Investigation on the Aerodynamic Performance of the Compressor Cascade Using Blended Blade and End Wall

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Weilin Yi ◽  
Jiabin Li ◽  
Lucheng Ji
Keyword(s):  
Flow Field ◽  
Incidence Angle ◽  
Compressor Cascade ◽  
Experiment Data ◽  
Corner Separation ◽  
Pressure Loss Coefficient ◽  
Numerical Studies ◽  
Sst Turbulence Model ◽  
End Wall ◽  
Total Pressure Loss Coefficient

Abstract Corner separation limits the increase of the aerodynamic loading in the compressor. Previous numerical studies indicate that the Blended Blade and End Wall (BBEW) technology is useful in delaying, or reducing, or even eliminating the corner separation. This paper presents combined experimental and numerical investigations on a BBEW cascade and its prototype. The experimental results show that the design of Blended Blade and End Wall (BBEW) can improve the performance of the cascade when the incidence angle was positive or at the design point, and the total pressure loss coefficient was reduced by 7 %-8 %. The performance improvement mainly located from 10 %-25 % span heights. Compared with the experiment data, the SST turbulence model shows the best results of the flow field. Based on the numerical results, the details of the flow field and the effect of the Blended Blade and End Wall (BBEW) design on the corner separation are discussed and analyzed.

Experimental and Numerical Investigation on the Aerodynamic Performance of a Compressor Cascade Using Blended Blade and End Wall

2017 ◽  
Author(s):  
Jiabin Li ◽  
Lucheng Ji ◽  
Weilin Yi
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
Turbulence Model ◽  
Numerical Study ◽  
Incidence Angle ◽  
Good Effect ◽  
Compressor Cascade ◽  
Corner Separation ◽  
Sst Turbulence Model ◽  
End Wall

Nowadays, the corner separation, occurring near the corner region formed by the suction surface of blade and end wall, has been an important limitation for the increasing of the aerodynamic loading in the compressor. The previous numerical studies indicate that the Blended Blade and End Wall (BBEW) technology is useful in delaying, or reducing, or even eliminating the corner separation. To further validate the concept, this paper presents combined experimental and numerical investigations on a BBEW cascade and its prototype. Firstly, the NACA65 linear compressor cascade with the turning angle 42 degrees was designed and tested in a low-speed wind tunnel. Then, the cascade with blended blade and end wall design was made and tested in the same wind tunnel. The experimental results show that the design of blended blade and end wall can improve the performance of the cascade when the incidence angle was positive or at the design point, and the total pressure loss coefficient was reduced by 7%–8%. The performance improvement mainly located from 10%–25% span heights. Secondly, based on the experimental data, the numerical study made by our internal code Turbo-CFD shows the difference of the simulation precision of the results, obtained from four different turbulence model after the mesh independence test. The four turbulence model is Spalart-Allmaras model, standard k-ε model, standard k-ω model, and shear stress transport k-ω model. For this case, the SST turbulence model has better performance compared with others. Thirdly, based on the results which were calculated with the turbulence model SST, the effect of the blended blade and end wall design was discussed. The numerical study shows that the design with the blended blade and end wall can have a good effect on the corner flow of the cascade. The strong three-dimensional corner separation, caused by the accumulation of the flow happening at the trail of the suction side was avoided, and the flow losses of the prototype cascade were reduced. Above all, the experiment shows that the design with blended blade and end wall can improve the performance of the cascade. Compared with the experiment data, the SST turbulence model shows the best results of the flow field. Based on the numerical results, the details of the flow field and the effect of the blended blade and end wall design on the corner separation are discussed and analyzed.

scholarly journals Effects of Surface Roughness, Freestream Turbulence, and Incidence Angle on the Performance of a 2-D Compressor Cascade

1990 ◽  
Author(s):  
W. C. Elrod ◽  
P. I. King ◽  
E. M. Poniatowski
Keyword(s):  
Surface Roughness ◽  
Total Pressure ◽  
Incidence Angle ◽  
Two Dimensional ◽  
Freestream Turbulence ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Linear Cascade ◽  
Pressure Loss Coefficient ◽  
Total Pressure Loss Coefficient

The effects of surface roughness, freestream turbulence, and incidence angle on the performance of a two-dimensional compressor cascade were investigated. The test section consisted of seven NACA 65-A506 airfoils arranged in a linear cascade. Four different surface roughness conditions were applied to the first 25 percent chord on the suction surface of each of the five middle blades in the cascade. Freestream turbulence levels of approximately one and seven percent were used. Incidence angles of −3, zero and +3 degrees were investigated. Of the three parameters tested, freestream turbulence exerted the largest influence on blade performance. The total pressure loss coefficient increased with increased roughness and was reduced for large turbulence. Changes in flow incidence had a lesser effect on the performance of the blade.

The Use of Blended Blade and End Wall in Compressor Cascade: Optimization Design and Flow Mechanism

2018 ◽  
Author(s):  
Jiabin Li ◽  
Lucheng Ji ◽  
Weilin Yi
Keyword(s):  
Pressure Gradient ◽  
Optimization Design ◽  
Suction Side ◽  
Boundary Layer Separation ◽  
Axial Position ◽  
Flow Mechanism ◽  
Compressor Cascade ◽  
Pressure Loss Coefficient ◽  
End Wall ◽  
Total Pressure Loss Coefficient

Nowadays, the flow field at the compressor is more and more complex with the increasing of the aerodynamic loading. The complex flow in the endwall regions is thus key to aerodynamic blockage, loss production, and finally its performance deterioration. The design of Blended Blade and End Wall (BBEW) contouring technology had been proved to be useful in delaying, reducing, and eliminating the corner separation in the compressor. The BBEW technology can adjust the dihedral angle between the suction and the endwall in 30% of the spanwise easily, which is different with the fillet. However, the design of the BBEW always relies on the experiences of the designers, and the effective design results cannot be the optimal result. This paper presents an optimization design method for the BBEW technology, and analyses the flow mechanism of the BBEW design. Firstly, the parameters for the BBEW design is simplified as two, one is the maximum blended width, the other is the axial position of the maximum blended width. The optimal result can be obtained through the response surface method. Secondly, based on the optimization method, this paper make an optimization BBEW design at the suction side of a NACA65 linear compressor cascade with the turning angle 42 degrees. The numerical results show that the optimal BBEW design can eliminate the boundary layer separation at the corner intersection region, and reduce the suction side separation. When the incidence angle is 0 degrees, the BBEW technology can reduce the total pressure loss coefficient by 5%, and reduce the aerodynamic blockage coefficient by 14%. The aerodynamic performance of the cascade shows a more obvious improvement with the BBEW design at a larger incidence. The total pressure loss coefficient of the cascade is reduced by 20% at 15 degrees incidence. The numerical study shows that the design with the BBEW can control the axial development of the dihedral angle between the suction side and the endwall, which can eliminate the boundary layer separation at the corner intersection region. What’s more, the BBEW technology can produce a pressure gradient at the axial position of the maximum blended width, and value of the pressure gradient in proportion to the maximum blended width. This pressure gradient enhance the kinetic energy of the low energy fluid at the endwall region, which is consist of the secondary cross flow, thus elevating the capability to withstand the adverse pressure gradient, and improve the suction side separation around the trailing edge.

Effect of End-Wall Vortex Generator Jet Parameters on Flow Control in High Subsonic Compressor Cascade

2018 ◽  
Author(s):  
Cong Chen ◽  
Jianyang Yu ◽  
Fu Chen
Keyword(s):  
Pressure Loss ◽  
Total Pressure ◽  
Vortex Generator ◽  
Total Pressure Loss ◽  
Compressor Cascade ◽  
Control Effect ◽  
Pressure Loss Coefficient ◽  
Vortex Generator Jet ◽  
End Wall ◽  
Total Pressure Loss Coefficient

In order to explore the control mechanism of vortex generator jet, which is located in the passage (PVGJ), on the separation flow, the influence of the pitch angle, skew angle, locations and jet-to-inflow ratio are studied using numerical methods in a high subsonic compressor cascade. The changing of the flow pattern is also analyzed in detail. The results show that the control effect of the end-wall vortex generator jet located in the passage is better than the leading edge one and the aerodynamic performance is effectively improved. The maximum total pressure loss coefficient decreases by 12% and the static pressure coefficient increases by 5.2% while the jet-to-inflow ratio is only 0.3%. The control effect is sensitive to the change of jet parameters. When 0 deg < β < 80 deg, 20 deg < α < 50 deg,, x < 0.5B, y < 0.15t, the vortex generation jet could acquire an ideal control effect. As the jet mass increases, the total pressure loss coefficient gradually reduces. The VGJ prevent separation mainly by bringing high momentum fluid into the near wall region and by promoting momentum transport through turbulent mixing in previous studies. Both the LVGJ and PVGJ mainly take advantage of jet vortex to prevent the cross flow from interacting with the suction side boundary layer.

Effect of Boundary Layer Suction on the Corner Separation in a Highly Loaded Axial Compressor Cascade

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Tian Liang ◽  
Bo Liu ◽  
Stephen Spence
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Axial Compressor ◽  
Compressor Cascade ◽  
Flow Uniformity ◽  
Suction Surface ◽  
Corner Separation ◽  
Boundary Layer Suction ◽  
End Wall ◽  
Highly Loaded

Abstract Control of corner separation in axial compressor blade rows has attracted much interest due to its potential to improve compressor efficiency and the energy utilization in turbomachinery. This paper investigates the effectiveness and mechanisms of boundary layer suction in controlling the corner separation of a highly loaded axial compressor cascade. Numerical simulations have been carried out to investigate the effect of different suction schemes on the loss downstream of the cascade and the change in incidence characteristics with the variation of the suction flowrate. The results show that the effectiveness of flow suction in controlling the flow separation depends heavily on the proportion of the blade for which it is applied. It was found that suction along part of the blade span on the suction surface could effectively remove the separation at the region of the span influenced by the suction slot. However, this resulted in a deterioration of the flow field at other parts of the span. The full-span suction scheme on the suction surface not only eliminated the separation of the boundary layer in the middle of the blade but also significantly improved the flow uniformity near the end-wall. Despite the improvement in flow uniformity using the full-span suction scheme, a three-dimensional (3D) corner separation still existed due to the strong cross-passage pressure gradient. To improve the flow field uniformity further, two combined suction schemes with one spanwise slot on the suction surface and another slot on the end-wall were designed in order to fully remove both the separated flow on the blade suction surface and the 3D corner separation. It was found that the total pressure loss coefficient was reduced significantly by 63.8% with suction flowrates of 1.88% and 0.82% for the slots on the suction surface and the end-wall, respectively. Further work showed that the behavior of the loss coefficient is different as the combination of suction flowrates is changed for different incidence. The cascade loss at high incidence operation can be more effectively reduced with suction control on the end-wall. When implementing combined suction, it is necessary to determine the best combination of suction flowrate according to the incidence level.

Numerical Investigation of Intermittent Corner Separation in a Linear Compressor Cascade

2016 ◽  
Author(s):  
Wei Ma ◽  
Feng Gao ◽  
Xavier Ottavy ◽  
Lipeng Lu ◽  
A. J. Wang
Keyword(s):  
Flow Field ◽  
Large Scale ◽  
Leading Edge ◽  
Suction Side ◽  
Detached Eddy Simulation ◽  
Compressor Cascade ◽  
Linear Compressor ◽  
Corner Separation ◽  
Eddy Simulation ◽  
Linear Compressor Cascade

Recently bimodal phenomenon in corner separation has been found by Ma et al. (Experiments in Fluids, 2013, doi:10.1007/s00348-013-1546-y). Through detailed and accurate experimental results of the velocity flow field in a linear compressor cascade, they discovered two aperiodic modes exist in the corner separation of the compressor cascade. This phenomenon reflects the flow in corner separation is high intermittent, and large-scale coherent structures corresponding to two modes exist in the flow field of corner separation. However the generation mechanism of the bimodal phenomenon in corner separation is still unclear and thus needs to be studied further. In order to obtain instantaneous flow field with different unsteadiness and thus to analyse the mechanisms of bimodal phenomenon in corner separation, in this paper detached-eddy simulation (DES) is used to simulate the flow field in the linear compressor cascade where bimodal phenomenon has been found in previous experiment. DES in this paper successfully captures the bimodal phenomenon in the linear compressor cascade found in experiment, including the locations of bimodal points and the development of bimodal points along a line that normal to the blade suction side. We infer that the bimodal phenomenon in the corner separation is induced by the strong interaction between the following two facts. The first is the unsteady upstream flow nearby the leading edge whose angle and magnitude fluctuate simultaneously and significantly. The second is the high unsteady separation in the corner region.

A New Concept of a Two-Dimensional Supersonic Relative Inlet Mach Number Compressor Cascade

2009 ◽  
Author(s):  
Toyotaka Sonoda ◽  
Markus Olhofer ◽  
Toshiyuki Arima ◽  
Bernhard Sendhoff
Keyword(s):  
Mach Number ◽  
Total Pressure ◽  
Optimization Method ◽  
Superior Performance ◽  
Compressor Cascade ◽  
Pressure Loss Coefficient ◽  
Supersonic Inlet ◽  
Flow Mechanisms ◽  
Improved Performance ◽  
Total Pressure Loss Coefficient

In this study, a numerical shape optimization method based on evolutionary algorithms coupled with a verified CFD solver has been applied to the ambitious target of a shock free 2-D supersonic inlet Mach number compressor cascade. The study is based on the DLR-PAV-1.5 supersonic compressor cascade designed by the pre-compression blading concept. The DLR cascade airfoil has been optimized using a verified CFD code. A superior performance of the optimized supersonic cascade with about 24% reduction of the total pressure loss coefficient compared to the original cascade has been realized. The flow mechanisms observable around the blade with improved performance and the resulting design concept are discussed in this paper.

Control of the Corner Separation in a Linear Cascade by Trailing Gaps

2017 ◽  
Author(s):  
Wenfeng Zhao ◽  
Bin Jiang ◽  
Qun Zheng
Keyword(s):  
Flow Field ◽  
Suction Surface ◽  
Optimal Length ◽  
Corner Separation ◽  
Linear Cascade ◽  
High Loss ◽  
Axial Compressors ◽  
Pressure Surface ◽  
Sst Turbulence Model ◽  
The Stability

Hub corner is the high-loss area in the blade passages of turbo machinery. It is well known that the flow separation and vortex development in this area affects directly not only the energy losses and efficiency, but also the stability of axial compressors. Linear compressor cascades with partial gaps and trailing gaps which can blow away the corner separation by the pressure difference between the suction surface and pressure surface are numerically simulated in this paper. A proposed linear cascade model with gaps has been built. The steady flow field in a linear cascade with different length gaps is studied by numerical simulation of RANS with SST turbulence model and γ-Reθ transition model focusing on the streamline structure between the corner separation vortex and the gap leakage vortex, especially the interaction of the two vertical vortex. When the length of trailing edge gaps is enough (in this paper, the optimal length of the gap is 30% chord), the corner vortex basically disappears completely. At the same time, the mode of flow field changes from the closed separation to the open separation.

Modification of Shear Stress Transport Turbulence Model Using Helicity for Predicting Corner Separation Flow in a Linear Compressor Cascade

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Yangwei Liu ◽  
Yumeng Tang ◽  
Ashley D. Scillitoe ◽  
Paul G. Tucker
Keyword(s):  
Shear Stress ◽  
Turbulence Model ◽  
Incidence Angle ◽  
Computational Cost ◽  
Separation Flow ◽  
Compressor Cascade ◽  
Production Term ◽  
Corner Separation ◽  
Shear Stress Transport ◽  
Sst Model

Abstract Three-dimensional corner separation significantly affects compressor performance, but turbulence models struggle to predict it accurately. This paper assesses the capability of the original shear stress transport (SST) turbulence model to predict the corner separation in a linear highly loaded prescribed velocity distribution (PVD) compressor cascade. Modifications for streamline curvature, Menter’s production limiter, and the Kato-Launder production term are examined. Comparisons with experimental data show that the original SST model and the SST model with different modifications can predict the corner flow well at an incidence angle of −7 deg, where the corner separation is small. However, all the models overpredict the extent of the flow separation when the corner separation is larger, at an incidence angle of 0 deg. The SST model is then modified using the helicity to take account of the energy backscatter, which previous studies have shown to be important in the corner separation regions of compressors. A Reynolds stress model (RSM) is also used for comparison. By comparing the numerical results with experiments and RSM results, it can be concluded that sensitizing the SST model to helicity can greatly improve the predictive accuracy for simulating the corner separation flow. The accuracy is quite competitive with the RSM, whereas in terms of computational cost and robustness it is superior to the RSM.

Numerical Simulation of Deposition Phenomena on High-Pressure Turbine Vane Using UPACS

2019 ◽  
Author(s):  
Kenta Mizutori ◽  
Koji Fukudome ◽  
Makoto Yamamoto ◽  
Masaya Suzuki
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Flow Field ◽  
Pressure Loss ◽  
Total Pressure ◽  
Total Pressure Loss ◽  
High Pressure Turbine ◽  
Pressure Loss Coefficient ◽  
Turbine Vane ◽  
Total Pressure Loss Coefficient

Abstract We performed numerical simulation to understand deposition phenomena on high-pressure turbine vane. Several deposition models were compared and the OSU model showed good adaptation to any flow field and material, so it was implemented on UPACS. After the implementation, the simulations of deposition phenomenon in several cases of the flow field were conducted. From the results, particles adhere on the leading edge and the trailing edge side of the pressure surface. Also, the calculation of the total pressure loss coefficient was conducted after computing the flow field after deposition. The total pressure loss coefficient increased after deposition and it was revealed that the deposition deteriorates aerodynamic performance.

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