Evaluation of Compressor Blading With Blade End Slots and Full-Span Slots in a Highly Loaded Compressor Cascade

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Yumeng Tang ◽  
Yangwei Liu ◽  
Lipeng Lu
Keyword(s):  
Incidence Angle ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Main Flow ◽  
The Self ◽  
Flow Structures ◽  
Compressor Cascade ◽  
Corner Separation ◽  
High Incidence ◽  
Highly Loaded

Abstract Blade end slots were proposed to control corner separation in a highly loaded compressor cascade in our previous studies. This study focuses on the evaluation of compressor blading with blade end slots and full-span slots. First, the two-dimensional configuration performance is evaluated both for the datum and slotted profiles. The slotted configuration could effectively suppress separation, especially under positive incidence conditions when the separation is large. Thus, two three-dimensional blading with full-span slots and blade end slots (20% span height from the endwall) are compared. Results show that blading with full-span slots could effectively reduce the loss and enlarge pressure rise under relative high incidence angles, while blading with blade end slots could effectively reduce the loss and enlarge pressure rise above an incidence angle of −4 deg. Blading with slots alters the flow structures and reorganizes the flow in the blade end regions. The self-adaptive jets from the slots reenergize the low-momentum flow downstream and restrain its migration toward the mid-span, so that the corner separation is reduced and the performance is enhanced. The loss for the end slotted blade is lower than that of the full-span slotted blade under incidence angles within 4 deg. This is because the additional mixing loss of the jet and the main flow are caused by the full-span slots at the mid-span regions where the flow remains attached for the blade end slots.

Evaluation of Compressor Blading With Blade End Slots and Full-Span Slots in a Highly Loaded Compressor Cascade

2019 ◽  
Author(s):  
Yumeng Tang ◽  
Yangwei Liu ◽  
Lipeng Lu
Keyword(s):  
Incidence Angle ◽  
Three Dimensional ◽  
Main Flow ◽  
The Self ◽  
Flow Structures ◽  
Two Dimensional ◽  
Compressor Cascade ◽  
Aero Engine ◽  
Compressor Performance ◽  
Highly Loaded

Abstract High loading design is a permanent pursuit in the field of the modern compressors to reduce the size and weight of the aero-engine. Blading with slots is a potential way to improve compressor performance. An innovative double-slot scheme was proposed and validated to control corner separation in a highly loaded compressor cascade in our previous studies. To evaluate the three-dimensional (3D) performance of blading with slots, the current research compares the performance of blading with full-span slots to that with blade end slots. First, the two-dimensional (2D) configuration performance is evaluated both for the datum and slotted profiles. The slotted configuration could effectively supress separation, especially under positive incidence conditions where the separation of the datum profile is large. Thus, two 3D blading forms, the full-span slots and the blade end slots (covering 20% of the span from the endwall), are compared within. Results show that blading with full-span slots could effectively reduce the loss under positive incidence angles, while blading with blade end slots could effectively reduce the loss above an incidence angle of −4°. The loss for the end slotted blade is lower than that of the full-span slotted blade under most incidence angles (within the range of 4°). The additional mixing loss of the jet and the main flow are caused by the full-span slots at the mid-span regions where the flow remains attached for the unslotted geometry. Blading with slots alters the flow structures and reorganises the flow in the blade end regions. The self-adaptive jets from the slot outlet push the accumulated low-momentum flow downstream and restrain its migration toward the mid-span, such that the uniform main flow in the blade mid-span region is enhanced.

Active Control of the Corner Separation on a Highly Loaded Compressor Cascade With Periodic Nonsteady Boundary Conditions by Means of Fluidic Actuators

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Marcel Staats ◽  
Wolfgang Nitsche
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Active Flow Control ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Compressor Cascade ◽  
Pulsed Detonation Engine ◽  
Detonation Engine ◽  
The Impact ◽  
Highly Loaded

This paper discusses the impact of a nonsteady outflow condition on the compressor stator flow that is forced through a mimic in the wake of a linear low-speed cascade to simulate the conditions that would be expected in a pulsed detonation engine. 2D/3C-PIV measurements were made to describe the flow field in the passage. Detailed wake measurements provide information about static pressure rise as well as total pressure loss. The stator profile used for the investigations is highly loaded and operates with three-dimensional flow separations under design conditions and without active flow control. It is shown that sidewall actuation helps stabilize the flow field at every phase angle and extends the operating range of the compressor stator. Furthermore, the static pressure gain can be increased by 6% with a 4% loss reduction in time-averaged data.

Active Control of the Corner Separation on a Highly Loaded Compressor Cascade With Periodic Non-Steady Boundary Conditions by Means of Fluidic Actuators

2015 ◽  
Author(s):  
Marcel Staats ◽  
Wolfgang Nitsche
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Active Flow Control ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Side Wall ◽  
Compressor Cascade ◽  
Detonation Engine ◽  
The Impact ◽  
Highly Loaded

This contribution discusses the impact of a non-steady outflow condition on the compressor stator flow that is forced through a mimic in the wake of a linear low speed cascade to simulate the conditions that would be expected in a pulsed detonation engine. 2D/3C-PIV measurements were made to describe the flow field in the passage. Detailed wake measurements provide information about static pressure rise as well as total pressure loss. The stator profile used for the investigations is highly loaded and operates with three-dimensional flow separations under design conditions and without active flow control. It is shown that side wall actuation helps to stabilize the flow field at every phase angle and extends the operating range of the compressor stator. Furthermore, the static pressure gain can be increased by 6% with a 4% loss reduction in time averaged data.

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.

Location Effect of Boundary Layer Suction on Compressor Hub-Corner Separation

2014 ◽  
Author(s):  
Ping-Ping Chen ◽  
Wei-Yang Qiao ◽  
Karsten Liesner ◽  
Robert Meyer
Keyword(s):  
Boundary Layer ◽  
Pressure Loss ◽  
Total Pressure ◽  
Three Dimensional ◽  
Base Flow ◽  
Total Pressure Loss ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Corner Separation ◽  
Boundary Layer Suction

The large secondary flow area in the compressor hub-corner region usually leads to three-dimensional separation in the passage with large amounts of total pressure loss. In this paper numerical simulations of a linear high-speed compressor cascade, consisting of five NACA 65-K48 stator profiles, were performed to analyze the flow mechanism of hub-corner separation for the base flow. Experimental validation is used to verify the numerical results. Active control of the hub-corner separation was investigated by using boundary layer suction. The influence of the selected locations of the endwall suction slot was investigated in an effort to quantify the gains of the compressor cascade performance. The results show that the optimal chordwise location should contain the development section of the three-dimensional corner separation downstream of the 3D corner separation onset. The best pitchwise location should be close enough to the vanes’ suction surface. Therefore the optimal endwall suction location is the MTE slot, the one from 50% to 75% chord at the hub, close to the blade suction surface. By use of the MTE slot with 1% suction flow ratio, the total-pressure loss is substantially decreased by about 15.2% in the CFD calculations and 9.7% in the measurement at the design operating condition.

Active Flow Control on a Highly Loaded Compressor Stator Cascade With Synthetic Jets

2016 ◽  
Author(s):  
Yong Qin ◽  
Ruoyu Wang ◽  
Yanping Song ◽  
Fu Chen ◽  
Huaping Liu
Keyword(s):  
Flow Separation ◽  
Coupling Effect ◽  
Active Flow Control ◽  
Pressure Rise ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Main Flow ◽  
Control Effect ◽  
Actuation Frequency ◽  
Highly Loaded

Numerical investigations on the control effects of synthetic jets are conducted upon a highly loaded compressor stator cascade. The influence of forcing parameters including actuation frequency, jet amplitude and slot location are analyzed in detail with the single-slit synthetic jet. Besides, a new slot arrangement is put forward for the purpose of effectively controlling flow separation. Simulation results validate the remarkable effectiveness of the single-slit synthetic jet on controlling flow separation. Owing to the coupling effect between the jet and the main flow, the actuation appears to be most efficient under the characteristic frequency of the main flow passing through the airfoil. Additionally, with the increase of jet momentum coefficient, the control effect is enhanced at first and then decreased, depending on the two aspects: the improvements of aerodynamic performance by momentum injection and the additional flow losses caused by the jet. Compared to other actuator configurations, the segment synthetic jet with three sections can more effectively deflect the end-wall cross flow and thus impede the development of corner vortex, which helps to restrain the accumulation of low momentum fluid towards the corner, emphasizing the importance of slot arrangement. Accordingly, under the optimum condition, the total pressure loss coefficient gains a 15.8% reductions and the static pressure rise coefficient is increased by 5.01%.

Topological analysis of plasma flow control on corner separation in a highly loaded compressor cascade

2012 ◽  
Vol 28 (5) ◽  
pp. 1277-1286 ◽  
Author(s):  
Xiao-Hu Zhao ◽  
Yun Wu ◽  
Ying-Hong Li ◽  
Xue-De Wang ◽  
Qin Zhao
Keyword(s):  
Flow Control ◽  
Plasma Flow ◽  
Topological Analysis ◽  
Compressor Cascade ◽  
Corner Separation ◽  
Plasma Flow Control ◽  
Highly Loaded

Experimental investigation on separation control by slot jet in highly loaded compressor cascade

2017 ◽  
Vol 232 (9) ◽  
pp. 1704-1714 ◽  
Author(s):  
Hu Jiaguo ◽  
Wang Rugen ◽  
Li Renkang ◽  
He Chen ◽  
Li Qiushi
Keyword(s):  
High Efficiency ◽  
Incidence Angle ◽  
Suction Side ◽  
Separation Control ◽  
Compressor Cascade ◽  
Turning Angle ◽  
Control Approach ◽  
Stable Operating ◽  
Operating Margin ◽  
Highly Loaded

Separation control in compressor cascade is very significant for modern high efficiency compressor. This paper introduces a separation control approach using self-supplied jet in a highly loaded cascade. A novel arc slot is created into the cascade at the full span range, which connects the flow fields between the pressure and suction side. Because of the pressure difference, the slot enables to induce the jet flow into the suction side separation. Experiments are conducted to evaluate the separation control effects and preliminarily study the mechanism. The results show that the slot cascade acquires more ordered outflow by reducing the suction side separation and suppressing the complex vortices. Due to the great reduction of the separation, the total loss significantly decreases by 21.9% and the flow turning angle increases by 2.1° in average. According to the improvements of the cascade performance, the stable operating margin of the highly loaded cascade is greatly improved at least 3° in terms of the incidence angle.

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