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Improving flight performance of UAVs by ice shape modulation

Chinese Journal of Aeronautics 2024年第8期37卷 49-62页

作者： Jiajun ZHANG Xuecheng LIU Hua LIANG Like XIE Biao WEI haohua zong Yun WU Yinghong Li National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering UniversityXi’an 710038China Institute of Aero-Engine School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

Aircraft icing poses a great threat to flight *** response to the characteristics of high-power consumption,large volume,and heavy weight of traditional anti-/de-icing technologies,the concept of ice shape modulation is proposed,which is called ice tolerant ***,the flight performance of Unmanned Aerial Vehicle(UAV)was compared in three states:no ice,full ice,and modulated ice through flight *** was found that ice shape modulation has a significant improvement effect on the aerodynamic performance of aircraft under icing *** the three modulated ice shape conditions in this experiment,the lift coefficient of the UAV under different ice shape modulation conditions increased by 18%–33%,and the stalling angle was delayed by 3°-5°.Subsequently,the pressure distribution,streamlines in the flow field,and detached vortex distribution of the UAV model in these three states were obtained through numerical simulation,to study the mechanism of ice shape modulation on the aerodynamic performance of *** simulation found that the reason for the improvement of the wings effect after ice shape modulation is that the modulated area forms a leading-edge protrusion structure similar to a vortex *** structure prolongs the mixed flow region on the wings surface and reduces the trend of flow separation,which plays a role in increasing lift and reducing drag for UAVs under icing ***,a reverse reachable set that can be used for unexpected state recovery is used as the definition of flight safety boundaries,and an aircraft dynamics model is established to obtain flight safety boundaries for different *** has found that the flight safety boundary of the UAV in a no ice state is greater than that in a modulated ice state,and the safety boundary in a modulated ice state is greater than that in a full ice *** with the full ice state,the flight safety boundary after modulation has expanded by 27.0%.The sch

关键词： Ice shape modulation Aerodynamic performance Reachable set Flight safety UAV

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Airfoil friction drag reduction based on grid-type and super-dense array plasma actuators

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Plasma Science and Technology 2024年第2期26卷 94-103页

作者：方子淇宗豪华吴云梁华苏志 School of Aerospace Engineering Xi'an Jiaotong UniversityXi'an 710049People's Republic of China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049People's Republic of China National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering UniversityXi'an 710038People's Republic of China

To improve the cruise flight performance of aircraft, two new configurations of plasma actuators(grid-type and super-dense array) were investigated to reduce the turbulent skin friction drag of a low-speed airfoil. The induced jet characteristics of the two actuators in quiescent air were diagnosed with high-speed particle image velocimetry(PIV), and their drag reduction efficiencies were examined under different operating conditions in a wind tunnel. The results showed that the grid-type plasma actuator was capable of producing a wall-normal jet array(peak magnitude: 1.07 m/s) similar to that generated in a micro-blowing technique, while the superdense array plasma actuator created a wavy wall-parallel jet(magnitude: 0.94 m/s) due to the discrete spanwise electrostatic forces. Under a comparable electrical power consumption level,the super-dense array plasma actuator array significantly outperformed the grid-type configuration,reducing the total airfoil friction drag by approximately 22% at a free-stream velocity of 20 m/*** magnitude of drag reduction was proportional to the dimensionless jet velocity ratio(r), and a threshold r = 0.014 existed under which little impact on airfoil drag could be discerned.

关键词： plasma actuator flow control drag reduction airfoil

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Characteristic of rich-mixture ignition kernel driven by nanosecond repetitive pulsed discharge

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Science China(Technological Sciences) 2016年第1期59卷 109-116页

作者： LIN BingXuan WU Yun LI YiWen JIA Min zong haohua DING Jian LI YingHong College of Aeronautical and Astronautical Engineering Air Force Engineering University School of Electrical Engineering Xi'an Jiaotong University

Plasma-assisted ignition is a promising technology to improve engine performance. Nanosecond repetitive pulsed discharge is widely used in plasma-assisted ignition owing to its chemical activations and thermal and hydrodynamic expansions. However, the influence of ultrafast heating and hydrodynamic effects on the development of the rich-mixture ignition kernel is largely unknown. The present study aims to illustrate these effects using electrical and schlieren measurement. The number and the frequency of discharge pulses are exactly controlled to establish the relationship among the discharge energy, frequency, and rich-mixture ignition-kernel characteristics. The evolution of the ignition kernel in the early stage is mainly dominated by the discharge energy and frequency, i.e., a greater energy and a higher frequency yield a larger ignition kernel. Moreover, the influence of both the energy and frequency on the ignition kernel gradually disappears as the ignition kernel develops. According to the experimental data and theoretical analysis, the calculated laminar burning velocity is 0.319 m/s with a Markstein length of 13.43±0.11 cm when the voltage is 5.9 k V, the frequency is 3 k Hz, and the equivalence ratio is 1.3. This result indicates that the rich-mixture flame is stable in the early stage of ignition.

关键词： plasma-assisted ignition NRP discharge rich-mixture ignition kernel laminar burning velocity markstein length

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Improving aircraft aerodynamic performance with bionic wing obtained by ice shape modulation

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Chinese Journal of Aeronautics 2023年第2期36卷 76-86页

作者： Like XIE Hua LIANG haohua zong Yun WU Yinghong LI Zhi SU Xuecheng LIU Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049China

For Unmanned Aerial Vehicles(UAVs)with limited electrical power to achieve effectively anti-/de-icing at the leading edge of the wing,a strategy of ice shape modulation was *** simulated ice shape pieces printed by 3D printing technology are mounted on a NACA0012 finite wing model,and its lift/drag coefficients and suction-side velocity fields are measured by the six-component force balance and the Particle Imaging Velocimetry(PIV),*** ratio of the spanwise length of a single ice shape piece to chord length and the spanwise length of the non-icing area between the two adjacent single ice shape pieces are defined as dimensionless ice shape length(w/c)and dimensionless modulation ratio(w/λ),*** results indicate that for a fixed w/λ,the wing lift coefficient first increases and then drops with increasing w/c,and a peak value exists when w/c is between 0.1 and *** lower the w/λis,the higher the wing lift coefficient will *** periodical variation of the flow separation area along the spanwise direction is attributed on the one hand to the acceleration effect of the flow field in the non-icing area which reduces the separation area,and on the other hand to the cross-flow caused by the streamwise vortices from the non-icing area to the icing area which promotes the mixing of the flow field(similar to vortex generators).The obtained modulation law is verified through flight tests and provides guidance for the use of ice shape modulation scheme for UAVs that cannot be completely anti-/deicing under severe weather conditions.

关键词： Dimensionless ice shape length Dimensionless modulation ratio Ice shape modulation NACA0012 finite wing Particle imaging velocimetry(PIV) Unmanned aerial vehicles(UAVs)

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Geometrical and electrical optimization of NS-SDBD streamwise plasma heat knife for aircraft anti-icing

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Chinese Journal of Aeronautics 2023年第2期36卷 87-99页

作者： Zhi SU Hua LIANG haohua zong Jun LI Xu FANG Biao WEI Jie CHEN Weiliang KONG Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038China Institute of Aero-engine School of Mechanical EngineeringXi'an Jiaotong UniversityXi'an 710049China Northwest Institute of Nuclear Technology Xi'an 710024China The Green Aerotechnics Research Institute Chongqing Jiaotong UniversityChongqing 404100China

Ice accretion on aircraft encountering supercooled water droplets in clouds poses great risks to flight performance and *** the aim of optimizing the newly developed streamwise plasma heat knife method for anti-icing,a parametric investigation is carried out in this *** influence of the detailed voltage profile on the heating effects of a Surface Dielectric Barrier Discharge driven by Nanosecond Pulses(NS-SDBD)is investigated,and a comparison of the antiicing performance among different configurations of streamwise plasma heat knife is *** results show that columnar high-temperature regions produced by a multi-streamer discharge appear at small pulse rise time,but become diffuse as the pulse rise time *** optimal pulse rise time exists to provide a wide range and high value of temperature,which is found to be 150 ns for the setup in the present *** influence of the pulse fall time is much weaker than that of the rise *** range and value of the temperature decrease with increasing pulse fall time.A greater pulse width is found to improve the heating effect by increasing the discharge *** a spanwise electrode is placed connecting the streamwise electrodes of the streamwise plasma heat knife at the airfoil leading edge,the anti-icing performance becomes poorer,whereas good performance is achieved when the spanwise electrode is at the edge of the streamwise *** on this,a three-level configuration of the plasma heat knife is proposed,and its anti-icing performance is found to be much better than that of the original configuration.

关键词： Airfoil icing mitigation Dielectric barrier discharge Nanosecond pulse Voltage profile Plasma

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Minimizing airfoil drag at low angles of attack with DBD-based turbulent drag reduction methods

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Chinese Journal of Aeronautics 2023年第4期36卷 104-119页

作者： Zhi SU haohua zong Hua LIANG Jun LI Like XIE Xuecheng LIU Weiliang KONG Borui ZHENG Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an 710038China Institute of Aero-engine School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China The Green Aerotechnics Research Institute of Chongqing Jiaotong University Chongqing 404100China

Dielectric Barrier Discharge(DBD)based turbulent drag reduction methods are used to reduce the total drag on a NACA 0012 airfoil at low angels of *** interaction of DBD with turbulent boundary layer was investigated,based on which the drag reduction experiments were *** results show that unidirectional steady discharge is more effective than oscillating discharge in terms of drag reduction,while steady impinging discharge fails to finish the mission(*** increase).In the best scenario,a maximum relative drag reduction as high as 64%is achieved at the freestream velocity of 5 m/s,and a drag reduction of 13.7%keeps existing at the freestream velocity of 20 m/*** unidirectional discharge,the jet velocity ratio and the dimensionless actuator spacing are the two key parameters affecting the *** drag reduction magnitude varies inversely with the dimensionless spacing,and a threshold value of the dimensionless actuator spac-ing of 540(approximately five times of the low-speed streak spacing)exists,above which the drag *** the jet velocity ratio smaller than 0.05,marginal drag variation is *** con-trast,when the jet velocity ratio larger than 0.05,the experimental data bifurcates,one into the drag increase zone and the other into the drag reduction zone,depending on the value of dimensionless actuator *** both zones,the drag variation magnitude increases with the jet velocity *** total drag reduction can be divided into the reduction in pressure drag and turbulent friction drag,as well as the increase in friction drag brought by transition *** reduction in tur-bulent friction drag plays an important role in the total drag reduction.

关键词： Dielectric barrier discharge Dimensionless scaling Plasma actuator Turbulent friction drag Wake

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Parametric study of high-frequency characteristics of plasma synthetic jet actuator

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Plasma Science and Technology 2021年第12期23卷 140-149页

作者： Guozheng SONG haohua zong Hua LIANG Zhi SU Like XIE Xing ZHENG Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038People's Republic of China School of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049People's Republic of China

A major issue of plasma synthetic jet actuator(PSJA)is the severe performance deterioration at high working *** this study,experiments and numerical simulation are combined together to investigate the influence of thermal conductivity,throat length(Lth)and discharge duration(Td)on the high-frequency characteristics of *** show that the variation of the actuator thermal conductivity and discharge duration will not alter the saturation frequency of the actuator,whereas decreasing the throat length results in an increase of the saturation *** a short-duration capacitive discharge of 1.7μs,a clear shock wave is issued from the orifice,followed by a weak *** a comparison,when the discharge duration is increased up to 202.6μs,a strong jet column is formed and no obvious shock wave can be *** on numerical simulation results,it becomes clear that the long-duration pulse-DC discharge is able to heat the cavity gas to a much higher temperature(3141 K)than capacitive discharge,greatly improving the conversion efficiency of the arc discharge energy to the internal energy of the cavity *** addition,high-speed Schlieren imaging is deployed to study the performance degradation mechanism of PSJA at high working *** of the exit jet grayscale indicates that as long as the saturation frequency is exceeded,the actuator becomes unstable due to insufficient refresh *** higher the discharge frequency,the more frequently the phenomenon of‘misfires’will occur,which explains well the decaying jet total pressure at above saturation frequency.

关键词： thermal conductivity throat length discharge duration plasma synthetic jet saturation frequency

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Experimental study on plasma actuation characteristics of nanosecond pulsed dielectric barrier discharge

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Plasma Science and Technology 2022年第1期24卷 129-138页

作者： Hao ZHENG Hua LIANG Jie CHEN haohua zong Xiangzhe MENG Like XIE Yinghong LI Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038People’s Republic of China Chinese Flight Test Establishment Xi’an 710089People’s Republic of China School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China

Combining high-speed schlieren technology and infrared imaging technology,related research has been carried out on the influence of parameters such as actuation voltage,repetition frequency,and electrode size of an actuator on the discharge characteristics,induced flow field characteristics,and thermal characteristics of nanosecond pulsed dielectric barrier *** results show that increasing the value of the actuation voltage can significantly increase the actuation intensity,and the plasma discharge area is significantly *** the repetition frequency can increase the number of discharges per unit *** will cause more energy input and induce more changes in the flow *** effect of temperature rise is more *** width of the covered electrode will affect the potential distribution during the discharge process,which in turn will affect the extension process of the plasma discharge *** the same actuation intensity,the wider the covered electrode,the larger range the induced flow field and temperature rise *** experimental analyses of high-frequency actuation characteristics,temperature field characteristics,flow field characteristics and actuation parameter settings provide support for the parameter selection and partial mechanism analysis of plasma anti-icing.

关键词： NS-DBD actuation voltage repetition frequency induced flow field temperature rise

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Control of flow separation over a wing model with plasma synthetic jets

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Plasma Science and Technology 2022年第6期24卷 135-147页

作者： Zhi SU Guozheng SONG haohua zong Hua LIANG Jun LI Like XIE Xuecheng LIU Weiliang KONG Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'an 710038People's Republic of China Institute of Aero-Engine School of Mechanical EngineeringXi’an Jiaotong UniversityXi'an 710049People's Republic of China The Green Aerotechnics Research Institute of Chongqing Jiaotong University Chongqing 404100People's Republic of China

An array of 30 plasma synthetic jet actuators(PSJAs)is deployed using a modified multichannel discharge circuit to suppress the flow separation over a straight-wing *** lift and drag of the wing model are measured by a force balance,and the velocity fields over the suction surface are captured by a particle imaging velocimetry *** show that the flow separation of the straight wing originates from the middle of the model and expands towards the wingtips as the angle of attack *** flow separation can be suppressed effectively by the PSJAs *** best flow control effect is achieved at a dimensionless discharge frequency of F^+=1,with the peak lift coefficient increased by 10.5%and the stall angle postponed by 2°.To further optimize the power consumption of the PSJAs,the influence of the density of PSJAs on the flow control effect is investigated.A threshold of the density exits(with the spanwise spacing of PSJAs being 0.2 times of the chord length in the current research),below which the flow control effect starts to deteriorate *** addition,for comparison purposes,a dielectric barrier discharge(DBD)plasma actuator is installed at the same location of the *** the same power consumption,4.9%increase of the peak lift coefficient is achieved by DBD,while that achieved by PSJAs reaches 5.6%.

关键词： flow separation plasma synthetic jet density dielectric barrier discharge

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水平轴风力机主动尾流控制综述

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空气动力学学报 2022年第4期40卷 51-68页

作者：宗豪华孙恩博西安交通大学机械工程学院西安710049

对于大型风电场而言,由尾流干扰引起的产能损失最高可达30%~40%。主动尾流控制(AWC)技术通过上游风力机的偏航来诱导尾流侧向偏转,以减弱对后排风力机的尾流干扰、增加风电场的总产能,应用前景极其广阔。本文从无偏航风力机尾流模型、... 详细信息

对于大型风电场而言,由尾流干扰引起的产能损失最高可达30%~40%。主动尾流控制(AWC)技术通过上游风力机的偏航来诱导尾流侧向偏转,以减弱对后排风力机的尾流干扰、增加风电场的总产能,应用前景极其广阔。本文从无偏航风力机尾流模型、偏航风力机尾流模型、多风力机尾流叠加方法和风电场产能优化四个角度,综述了AWC技术在过去近20年的研究进展,并对该技术走向工程应用中所亟需解决的问题进行了展望。整体来看,该项技术已经基本成熟。研究人员从最初的理论、仿真和风洞实验研究,走向了实际风电场的效果验证。在理论预测层面,高斯尾流亏损模型、基于旋涡诱导横向速度的一次和二次尾流偏转模型、具备动量守恒特性的尾流叠加方法正在成为风电场产能预测的标配。实际工程应用层面,风力机间距、排数、湍流度、大气边界层热稳定性、风向和风速变化均会影响AWC所带来的产能收益;典型条件下,应用AWC技术后,全尾流干扰风向上的风电场产能可提高约5%~15%,各个风向平均后的年均收益约为1%~3%。

关键词：风力机尾流偏航控制产能优化综述

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