An Experimental Investigation About the Effect of the Partial Casing Treatment on a Transonic Axial-Flow Compressor Performance Under Inlet Distortion

2012 ◽  
Author(s):  
Maoyi Li ◽  
Wei Yuan ◽  
Xizhen Song ◽  
Yajun Lu ◽  
Zhiping Li ◽  
...  
Keyword(s):  
Total Pressure ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Peak Efficiency ◽  
Stall Margin ◽  
Casing Treatment ◽  
Axial Flow Compressor ◽  
Inlet Distortion ◽  
Flow Compressor ◽  
Total Pressure Ratio

The traditional annulus casing treatment often pays the price of lowered efficiency for improving the stall margin of a compressor under inlet distortion. In view of the unsymmetry of the inlet flow-field of compressors, partial casing treatment was used to control the flow in a transonic axial-flow compressor with arc-skewed-slots deployed at different circumferential positions under inlet distortion. The experimental results indicate that when the partial casing treatment is arranged on the undistorted and distorted sectors, the stall margin is enhanced by 8.02%, with the relative peak efficiency improved simultaneously by 2.143%, compared with the case of solid casing at 98% rotating speed. By contrast, the traditional casing treatment increases the stall-margin by 23.13%, but decreases the relative peak efficiency by 0.752%. By analyzing dynamic and static experimental data, the mechanism underlying the partial casing treatment was also studied in detail here. The disturbances of inlet flow were restrained by annulus casing treatment, nevertheless the total pressure ratio was decreased obviously in the distorted sector. As a result, the stall-margin is improved, but the relative peak efficiency is decreased too. When the partial casing treatment was arranged on the undistortded and distorted sectors, the stall disturbances was thereby restrained. So the stall margin was enhanced. In addition, the total pressure ratio was improved by the partial casing treatment in the distorted and transition sectors, and thus the relative peak efficiency was also increased markedly.

Experimental Studies on Stall Behavior in a Single Stage Transonic Axial Flow Compressor

2013 ◽  
Author(s):  
Dilipkumar Bhanudasji Alone ◽  
Subramani Satish Kumar ◽  
Shobhavathy M. Thimmaiah ◽  
Janaki Rami Reddy Mudipalli ◽  
A. M. Pradeep ◽  
...  
Keyword(s):  
Mach Number ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Tangential Velocity ◽  
Axial Flow ◽  
Single Stage ◽  
Flow Angle ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Total Pressure Ratio

This paper describes the study of flow behavior of the transonic compressor stage in un-stalled and stalled conditions. Experiments were carried out in an open circuit single stage transonic axial flow compressor test rig. The test compressor was designed for 1.35 total to total pressure ratio at corrected mass flow rate of 22 kg/s. Both steady and unsteady measurements were carried out. The operating envelop of the compressor was experimentally determined to demark the stable and unstable operating range of the compressor at different operating speeds. Variations in the rotor inlet axial and tangential velocity in the tip region were studied using a calibrated single component hot wire probe. The compressor blade element performance was obtained at full flow and near stall conditions using a three hole aerodynamic probe. The variation in flow parameters like absolute flow angle, axial Mach number, absolute Mach number, tangential Mach number, static and total pressure ratio profiles at the rotor exit were obtained and their variations along the blade height were studied at full flow and near stall conditions. Static pressure variation in the tip region along the rotor chord was studied which showed reduction in slope as stall approached. Hotwire measurements showed abrupt variation in the axial velocity as compared to tangential velocity at stalled condition. It was observed that the flow turned in tangential direction at stall, as tangential component of velocity shows more fluctuations at stall in comparison with unstalled condition. The FFT analysis of the raw signals was performed and it was observed that the nature of the rotating stall was abrupt and stall cell travels nearly at half the rotor speed.

scholarly journals Flow mechanism of affecting an axial flow compressor performance and stability with cross-blade slot casing treatments

2018 ◽  
Vol 233 (1) ◽  
pp. 17-36 ◽  
Author(s):  
HaoGuang Zhang ◽  
XuDong Zhang ◽  
YanHui Wu ◽  
WuLi Chu ◽  
HaiYang Kuang
Keyword(s):  
Axial Flow ◽  
Low Energy ◽  
Peak Efficiency ◽  
Stall Margin ◽  
Casing Treatment ◽  
Flow Loss ◽  
Stall Margin Improvement ◽  
And Performance ◽  
Flow Compressor ◽  
Casing Treatments

The objective of this study is to evaluate the effect of cross-blade slot casing treatment on the stability and performance of an axial flow compressor rotor. The experimental and unsteady calculated results both show that cross-blade slot casing treatment can generate about 22% stall margin improvement, and the compressor peak efficiency is reduced by about 13%. The detailed flow-field analyses indicate that the sucked and injected flow caused by the slots of cross-blade slot casing treatment can restrain the rotor tip passage blockage, which is made by the low energy tip clearance leakage vortex. When cross-blade slot casing treatment is applied, not only the rotor wheel flange work becomes lower in most of the rotor blade span, but also the flow loss in the blade tip passage becomes fairly large due to the strong interaction between the mainstream and the injected flows made by the slots. As a result, the compressor total pressure ratio and efficiency for cross-blade slot casing treatment are reduced obviously. Three kinds of new cross-blade slot casing treatment were designed according to the previous successful experience and investigated in this paper. The numerical results show that the new three cross-blade slot casing treatments both generate about 54% stall margin improvement at the cost of minor peak efficiency. For one new cross-blade slot casing treatment (CSCT2), the compressor peak efficiency is reduced by about 0.3%. The low energy TLV, which is present for cross-blade slot casing treatment, is removed by the strong sucked flow made by CSCT2. Moreover, the interaction between the mainstream and the injected flows caused by CSCT2 becomes weak obviously, and the corresponding flow loss is reduced greatly. Hence, the compressor stability and performance with CSCT2 are higher than those with cross-blade slot casing treatment.

Numerical Investigations of the Coupled Flow Through a Subsonic Compressor Rotor and Axial Skewed Slot

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Xingen Lu ◽  
Wuli Chu ◽  
Junqiang Zhu ◽  
Yangfeng Zhang
Keyword(s):  
Axial Flow ◽  
Tip Clearance ◽  
Stall Margin ◽  
Tip Clearance Flow ◽  
Casing Treatment ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Clearance Flow ◽  
Flow Through ◽  
Flow Compressor

In order to advance the understanding of the fundamental mechanisms of axial skewed slot casing treatment and their effects on the subsonic axial-flow compressor flow field, the coupled unsteady flow through a subsonic compressor rotor and the axial skewed slot was simulated with a state-of-the-art multiblock flow solver. The computational results were first compared with available measured data, that showed the numerical procedure calculates the overall effect of the axial skewed slot correctly. Then, the numerically obtained flow fields were interrogated to identify the physical mechanism responsible for improvement in stall margin of a modern subsonic axial-flow compressor rotor due to the discrete skewed slots. It was found that the axial skewed slot casing treatment can increase the stall margin of subsonic compressor by repositioning of the tip clearance flow trajectory further toward the trailing of the blade passage and retarding the movement of the incoming∕tip clearance flow interface toward the rotor leading edge plane.

Effect of inlet distortion on the performance of axial transonic contra-rotating compressor

2016 ◽  
Vol 232 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Hanru Liu ◽  
Yangang Wang ◽  
Songchuan Xian ◽  
Wenbin Hu
Keyword(s):  
Total Pressure ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Tip Leakage Flow ◽  
Stall Margin ◽  
Tip Leakage ◽  
Inlet Distortion ◽  
Flow Mixing ◽  
Inflow Conditions ◽  
Total Pressure Ratio

The present paper numerically conducted full-annulus investigation on the effects of circumferential total pressure inlet distortion on the performance and flow field of the axial transonic counter-rotating compressor. Results reveal that the inlet distortion both deteriorates the performance of the upstream and downstream rotors resulting in reduction of total pressure ratio, efficiency and stall margin of the transonic contra-rotating compressor. Regarding the development of distortion inside compressor, the downstream rotor reinforces the air-flow mixing effects and, thus, attenuates the distortion intensity significantly. Under the distorted inflow conditions, the detached shockwave at the leading edge of downstream rotor interacts with the tip leakage flow and causes the blockage of the blades passage, which is one important reason for the transonic contra-rotating compressor stall.

Effect of hub clearance of cantilever stator on aerodynamic performance and flow field of a transonic axial-flow compressor

2021 ◽  
pp. 095441002199370
Author(s):  
Botao Zhang ◽  
Bo Liu ◽  
Xiaochen Mao ◽  
Hejian Wang
Keyword(s):  
Flow Field ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Aerodynamic Performance ◽  
Tip Clearance ◽  
Leakage Flow ◽  
Stall Margin ◽  
Axial Flow Compressor ◽  
Stator Blade ◽  
Flow Compressor

To investigate the effect of hub clearance of cantilever stator on the aerodynamic performance and the flow field of the transonic axial-flow compressor, the performance of single-stage compressors with the shrouded stator and cantilever stator was studied numerically. It is found that the hub corner separation on the stator blade suction surface (SS) was modified by introducing the hub leakage flow. The separation vortex on the SS of the stator blade root at about 10% axial chord length caused by the interaction of the shock wave and boundary layer was also controlled. Compared with the tip clearance size of the rotor blade, the stator hub clearance size (HCS) has a much less effect on the overall aerodynamic performance of the compressor, and there is no obvious effect on the flow field in the upstream blade row. With the increase of HCS, the leakage loss and the blockage degree in the flow field near the stator hub are increased and further make the adiabatic efficiency and the total pressure ratio of the compressor gradually decrease. Meanwhile, the stall margin of the compressor was changed slightly, but the response of the stall margin to the change of the HCS is nonlinear and insensitive. The stator hub leakage flow (HLF) can not only change the flow field near the hub but also redistribute the flow law within the range of the entire blade span. It will contribute to further understand the mechanism of the HLF and provide supports for the design of the cantilever stator of transonic compressors.

Experimental and numerical investigation of a subsonic compressor with bend-skewed slot-casing treatment

2006 ◽  
Vol 220 (12) ◽  
pp. 1785-1796 ◽  
Author(s):  
X Lu ◽  
W Chu ◽  
Y Zhang ◽  
J Zhu
Keyword(s):  
Rotor Blade ◽  
Axial Flow ◽  
Efficiency Gain ◽  
Stall Margin ◽  
Blade Passage ◽  
Casing Treatment ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor ◽  
Isentropic Efficiency

On the basis of the test results of discrete axial and blade angle slot casing treatment, a new type of casing treatment was designed for a subsonic axial flow compressor rotor by optimizing various geometry parameters. To obtain a wide operating range and to minimize penalties in terms of isentropic efficiency, seven compressor configurations incorporating casing treatments of 0, 16.6, 33.3, 50, 66.6, 83.3, and 100 per cent rotor exposures were experimentally investigated. The results showed that significant improvements in stall margin are possible in all exposures and insignificant isentropic efficiency sacrifices are recorded in some exposures. Nearly 21.43 per cent stall margin improvement in terms of the corrected mass flow-rate was achieved with 33.3 per cent rotor blade tip axial chord exposure. The compressor built with 16.6 per cent rotor exposure was the best configuration in terms of maximum isentropic efficiency gain. The second issue of the paper was to offer a contribution to the understanding of the physical mechanism by which bend-skewed slot-casing treatment improves stall margin under subsonic conditions. By applying a concept similar to ‘Domain scaling’ approach (as often used in multistage turbomachinery flow-fields) to the interface between the rotor blade passage and end-wall treatments, a time-dependent three-dimensional numerical simulation was performed for the subsonic axial-flow compressor rotor with bend-skewed slot-casing treatment. The numerical results agreed well with the available experimental results. Detailed analyses of the coupled flow through bend-skewed slot-casing treatment and rotor blade passage under subsonic conditions led to some preliminary conclusions as to the flow physics involved in the stall margin improvements afforded by the use of bend-skewed slot-casing treatment.

Numerically Understand the Combined Effect of Tip Clearance and Circumferential Grooves Casing Treatment on the Performance of Single Stage Transonic Axial Flow Compressor

2015 ◽  
Author(s):  
Mitesh Goswami ◽  
Dilipkumar Bhanudasji Alone ◽  
Harish S. Choksi
Keyword(s):  
Axial Flow ◽  
Single Stage ◽  
Tip Clearance ◽  
Combined Effect ◽  
Stall Margin ◽  
Casing Treatment ◽  
Axial Flow Compressor ◽  
Circumferential Groove ◽  
Flow Compressor ◽  
Stage Efficiency

This paper deals with the numerical studies on the combined effect of tip clearance and axisymmetric circumferential grooves casing treatment (CGCT) on the overall performance and stall margin of a single stage transonic axial flow compressor. Steady state numerical analysis was carried out by solving three dimensional Reynolds-averaged-Navier-Stokes (RANS) Equations using the Shear Stress Transport (SST) k-ω Turbulence Model. The numerical stall inception point was identified from the last converged point by the convergence criteria, and the stall margin was numerically predicted. Additionally, the stall margin and the isentropic peak stage efficiencies of the circumferential casing grooves with various tip clearances were compared and evaluated in order to explore the influence of the tip clearance. Results obtained were compared with those obtained on the baseline compressor with the smooth casing (SC). Further computational studies were conducted to study the role of the tip leakage flow in axial compressor in triggering the stall. The relationship between the tip clearance flow, flow field and surge margin extension from circumferential groove casing treatment with various rotor tip clearances were studied numerically. The application of the circumferential groove casing treatment with varying clearance leads to significant improvement in the operating stability of compressor with slight reduction in the isentropic peak stage efficiency for small tip clearances, whereas there was slight increment in the isentropic peak stage efficiency at higher tip clearance of 2.5 mm.

On Understanding the Effect of Plenum Chamber of a Bend Skewed Casing Treatment on the Performance of a Transonic Axial Flow Compressor

2014 ◽  
Author(s):  
Dilipkumar B. Alone ◽  
Subramani Satish Kumar ◽  
Shobhavathy Thimmaiah ◽  
Janaki Rami Reddy Mudipalli ◽  
A. M. Pradeep ◽  
...  
Keyword(s):  
Axial Flow ◽  
Single Stage ◽  
Compressor Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Plenum Chamber ◽  
Axial Flow Compressor ◽  
Chamber Volume ◽  
Stable Operating ◽  
Flow Compressor

Bend skewed casing treatment was designed to improve the stable operating range of single stage transonic axial flow compressor and also to understand the effects of its plenum chamber volume on the performance. This paper presents the original experimental research work undertaken to study the effect of plenum chamber depth and thus its volume on the performance of single stage transonic axial flow compressor coupled with the bend skewed casing treatment. The bend skewed casing treatment with porosity of 33% was selected for the present experimental study. The bend skewed casing treatment has slot width equal to the maximum thickness of the rotor blade. The casing treatment geometry has an axial front segment and a 45° staggered rear segment following the blade tip stagger. Both the segments were skewed by 45° in the radial plane, in such a way that the flow emerging from the casing slots would do so with swirl contrary to the direction of rotor rotation. The plenum chamber which can also be called as stagnation zone exists above the skewed slots. The plenum chamber has an axial length equal to the axial length of the casing treatment slots. The maximum depth of the plenum chamber was 11 mm and which was equal to the depth of bend skewed casing slots. The depth of plenum chamber was varied from zero, half the slot depth, and equal to slot depth in order to get variable volume. The porosity and axial location of the casing treatment relative to the rotor tip chord were chosen from the earlier experimental programs on effect of bend skewed casing treatment porosities and axial coverages for the present compressor stage. Optimum performance of the transonic compressor stage was obtained at 20% and 40% axial coverages and for 33% porosity configurations. The axial coverages of 20% and 40% were chosen for the present study to understand the effects of plenum chamber volume on the performance of single stage transonic axial flow compressor. The performance of the compressor stage with solid casing and casing treatment with different plenum volume was obtained and compared at different operating speeds. The compressor performance was derived for the fixed casing treatment porosity of 33% and for three different configurations of plenum chamber volumes at two different axial coverages. Experimental investigations reveal that the plenum chamber volume does have an impact on the stable operating range of the compressor. The compressor stall margin improves with increase in the plenum chamber volume. Bend skewed casing treatment coupled with plenum chamber of depths equal to the slots depth results in maximum stall margin improvement of 37.62% as compared to 26.40% without plenum chamber over the solid casing at 40% axial coverage. For this combination 0.8% improvement in the peak stage efficiency above the solid casing was noticed at 60% design speed.

Unsteady Total Pressure Field Downstream of an Embedded Stator in a Multistage Axial Flow Compressor

1997 ◽  
Vol 119 (4) ◽  
pp. 985-994 ◽  
Author(s):  
N. Suryavamshi ◽  
B. Lakshminarayana ◽  
J. Prato ◽  
J. R. Fagan
Keyword(s):  
Total Pressure ◽  
High Speed ◽  
Pressure Field ◽  
Axial Flow ◽  
Temporal Variations ◽  
Pressure Probe ◽  
Peak Efficiency ◽  
Axial Flow Compressor ◽  
Multistage Compressors ◽  
Flow Compressor

The results from measurements of the unsteady total pressure field downstream of an embedded stage of a three stage axial flow compressor are presented in this paper. The measurements include area traverses of a high response kulite total pressure probe and a pneumatic five hole probe downstream of stator 2 at the peak efficiency operating point for the compressor. These data indicate that both the shaft-resolved and unresolved fluctuations contribute to the unsteadiness of the total pressure field in multistage compressors. Specifically, regions associated with high levels of unsteadiness and, consequently, high levels of mixing including both the hub and casing end walls and the airfoil wakes have significant levels of shaft resolved and unresolved unsteadiness. Temporal variations of stator exit flow are influenced by both shaft resolved and unresolved unsteadiness distributions. The limitations of state-of-the-art instrumentation for making measurements in moderate and high speed turbomachinery and the decomposition used to analyze these data are also discussed.

scholarly journals Effect of the Rear Stage Casing Treatment on the Overall Performance of a Multistage Axial-Flow Compressor

1982 ◽  
Author(s):  
Yao-Lin Gao ◽  
Ke-Ming Li
Keyword(s):  
High Speed ◽  
Axial Flow ◽  
Rotor Blades ◽  
Stall Margin ◽  
Casing Treatment ◽  
Axial Flow Compressor ◽  
Surge Margin ◽  
Engine Compressor ◽  
Overall Performance ◽  
Flow Compressor

This paper discusses the effect of tip treatment in the rear stages of a compressor on the high speed stall margin and efficiency. A nine stage engine compressor was tested in a rig with and without casing treatment on the tip sections of the last three rotors. Another series of tests were conducted on a modified compressor with twisted rotor blades in the rear stages. For both compressors, tip treatment improved high speed surge margin. The first compressor encountered no loss of efficiency with the addition of tip treatment, but the second compressor suffered a loss of efficiency.

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