Design Optimization of Circumferential Casing Grooves for a Transonic Axial Compressor to Enhance Stall Margin

Author(s):  
Kwang-Jin Choi ◽  
Jin-Hyuk Kim ◽  
Kwang-Yong Kim

This paper presents a design optimization of an axial compressor with NASA Rotor 37 and five circumferential casing grooves for enhancement of stall margin. Three-dimensional Reynolds-averaged Navier-Stokes equations with the shear stress transport turbulence model are discretized by finite volume approximations and solved on hexahedral grids for the flow analyses. The validation of the numerical results is performed in comparison with experimental data for pressure ratio and adiabatic efficiency. The Latin-hypercube sampling as design-of-experiments is used to generate the twelve design points within the design space. A stall margin parameter is considered as an objective function with two design variables defining the geometry of the circumferential casing grooves. The radial basis neural network method employed as a surrogate model for the design optimization of the circumferential casing grooves is trained on the numerical solutions by carrying out leave-one-out cross-validation for the data set. The results show that the stall margin of the optimum shape is enhanced considerably by the design optimization compared to the cases with smooth casing and the reference grooves.

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 159
Author(s):  
Tien-Dung Vuong ◽  
Kwang-Yong Kim

The present work performed a comprehensive investigation to find the effects of a dual-bleeding port recirculation channel on the aerodynamic performance of a single-stage transonic axial compressor, NASA Stage 37, and optimized the channel’s configuration to enhance the operating stability of the compressor. The compressor’s performance was examined using three parameters: The stall margin, adiabatic efficiency, and pressure ratio. Steady-state three-dimensional Reynolds-averaged Navier–Stokes analyses were performed to find the flow field and aerodynamic performance. The results showed that the addition of a bleeding channel increased the recirculation channel’s stabilizing effect compared to the single-bleeding channel. Three design variables were selected for optimization through a parametric study, which was carried out to examine the influences of six geometric parameters on the channel’s effectiveness. Surrogate-based design optimization was performed using the particle swarm optimization algorithm coupled with a surrogate model based on the radial basis neural network. The optimal design was found to increase the stall margin by 51.36% compared to the case without the recirculation channel with only 0.55% and 0.28% reductions in the peak adiabatic efficiency and maximum pressure ratio, respectively.


2013 ◽  
Vol 284-287 ◽  
pp. 872-877 ◽  
Author(s):  
Dae Woong Kim ◽  
Jin Hyuk Kim ◽  
Kwang Yong Kim

This paper presents a parametric study on aerodynamic performance of a transonic axial compressor combined with a casing groove and tip injection using three-dimensional Reynolds-average Navier-Stokes equations. The front and rear lengths and height of the groove are selected as the geometric parameters to investigate their effects on the stall margin and peak adiabatic efficiency. These parameters are changed with constant injection. The validation of the numerical results is performed in comparison with experimental data for the total pressure ratio and adiabatic efficiency. As the results of the parametric study, the maximum stall margin and peak adiabatic efficiency are obtained in the axial compressor having 70% groove height of the reference groove. The stall margin and peak adiabatic efficiency in other cases are also improved in comparison with the axial compressors with the smooth casing and reference groove. The results show that both the stall margin and the peak adiabatic efficiency are considerably improved by the application of the casing groove combined with tip injection in an axial compressor.


Author(s):  
Yiming Zhong ◽  
WuLi Chu ◽  
HaoGuang Zhang

Abstract Compared to the traditional casing treatment, the self-recirculating casing treatment (SCT) can improve or not decrease the compressor efficiency while achieving the stall margin improvement. For the bleed port, the main design indicator is to reduce the flow loss caused by suction, while providing sufficient jet flow and jet pressure to the injector. In order to gain a better study of the bleed port stabilization mechanisms, the bleed configuration was parameterized with the bleed port inlet width and the bleed port axial position. Five kinds of recirculating casing treatments were applied to a 1.5-stage transonic axial compressor with the method of three-dimensional unsteady numerical simulation. Fifteen identical self-recirculating devices are uniformly mounted around the annulus. The numerical results show that the SCT can improve compressor total pressure ratio and stability, shift the stall margin towards lower mass flows. Furthermore, it has no impact on compressor efficiency. The optimal case presents that stability margin is improved by 6.7% employing 3.1% of the annulus mass flow. Expanding bleed port inlet width to an intermediate level can further enhance compressor stability, but excessive bleed port inlet width will reduce the stabilization effect. The optimal bleed port position is located in the blocked area of the low energy group at the top of the rotor. In the case of solid casing, stall inception was the tip blockage, which was mainly triggered by the interaction of the tip leakage vortex and passage shock. From radial distribution, the casing treatment predominantly affects the above 70% span. The reduction of tip reflux region by suction effect is the main reason for the extension of stable operation range. The SCT also has an obvious stability improvement in tip blockage stall, while delaying the occurrence of compressor stall.


2013 ◽  
Vol 37 (3) ◽  
pp. 283-292 ◽  
Author(s):  
Dae-Woong Kim ◽  
Jin-Hyuk Kim ◽  
Kwang-Yong Kim

Aerodynamic performance of a transonic axial compressor with a casing groove combined with injection has been investigated in this work. Three-dimensional Reynolds-averaged Navier–Stokes equations with k-ε turbulence model are discretized by finite volume approximations and solved on hexahedral grids for the flow analyses. For parametric study, the front and rear lengths and height of the casing groove are selected as the geometric parameters and are changed with constant injection to investigate their effects on the stall margin and peak adiabatic efficiency. As a result of the parametric study, the maximum stall margin and peak adiabatic efficiency are found to be obtained in the axial compressor having 70% height of the reference groove. The results show that the application of the casing groove combined with injection to an axial compressor is effective for the simultaneous improvement of both the stall margin and peak adiabatic efficiency of the compressor.


Author(s):  
Sang-Bum Ma ◽  
Kwang-Yong Kim

In this study, aerodynamic performance of the centrifugal compressor was investigated by using a recirculating device called discrete cavities. A parametric study was conducted using six parameters related to the geometry of the discrete cavities, i.e., the inclined angle, the port angle and width, the length of cavity, the axial location of each cavity, and the number of cavities. Three-dimensional Reynolds-averaged Navier-Stokes equations with shear stress transport turbulence model were used for aerodynamic analysis of the centrifugal compressor with discrete cavities. The hexahedral grid was used in impeller domain and tetrahedral grid was used in volute and inclined discrete cavities. The numerical results for the adiabatic efficiency and the total pressure ratio (inlet to outlet) showed good agreements with experimental data. It was found that inclination of the discrete cavities further increased the stall margin without loss of efficiency compared to the uninclined discrete cavities.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2346
Author(s):  
Tien-Dung Vuong ◽  
Kwang-Yong Kim

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.


Author(s):  
Tao Ning ◽  
Chun-wei Gu ◽  
Xiao-tang Li ◽  
Tai-qiu Liu

An optimization method combined of a genetic algorithm, an artificial neural network, a CFD solver and a blade generator, is developed in this research and applied in the three-dimensional blading design of a newly designed highly-loaded 5-stage axial compressor. The adaptive probabilities of crossover and mutation, non-uniform mutation operator and elitism operator are employed to improve the convergence of the genetic algorithm. Considering both the optimization efficiency and effectiveness, a mixture of high-fidelity multistage CFD method and approximate surrogate model of the feed-forward ANN is used to evaluate the fitness. In particular, the database is updated dynamically and used to re-train the surrogate model of ANN for improving the accuracy for predicting. The last stator of the compressor is optimized at the near stall operating point. The tip bow with relative bow height Hb and bow angle αb are treated as design parameters. The adiabatic efficiency as well as the penalty of mass flow and total pressure ratio constitute the objective functions to be maximized. The optimum (Hb = 0.881, αb = 14.7°) obtains 0.4% adiabatic efficiency increase for the whole compressor at the optimized operating point. The detailed aerodynamic is compared between the baseline and optimized stator, and the mechanism is analyzed. The optimized version obtains 5.1% increase in stall margin and maintains the efficiency at the design point.


Author(s):  
Cong-Truong Dinh ◽  
Sang-Bum Ma ◽  
Kwang-Yong Kim

This paper presents an investigation of a circumferential feed-back channel located on shroud surface in rotor domain to find its effects on aerodynamic performance of a single-stage axial compressor, NASA Stage 37, using three-dimensional Reynolds-averaged Navier-Stokes equations. Validation of numerical results was performed using experimental data for both of single rotor and single-stage compressors. A parametric study of the feed-back channel was performed using various geometric parameters related to the locations and shapes of the channel inlet and outlet. The numerical results showed that a reference circumferential feed-back channel increased the stall margin by 26.8% with 0.14% reduction in the peak adiabatic efficiency, compared to the case without the feed-back channel.


2017 ◽  
Vol 0 (0) ◽  
Author(s):  
C. T. Dinh ◽  
K. Y. Kim

AbstractThis paper presents a performance evaluation of non-axisymmetric casing grooves combined with airflow injection in a transonic axial compressor with NASA Rotor 37, using three-dimensional Reynolds-averaged Navier-Stokes equations with the k-ε turbulence model. An axisymmetric casing groove was divided circumferentially into 36 non-axisymmetric grooves. The numerical results for adiabatic efficiency and total pressure ratio were validated with experimental data. A parametric study for stall margin, stable range extension, peak adiabatic efficiency, and total pressure ratio at peak adiabatic efficiency of the compressor was performed using five parameters: the front and rear lengths, the height of the casing groove, the injection mass flow rate, and the injection angle. The non-axisymmetric casing grooves combined with injection improve greatly the stall margin and stable range extension of the transonic axial compressor, but reduce only slightly the peak adiabatic efficiency in all cases, compared to the results for a smooth casing.


2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Qiushi Li ◽  
Hong Wu ◽  
Ming Guo ◽  
Jie-Zhi Wu

In a companion paper (2008, “Vorticity Dynamics in Axial Compressor Flow Diagnosis and Design,” ASME J. Fluids Eng., 130, p. 041102), a study has been made on the critical role of circumferential vorticity (CV) in the performance of axial compressor in through-flow design (TFD). It has been shown there that to enhance the pressure ratio, the positive and negative CV peaks should be pushed to the casing and hub, respectively. This criterion has led to an optimal TFD that indeed improves the pressure ratio and efficiency. The CV also has great impact on the stall margin as it reflects the end wall blockage, especially at the tip region of the compressor. While that work was based on inviscid and axisymmetric theory, in this paper, we move on to the diagnosis and optimal design of fully three-dimensional (3D) viscous flow in axial compressors, focusing on the boundary vorticity flux (BVF), which captures the highly localized peaks of pressure gradient on the surface of the compressor blade, and thereby signifies the boundary layer separation and dominates the work rate done to the fluid by the compressor. For the 2D cascade flow we show that the BVF is directly related to the blade geometry. BVF-based 2D and 3D optimal blade design methodologies are developed to control the velocity diffusion, of which the results are confirmed by Reynolds-averaged Navier–Stokes simulations to more significantly improve the compressor performance than that of CV-based TFD. The methodology enriches the current aerodynamic design system of compressors.


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