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Journal of Thermal Science 2021年第1期30卷 257-270页

作者： WANG Yucheng ZHAO Wensheng WANG Pengfei JIANG Jin LUO Xiangyu Key Laboratory of Hydraulic Machinery Transients Ministry of EducationWuhan UniversityWuhan 430072China School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China

Elliptical fin-and-tube heat exchangers are commonly used in air conditioning,heating,refrigeration industries,and *** study numerically investigates the effect of vortex generators on the performance of elliptical fin-and-tube heat exchanger under different inclination *** this study,air flow that is in the transitional regime is selected as the working *** numbers at the inlet are varied in a range of 1300 to 2100,and the shear stress transport k-ωturbulence model is selected to solve the non-closure of basic turbulence *** ellipticity ratios of the tubes which are used for the analysis are between 0.6 and 1.0,and the inclination angles are varied from 15°to 75°.The effects of different inclination angles of vortex generators on the Colburn factor j,friction factor f,and efficiency index j/f are *** friction and Colburn factors are observed to increase with increasing vortex generator inclination *** is found that the efficiency factors for a 15°vortex generator inclination angle at 0.6,0.7,0.8,and 0.9 ellipticity ratios improve compared to the corresponding cases with no vortex ***,the vortex generator cannot improve the efficiency factor of the circular tube heat *** 3 D CFD method employed by this study has great potential for use in optimally designing the arrangement of the vortex generators to enhance the performance of heat exchangers.

关键词： heat exchanger vortex generator Colburn factor friction factor heat exchanger efficiency

Imaging of the Space-time Structure of a vortex generator in Supersonic Flow

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Chinese Journal of Aeronautics 2012年第1期25卷 57-63页

作者： WANG Dengpan XIA Zhixun ZHAO Yuxin WANG Bo ZHAO Yanhui Science and Technology on Scramjet Laboratory National University of Defense TechnologyChangsha 410073China

The fine space-time structure of a vortex generator （VG） in supersonic flow is studied with the nanoparticle-based planar laser scattering （NPLS） method in a quiet supersonic wind tunnel. The fine coherent structure at the symmetrical plane of the flow field around the VG is imaged with NPLS. The spatial structure and temporal evolution characteristics of the vortical structure are analyzed, which demonstrate periodic evolution and similar geometry, and the characteristics of rapid movement and slow change. Because the NPLS system yields the flow images at high temporal and spatial resolutions, from these images the position of a large scale structure can be extracted precisely. The position and velocity of the large scale structures can be evaluated with edge detection and correlation algorithms. The shocklet structures induced by vortices are imaged, from which the generation and development of shocklets are discussed in this paper.

关键词： vortex generator nanoparticle-based planar laser scattering vortical structure evolution characteristic shocklet

Experimental investigation of vortex generator influences on propeller cavitation and hull pressure fluctuations

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Journal of Hydrodynamics 2020年第1期32卷 82-92页

作者： Hong-bo Huang Yun Long Bin Ji National Key Laboratory on Ship Vibration and Noise China Ship Scientific Research CenterWiuxi 214082China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China

In this paper,the transient turbulent cavitating flow around a marine propeller behind a ship was investigated experimentally with emphasis on how vortex generator(VG)influences propeller cavitation and hull pressure *** experiments were carried out in China Large Cavitation Channel with the closed test section covering 10.5 m in length and cross-section of 2.2 m^2×2.0m^*** experiment recorded instantaneous cavitation photos of the propeller and pressure fluctuations on the hull *** results demonstrate that without vortex generator,the sheet cavitation inception begins at-50°(310°),and then from-50°(310°)to 30°,the extent and area of sheet cavitation *** vortex generator installed on the hull,the sheet cavitation inception occurs in advance at-60°(300°),and the sheet cavitation expands to larger rotation range due to the vortex *** is shown that the vortex generator with proper geometry and installed location may contribute the highly nonuniform wake to be more uniform,and can make the change of propeller cavitation to be milder,which decrease the pressure fluctuations in this *** analysis indicates that the vortex generator may promote the energy distribution to be more uniform in physical and spectral space in some degree.

关键词： Cavitating flow pressure fluctuations propeller and ship hull vortex generator

Influence of sub boundary layer vortex generator height and attack angle on cross-flows in the hub region of compressors

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Chinese Journal of Aeronautics 2022年第8期35卷 30-44页

作者： Hao FU Ling ZHOU Lucheng JI School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Institute for Aero Engine Tsinghua UniversityBeijing 100084China

It has been recently shown that Sub Boundary layer vortex generator(SBVG,abbreviated as VG hereafter)can suppress the Cross-Flow(CF),and therefore,can eliminate corner separation and increase aerodynamic loading when installed on the end wall inside middle-load compressor ***,when VGs are applied in high-load compressors,it is difficult to achieve ideal *** is because the definition of the VG attack angle in the presence of CF in existing research is confusing,and the stronger CF in high-load compressors worsens the problem and results in an improper design and optimization range of VG attack ***,this paper clarifies the definition of the VG attack angle in the presence of CF and reveals the CF controlling mechanism of VG on a flat *** differences in the flow phenomena around a VG both with and without CF are also *** numerical results show that a larger height or attack angle of the VG generates a greater CF suppression ***,the cross velocity increases when surmounting the primary vortex induced by the VG,except that this enhanced CF is less conspicuous for larger VG *** to the cases without CF,the VG suffers an additional loss because of the stronger separation and primary vortex loss caused by the CF.

关键词： Compressors Corner separation Cross-flow Flat plate vortex generator

Effect of vortex generator spanwise height distribution pattern on aerodynamic characteristics of a straight wing

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Advances in Aerodynamics 2023年第1期5卷 68-82页

作者： Lishu Hao Bao Hu Yongwei Gao Binbin Wei School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China School of Aerospace Engineering Xi’an Jiaotong UniversityXi’an 710049China

vortex generator(VG)is a passive flow control technology,which can effectively inhibit flow ***,significant research efforts have been devoted to the study on the application of VG in airfoil,wing/blade and aircraft flow separation ***,the research on the variable height distribution of VG along the wingspan still *** study focuses on the experimental investigation of the influence of variable height distribution of ramp VG on aerodynamic ***,VG was designed,such that it was composed of two parts,one fixed region and one deformed region,which allowed for height *** height of VGs along the wingspan presented equal-height,triangular and trapezoidal distribution,forming a total of 15 VG ***,the connection mode of the model,the change of angle of attack and the collection and processing of aerodynamic data were ***,a wind tunnel experiment was performed to investigate the influence of height distribution of VG on aerodynamic characteristics of *** experimental results show that:(1)the height distribution of the three types of VGs could inhibit the stall flow and improve the aerodynamic performance of the wing;(2)“Triangular translation 3”and“Trapezoi-dal translation 2”were the best layouts,both of which could increase the maximum lift coefficient,delay stall,and significantly increase the lift-to-drag ratio at high angle of attack;(3)the influence of VG height and position factors on wing stall characteristics was analyzed by using the rough set theory,and the key position information of VG arrangement was *** study indicates that the variable height distribution is obviously better than the equal height distribution,which can provide ideas and refer-ences for the active control of variable height distribution of VGs.

关键词： vortex generator Flow control Rough set theory Wind tunnel experiment

Serpentine Inlet Performance Enhancement Using vortex generator Based Flow Control

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Chinese Journal of Aeronautics 2006年第1期19卷 10-17页

作者：孙姝郭荣伟 Internal Flow Research Center Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

In order to provide the line-of-sight blockage of the engine face for an advanced Uninhabited Combat Air Vehicle（UCAV）, a highly curved serpentine inlet is proposed and experimentally studied. Based on the static pressure distribution measurement along the wall, the flow separation is found at the top wall of the second S duct for the baseline inlet design, which yields a high flow distortion at the exit plane. To improve the flow uniformity, a single array of vortex generators （VGs） is employed within the inlet. In this experimental study, the effects of mass flow ratio, free stream Mach number, angle of attack and yaw on the performance of a serpentine inlet instrumented with VGs are obtained. Results indicate：（1） Compared with the baseline serpentine design without flow control, the application of the VGs promotes the mixing of core flow and the low momentum flow in the boundary layer and thus prevents the flow separation. Under the design condition, the exit flow distortion （-↑△σ0） decreases from 11.7% to 2.3% by using the VGs. （2） With the descent of the free stream Mach number the total pressure loss decreases. However, the circular total pressure distortion increases. When the angle of attack rises from - 4° to 8°, the total pressure recovery and the circular total pressure distortion both go down. In addition, with the increase of yaw the total pressure recovery is fairly constant, while the circular total pressure distortion ascends gradually. （3） When Mao = 0.6-0.8, a = -4°-8° and β = 0°-6°, the total pressure recovery varies between 0.936 and 0. 961, the circular total pressure distortion coefficient varies between 1.4 % and 5.4 % and the synthesis distortion coefficient has a ranges from 3.8 % to 7.0 %. The experimental results confirm the excellent performance of the newly designed serpentine inlet incorporating VGs.

关键词： line-of-sight blockage serpentine inlet flow separation vortex generator total pressure recoveryi circular total pressure distortion synthesis distortion coefficient

THE INVESTIGATION ON CALCULATING THE EFFECT OF NOISES FROM UNDERWATER vortex generator ON SAIL HULL

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THE INVESTIGATION ON CALCULATING THE EFFECT OF NOISES FROM U...

Control of Corner Separation for a Linear Compressor Cascade via Bionic Slanting Riblets at the Endwall

2016年全国压电和声波理论及器件应用研讨会

作者： Yong-wei LIU De-jiang SHANG Qi LI Sheng-feng FU Hong-yang CHEN Acoustic Science and Technology Laboratory Harbin Engineering University College of Underwater Acoustic Engineering Harbin Engineering University National Key Laboratory on Ship Vibration & Noise China Ship Development and Design Center

Background, Motivation and Objective In the airplane, vortex generator is used to suppress flow separation. There are several kinds of vortex generators, such as conventional, boundary layer, sub-boundary layer, mininature, and jet-flow. When ships run at high speed, cavitation is formed in the bulge area. Because cavitation can make big noises, it will be a threat to the sonar. Cavitation can also destroy the blades of propellers. In the paper, a method has been proposed that underwater cavitation is suppressed through the utilization of vortex generation. However, two noises have been produced by vortex generator. One is flow noise from vortex generator;the other is radiated noise from the vibration of vortex generator by the flow. Unfortunately, there are only a little research has been done on the noises from underwater vortex generator. Statement of Contribution/Methods In the paper, the numerical model of underwater sail hull is built up. The flow field of sail hull model is calculated by the software, FLUENT. After the data is dealt with fast fourier transform, FFT, the sound field of sail hull model has been calculated by the software, ACTRAN. Then, the trapezoidal vortex generator is placed on the model of sail hull. The sound field of sail hull model with trapezoidal vortex generator has been calculated through the listed process. After that, the effect of flow noise and radiated noise from vortex generator on sail hull model has been investigated. Results Through the comparison of flow field, we find that vortex generator has changed the transition area of sail hull model. The results indicate that flow noise and radiated noise from underwater vortex generator is very little, compared to that of sail hull model. The total level of sound radiation power from the model of sail hull and with vortex generator is less than that of sail hull model. Because vortex generator changes the direction of water flow, the excitation of sail hull model by the flow has be

关键词： vortex generator Flow noise Radiated noise Transition area

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Journal of Thermal Science 2025年第1期34卷 129-144页

作者： ZHANG Peng LI Yonghong CHENG Rixin Key Laboratory of Civil Aircraft Airworthiness Technology Civil Aviation University of ChinaTianjin 300300China College of Aeronautical Engineering Civil Aviation University of ChinaTianjin 300300China

A new passive control approach,utilizing bionic slanting riblets,is employed to mitigate the flow close to the blade endwall in a linear cascade,and its effectiveness and mechanism in controlling corner separation are investigated through numerical *** slanting riblets are positioned at the endwall upstream of the cascade channel,and the influence of riblet height,yaw angle and relative position on the control of corner separation is *** findings indicate that the application of slanting riblets can efficiently counteract corner separation across the stable operational ***,the introduction of riblets with a height of merely 0.1 times the boundary layer thickness results in a significant reduction in total pressure loss by up to 14.53%,while simultaneously enhancing the static pressure coefficient by 21.74%.Flow analysis reveals that minute vortices produced within the riblet channels tend to coalesce,forming a potent large-scale vortex near the boundary layer's base *** phenomenon results in reduced additional losses compared to conventional vortex ***,the induced vortex promotes enhanced mixing between the mainstream flow and boundary layer,inhibiting the lateral displacement of low-energy fluids within the endwall boundary ***,this delays the onset of separation vortex formation and eliminates vortex rings in the corner region,ultimately enhancing the aerodynamic efficiency of the cascade.

关键词： corner separation compressor cascade slanting riblets additional losses vortex generator

Numerical Study on the Effect of vortex generators on the Aerodynamic Drag of a High-Speed Train

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Fluid Dynamics & Materials Processing 2024年第2期20卷 463-473页

作者： Tian Li Hao Liang Zerui Xiang Jiye Zhang State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China School of Design Southwest Jiaotong UniversityChengdu610031China

A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed *** the shear stress transport(SST)k-ωturbulence model,the effect of various vortex generator types on the aerodynamic characteristics of an ICE2(Inter-city Electricity)train has been *** results indi-cate that the vortex generators with wider triangle,trapezoid,and micro-ramp arranged on the surface of the tail car can signiﬁcantly change the distribution of surface pressure and affect the vorticity intensity in the *** alteration effectively reduces the resistance of the tail ***,the micro-ramp vortex generator with its convergent structure at the rear exhibits enhancedﬂow-guiding capabilities,resulting in a 15.4%reduction in the drag of the tail car.

关键词： vortex generator aerodynamic drag reduction numerical simulation

Manipulation of vertical fence wake using passive vortex generators

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排灌机械工程学报 2014年第5期32卷 369-372,377页

作者： Kim Hyoung-Bum Kim Seoung-Jun Tu Xin-Cheng Park Seung-Ha Kim Seoung-Jun Tu Xin-Cheng Park Seung-Ha Research Center for Aircraft Parts Technology Gyeongsang National University School of Mechanical Engineering Gyeongsang National University R & D Center DongHwa Entec School of Mechanical Engineering Gyeongsang National University Jinju 660 -701 S. Korea R & D Center DongHwa Entee Busan 618-230 S. Korea

The effect of streamwise vortices generated from passive vortex generators was investigated to manipulate the separation bubble behind the vertical fence. The experiments were carried out in a circulating water channel and the velocity fields were measured using 2D and stereoscopic PIV *** distance between the vortex generator and fence and the effect of the Reynolds number were investigated. In addition,the effect of boundary layer thickness was also investigated. The averaged recirculation lengths were compared with that of uncontrolled fence flow. The results showed the oscillatory variation of recirculation region appeared under the existence of vortex generators. The reduction of the separation bubble became larger when the fence was submerged in the thick boundary layer with increasing the distance between the generator and fence. When the boundary layer is thin,vortex generator can only suppress the separation bubble under the specific condition.

关键词： vortex generator flow separation stereoscopic PIV experiment