Effect of Rotor Tip Casing Treatment on the Performance and Stall Margin of a Transonic Axial Compressor Stage

2017 ◽  
Vol V6 (10) ◽  
Author(s):  
Prof. Tukaram P. H. ◽  
Prof. Subbaramaiah S. V ◽  
Subbaramu S. ◽  
Keyword(s):  
Axial Compressor ◽  
Compressor Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Transonic Axial Compressor

Numerical Investigation on Slot Casing Treatment in a Transonic Axial Compressor Stage: Part 1 — Casing Treatment Design

2016 ◽  
Author(s):  
Mingmin Zhu ◽  
Xiaoqing Qiang ◽  
Jinfang Teng
Keyword(s):  
Axial Compressor ◽  
Leakage Flow ◽  
Compressor Stage ◽  
Tip Leakage Flow ◽  
Suction Surface ◽  
Stall Margin ◽  
Rotating Speed ◽  
Casing Treatment ◽  
Tip Leakage ◽  
Stall Margin Improvement

Slot-type casing treatment generally has a great potential of enhancing the operating range for tip-critical compressor rotors, however, with remarkable efficiency drop. Part I of this two-part paper was committed to develop a slot configuration with desired stall margin improvement and minimized efficiency loss. Steady simulation was carried out in a 1.5 transonic axial compressor stage at part design rotating speed. At this rotating speed this compressor stage operated at a subsonic condition and showed a rather narrow operating range, which needed to be improved badly. Flow fields analysis at peak efficiency and near stall point showed that the development of tip leakage vortex and resulting blockage near casing resulted in numerical stall. Three kinds of skewed slots with same rotor exposure and casing porosity were designed according to the tip flow field and some empirical strategies. Among three configurations, arc-curved skewed slot showed minimum peak efficiency drop with considerable stall margin improvement. Then rotor exposure and casing porosity were varied based on the original arc-curved skewed slot, with a special interest in detecting their impact on the compressor stability and overall efficiency. Result showed that smaller rotor exposure and casing porosity leaded to less efficiency drop. But meanwhile, effectiveness of improving compressor stability was weakened. The relation between efficiency drop and stall margin improvement fell on a smooth continuous curve throughout all slots configurations, indicating that the detrimental effect of casing treatment on compressor was inevitable. Flow analysis was carried out for cases of smooth casing and three arc-curved configurations at smooth casing near stall condition. The strength of suction/injection, tip leakage flow behavior and removal of blockage near casing were detailed examined. Larger rotor tip exposure and slots number contributed to stronger injection flow. The loss generated within the mixing process of injection flow with main flow and leakage flow is the largest source of entropy increase. Further loss mechanisms were interpreted at eight axial cuts, which were taken through the blade row and slots to show the increase in entropy near tip region. Entropy distributions manifested that loss generations with smooth casing were primarily ascribed to low-momentum tip leakage flow/vortex and suction surface separation at leading edge. CU0 slot, the arc-curved slots with 50% rotor tip exposure, was capable of suppressing the suction surface separation loss. Meanwhile, accelerated tip leakage flow brought about additional loss near casing and pressure surface. Upstream high entropy flow would be absorbed into the rear portion of slots repeatedly, resulting in further loss.

A CFD Study of Circumferential Groove Casing Treatments in a Transonic Axial Compressor

2010 ◽  
Author(s):  
Haixin Chen ◽  
Xudong Huang ◽  
Ke Shi ◽  
Song Fu ◽  
Matthew A. Bennington ◽  
...  
Keyword(s):  
Axial Compressor ◽  
Data Sampling ◽  
Stall Margin ◽  
Casing Treatment ◽  
Circumferential Groove ◽  
Compressor Rotor ◽  
Radial Profiles ◽  
Flow Mechanisms ◽  
Transonic Axial Compressor ◽  
And Performance

Numerical investigations were conducted to predict the performance of a transonic axial compressor rotor with circumferential groove casing treatment. The Notre Dame Transonic Axial Compressor (ND-TAC) was simulated by Tsinghua University with an in-house CFD code (NSAWET) for this work. Experimental data from the ND-TAC were used to define the geometry, boundary conditions and data sampling method for the numerical simulation. These efforts, combined with several unique simulation approaches, such as non-matched grid boundary technology to treat the periodic boundaries and interfaces between groove grids and the passage grid, resulted in good agreement between the numerical and experimental results for overall compressor performance and radial profiles of exit total pressure. Efforts were made to study blade level flow mechanisms to determine how the casing treatment impacts the compressor’s stall margin and performance. The flow structures in the passage, the tip gap and the grooves as well as their mutual interactions were plotted and analyzed. The flow and momentum transport across the tip gap in the smooth wall and the casing treatment configurations were quantitatively compared.

Aeroelastic aspects of Axial Compressor Stage with Self-Recirculating Casing Treatment

2021 ◽  
pp. 1-34
Author(s):  
S Satish Kumar ◽  
Dilipkumar Bhanudasji Alone ◽  
Shobhavathy Thimmaiah ◽  
J Rami Reddy Mudipalli ◽  
Lakshya Kumar ◽  
...  
Keyword(s):  
Flow Condition ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Successful Implementation ◽  
Compressor Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Compressor Rotor ◽  
Forcing Function ◽  
Treatment Designs

Abstract For successful implementation of casing treatment designs in axial compressors, apart from the stall margin improvement benefits, aeroelasticity also plays a major role. This manuscript addresses the not often discussed aeroelastic aspects of a new discrete type of passive Self-Recirculating Casing Treatment (RCT) designed for a transonic axial compressor stage. Experiments are carefully designed for synchronized measurement of the unsteady fluidic disturbances and vibrations during rotating stall for compressor with baseline solid casing and Self-RCT. The modal characteristics of the axial compressor rotor-disk assembly are studied experimentally and numerically. Experimentally it is observed that the rotating stall cells excite the blades in their fundamental mode in a compressor with baseline solid casing at the stall flow condition. In contrast, there is no excitation of the blades in the compressor with self-recirculating casing treatment at the same solid casing stall flow condition. Also, the self-recirculating casing treatment compared to the solid casing can significantly reduce the overall vibration levels of the blades that are excited at the stall flow condition. The casing treatment is able to alter the flow field near the tip region of the rotor blade, and hence influencing the forcing function of the rotating cantilever blades to have the aeroelastic benefit.

scholarly journals Improvement of Moderately Loaded Transonic Axial Compressor Performance Using Low Porosity Bend Skewed Casing Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Dilipkumar Bhanudasji Alone ◽  
S. Satish Kumar ◽  
Shobhavathy M. Thimmaiah ◽  
Janaki Rami Reddy Mudipalli ◽  
A. M. Pradeep ◽  
...  
Keyword(s):  
Axial Compressor ◽  
Axial Flow ◽  
Experimental Results ◽  
Compressor Stage ◽  
Stall Margin ◽  
Casing Treatment ◽  
Plenum Chamber ◽  
Chamber Volume ◽  
Maximum Improvement ◽  
Low Porosity

This paper presents experimental results of a single stage transonic axial flow compressor coupled with low porosity bend skewed casing treatment. The casing treatment has a plenum chamber above the bend slots. The depth of the plenum chamber is varied to understand its impact on the performance of compressor stage. The performance of the compressor stage is evaluated for casing treatment and plenum chamber configurations at two axial locations of 20% and 40%. Experimental results reveal that the stall margin of the compressor stage increases with increase in the plenum chamber volume. Hot-wire measurements show significant reduction in the turbulence intensity with increase in the plenum chamber volume compared to that with the solid casing at the stall condition. At higher operating speeds of 80% and at 20% axial coverage, the stall margin of the compressor increases by 20% with half and full plenum depth. The improvement in the peak stage efficiency observed is 4.6% with half plenum configuration and 3.34% with the full plenum configuration. The maximum improvement in the stall margin of 29.16% is obtained at 50% operating speed with full plenum configurations at 40% axial coverage.

scholarly journals Stability Enhancement of a Single-Stage Transonic Axial Compressor Using Inclined Oblique Slots

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2346
Author(s):  
Tien-Dung Vuong ◽  
Kwang-Yong Kim
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Single Stage ◽  
Rotor Blades ◽  
Navier Stokes ◽  
Optimized Design ◽  
Stall Margin ◽  
Casing Treatment ◽  
Transonic Axial Compressor

A casing treatment using inclined oblique slots (INOS) is proposed to improve the stability of the single-stage transonic axial compressor, NASA Stage 37, during operation. The slots are installed on the casing of the rotor blades. The aerodynamic performance was estimated using three-dimensional steady Reynolds-Averaged Navier-Stokes analysis. The results showed that the slots effectively increased the stall margin of the compressor with slight reductions in the pressure ratio and adiabatic efficiency. Three geometric parameters were tested in a parametric study. A single-objective optimization to maximize the stall margin was carried out using a Genetic Algorithm coupled with a surrogate model created by a radial basis neural network. The optimized design increased the stall margin by 37.1% compared to that of the smooth casing with little impacts on the efficiency and pressure ratio.

Experimental Study of a High-Throughflow Transonic Axial Compressor Stage

1984 ◽  
Vol 106 (3) ◽  
pp. 552-560 ◽  
Author(s):  
A. J. Wennerstrom
Keyword(s):  
Experimental Study ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Experimental Results ◽  
Vortex Generators ◽  
Compressor Stage ◽  
Stall Margin ◽  
Transonic Axial Compressor ◽  
Design Speed ◽  
Isentropic Efficiency

Design information and experimental results are presented for a transonic axial compressor stage passing 40 lbs/s-ft2 frontal area (195 Kg/s-m2) with a pressure ratio of 1.95 at 1500 ft/s (457 m/s) tip speed. The design incorporates several unusual features that helped it achieve a peak isentropic efficiency over 88 percent at design speed. The compressor was evaluated at three rotor tip clearances and an optimum was found. Vortex generators placed upstream on the casing proved relatively ineffective in influencing stall margin. Vortex generators installed on the rotor did improve stall margin and also increased efficiency at speeds of 90 percent and below.

A Computational Fluid Dynamics Study of Circumferential Groove Casing Treatment in a Transonic Axial Compressor

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Haixin Chen ◽  
Xudong Huang ◽  
Ke Shi ◽  
Song Fu ◽  
Mark Ross ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Axial Compressor ◽  
Data Sampling ◽  
Stall Margin ◽  
Casing Treatment ◽  
Circumferential Groove ◽  
Compressor Rotor ◽  
Radial Profiles ◽  
Transonic Axial Compressor

Numerical investigations were conducted to predict the performance of a transonic axial compressor rotor with circumferential groove casing treatment. The Notre Dame Transonic Axial Compressor (ND-TAC) was simulated at Tsinghua University with an in-house computational fluid dynamics (CFD) code (NSAWET) for this work. Experimental data from the ND-TAC were used to define the geometry, boundary conditions, and data sampling method for the numerical simulation. These efforts, combined with several unique simulation approaches, such as nonmatched grid boundary technology to treat the periodic boundaries and interfaces between groove grids and the passage grid, resulted in good agreement between the numerical and experimental results for overall compressor performance and radial profiles of exit total pressure. Efforts were made to study blade level flow mechanisms to determine how the casing treatment impacts the compressor's stall margin and performance. The flow structures in the passage, the tip gap, and the grooves as well as their mutual interactions were plotted and analyzed. The flow and momentum transport across the tip gap in the smooth wall and the casing treatment configurations were quantitatively compared.

Recirculation-groove coupled casing treatment for a transonic axial compressor

2021 ◽  
Vol 111 ◽  
pp. 106556
Author(s):  
Tien-Dung Vuong ◽  
Kwang-Yong Kim ◽  
Cong-Truong Dinh
Keyword(s):  
Axial Compressor ◽  
Casing Treatment ◽  
Transonic Axial Compressor

scholarly journals Effects of Endwall Suction and Blowing on Compressor Stability Enhancement

1989 ◽  
Author(s):  
N. K. W. Lee ◽  
E. M. Greitzer
Keyword(s):  
Flow Injection ◽  
Axial Compressor ◽  
Pressure Rise ◽  
Primary Objective ◽  
Stall Margin ◽  
Casing Treatment ◽  
Blade Row ◽  
Stall Margin Improvement ◽  
Stability Enhancement ◽  
Suction And Blowing

An experimental investigation was carried out to examine the effects on stall margin of flow injection into, and flow removal out of, the endwall region of an axial compressor blade row. A primary objective of the investigation was clarification of the mechanism by which casing treatment (which involves both removal and injection) suppresses stall in turbomachines. To simulate the relative motion between blade and treatment, the injection and removal took place through a slotted hub rotating beneath a cantilevered stator row. Overall performance data and detailed (time-averaged) flowfield measurements were obtained. Flow injection and removal both increased the stalling pressure rise, but neither was as effective as the wall treatment. Removal of high blockage flow is thus not the sole reason for the observed stall margin improvement in casing or hub treatment, as injection can also contribute significantly to stall suppression. The results also indicate that the increase in stall pressure rise with injection is linked to the streamwise momentum of the injected flow, and it is suggested that this should be the focus of further studies.

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