Performance Enhancement of a Transonic Axial Flow Compressor with Circumferential Casing Grooves to Improve the Stall Margin

Abstract This paper numerically investigates the effect of slots on the performance of a highly subsonic axial flow compressor. The axial flow compressor consisting of 21 rotor blades with NACA 65 series blade profile was used for the simulations. The present results were obtained using different turbulence models and shear stress transport model was found to be the best one. Studies were conducted to determine the influence of length, depth and skew angle of the slot on the compressor performance. The slot width and centre-to-centre distance between the successive slots were maintained at 6.3% Ca and 11% Ca, respectively. The present study was carried out at different slot lengths (0 to 100% of axial chord, 20 to 100% of axial chord and 40 to 100% of axial chord), slot depths (7.9, 11 and 15.7% Ca) and skew angles (0°, 30°, 45° and 60°). The slot length of 20 to 100% of Ca, depth of 15.7% Ca and skew angle of 60° resulted in the best compressor performance leading to 22.1% stall margin improvement. Subsequently, flow characteristics were studied without and with slots.

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Influence of Rain Ingestion on the Endwall Treatment in an Axial Flow Compressor

Journal of Turbomachinery ◽

10.1115/1.4040550 ◽

2018 ◽

Vol 140 (8) ◽

Cited By ~ 3

Author(s):

Jichao Li ◽

Juan Du ◽

Mingzhen Li ◽

Feng Lin ◽

Hongwu Zhang ◽

...

Keyword(s):

Rotor Blade ◽

Axial Flow ◽

Pressure Rise ◽

Water Film ◽

Stall Margin ◽

Axial Flow Compressor ◽

Water Ingestion ◽

Blade Row ◽

Flow Compressor ◽

The Stability

The effects of water ingestion on the performance of an axial flow compressor are experimentally studied with and without endwall treatment. The background to the work is derived from the assessment of airworthiness for an aero-engine. The stability-enhancing effects with endwall treatments under rain ingestion are not previously known. Moreover, all the endwall treatments are designed under dry air conditions in the compressor. Water ingestion at 3% and 5% relative to the design mass flow proposed in the airworthiness standard are applied to initially investigate the effects on the performance under smooth casing (SC). Results show that the water ingestions are mainly located near the casing wall after they move through the rotor blade row. The pressure rise coefficient increases, efficiency declines, and torque increases under the proposed water ingestion. The increase of the inlet water increases the thickness of the water film downstream the rotor blade row and aggravates the adverse effects on the performances. Subsequently, three endwall treatments, namely circumferential grooves, axial slots, and hybrid slots–grooves, are tested with and without water ingestion. Compared with no water ingestion, the circumferential grooves basically have no resistance to the water ingestion. The axial slots best prevent the drop of the pressure rise coefficient induced by water ingestion, and hybrid slots–grooves are the second-best place owing to the contribution of the front axial slots. Therefore, the hybrid slots–grooves can not only extend the stall margin with less efficiency penalty compared with axial slots, but also prevent rain ingestion from worsening the compressor performance.

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Flow Studies on a Single Stage Transonic Axial Flow Compressor Retrofitted With Circumferential Grooves and Varied Rotor-Stator Axial Gap

Volume 1: Compressors, Fans and Pumps; Turbines; Heat Transfer; Combustion, Fuels and Emissions ◽

10.1115/gtindia2017-4592 ◽

2017 ◽

Author(s):

Anand P. Darji ◽

Dilipkumar Bhanudasji Alone ◽

Chetan S. Mistry

Keyword(s):

Numerical Study ◽

Computational Study ◽

Axial Flow ◽

Single Stage ◽

Experimental Results ◽

Stall Margin ◽

Axial Flow Compressor ◽

Transonic Compressor ◽

Stall Margin Improvement ◽

Flow Compressor

A transonic axial flow compressor undergoes severe vibrations due to instabilities like stall and surge when it operates at lower mass flow rate in the absence of any control devices. In present study, the attempt was made to understand the combine impact of circumferential casing grooves (CCG) of constant aspect ratio and different axial spacing between rotor and stator on the operating stability of single stage transonic axial compressor and that of rotor alone using numerical simulation. The optimum rotor-stator gap in the presence of grooved casing treatment was identified. The steady state numerical analysis was performed by using three-dimensional Reynolds Average Navier-Stokes equation adapting shear stress transport (SST) k-ω turbulence model. The study is reported in two sections. First section includes the detailed numerical study on baseline case having smooth casing wall (SCW). The computational results were validated with the experimental results available at Propulsion Division of CSIR-NAL, Bangalore. The computational study shows good agreement with experimental results. The second section comprises the effects of optimum designs of CCG and various axial spacing on the stall margin improvement of transonic compressor. Current computational study shows that the axial spacing between rotor and stator is an important parameter for improvement in stall margin not only for SCW but also for CCG. Therefore, the highest stall margin improvement of 9% has achieved for 75% axial spacing.

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Numerical analysis of the effects of circumferential groove casing suction in a counter-rotating axial ﬂow compressor

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650920951692 ◽

2020 ◽

pp. 095765092095169

Author(s):

Tian Liang ◽

Bo Liu ◽

Stephen Spence ◽

Liying Jiao

Keyword(s):

Axial Flow ◽

Main Flow ◽

Leakage Flow ◽

Tip Leakage Flow ◽

Stall Margin ◽

Tip Leakage ◽

Axial Flow Compressor ◽

Circumferential Groove ◽

Flow Compressor ◽

The Impact

To extend the current understanding of the circumferential groove casing suction applied to a counter-rotating axial ﬂow compressor, the impact of different axial locations of the circumferential suction groove on the characteristics of the tip leakage flow (TLF) and the corresponding physical mechanisms producing the stability enhancement have been studied based on validated numerical simulations. The results show that the optimal location for the suction groove is at around 20% axial chord, which demonstrated a high potential for reducing additional stall mass flow coefficient with about 8.4% increment in the stall margin. After the casing suction groove was applied, the interface between the incoming main ﬂow and TLF was pushed significantly downstream in the second rotor. The blade loading in the region below the groove, the tip leakage flow angle and the reversed axial momentum ﬂux injected into main ﬂow passage through the tip gap were all reduced, which contributed to the stall margin improvement. Detailed analysis of the tip leakage ﬂow structures showed that the TLF originating from different chord locations played different roles in the stall inception process. It was found to be more effective to improve stall margin and adiabatic efficiency by controlling the front part of the TLF, which was most sensitive.

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

Journal of Turbomachinery ◽

10.1115/1.2948959 ◽

2008 ◽

Vol 131 (1) ◽

Cited By ~ 16

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.

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Tip air injection to extend stall margin of multi-stage axial flow compressor with inlet radial distortion

Aerospace Science and Technology ◽

10.1016/j.ast.2019.105554 ◽

2020 ◽

Vol 96 ◽

pp. 105554 ◽

Cited By ~ 3

Author(s):

Jichao Li ◽

Juan Du ◽

Shaojuan Geng ◽

Fan Li ◽

Hongwu Zhang

Keyword(s):

Axial Flow ◽

Air Injection ◽

Stall Margin ◽

Axial Flow Compressor ◽

Radial Distortion ◽

Multi Stage ◽

Flow Compressor

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Axial Flow Compressor Design Optimization: Part I—Pitchline Analysis and Multivariable Objective Function Influence

Journal of Turbomachinery ◽

10.1115/1.2927673 ◽

1990 ◽

Vol 112 (3) ◽

pp. 399-404 ◽

Cited By ~ 11

Author(s):

A. Massardo ◽

A. Satta

Keyword(s):

Objective Function ◽

Axial Flow ◽

Problem Formulation ◽

Mathematical Programming Problem ◽

Penalty Function Method ◽

Stall Margin ◽

Variable Metric ◽

Axial Flow Compressor ◽

Minimization Technique ◽

Flow Compressor

The design of an axial flow compressor stage has been formulated as a nonlinear mathematical programming problem with the objective of minimizing the aerodynamic losses and the weight of the stage, while maximizing the compressor stall margin. Aerodynamic as well as mechanical constraints are considered in the problem formulation. A method of evaluating the objective function and constraints of the problem with a pitchline analysis is presented. The optimization problem is solved by using the penalty function method in which the Davidon-Fletcher-Powell variable metric minimization technique is employed. Designs involving the optimization of efficiency, weight of the stage, and stall margin are presented and the results discussed with particular reference to a multivariable objective function.

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

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410021993700 ◽

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.

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

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/0954406jmes385 ◽

2006 ◽

Vol 220 (12) ◽

pp. 1785-1796 ◽

Cited By ~ 14

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.

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

ASME 2015 Gas Turbine India Conference ◽

10.1115/gtindia2015-1210 ◽

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.

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