Numerical simulation of flow instabilities in high speed multistage compressors

Hu, Jun; Peters, Thomas M.; Fottner, Leonhard

doi:10.1007/s11630-999-0020-x

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…And the initial circumferential disturbance is simply taken as go = A0 sin 0; A0 = 0.005 (14) as At this point, we have that ~50 = 2W and ¢0 = ¢c0 + 2H.…”

Section: Initial Conditionsmentioning

confidence: 99%

A new simplified model of post stall transients in axial compression systems

Fottner²

1999

J. of Therm. Sci.

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Based on the theory developed by Moore and Greitzer, a new simplifying approximation, which takes into account the influence of higher harmonics of rotating waves, is proposed in this paper to get a simplified model of post stall transients in axial compression systems. This approximation leads to a set of three simultaneous nonlinear first order partial differential equations. The further investigation of post stall behavior for different response modes of instabilities (rotating stall and/or surge), recoverability, prestall period during stall inception, and the effect of compression system parameters on them can be carried out by this model and has been discussed in detail in the present paper. It has been found that stall inception exhibits a large prestall period in the region with small slope of compressor characteristic, and in this region, final throttle setting, compressor characteristic and time-lag parameters have a strong influence on the period. The inertia parameters of blade rows have a strong influence on the recoverability of compression systems and the blockage of stall cell at recovery point. Some qualitative comparisons with available experimental results and experience are made, and it shows that the proposed model is very simple and reliable. It is well known, t h a t the useful o p e r a t i n g range of t u r b o m a c h i n e r y compression systems is limited by the onset of one of the two kinds of fluid d y n a m i c instabilities: r o t a t i n g stall a n d surge, a n d b o t h of t h e m will degrade compression s y s t e m performance and d u r a b i l i t y [1]. These two kinds of instabilities, however, have some basic distinct characteristics. For instance, when r o t a t i n g stall occurs in the compres-Received, 1999. sion system, it is very difficult to r e t u r n to an unstalled s i t u a t i o n because of the hysteresis, a n d if the system enters the nonrecoverable stall, the only remedy m a y be to shut down the system and r e s t a r t it [2]. But it is not very difficult to recover from surge to a stable o p e r a t i o n by opening the t h r o t t l e again. Therefore, the p r o b l e m of post stall transients, the recovery process from stalled flow, and the influence of syst e m p a r a m e t e r s in a compression system have been concerned a b o u t by aircraft engine researchers and designers[3~15].

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“…And the initial circumferential disturbance is simply taken as go = A0 sin 0; A0 = 0.005 (14) as At this point, we have that ~50 = 2W and ¢0 = ¢c0 + 2H.…”

Section: Initial Conditionsmentioning

confidence: 99%

A new simplified model of post stall transients in axial compression systems

Fottner²

1999

J. of Therm. Sci.

Self Cite

View full text Add to dashboard Cite

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“…Central to the modeling is to describe the blade effect in reasonable reduction of dimensionality to lower the computational cost. According to the ideology, the actuator disk model (Hu et al, 1999) and body force model (Gong et al, 1999;Longley, 2007;Righi et al, 2018) have been established. In the actuator disk model, the blade row is treated as a discontinuity and the flow process inside the blade passage is not solved.…”

Section: Introductionmentioning

confidence: 99%

Unsteady body force model for rotating stall in axial compressor with various inlet conditions

Guo

2023

Journal of Theoretical and Applied Mechanics

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To analyze the dynamic stall of multistage axial compressors, a three-dimensional unsteady numerical model is established based on the body force model. For a two-stage axial compressor with a clean inlet, the calculated maximum steady static pressure rise coefficient is only 0.1% different compared with the experimental data. The characteristic frequency of the dynamic stall evolution basically agrees with the experimental results, which proves the effectiveness of the model. For the compressor with a combined radial-circumferential total pressure inlet distortion, the predictions preliminarily verify the ability of the model for qualitative description of the flow instability process with the complex inlet distortion.

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A Refined Model to Predict Boundary of Instability of Axial Compressors

Wang,

Tu,

et al. 2024

Journal of Propulsion and Power

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A quantitative model to predict the boundary of instability of axial compressors based on their maximum loading capability is proposed in this paper, which is an improved version of the classic method of stalling pressure rise. The original model correlates the maximum pressure rise of a compressor to a characteristic geometric parameter, which is an analogue of the normalized length of diffusion in two-dimensional diffusers. However, the influence of the aspect ratio of the passage is overlooked in this analogy, which leads to significant discrepancies in its predictions for compressors, especially those with varying blade aspect ratios. Our model contains two improvements to address this issue. The first involves refining in the definition of the normalized length of diffusion, whereas the second introduces a supplementary correction factor for the aspect ratio of the blades. Nearly 20 low-speed compressor configurations, with variations in solidity, aspect ratio, tip clearance, and axial spacing, were tested to develop the proposed model. It can reduce error in the predicted stalling static pressure rise from 10% to 5%. Experimental data robustly verify the accuracy of our model, making it a more reliable predictive tool of instability boundary in the preliminary design of axial compressors.

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Numerical simulation of flow instabilities in high speed multistage compressors

Cited by 3 publications

References 11 publications

A new simplified model of post stall transients in axial compression systems

A new simplified model of post stall transients in axial compression systems

Unsteady body force model for rotating stall in axial compressor with various inlet conditions

A Refined Model to Predict Boundary of Instability of Axial Compressors

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