Further Investigation on Acoustic Stall-Warning Approach in Compressors

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Xu Dong ◽  
Fanyu Li ◽  
Ruize Xu ◽  
Dakun Sun ◽  
Xiaofeng Sun
Keyword(s):  
Numerical Simulation ◽  
Signal Amplitude ◽  
Operating Point ◽  
Stabilization System ◽  
Stall Margin ◽  
Casing Treatment ◽  
Statistical Estimates ◽  
Sensor Position ◽  
Stall Warning ◽  
Stall Precursor

A further investigation of an acoustic theory-based stall-warning approach is presented in this paper, which contains the basis of this approach and an application on a low-speed compressor (LSC) with a stabilization system. In the present work, this stall-warning approach is first explained through a numerical simulation in which the periodicity of pressure signals is analyzed, and then application experiments of this approach are actualized on a LSC with a stall precursor-suppressed (SPS) casing treatment (CT) as a stabilization system. For this stall-warning approach, a parameter named Rc is calculated through pressure signals of compressor to evaluate the periodicity of pressure signal, and statistical estimates are implemented on Rc so that the probabilities for Rc less than a threshold Rcth can be used as a criterion for stall warning. The numerical and experimental results both show that the signal resolution is determined by the sensor position, the prestall signal amplitude decreases rapidly with the increase of the distance between sensor and blades. Results also show that the probability increases significantly when the operating point is nearing the stall boundary. And at the same operating point, the probability value of Rc will decrease when the SPS CT is engaged. Through this stall-warning approach, a stabilization system based on SPS CT can be activated when the stall margin needs to be extended.

Stall Warning Approach With Application to Stall Precursor-Suppressed Casing Treatment

2016 ◽  
Author(s):  
Li Fanyu ◽  
Li Jun ◽  
Dong Xu ◽  
Sun Dakun ◽  
Sun Xiaofeng
Keyword(s):  
Pressure Sensor ◽  
Dynamic Pressure ◽  
Leading Edge ◽  
Warning Signal ◽  
Stall Margin ◽  
Low Speed ◽  
Casing Treatment ◽  
Statistical Estimates ◽  
Stall Warning ◽  
Stall Precursor

The present work develops a stall warning approach with application to a stall enhancement system. This technique is proposed on the basis of the periodicity of pressure signals sampled by the dynamic pressure sensor which is located on the casing wall at the rotor leading edge. A parameter called Rc, defined to evaluate this periodicity, is calculated by pressure signals within 1 blade pitches in the current one and previous one shaft period. Statistical estimates are implemented on Rc within statistical windows which move with sampling. The probabilities of Rc less than a threshold Rcth are calculated and used as a criterion for stall warning. Experiments are carried out on a low speed compressor with a stall precursor-suppressed (SPS) casing treatment, an efficient stall enhancement system. Results show that the probability increases significantly when the stall boundary is approached. At the same work point, the value of probability will decrease when the SPS casing treatment is turned on. This approach successfully generates a stall warning signal and then triggers the SPS casing treatment when the stall margin needs to be extended.

Application of Stall Warning Approach with Stall Precursor-Suppressed Casing Treatment on a Two-Stage Compressor

2019 ◽  
Vol 28 (5) ◽  
pp. 862-874 ◽  
Author(s):  
Ruize Xu ◽  
Dakun Sun ◽  
Xu Dong ◽  
Fanyu Li ◽  
Xiaofeng Sun ◽  
...  
Keyword(s):  
Two Stage ◽  
Casing Treatment ◽  
Stall Warning ◽  
Stall Precursor

Effect of Novel Casing Treatment on the Suppression of Stall Precursor in a Transonic Compressor

2014 ◽  
Author(s):  
Dakun Sun ◽  
Xiaofeng Sun ◽  
Xiaohua Liu ◽  
Feng Lin ◽  
Nie Chao Qun
Keyword(s):  
Perforated Plate ◽  
Area Ratio ◽  
Open Area ◽  
Stall Inception ◽  
Stall Margin ◽  
Casing Treatment ◽  
Transonic Compressor ◽  
Stall Margin Improvement ◽  
Stall Precursor ◽  
Casing Treatments

A kind of novel casing treatment is proposed to realize stall margin enhancement by suppressing stall precursor in turbomachinery. In view of its different configuration and mechanism, such casing treatment is named as stall precursor-suppressed casing treatment in the present work, or SPS casing treatment for short. In the present work, the experiments of SPS casing treatment are conducted in a transonic compressor J69 Rotor/Stage. The SPS casing treatment which consists of a backchamber and a perforated plate is designed according to a proposed theoretical model. It is noted that the open area ratio of the casing treatment is only 4–12%, which is much smaller than traditional casing treatments with over 50% open area ratio. The tests show that the SPS casing treatment can improve the stall margin by 8–12% for J69 Rotor, and 4–12% for J69 Stage. Meanwhile, the mechanism of stall margin improvement with such casing treatment will be revealed in this investigation. Comparing with the evolution of the precursors without casing treatments, the propagation of the stall inception waves will be suppressed and the non-linear development of the stall process will be delayed under the casing treatment case.

Effects of Rotating Inlet Distortion on Compressor Stability With Stall Precursor-Suppressed Casing Treatment

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Xu Dong ◽  
Dakun Sun ◽  
Fanyu Li ◽  
Donghai Jin ◽  
Xingmin Gui ◽  
...  
Keyword(s):  
Stability Problem ◽  
Axial Fan ◽  
Stall Margin ◽  
Casing Treatment ◽  
Inlet Distortion ◽  
Large Size ◽  
Flow Disturbances ◽  
Stall Margin Improvement ◽  
The Stability ◽  
Stall Precursor

This paper conducts an experimental research of rotating inlet distortion on a low-speed large size test compressor with emphasis on the stability problem of axial fan/compressors, and the stall margin enhancement with a kind of stall precursor-suppressed (SPS) casing treatment. Some results on compressor stall margin and prestall behavior under the restriction of rotating inlet distortion are presented. The experimental results show that whether the inlet distortion is co-rotating or counter-rotating, the SPS casing treatment can still improve the stall margin without leading to additional efficiency loss caused by such configuration. The experiment results also show that the mechanism of the stall margin improvement with such casing treatment is associated with delaying the nonlinear development of the stall precursor waves and weakening the unsteady flow disturbances in a compression system.

Further Investigation on Transonic Compressor Stall Margin Enhancement With Stall Precursor-Suppressed Casing Treatment

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Dakun Sun ◽  
Chaoqun Nie ◽  
Xiaohua Liu ◽  
Feng Lin ◽  
Xiaofeng Sun
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Solid Wall ◽  
Stall Inception ◽  
Stall Margin ◽  
Casing Treatment ◽  
Transonic Compressor ◽  
Stall Precursor

A kind of casing treatment, named as stall precursor-suppressed (SPS), has been developed recently, which was proved to be able to effectively improve stall margin (SM) without significant efficiency loss in low-speed axial flow compressors and a transonic compressor rotor. In this paper, the effectiveness of the SPS casing treatment is investigated in a single-stage transonic compressor. Based on an extended stall inception model, the quantitative evaluation of the SM enhancement by the SPS casing treatment is presented for the transonic compressor stage. The model predicts that a 2.5–6.8% of stall margin improvement (SMI), which is defined in terms of mass flow rate at stall inception, can be achieved at the design rotational speed. The experimental results show that the SPS casing treatment can achieve 3.5–9.3% of the SMI at 95% design rotational speed. Due to the fact that the distributions of the total pressure ratio along the spanwise direction are kept the same as those of the solid wall casing at the same mass flow rate, the SPS casing treatments with a small open area ratio and large backchamber enhance the SM without a recognizable efficiency loss and a migration of the pressure-rise characteristics. Furthermore, the mechanism of SMI with the SPS casing treatment is investigated in the experiments. In comparison with the solid wall casing, the emergence and the evolution of the stall inception waves are suppressed and the nonlinear development of the stall process is delayed with the SPS casing treatment.

Effects of Stall Precursor-Suppressed Casing Treatment on a Low-Speed Compressor With Swirl Distortion

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Xu Dong ◽  
Dakun Sun ◽  
Fanyu Li ◽  
Donghai Jin ◽  
Xingmin Gui ◽  
...  
Keyword(s):  
Pressure Rise ◽  
Pressure Profile ◽  
The Novel ◽  
Stall Margin ◽  
Low Speed ◽  
Casing Treatment ◽  
Inlet Distortion ◽  
Flight Vehicles ◽  
Compressor Performance ◽  
Stall Precursor

Swirl inlet distortion is usually encountered in modern flight vehicles since their inlet ducts usually consist of one or two bends, such as S-inlet duct. An experimental device is first designed to simulate the swirl inlet distortion and then used to test the effectiveness of a novel casing treatment (CT) on a low-speed compressor under the swirl distortions of various intensities. The influences of co- and counter-rotating swirl inlet distortion on the test compressor and the stabilization ability of this novel CT are well demonstrated by the illustrations of static pressure rise curves and efficiency curves. The dynamic prestall pressure signals are also captured to reflect the perturbation energy in the flow field through which the mechanism of the novel CT will be indicated. The relevant results show that counter-rotating swirl distortion in small intensity could increase the compressive ability of compressor with small efficiency loss, and the co-rotating swirl distortion always brings about detrimental effects on compressor performance. At the same time, the distortion of twin swirls can cause nonuniform total pressure profile which can seriously damage the compressor performance. Besides, the stall precursor-suppressed (SPS) CT shows a good capability of stall margin (SM) enhancement no matter what swirl inlet distortions are encountered in the test compressor.

Effects of Rotating Inlet Distortion on Two-Stage Compressor Stability With Stall Precursor-Suppressed Casing Treatment

2018 ◽  
Author(s):  
Dakun Sun ◽  
Jia Li ◽  
Xu Dong ◽  
Benhao Gu ◽  
Xiaofeng Sun
Keyword(s):  
Wire Mesh ◽  
Two Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Inlet Distortion ◽  
Compressor Rotor ◽  
Mesh Screen ◽  
Stall Margin Improvement ◽  
Stall Precursor ◽  
Different Levels

Experimental research about rotating inlet distortion is carried out on a two-stage compressor with emphasis on the compressor stability as well as the stall margin improvement with a kind of stall precursor-suppressed (SPS) casing treatment in this paper. The wire mesh screen is placed at the upstream of the IGV and can rotate at various speeds in co- and counter-direction of the compressor rotor to simulate the rotating inlet distortion in different levels. The results show that the rotating inlet distortion can deteriorate the compressor stall margin and the SPS casing treatment can extend the compressor stall margin (1.95%–7.90%) without additional efficiency loss. The pre-stall behavior of compressor is also analyzed to uncover the mechanism of the stall margin improvement with such casing treatment. Results show that casing treatment of this configuration can weaken the unsteady disturbances in compression system.

An Evaluation Approach for the Stall Margin Enhancement With Stall Precursor-Suppressed Casing Treatment

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Dakun Sun ◽  
Xiaohua Liu ◽  
Xiaofeng Sun
Keyword(s):  
Quantitative Evaluation ◽  
Design Parameters ◽  
Extended Model ◽  
Stall Inception ◽  
Stall Margin ◽  
Casing Treatment ◽  
Evaluation Approach ◽  
Change Trend ◽  
Stall Precursor ◽  
Casing Treatments

It is known that a kind of stall precursor-suppressed (SPS) casing treatment can be used to enhance compressor stall margin (SM) without recognizable efficiency loss. The further requirement in this regard is to develop an effective way to determine the variation range of the SM improvement during the design of such SPS casing treatment. In this investigation, based on the extrapolation hypothesis and the existing work, an extended stall inception model for quantitative evaluation of the SM enhancement is presented for both subsonic and transonic compressors with the SPS casing treatment. The capability of the extended model to quantitatively evaluate the SM enhancement with the SPS casing treatment is validated against the experimental data. The quantitative evaluation results show that the SPS casing treatments with different geometric parameters can improve the SM by a diverse percentage. In particular, for the facilities used in the present investigation, the experiments show that the SPS casing treatments can cause relevant increases of the SM. The change trend of the SM enhancement with various design parameters of the SPS casing treatment is in line with the corresponding theoretical results.

scholarly journals Axial Flow Compressor Stability Enhancement: Circumferential T-Shape Grooves Performance Investigation

Aerospace ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 12
Author(s):  
Marco Porro ◽  
Richard Jefferson-Loveday ◽  
Ernesto Benini
Keyword(s):  
Vortex Breakdown ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Suction Side ◽  
Treatment Technique ◽  
Tip Leakage Flow ◽  
Stall Inception ◽  
Stall Margin ◽  
Casing Treatment ◽  
Stall Margin Improvement

This work focuses its attention on possibilities to enhance the stability of an axial compressor using a casing treatment technique. Circumferential grooves machined into the case are considered and their performances evaluated using three-dimensional steady state computational simulations. The effects of rectangular and new T-shape grooves on NASA Rotor 37 performances are investigated, resolving in detail the flow field near the blade tip in order to understand the stall inception delay mechanism produced by the casing treatment. First, a validation of the computational model was carried out analysing a smooth wall case without grooves. The comparisons of the total pressure ratio, total temperature ratio and adiabatic efficiency profiles with experimental data highlighted the accuracy and validity of the model. Then, the results for a rectangular groove chosen as the baseline case demonstrated that the groove interacts with the tip leakage flow, weakening the vortex breakdown and reducing the separation at the blade suction side. These effects delay stall inception, improving compressor stability. New T-shape grooves were designed keeping the volume as a constant parameter and their performances were evaluated in terms of stall margin improvement and efficiency variation. All the configurations showed a common efficiency loss near the peak condition and some of them revealed a stall margin improvement with respect to the baseline. Due to their reduced depth, these new configurations are interesting because they enable the use of a thinner light-weight compressor case as is desirable in aerospace applications.

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