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

Stall Warning Using the Rotor Tip Pressure in a Transonic Axial Compressor With Circumferential Grooves

2018 ◽  
Author(s):  
Byeung Jun Lim ◽  
Tae Choon Park ◽  
Young Seok Kang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Compressor ◽  
Rotating Stall ◽  
Single Stage ◽  
Stall Inception ◽  
Casing Treatment ◽  
Stall Warning ◽  
Transonic Axial Compressor

In this study, characteristics of stall inception in a single-stage transonic axial compressor with circumferential grooves casing treatment were investigated experimentally. Additionally, the characteristic of increasing irregularity in the pressure inside circumferential grooves as the compressor approaches the stall limit was applied to the stall warning method. Spike-type rotating stall was observed in the single-stage transonic axial compressor with smooth casing. When circumferential grooves were applied, the stall inception was suppressed and the operating point of the compressor moved to lower flow rate than the stall limit. A spike-like disturbance was developed into a rotating stall cell and then the Helmholtz perturbation was overlapped on it at N = 80%. At N = 70 %, the Helmholtz perturbation was observed first and the amplitude of the wave gradually increased as mass flow rate decreased. At N = 60%, spike type stall inceptions were observed intermittently and then developed into continuous rotating stall at lower mass flow rate. Pressure measured at the bottom of circumferential grooves showed that the level of irregularity of pressure increased as flow rate decreased. Based on the characteristic of increasing irregularity of the pressure signals inside the circumferential grooves as stall approaches, an autocorrelation technique was applied to the stall warning. This technique could be used to provide warning against stall and estimate real-time stall margins in compressors with casing treatments.

Aeroelastic Flutter Investigation and Stability Enhancement of a Transonic Axial Compressor Rotor Using Casing Treatment

2017 ◽  
Author(s):  
Kirubakaran Purushothaman ◽  
Sankar Kumar Jeyaraman ◽  
Ajay Pratap ◽  
Kishore Prasad Deshkulkarni
Keyword(s):  
Flow Separation ◽  
Aerodynamic Force ◽  
Damping Ratio ◽  
Axial Compressor ◽  
Casing Treatment ◽  
Aerodynamic Damping ◽  
Compressor Rotor ◽  
Aeroelastic Flutter ◽  
Blade Tip ◽  
Transonic Axial Compressor

This study discusses in detail the aeroelastic flutter investigation of a transonic axial compressor rotor using computational methods. Fluid structure interaction approach is used in this method to evaluate the unsteady aerodynamic force and work done of a vibrating blade in CFD domain. Energy method and work per cycle approach is adapted for this flutter prediction. A framework has been developed to estimate the work per cycle and aerodynamic damping ratio. Based on the aerodynamic damping ratio, occurrence of flutter is estimated for different inter blade phase angles. Initially, the baseline rotor blade design was having negative aerodynamic damping at part speed conditions. The main cause for this flutter occurrence was identified as large flow separation near blade tip region due to high incidence angles. The unsteadiness in the flow was leading to aerodynamic force fluctuation matching with natural frequency of blade, resulting in excitation of the blades. Hence axially skewed slot casing treatment was implemented to reduce the flow separation at blade tip region to alleviate the onset of flutter. By this method, the stall margin and aerodynamic damping of the test compressor was improved and flutter was avoided.

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.

Study of Sloped Trench Casing Treatment on Performance and Stability of a Transonic Axial Compressor

2007 ◽  
Author(s):  
Hui Zhang ◽  
Hongwei Ma
Keyword(s):  
Performance Improvement ◽  
Axial Compressor ◽  
Tip Clearance ◽  
Smooth Transition ◽  
Nasa Lewis Research ◽  
Casing Treatment ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Simulation Results ◽  
A Performance

This paper presents a numerical investigation of effects of sloped trench casing treatment over the rotor tip on the aerodynamic performance and stability of a transonic axial compressor rotor (NASA Rotor 37). The axially cutting tip of blade is the marked characteristic of the casing treatment which is differ with casing treatments without adjustment of the blade tip. The numerical method has been verified by experimental results in the case of the smooth casing with the tip clearance of 0.356 mm at the design wheel speed (17188.7 rpm). The simulation results are well consistent with the measurement results. The experiment results of NASA Rotor 37 cite from NASA Lewis Research Center. The simulation results show a performance improvement of the compressor on the sloped trench casing. The flow fields of the smooth and sloped trench casings were compared, and results show the sloped trench geometry provides a barrier to minimize the forward flow from the tip clearance vortex. In addition, the sloped trench allows the forward facing step at the aft end to be replaced by an aerodynamically smooth transition to guide the flow from the recess into the mainstream. These results show a performance improvement of the compressor.

Difference in the Working Principle of Axial Slot and Tip Blowing Casing Treatments

2016 ◽  
Author(s):  
André Inzenhofer ◽  
Cyril Guinet ◽  
Andreas Hupfer ◽  
Bernd Becker ◽  
Patrick Grothe ◽  
...  
Keyword(s):  
Flow Field ◽  
Axial Compressor ◽  
Casing Treatment ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Negative Effect ◽  
Working Principle ◽  
Transonic Axial Compressor ◽  
The Difference ◽  
Casing Treatments

Tip blowing and axial slot casing treatments have shown their ability to enhance the stability of a transonic axial compressor with different effects on efficiency. For an effective application of these casing treatments, a good knowledge of the influence of the casing treatment on the rotor flow field is important. There is still a need for more detailed investigations, in order to understand the interaction between the treatment and the near casing 3D flow field. For transonic compressor rotors this interaction is more complex, as super- and subsonic flow regions alternate while interacting with the casing treatment. In the present study, an axial slot and a tip blowing casing treatment, which have been developed and optimized for the same tip critical transonic axial compressor rotor (reference rotor) by Streit et al. [1] and Guinet et al. [2], are subject of the investigation. Both casing treatment types showed their capabilities to enhance the compressor stability without losing by means of CFD simulations. Since the higher compressor stability allows a higher blade loading, Streit et al. reduced the blade number of the rotor. Thus, the efficiency was increased due to the reduction of friction losses. However, applying the tip blowing casing treatment to the reduced rotor shows a negative effect on the efficiency. Both casing treatment types recirculate flow from a downstream to an upstream location of the rotor and reinject it to enhance the near casing flow field. Although the working principle of the two casing treatment types are similar, the transfer of the casing treatments from the reference to the reduced rotor show different trends in efficiency. Therefore, the effect of recirculation cannot explain the difference in efficiency. Hence, applying axial slots must include additional flow features, compared to recirculation channels. Compensating effects as in circumferential groove casing treatments and other flow interactions between the near casing flow field and the slot flow are considered. These additional mechanisms of the axial slot casing treatment will be identified and isolated by comparing the two different casing treatment types. The numerical simulations are carried out on a 1.5 stage transonic axial compressor using URANS simulations.

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.

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