Numerical study on dynamic characteristics for sharp opening procedure of boundary-layer suction slot

In the present paper a numerical and experimental study aiming at the enhancement of the working range of a transonic compressor via boundary layer suction (BLS) is presented. The main objective of the investigation is to study the influence of BLS on the interference between shock wave and boundary layer and to identify the possible benefit of BLS on the compressor working characteristics. An extensive numerical study has been carried out for the DATUM blade and for 2 different suction location configurations for one speed line and varying back-pressure levels, ranging from choked conditions to stall. It was found that the working range of the transonic compressor with a nominal inlet Mach number of 1.2 and a nominal pre-shock Mach number of 1.35 could be increased by sucking 2% of flow on the SS away, in such a way that the maximum pressure ratio and maximum diffusion could both be increased by 10%, when compared to the DATUM case. For smaller pressure ratios with respect to the design pressure ratio, the BLS is located in a supersonic flow region and thus creates additional losses due to a more divergent flow channel, which additionally accelerates the flow and results in a higher pre-shock Mach number creating higher losses. First measurements carried out in LTTs annular cascade, do show reasonable agreement with the computations in terms of inlet Mach number, flow angle, main shock location and stall limit. The most pronounced difference between measurements and computations is the occurrence of a terminal normal channel shock behind a bowed detached shock wave and a separation on the SS of the blade, which were both not predicted by the CFD.

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Investigation of a Laminar Boundary-Layer Suction Slot

AIAA Journal ◽

10.2514/3.51136 ◽

1982 ◽

Vol 20 (6) ◽

pp. 790-796 ◽

Cited By ~ 8

Author(s):

A. S. W. Thomas ◽

K. C. Cornelius

Keyword(s):

Boundary Layer ◽

Laminar Boundary Layer ◽

Boundary Layer Suction ◽

Suction Slot

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Design strategies and numerical simulation of highly loaded aspirated compressor blades

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650917736921 ◽

2017 ◽

Vol 232 (4) ◽

pp. 315-336

Author(s):

Zhiyuan Cao ◽

Bo Liu ◽

Ting Zhang ◽

Yibing Xu

Keyword(s):

Boundary Layer ◽

Velocity Distribution ◽

Design Methodology ◽

Design Strategies ◽

Suction Surface ◽

Compressor Blades ◽

Stall Margin ◽

Boundary Layer Suction ◽

Suction Slot ◽

Highly Loaded

Boundary layer suction can effectively eliminate flow separations and increase aerodynamic loading of axial compressors. The design methodology of highly loaded aspirated compressor blades was developed and illustrated in this study. In this work, Computational Fluid Dynamics (CFD) methods were first validated with existing data and then used to develop the design strategy of aspirated compressor blades. Design strategies for higher blade performances, including higher loading, larger stall margin and larger blade thickness near the suction slot of aspirated blades, were investigated through analyzing a series of highly loaded aspirated cascades with diffusion factors (DF) around 0.71. Results showed that the design methodology proposed in this paper was appropriate for designing highly loaded aspirated compressor blades. Under the condition of no boundary layer suction (BLS), severe flow separations of highly loaded blades were tailored at the aft part of suction surface by adopting the “ski-slope” velocity distribution, which almost remained unchanged within a large incidence range. The “ski-slope” velocity distribution was appropriate for removing flow separations and beneficial for obtaining thicker blade. High loading of aspirated blade was achieved by the postpositional suction peak and minimum velocity distribution on pressure surface. The stall margin of highly loaded aspirated cascades could be enlarged by designing the velocity distribution upstream of the suction slot and by selecting suction peak position and solidity. A three-dimensional (3D) highly loaded aspirated cascade was designed based on a two-dimensional (2D) cascade. Both the trailing edge separation and corner separation of the 3D highly loaded aspirated cascade were eliminated successfully with coupled suction surface and endwall suction.

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A Numerical Investigation of Boundary Layer Suction in Compound Lean Compressor Cascades

Journal of Turbomachinery ◽

10.1115/1.2162181 ◽

2005 ◽

Vol 128 (2) ◽

pp. 357-366 ◽

Cited By ~ 17

Author(s):

Yanping Song ◽

Fu Chen ◽

Jun Yang ◽

Zhongqi Wang

Keyword(s):

Boundary Layer ◽

Numerical Investigation ◽

Numerical Study ◽

Pressure Rise ◽

Total Loss ◽

Compressor Cascade ◽

Suction Surface ◽

Flow Rates ◽

Boundary Layer Suction ◽

Suction Flow

This paper is focused on the numerical investigation of boundary layer suction (BLS) via a slot on the suction surfaces of two compound lean compressor cascades with large camber angles as well as a conventional straight compressor cascade for comparison. The objective of the investigation is to study the influence of boundary layer suction on the performance of compound lean compressor cascades, thus to discuss the possibility of the application of boundary layer suction to improve their performance. An extensive numerical study has been carried out under different spanwise lengths, different axial positions of the slots, and different suction flow rates. The results show that the total loss of all three cascades is reduced significantly by boundary layer suction, and the largest reduction occurs at the highest suction flow rate. The axial locations of the slot have little effect on the total loss of the three cascades, which means the slots are opened within the optimal axial range in this case. The slot opened along the full span is the best one to obtain the largest reduction in total loss for all three cascades due to the alleviation of flow separation in the corner between the endwall and the suction surface. Moreover, the flow turning is increased, and pressure rise at the rear of the passage is recovered along the whole blade height via boundary layer suction along the full span, enhancing the working range of the highly loaded compressor cascades.

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Effects of Boundary Layer Suction on the Performance of Compressor Cascades

Volume 6: Turbomachinery, Parts A and B ◽

10.1115/gt2006-90082 ◽

2006 ◽

Cited By ~ 8

Author(s):

Fu Chen ◽

Yanping Song ◽

Huanlong Chen ◽

Zhongqi Wang

Keyword(s):

Boundary Layer ◽

Flow Rate ◽

Flow Behavior ◽

Aerodynamic Performance ◽

Compressor Cascade ◽

Suction Surface ◽

Boundary Layer Suction ◽

Suction Flow ◽

Suction Slot ◽

Highly Loaded

The effects of boundary layer suction on the aerodynamic performance of compressor cascade are mainly determined by: (1) the location of the suction slot; (2) the suction flow rate; (3) the suction slot geometry; and (4) the aerodynamic parameters of the cascade (e.g. solidity and incidence). In this paper, an extensive numerical study has been carried out to investigate the effects of these influencing factors in a highly-loaded compressor cascade by comparing the aerodynamic performance of the cascade in order to give guidance for the application of boundary layer suction to improve the performance of modern highly-loaded compressors. The results show that boundary layer suction alleviates the accumulation of low-energy fluid at suction surface corners and enhances the ability of flow turning, and this improvement in flow behavior depends on the location of the suction slot and the suction flow rate. When the location of the suction slot and the suction flow rate are fixed, as the cascade solidity decreases from 1.819 to 1.364 and 1.091, the cascade total pressure loss is reduced at most by 25.1%, 27.7% and 32.9% respectively, and the cascade exit flow deviation is decreased by 3.1°, 4.2° and 5.0° accordingly. Moreover, boundary layer suction also has the largest effect in the cascade with smaller solidity at large positive incidences, which means that boundary layer suction is an effective way to widen the stable operating range of the highly-loaded compressor cascade. The suction slot geometry is described by the suction slot width and the suction slot angle with respect to the direction normal to the blade suction surface. The results show that the flow behavior is improved and the endwall loss is reduced further as the increase of the suction slot width. The suction slot angle has an obvious influence on the pressure inside the slot, therefore, should be considered in the design of the suction slot since the maximum pressure inside the slot is usually required.

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A Numerical Investigation of Boundary Layer Suction in Compound Lean Compressor Cascades

Volume 6: Turbo Expo 2005, Parts A and B ◽

10.1115/gt2005-68441 ◽

2005 ◽

Cited By ~ 8

Author(s):

Yanping Song ◽

Fu Chen ◽

Jun Yang ◽

Zhongqi Wang

Keyword(s):

Boundary Layer ◽

Numerical Investigation ◽

Numerical Study ◽

Pressure Rise ◽

Total Loss ◽

Compressor Cascade ◽

Suction Surface ◽

Flow Rates ◽

Boundary Layer Suction ◽

Suction Flow

This paper is focused on the numerical investigation of boundary layer suction (BLS) via a slot on the suction surfaces of two compound lean compressor cascades with large camber angles as well as a conventional straight compressor cascade for comparison. The objective of the investigation is to study the influence of boundary layer suction on the performance of compound lean compressor cascades, thus to discuss the possibility of the application of boundary layer suction to improve their performance. An extensive numerical study has been carried out under different spanwise lengths and different axial positions of the slots, and different suction flow rates. The results show that the total loss of all three cascades is reduced significantly by boundary layer suction, and the largest reduction occurs at the highest suction flow rate. The axial locations of the slot have little effect on the total loss of the three cascades, which means the slots are opened within the optimal axial range in this case. The slot opened along the full span is the best one to obtain the largest reduction in total loss for all three cascades due to the alleviation of flow separation in the corner between the endwall and the suction surface. Moreover, the flow turning is increased, and pressure rise at the rear of the passage is recovered along the whole blade height via boundary layer suction along the full span, enhancing the working range of the highly loaded compressor cascades.

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Effects of segmented layer suction and micro-vortex generator on a high-load compressor cascade performance

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/0954406220980502 ◽

2021 ◽

pp. 095440622098050

Author(s):

Shan Ma ◽

Wuli Chu ◽

Xiaolin Sun ◽

Zhengtao Guo ◽

Song Yan

Keyword(s):

Boundary Layer ◽

Pressure Loss ◽

Total Pressure ◽

Vortex Generator ◽

Total Pressure Loss ◽

Compressor Cascade ◽

Boundary Layer Suction ◽

Axial Location ◽

Micro Vortex Generator ◽

Suction Slot

The axial location of full-span boundary layer suction is studied to explore the influences of suction slot on the cascade performance. At the design condition, the slot with 50% axial location shows a superior capability to reduce the total pressure loss. At the near stall condition, the more upstream of the suction slot is moved, the more total pressure loss is reduced, and the suction slot with a location of 0.7 axial chord length cannot effectively reduces the total pressure loss in all conditions. Moreover, a rearranged segmented suction slot according to the distribution characteristics of the flow reversal region is developed and compared with full-span boundary layer suction. The segmented suction slot shows significant advantages in delaying the stall occurrence, and the stall point is delayed from 7.9° to 10.0° compared with the baseline. According to a quantitative analysis method selected to measure the performances of flow control technologies, the wake loss is significantly reduced by the segmented suction slot. Finally, a set of micro-vortex generator is introduced in the cascade with a segmented suction slot, and the conclusion indicates that the portion near the end-wall is very effective to reduce the flow loss.

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