propulsion Society

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In this paper, momentum transport analysis was proposed to investigate the effects of axial-slot casing treatment. The numerical simulation was performed on a transonic single rotor with and without casing treatment. The distribution of momentum in the tip region and slot opening was obtained. The result shows that casing treatments suppress the tip leakage flow and improve the axial momentum distribution near the tip. The decomposed momentum distribution demonstrates the flow interaction between casing treatment and tip region. The flow pumped into casing treatment is always with reverse axial momentum and the flow injected from casing treatment is always in positive axial momentum for these semi-circular slots. Furthermore, the influence of casing treatment axial position is also investigated by the analysis of momentum transportation. The numerical simulations were conducted in another two configurations with different axial positions. The results indicate that the axial momentum is not the only parameter that influences the stall margin. The strength of interaction between casing treatment and tip region should be neither too violent nor too weak. There might be an optimal momentum distribution that the demarcation point is just at the leading edge in axial momentum distribution.

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Unsteady Measurements of Periodic Effects in a Transonic Compressor With Casing Treatments

Cited by 25 publications

References 11 publications

A Casing Treatment with Axial Grooves for Centrifugal Compressors

A Casing Treatment with Axial Grooves for Centrifugal Compressors

Mechanism investigation of enhancing the stability of an axial flow rotor by blade angle slots

Momentum Transportation Analysis in Axial-slot Casing Treatment for Axial Compressors

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