Flow quality improvement of the wind tunnel testing for a highly-loaded compressor cascade at high incidence

2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Ming Cai ◽  
Limin Gao ◽  
Haoxue Li ◽  
Yangbo Ou
Keyword(s):  
Experimental Data ◽  
Compressor Cascade ◽  
Optimal Angle ◽  
High Incidence ◽  
Maximum Improvement ◽  
Flow Quality ◽  
Test Requirements ◽  
End Wall ◽  
Highly Loaded

Abstract To obtain reliable and accurate experimental data in cascade testing, the influencing factors and the improving method of the flow quality of a highly-loaded compressor cascade under high incidence were investigated through a series of numerical simulations and experiments. The numerical method was validated by experimental data and agreed well at both incidence angles of 0° and 6°. Under the original upper end wall, both experimental and numerical results indicated an unsatisfactory flow quality of the cascade with an obvious nonuniformity of inlet Mach number, and the incidence of the central blade is 3.6° larger than the theoretical value. Using a small curved upper wall can reduce the severe flow separation on the upper wall and achieve a maximum improvement in flow quality under the critical installation angle, where the incidence deviation of the central blade was reduced to 2.1°. Using the combination of adjustable tailboards and a small curved upper end wall can further improve the cascade flow quality. Under the optimal angle of the tailboards, both the inflow uniformity and the outflow periodicity of the three middle blade passages the test requirements, and the incidence deviation of the central blade is reduced to 0.2°.

Effect of Boundary Layer Suction on Aerodynamic Performance of High-Turning Compressor Cascade

2013 ◽  
Author(s):  
Longxin Zhang ◽  
Shaowen Chen ◽  
Hao Xu ◽  
Jun Ding ◽  
Songtao Wang
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Experimental Studies ◽  
Aerodynamic Performance ◽  
Parameter Distribution ◽  
Compressor Cascade ◽  
Boundary Layer Suction ◽  
End Wall ◽  
Low Speed Wind Tunnel ◽  
Good Agreement

Compared with suction slots, suction holes are (1) flexible in distribution; (2) alterable in size; (3) easy to fabricate and (4) high in strength. In this paper, the numerical and experimental studies for a high turning compressor cascade with suction air removed by using suction holes in the end-wall at a low Mach numbers are carried out. The main objective of the investigation is to study the influence of different suction distributions on the aerodynamic performance of the compressor cascade and to find a better compound suction scheme. A numerical model was first made and validated by comparing with the experimental results. The computed flow visualization and exit parameter distribution showed a good agreement with experimental data. Second, the model was then used to simulate the influence of different suction distributions on the aerodynamic performance of the compressor cascade. A better compound suction scheme was obtained by summarizing numerical results and tested in a low speed wind tunnel. As a result, the compound suction scheme can be used to significantly improve the performance of the compressor cascade because the corner separation gets further suppressed.

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.

Numerical and Experimental Findings of a Highly-Loaded Aspirated Cascade

2014 ◽  
Author(s):  
Bronwyn Power ◽  
Liping Xu ◽  
Steven Wellborn
Keyword(s):  
Experimental Tests ◽  
Reynolds Numbers ◽  
Compressor Cascade ◽  
Suction Control ◽  
Numerical Predictions ◽  
Soft Failure ◽  
Low Profile ◽  
Experimental Findings ◽  
End Wall ◽  
Highly Loaded

Comparisons between numerical predictions and experimental tests of a type of highly loaded aspirated compressor cascade are presented. The cascade profile features low solidity and low profile loss with applied blade and end-wall suction control. The cascade mid-span profile design was generated using multi-objective CFD optimization. Two successive levels of modeling were used to obtain the airfoil numerical predictions: the Euler/coupled-boundary layer solver, MISES, and RANS based CFD, executed in FLUENT and with mesh generation conducted in ICEM. A low-speed aspirated cascade rig was designed and built to allow for testing of the aspirated blade design at conditions approaching engine representative Reynolds numbers and inlet turbulence intensity levels. Both numerical and experimental results validated the aspirated cascade design concept. The results also showed evidence of a ‘soft’ failure mode for the aspirated blade when a reduced or zero suction level is applied.

Effect of Non-Axisymmetric End Wall on a Highly Loaded Compressor Cascade in Multi-Conditions

2021 ◽  
Author(s):  
Song Huang ◽  
Chengwu Yang ◽  
Ziliang Li ◽  
Ge Han ◽  
Shengfeng Zhao ◽  
...  
Keyword(s):  
Compressor Cascade ◽  
End Wall ◽  
Highly Loaded

scholarly journals Effective end wall profiling rules for a highly loaded compressor cascade

2016 ◽  
Vol 230 (6) ◽  
pp. 535-553 ◽  
Author(s):  
Xiangjun Li ◽  
Wuli Chu ◽  
Yanhui Wu ◽  
Haoguang Zhang ◽  
Stephen Spence
Keyword(s):  
Compressor Cascade ◽  
End Wall ◽  
Highly Loaded

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.

Орошение томата F1 Донской в открытом грунте Московской области

2019 ◽  
Author(s):  
D.I. Engalychev ◽  
N.A. Engalycheva ◽  
A.M. Menshikh
Keyword(s):  
Experimental Data ◽  
Agricultural Technology ◽  
Tomato Fruits ◽  
River Floodplain ◽  
Yield And Quality ◽  
Open Ground ◽  
Alluvial Meadow ◽  
Standard Production ◽  
Moscow River

Представлены экспериментальные данные о влиянии капельного орошения на урожайность и качество плодов томата при выращивании культуры в открытом грунте Московской области. На плодородных аллювиальных луговых почвах Москворецкой поймы при соблюдении агротехники без орошения в среднем за три года исследований в полевых условиях получена урожайность томата F1 Донской 31,9 т/га, с орошением 48,5 т/га, в т.ч. стандартной продукции 42,6 т/га.The article presents experimental data on the effect of drip irrigation on the yield and quality of tomato fruits when growing crops in open ground of the Moscow Region. On fertile alluvial meadow soils of the Moscow river floodplain, with the observance of agricultural technology without irrigation, the field yield of tomato hybrid F1 Donskoi on average for three years of research was 31.9 t/ha, with irrigation 48.5 t/ha, incl. standard production 42.6 t/ha.

MALIGNANT TUMORS ASSOCIATED WITH METABOLIC SYNDROME: THE EXPRESSION PROFILE OF THE TRANSCRIPTIONAL AND GROWTH FACTORS

2017 ◽  
Vol 63 (6) ◽  
pp. 817-823
Author(s):  
Natalya Yunusova ◽  
Irina Kondakova ◽  
Sergey Afanasev ◽  
Larisa Kolomiets ◽  
Alena Chernyshova
Keyword(s):  
Quality Of Life ◽  
Metabolic Syndrome ◽  
Growth Factors ◽  
Cell Motility ◽  
Expression Profile ◽  
Malignant Tumors ◽  
Molecular Targets ◽  
Factors Associated ◽  
High Incidence

The study of the pathogenetic features of malignant tumors associated with metabolic syndrome (MS) is relevant because of high incidence of these tumors. Investigations of the mechanisms of involvement of MS in the pathogenesis of cancer reasonably supplemented by the study of transcription and growth factors associated with energy imbalance of the cell and involved in proliferation, apoptosis, angiogenesis, cell motility and inflammation. More research is needed to identify the most promising molecular targets for therapy of malignant tumors associated with MS with a view to increasing the survival and quality of life of these patients.

Numerical Investigation of Passive Flow Control Using Wavy Blades in a Highly-Loaded Compressor Cascade

2018 ◽  
Author(s):  
Bo Wang ◽  
Yanhui Wu ◽  
Kai Liu
Keyword(s):  
Numerical Investigation ◽  
Flow Structure ◽  
Cross Flow ◽  
Leading Edge ◽  
Control Flow ◽  
Streamwise Vortices ◽  
Compressor Cascade ◽  
Control Effect ◽  
Suction Surface ◽  
Highly Loaded

Driven by the need to control flow separations in highly loaded compressors, a numerical investigation is carried out to study the control effect of wavy blades in a linear compressor cascade. Two types of wavy blades are studied with wavy blade-A having a sinusoidal leading edge, while wavy blade-B having pitchwise sinusoidal variation in the stacking line. The influence of wavy blades on the cascade performance is evaluated at incidences from −1° to +9°. For the wavy blade-A with suitable waviness parameters, the cascade diffusion capacity is enhanced accompanied by the loss reduction under high incidence conditions where 2D separation is the dominant flow structure on the suction surface of the unmodified blade. For well-designed wavy blade-B, the improvement of cascade performance is achieved under low incidence conditions where 3D corner separation is the dominant flow structure on the suction surface of the baseline blade. The influence of waviness parameters on the control effect is also discussed by comparing the performance of cascades with different wavy blade configurations. Detailed analysis of the predicted flow field shows that both the wavy blade-A and wavy blade-B have capacity to control flow separation in the cascade but their control mechanism are different. For wavy blade-A, the wavy leading edge results in the formation of counter-rotating streamwise vortices downstream of trough. These streamwise vortices can not only enhance momentum exchange between the outer flow and blade boundary layer, but also act as the suction surface fence to hamper the upwash of low momentum fluid driven by cross flow. For wavy blade-B, the wavy surface on the blade leads to a reduction of the cross flow upwash by influencing the spanwise distribution of the suction surface static pressure and guiding the upwash flow.

scholarly journals The design of RIP belts impacts the reliability and quality of the measured respiratory signals

2021 ◽  
Author(s):  
Kristofer Montazeri ◽  
Sigurdur Aegir Jonsson ◽  
Jon Skirnir Agustsson ◽  
Marta Serwatko ◽  
Thorarinn Gislason ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Sleep Apnea ◽  
Automatic Assessment ◽  
Signal Reliability ◽  
Respiratory Airflow ◽  
Flow Quality ◽  
The Mean ◽  
Home Sleep Apnea Testing ◽  
Apnea Testing

Abstract Purpose Evaluate the effect of respiratory inductance plethysmography (RIP) belt design on the reliability and quality of respiratory signals. A comparison of cannula flow to disposable cut-to-fit, semi-disposable folding and disposable RIP belts was performed in clinical home sleep apnea testing (HSAT) studies. Methods This was a retrospective study using clinical HSAT studies. The signal reliability of cannula, thorax, and abdomen RIP belts was determined by automatically identifying periods during which the signals did not represent respiratory airflow and breathing movements. Results were verified by manual scoring. RIP flow quality was determined by examining the correlation between the RIP flow and cannula flow when both signals were considered reliable. Results Of 767 clinical HSAT studies, mean signal reliability of the cut-to-fit, semi-disposable, and disposable thorax RIP belts was 83.0 ± 26.2%, 76.1 ± 24.4%, and 98.5 ± 9.3%, respectively. The signal reliability of the cannula was 92.5 ± 16.1%, 87.0 ± 23.3%, and 85.5 ± 24.5%, respectively. The automatic assessment of signal reliability for the RIP belts and cannula flow had a sensitivity of 50% and a specificity of 99% compared with manual assessment. The mean correlation of cannula flow to RIP flow from the cut-to-fit, semi-disposable, and disposable RIP belts was 0.79 ± 0.24, 0.52 ± 0.20, and 0.86 ± 0.18, respectively. Conclusion The design of RIP belts affects the reliability and quality of respiratory signals. The disposable RIP belts that had integrated contacts and did not fold on top of themselves performed the best. The cut-to-fit RIP belts were most likely to be unreliable, and the semi-disposable folding belts produced the lowest-quality RIP flow signals compared to the cannula flow signal.

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