CFD Investigation on the Circumferential Grooves Casing Treatment of Transonic Compressor

The stall mechanism of the NASA Rotor 37 is investigated through the analysis of the critical flow structures near the stall under the transonic condition. The performance of the rotor with Circumferential Grooves Casing Treatment (CGCT) is also studied based on the Reynolds-Averaging Navier-Stokes approach. The study finds that stall margin improvement can be achieved without significant penalty on the efficiency for the two CGCT configurations applied. The effects of circumferential grooves on the critical flow structures are studied through the analysis of the tip leakage mass and momentum transport that further reveal the CGCT mechanism. transonic compressor, Circumferential Grooves Casing Treatment, stall margin, leakage mass and momentum transportation analysisCasing treatment as a passive flow control method to extend the stable operating range for a tip critical rotor has been used for years. While it can give rise to improved stall margin, there is usually an associated efficiency penalty. This is due to the lack of good knowledge on the mechanism of casing treatment, and the design often largely depends on ad hoc experience. Circumferential Grooves Casing Treatment (CGCT) is simple and effective in stall margin improvement. Much research has been done in this area. Rabe & Hah [1] studied the effects of the CGCT on the flow field of a transonic compressor both experimentally and computationally. Those effects include the change of incidence of the main flow near the blade pressure side, tangential velocity effect, segmentation of blade tip leakage vortex (BTLV) and the in-and outflow effects. Wilke and Kau [2] conducted a numerical study on CGCT on a HPC front stage. The circumferential grooves were reported to suppress the extension of the BTLV and improve the stall margin. Shabbir & Adamcyzk [3] studied the physical mechanism of the CGCT with an analysis on the axial momentum budget for a low speed rotor. Müller et al. [4] studied the effects of CGCT on an axial single stage transonic compressor both experimentally and numerically with four configurations of CGCT. The configuration with deep grooves and large coverage showed the best results on the stall margin improvement in both design and off design speed.However, the mechanism of CGCT is still not fully understood. This paper mainly focuses on the effects of CGCT on some critical flow structures related to the stall process. The leakage mass and momentum transport are analyzed for a better understanding of the mechanisms of CGCT. Although the stall is a highly unsteady process, the steady RANS method captures the stall related critical flow structures well. Thus the RANS method is believed suitable for a relative study on the casing treatment.This paper first discusses the critical flow structures at the near stall condition of smooth wall (SW) configuration. Then the rotor performance with CGCT is presented and compared with SW case results. CGCT effects on the critical flow structures are discussed to explain the per-

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“…The numerical methods adopted have been validated against Rotor 37 in the references [5,6], thus the details are omitted in this paper.…”

Section: Configuration and Numerical Methodsmentioning

confidence: 99%

An analysis of the Circumferential Grooves Casing Treatment for transonic compressor flow

Huang

Chen

Shi

et al. 2010

Sci. China Phys. Mech. Astron.

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“…When the CGCT is adopted, the flux exchange between the groove-casing interfaces are dealt with using an overlap-area weighted reconstruction method [31]. The accuracy of NSAWET as applied to turbomachinery has been validated by previous studies [24,32,33].…”

Section: Methodsmentioning

confidence: 99%

Design and Optimization of Multiple Circumferential Casing Grooves Distribution Considering Sweep and Lean Variations on the Blade Tip

2018

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This paper focuses on the design and optimization of the axial distribution of the circumferential groove casing treatment (CGCT). Effects of the axial location of multiple casing grooves on the flow structures are numerically studied. Sweep and lean variations are then introduced to the blade tip, and their influences on the grooves are discussed. The results show that the ability of the CGCT to relieve the blockage varies with the distribution of grooves, and the three-dimensional blading affects the performance of both the blade and the CGCT. Accordingly, a multi-objective optimization combining the CGCT design with the sweep and lean design is conducted. Objectives, including the total pressure ratio and the adiabatic efficiency, are set at the design point; meanwhile, the choking mass flow and the near-stall performance are constrained. The coupling between the CGCT and the blade is improved, which contributes to an optimal design point performance and a sufficient stall margin. The sweep and lean in the tip redistribute the spanwise and chordwise loading, which enhances the ability of the CGCT to improve the blade's performance. This work shows that the present CGCT-blade integrated optimization is a practical engineering strategy to develop the working capacity and efficiency of a compressor blade while achieving the stall margin extension.

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“…The width of each groove consists of ten percent axial chord tip and the gap between two grooves was five percent of the axial chord tip. Previous Researchers (Huang et al, 2008;Kim et al, 2012) researched on the rectangular grooves depth, tip clearance and width to find the effects of these factors on stall margin. They revealed that using CGCT could enhance the performance and stable range of the axial flow compressor.…”

Section: Design and Illustration Of Cgctmentioning

confidence: 99%

“…Shabbir et al (2005) worked on low-speed rotor to check the CGCT physical mechanism with the analysis of the budget of axial momentum equation. Huang et al (2008) worked on the circumferential grooves' width and depth casing treatment to improve the stall margin and performance using numerical analysis and they proposed that mechanism of the stall was significantly affected by clearance tip. Khan et al (2011) worked on the CGCT, tip recess and combined model of both to evaluate the behavior of stall of NASA rotor 37.…”

Section: Introductionmentioning

confidence: 99%

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

Ahmad

Jiang

Zheng

et al. 2020

JAFM

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The stability range of the gas turbine engine compressors is being challenged in the modern days due to the intention of increasing per stage maximum loading. Casing treatment has been widely adopted as a realistic passive flow control means to improve the stall margin with a slight decrease of efficiency at the same time by various grooves of which shape (location, angles and so on) has a significant influence on controlling effect. However, the influence of some details in grooves is ignored in most of the case that may impact the specific flow field in the groove. A research on the impact of chamfer and fillet corners on the performance of casing treatment was proceeded by numerical simulation in this paper. The performance of different models of grooves on NASA Rotor 37 was investigated by discretizing 3D RANS based on finite volume method. Firstly, steady simulations were performed on NASA rotor 37 for validation. The CFD results and experimental data for adiabatic efficiency and pressure ratio were in good agreement. According to convergence criteria, the initiation of the stall was predicted. Few numbers of circumferential grooves casing treatment (CGCT) models have been proposed and tested numerically. Rectangular CGCT shape and smooth wall casing performances were analyzed. Moreover, the highest adiabatic efficiencies and stall margins of smooth wall casing, rectangular grooves and rectangular grooves with chamfer and fillet corners shapes models were compared to evaluate the influence of the shape of grooves on the stability and performance on axial flow compressor. The rectangular circumferential casing grooves and rectangular grooves with chamfer and fillet corners enhanced significantly stall margin and an operational range of the transonic axial flow compressor but adiabatic efficiency was slightly decreased.

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CFD Investigation on the Circumferential Grooves Casing Treatment of Transonic Compressor

Cited by 28 publications

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An analysis of the Circumferential Grooves Casing Treatment for transonic compressor flow

An analysis of the Circumferential Grooves Casing Treatment for transonic compressor flow

Design and Optimization of Multiple Circumferential Casing Grooves Distribution Considering Sweep and Lean Variations on the Blade Tip

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

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