Numerical investigation of the unsteady behaviour of tip clearance flow and its possible link to stall inception

Wu, Yuanhao; Li, Q; Chu, Wuli; Zhang, H; Su, Zixing

doi:10.1243/09576509jpe793

Cited by 27 publications

(13 citation statements)

References 23 publications

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“…Due to its great impacts on compressors, flow unsteadiness has drawn the attention of a large number of researchers [7][8][9][10][11][12][13][14][15][16][17][18][19]. The knowledge reported to date allows the flow unsteadiness to be divided into three categories; TLV breakdown, shock interaction and self-induced unsteadiness.…”

Section: List Of Abbreviationsmentioning

confidence: 99%

Numerical investigation into the mechanism regarding the inception and evolution of flow unsteadiness induced by the tip leakage flow in a transonic compressor

Spence

Lang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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Unsteady flow in the blade tip region of modern axial flow compressors is one of the sources of loss, noise, and blade vibration. In some cases, it is potentially linked to stall inception. In this paper, the complex flow fields in the blade tip region of a transonic axial flow compressor rotor have been numerically investigated. The predicted results were validated by experimental data. Analyses of monitoring results of numerical probes showed that three typical flow characteristics occurred as the operating condition approached the stability limit: no flow fluctuation at the first operating point; flow fluctuation with high frequency and low amplitude at the second operating point; flow fluctuation with low frequency and high amplitude at the third operating point. Further analysis of the tip flow field showed that the evolution of the tip leakage vortex experienced three stages as the rotor was throttled. At the first stage, the TLV did not breakdown. At the second stage, a bubble-type breakdown of the tip leakage vortex occurred. At the third stage, a spiral-type breakdown of tip leakage vortex occurred. The current study demonstrated that the flow unsteadiness that appears within the test rotor was induced by the tip leakage vortex breakdown. Furthermore, with the transformation of the vortex breakdown form, the characteristic frequency and amplitude of the flow oscillation substantially changed.

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Section: List Of Abbreviationsmentioning

confidence: 99%

Numerical investigation into the mechanism regarding the inception and evolution of flow unsteadiness induced by the tip leakage flow in a transonic compressor

Spence

Lang

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Study on the endwall flow evolving into the passage is not only an impor tant but also a difficult issue in the past few years. The stable operating range of axial compressors, especially "tip-critical compressors" [10][11][12] influenced tremendously by tip clearance size. In addition, shock wave establishes in transonic flows, which will incite interactions of shock wave and other flows [2,3].…”

Section: In V E S Tig a Tio N S On Th E E Ffects Of In Flo W C O N D mentioning

confidence: 99%

Investigations on the Effects of Inflow Condition and Tip Clearance Size to the Performance of a Compressor Rotor

Zhang

Wang

2014

Journal of Engineering for Gas Turbines and Power

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In v e s tig a tio n s on th e E ffects of In flo w C o n d itio n and T ip C le a ra n c e S ize to th e P e rfo rm a n c e of a C o m p re s s o r R o to rTo clearly clarify the effects of different upstream boundary layer thickness and tip clear ance size to the detailed tip flow field and flow mechanism, numerical simulations are performed on a subsonic compressor rotor, which is used for low-speed model testing of a rear stage embedded in a modern high-pressure compressor. First, available experi mental data are adopted to validate the numerical method. Second, comparisons are made for tip leakage vortex (TLV) structure, the interface of leakage flowlmainflow, endwall loss, isentropic efficiency and pressure-rise among different operating conditions. Then, effects of different clearance sizes and inflow boundary layer thicknesses are inves tigated. Finally, the self-induced unsteadiness at one near-stall (NS) operating condition is studied for different cases. Results show that the increment of tip clearance size has a deleterious effect on rotor efficiency and pressure-rise peiformance over the whole oper ating range, while thickening the inflow boundary layer is almost the same except that its pressure-rise performance will be increased at mass flow rate larger than design operat ing condition. Self-induced unsteadiness occurs at NS operating conditions, and its appearance largely depends on tip clearance size, while the effect of upstream boundary layer thickness is little. In tro d u c tio nAs one of the most important components in an aero-engine, the compressor directly determines its aerodynamic performance and stability margin. In addition, upstream conditions of the com pressor have a great impact on its working condition and perform ance. Due to this, it is urgent and essential to carry out detailed and indepth studies on the effect of inlet boundary condition to compressor performance and its internal flow mechanism. A cer tain clearance exists between casing and blade tip in axial com pressors. Studies of Brandt et al. [1] show that thickening the inflow boundary layer will cause the rollup point of the leakage vortex to move upstream and toward the leading edge, while the vortex trajectory is more inclined in the blade passage and the vor tex length decreases. This leads to higher total pressure loss in the endwall region.Flow in and around compressor tip clearance is very complex and has a profound effect on compressor performance. Study on the endwall flow evolving into the passage is not only an impor tant but also a difficult issue in the past few years. Complex endwall flow consists of tip leakage flow, secondary flow, interactions of leakage flow and endwall boundary layer, and interactions between leakage flow and mainflow. In addition, shock wave establishes in transonic flows, which will incite interactions of shock wave and other flows [2,3]. To improve compressor per formance and expand stability range, many passive/active control methods were proposed by researchers, such as casing t...

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“…3) The formation and development of the tip secondary vortex(TSV). Numerical simulation and experiments have been conducted on a single subsonic rotor by Wu et al (2010Wu et al ( , 2012. The research showed that TLV breakdown on the near stall condition and a tip secondary vortex originated from the interaction between the main flow and the tip leakage flow.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigations into the Origin of Tip Unsteadiness in a Transonic Compressor

Guo

Lang

Chen

et al. 2018

JAFM

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Three-dimensional numerical simulations are conducted to investigate the origin of flow unsteadiness and its associated unsteady flow phenomena in a transonic compressor rotor. The predicted results are compared with the available experimental data and a good agreement is achieved. The numerical monitoring results and further analyses of the flow field indicate that flow unsteadiness is detected in the passage with the operating condition approaching the stability limit, and the highest oscillating region is at the leading edge of the blade pressure surface; the tip leakage vortex breakdown is not a decisive factor for the flow unsteadiness, and the shock oscillation is a unsteady flow phenomenon resulted from the vibration of the recirculation region; a Utype vortex emerges in the tip leakage vortex breakdown region, and its periodic impingement on the pressure surface of the adjacent blade is treated as a trigger that leads to the flow unsteadiness.

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Numerical investigation of the unsteady behaviour of tip clearance flow and its possible link to stall inception

Cited by 27 publications

References 23 publications

Numerical investigation into the mechanism regarding the inception and evolution of flow unsteadiness induced by the tip leakage flow in a transonic compressor

Numerical investigation into the mechanism regarding the inception and evolution of flow unsteadiness induced by the tip leakage flow in a transonic compressor

Investigations on the Effects of Inflow Condition and Tip Clearance Size to the Performance of a Compressor Rotor

Numerical Investigations into the Origin of Tip Unsteadiness in a Transonic Compressor

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