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基于频率加权的后缘拍动变体机翼流场模态分解

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航空学报 2024年第18期45卷 63-78页

作者：张伟聂旭涛欧李苇夏智勋陈磊国防科技大学空天科学学院长沙410073 中国空气动力研究与发展中心绵阳621000

变体机翼是提高飞行器机动性能、高升低阻,满足复杂多变工况的重要解决途径之一,探索机翼变形对流场的影响机制是变形控制的基础。针对后缘拍动的柔性变体机翼,为准确分析拍动影响机制,提出了频率加权排序的动力学模态分解方法。针对不... 详细信息

变体机翼是提高飞行器机动性能、高升低阻,满足复杂多变工况的重要解决途径之一,探索机翼变形对流场的影响机制是变形控制的基础。针对后缘拍动的柔性变体机翼,为准确分析拍动影响机制,提出了频率加权排序的动力学模态分解方法。针对不同工况下数值模拟结果或试验数据,开展了频率加权法同常规初始值、模态范数排序方法的对比。结果显示频率加权法得到的2阶模态频率与拍动频率吻合,表明该方法能准确体现机翼后缘周期性拍动对流场结构影响,反映机翼变形对尾迹的破碎作用。在相同重构模态数量下,拍动频率为300.0 Hz时,基于数值模拟数据,频率加权法、初始值法、模态范数法重构的速度场误差分别为0.39%、0.58%、3.25%,基于粒子图像测速设备(PIV)试验数据的误差分别为7.56%、8.77%、10.56%,表明频率加权法误差最小,能较好用于主动拍动变体机翼的物理场分析及后续反馈控制。

关键词：变体机翼动力学模态分解频率加权拍动重构

Effect of three-electrode plasma synthetic jet actuator on shock wave control

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Science China(Technological Sciences) 2017年第1期60卷 146-152页

作者： ZHOU Yan xia zhixun LUO ZhenBing WANG Lin Science and Technology on Scramjet Laboratory National University of Defense Technology Changsha 410073 China

A three-electrode high-energy plasma synthetic jet(PSJ) actuator was used for shock wave control. This actuator is an enhanced version of the two-electrode actuator as a high-voltage trigger electrode is added to increase the cavity volume and the input energy while retaining a relatively low disruptive voltage. The electrical properties were studied using current-voltage measurements, and the energy consumption was calculated. To assess the jet strength, the penetration of PSJ was compared with empirical values, and the results show that the momentum flux ratio of PSJ for a capacitance of 0.96, 1.6, and 3 μF was approximately equal to 0.6, 1.0, and 1.3, respectively. The interaction of PSJ with shock waves was acquired using high-speed shadowgraph imaging. The shock was generated by a 25° compression ramp in Mach 2 flow, and PSJ actuator was placed up-stream of the compression ramp. Under the action of PSJ, the strength of the shock was notably weakened, and the near-wall part of the shock was entirely eliminated. The results show the good control effect of the three-electrode high-energy PSJ in high-speed flow.

关键词： plasma synthetic jet three-electrode shock wave active flow control

A novel optimal design for an application-oriented synthetic jet actuator

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Chinese Journal of Aeronautics 2014年第3期27卷 514-520页

作者： Deng Xiong xia zhixun Luo Zhenbing Wang Lin Science and Technology on Scramjet Laboratory National University of Defense Technology

The evaluation indicator for the performance of a synthetic jet actuator （SJA） is well-defined because of its various applications, which require optimal design to improve its performance and extend its field of application. This paper presents a novel approach to the optimal design of an SJA applied to enhance fuel/air mixture. It optimizes the combination of an actuator＇s geometric parameters by selecting the strength of vortex pairs as the evaluation indicator, coupled with orthogonal experiments and analysis of variance （AOV）. The results indicate that slot width is the most notable factor influencing the strength of vortex pairs, followed by cavity height and slot depth. The optimal value of the strength of vortex pairs increases by 32.5%over the experimental data of the base case, and more than 8.4%compared with the simulation results of the orthogonal experiments. It is concluded that the optimal method can effectively improve the performance of an SJA applied in mixing enhancement, reducing the test numbers and the associated design cycle and cost.

关键词： Analysis of variance Evaluation indicator Orthogonal experiment Strength of vortex pairs Synthetic jet

Experimental study on the ignition and combustion characteristics of a magnesium particle in water vapor

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Science China(Technological Sciences) 2012年第9期55卷 2601-2608页

作者： HUANG Xu xia zhixun HUANG LiYa HU JianXin Science and Technology on Scram jet Laboratory National University of Defense TechnologyChangsha 410073China College of Aerospace and Materials Engineering National University of Defense TechnologyChangsha 410073China

Magnesium is of interest for underwater propulsion due to the superior ignition behavior of magnesium particles and the highly exothermic Mg-water *** this work,the ignition and combustion characteristics of an individual millimeter-sized magnesium particle in water vapor were *** order to build an atmosphere of water vapor,an experiment system was established and validated by the experiments of magnesium particle in *** ignition and combustion of a single magnesium particle were accomplished in a combustor filled with water *** surface changes of the particle during the ignition and a steady-state vapor phase combustion were *** on the data obtained,ignition mechanism was analyzed and ignition temperature was *** steady-state combustion of the sample was controlled by diffusion in gas phase,and a one-dimensional,spherically symmetric quasi-steady model was adopted to describe the *** dependence of burning time on the diameter was investigated,and the conclusion that burning time is proportional to the square of the metal sample diameter was drawn.

关键词： magnesium particle water vapor ignition combustion experiment water ramjet

Effect of pressure on the performance of plasma synthetic jet actuator

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Science China(Physics,Mechanics & Astronomy) 2014年第12期57卷 2309-2315页

作者： WANG Lin xia zhixun LUO ZhenBing ZHANG Yu Science and Technology on Scramjet Laboratory National University of Defense Technology College of Aerospace Science Technology National University of Defense Technology

The effects of the ambient air pressure level on the performance of plasma synthetic jet actuator have been investigated through electrical and optical *** from 1 atm down to 0.1 atm were tested with a 10 Hz *** discharge measurement demonstrates that there is a voltage range to make the actuator work *** pressure level needs a higher breakdown voltage,and a higher discharge current and energy deposition are *** when the actuator works with the maximum breakdown voltage,the fraction of the initial capacitor energy delivered to the arc is almost *** preliminary study also confirms the effectiveness of the plasma synthetic jet at low ***,the maximum velocities of the precursor shock and the plasma jet induced by the actuator with maximum breakdown voltage are independent of the ambient pressure level;reach about 530 and 460 m/s *** mass flux of the plasma jet increases with ambient pressure increasing,but the strength of the precursor shock presents a local maximum at 0.6 atm.

关键词： synthetic jet plasma actuator high speed shadowgraph images ambient pressure level

Multi-resolution Analysis of Density Fluctuation of Coherent Structures About Supersonic Flow over VG

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Chinese Journal of Aeronautics 2012年第2期25卷 173-181页

作者： WANG Dengpan ZHAO Yuxin xia zhixun WANG Qinghua HUANG Xu Science and Technology on Scramjet Laboratory National University of Defense Technology Changsha 410073 China The ThirdInstitute the SecondArtillery Equipment Academy Beijing 100085 China

The density field around a vortex generator （VG） in supersonic flow is studied with a nanoparticle-based planar laser scattering （NPLS） method. Based on the calibration, i.e., the density distribution of the supersonic flow around a wedge, the density field of a supersonic VG is measured. According to movement characteristics of coherent structure in VG’s flow fields and the basic concepts of wavelet, the density fluctuating signals and multi-resolution characteristics of density field images are studied. The multi-resolution characteristics of density fluctuation can be analyzed with wavelet transformation of NPLS images. The wavelet approximate coefficients of density fluctuating signals exhibit their characteristics at different scales, and the corresponding detail coefficients show the difference of diverse layer smooth approximation in some way. Based on 2D wavelet decomposition and reconstruction of density field images, the approximate and detail signals at different scales are studied, and the coherent structures at different scales are extracted and analyzed.

关键词： vortex generator nanoparticle-based planar laser scattering coherent structure density fluctuation multi-resolution analysis

Performance study of a water ramjet engine

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Science China(Technological Sciences) 2011年第4期54卷 877-882页

作者： HUANG LiYa xia zhixun HU JianXin ZHU QianWen College of Aerospace and Materials Engineering National University of Defense TechnologyChangsha 410073China

A performance study of a water ramjet engine is *** engine is powered by the reaction of a magnesium-based propellant and ingested *** this study,a solid propellant,which consisted of a large percentage of magnesium,a binder and a small amount of oxidant,was used as a hydro reactive *** water was injected into the combustion chamber as a main oxidant.A scaled-down experimental engine was tested in a direct-connect ground testing system to characterize the factors influencing the engine *** results show that the increasing of total water/fuel ratio,an addition of secondary water intake along the combustion chamber,a larger magnesium content in the solid propellant,a smaller primary water injection angle towards the coming main flow,and a higher primary injection pressure were all able to promote the engine *** maximum engine performance was obtained in test 08,and with all tests,an appropriate set of parameters and conditions for the optimum engine performance were determined

关键词： underwater propulsion system ramjet engine magnesium water combustion performance experiment

Experimental characteristics of a two-electrode plasma synthetic jet actuator array in serial

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Chinese Journal of Aeronautics 2018年第12期31卷 2234-2247页

作者： Yan ZHOU zhixun xia Zhenbing LUO Lin WANG Xiong DENG Science and Technology on Scramjet Laboratory National University of Defense Technology

Plasma Synthetic Jet(PSJ) actuators have shown wide and promising application prospects in high-speed flow control, due to their advantages including high exhaust speed, wide frequency band, rapid response, and non-moving components. Although previous studies on PSJ actuators are abundant, most of them have focused on the performance of a single actuator. However, in practice, an actuator array is very necessary for large-scale aerodynamic actuation on account of the small affected area of a single PSJ. In this paper, the characteristics of a twoelectrode plasma synthetic jet actuator array in serial are investigated experimentally. Compared to a parallel actuator array, the serial actuator array requires simpler power supply design and is much easier to realize. High-speed photography of the discharge evolution, voltage-current measurement, and shadowgraphy visualization are used in the investigation. Experimental results show that, for the serial actuator array, weak discharges happen firstly between energized and suspending electrodes, and then a strong pulse arc discharge is triggered. The breakdown voltage in serial is irrelevant to such factors as the number of actuators, the maximum or minimum gap in serial,the connection sequence, etc. It is mainly determined by the sum of gaps. For serial actuators with the same anode-to-cathode spacing, the energy deposition is the same, and the jet is synchronous and similar. Because of the entrainment and merging of adjacent jet vortices, the jet front speed of an aligned synchronous jet array increases as the orifice distance decreases. To achieve the highest jet front velocity, the orifice of the actuator has an optimal diameter.

关键词： Capacitive power supply Flow control Plasma synthetic jet Pulse arc discharge Serial actuator array Two-electrode

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