折叠变体飞行器风洞试验特种模型设计

特种高速风洞试验模型设计一直是风洞试验领域的难点问题.针对某变体飞行器高速风洞试验任务提出的运动性能指标,设计开发了可控的折叠变体试验模型,对其设计方案及工作原理进行了阐述,对折叠变体传动机构进行了优化和角度误差的分析与计算.结果表明该试验模型能够对机翼折叠变体角度进行连续、稳定和精确控制,完全达到了设计要求的各项指标.     

折叠变体飞行器风洞试验模型研发

变体飞行器一直是航空领域研究的热点问题.针对某变体飞行器风洞试验任务提出的运动性能指标,设计开发了可控的折叠变体试验模型,对其设计方案及工作原理进行了阐述,对折叠变体机构进行了运动学与动力学分析,建立了位移、速度和加速度控制的数学模型,得出了机构的最大受力状态及各连接杆件的最大受力值,并进行了角度误差的分析与计算.结果表明,该试验模型能够对机翼折叠变体角度进行连续、稳定和精确控制,完全达到了设计要求的各项指标.     

跨超声速风洞模型自动滚转支撑装置设计

风洞试验常需要自动改变模型的滚转角,必须有相应滚转支撑装置。针对跨超声速风洞模型受到冲击载荷作用,以及对支撑装置外形尺寸的限制,设计了一种新型的自动滚转支撑装置。选取符合支撑装置外形限制的伺服电机和谐波减速器作为驱动源和高速级传动机构,并运用电磁制动器对非滚转状态下的模型进行锁紧。低速级传动采用行星传动,直接承受模型滚转载荷。对行星传动从结构和加工工艺方面进行了设计研究。分析计算结果表明,支撑装置壳体、太阳轮等关键部件强度足够。跑合和加载实验结果表明,支撑装置借助其控制系统能够运用于模型的跨超速试验。     

一种用于折叠翼飞机的行星齿轮机构动力学分析

针对折叠翼飞机的折叠机构,在齿轮啮合机构基础上提出一种行星齿轮传动机构实现机翼折叠,利用ADAMS软件对两种机构进行了动力学仿真分析.通过对两种机构的对比分析,证明针对折叠翼飞机设计的行星齿轮机构较原齿轮啮合机构能够有效减小齿轮间的接触力,改善机构的运动平稳特性,降低对驱动电机转矩的要求,有利于提高机构的效率.经仿真分析,证明所设计的行星齿轮传动机构可作为折叠翼飞机的折叠传动机构方案.     

基于双导程蜗杆的风洞模型支撑机构设计

风洞是航空航天飞行器研发的基础性关键性地面设备,模型支撑系统是风洞的关键部件,其运动精度和动态特性直接影响风洞试验数据精准度和可信度。采用双导程蜗杆副作为模型支撑系统的传动部件,对转窗机构进行有限元分析和优化设计,将计算结果运用在机构设计中。模型支撑系统试验结果表明各项指标满足设计要求。     

高速行星牵引增速机构研究

对用于高速传动的中空滚子行星牵引增速机构进行了设计研究和试验测试，对该机构输出轴的径向刚度和回转精度进行了分析，并提出了测量传动机构的传动比变化率监测机构运行。分析和试验表明，行星牵引增速机构安全能够胜任高速，超高速传动。     

一种变体飞机机翼折叠作动器的优化设计

作动器在变体飞机设计中占有很重要的地位,它要求重量轻,作动力强,安全可靠且适于安装在变体飞机内部。笔者针对折叠机翼变体飞机,设计了一种用于机翼折叠的作动器,并通过改进的遗传算法对其主要参数进行优化,使作动器在满足设计指标的情况下达到质量最轻。根据优化结果,试制出作动器并进行了加载试验,证明了将这种改进的遗传算法应用于该作动器参数优化的可行性与有效性。最后,制作了安装有作动器的全尺寸折叠机翼验证机模型,用来模拟机翼折叠功能,经验证达到了作动器设计指标。     

高速风洞3D打印金属模型制造与试验

风洞试验金属模型是飞行器开展高速风洞试验的重要载体,对模型制造表面粗糙度、强度和刚度性能、制造效率等要求高。金属3D打印技术已经在航空航天、医疗等领域得到了广泛的应用,其技术逐步成熟,且具有传统机械加工所不具备的特殊优势,因此,在高速风洞试验金属模型制造中具有广泛的应用前景。为促进金属3D打印技术在高速风洞试验中的应用,针对高速风洞金属模型制造的特殊要求,基于金属3D打印技术开展了高速风洞试验模型制造和性能测试研究,包括30CrMnSiA金属材料粉末制备、试件性能测试、模型流固耦合分析、基于高速风洞试验的中空模型设计和3D打印制造等,并在高速风洞中开展了验证试验,结果表明3D打印的高速风洞金属模型能够满足风洞试验要求,并成功应用于多项高速风洞试验金属模型3D打印制造。通过该研究,成功突破了金属粉末制造、模型强度刚度性能和表面粗糙度保证、3D打印风洞试验金属模型设计等关键技术,成功实现了金属3D打印技术在高速风洞试验中的应用。     

平行分度凸轮机构刚柔耦合动力学仿真

针对平行分度凸轮机构的特点,提出了基于刚柔耦合理论的动力学建模方法.利用Pro/E,Adams和Ansys软件建立了平行分度凸轮机构的动力学模型,针对不同传动函数对应的凸轮机构进行了仿真和分析.得出结论:变余弦传动函数适合于低速和对传动精度要求不高的场合,盖特曼传动函数和复合传动函数适合于高速、重载、精密传动的场合.复合传动函数是适合高速分度凸轮机构的动力学特性较好的传动函数.     

折叠式电动车折叠机构方案设计及尺寸优化

根据折叠式电动车的功能要求,设计出一种折叠机构,并对折叠机构进行尺寸优化.根据折叠式电动车展开和折叠两种状态的要求设计出一种六杆机构,对该机构进行尺寸综合,分别建立展开和折叠两种状态下的数学模型.建立优化模型并确定设计参数,以折叠后尺寸最小和整车最轻便为目标建立优化模型的目标函数,根据功能和面向用户的人机工程、整车刚度等要求建立约束条件,采用MATLAB中的多目标优化算法,计算得到最优结果.建立优化后的折叠机构的三维模型,在插件Motion中进行运动仿真,验证了机构的合理性.     

A wind tunnel for anemometer calibration in the range of 0.2-1.25 m/s

In order to calibrate different types of anemometers in a low-speed range (0.2-1.25 m/s) using pressure measurements, a wind tunnel has been built and characterized. The wind tunnel has a low-speed section and a high-speed section. The wind tunnel calibration has been performed by means of comparison of airspeed at the test cross section (low-speed) and at the reference cross section (high-speed). Measurements have been taken with a calibrated hot-wire anemometer and static and total probes respectively. A linear fitting is used to relate reference and test airspeed. A model based on mass conservation law has been developed. Calculations have been made with and without introducing the effect of the speed profile. Uncertainties of the experimental calibration are presented.     

The difference in the uplift force at each support point of a container crane between FSI analysis and a wind tunnel test

We analyzed the difference between FSI (fluid-structure interaction) analysis and a wind tunnel test regarding the uplift force at each support point of a container crane and also design stowing devices — a tie-down rod and a stowage pin — and an alarm system to prevent overturning of a container crane under wind loads. We know that FSI analysis agrees more with wind tunnel tests than with structural analysis, but the results of FSI analysis are different from those of the tests. To evaluate the effect of the wind load on the stability of the crane, two container cranes that are widely used in container terminals-50 ton-class and 61 ton-class container cranes-are adopted for the analytic model and 19 values are considered for the wind direction as the design parameter. First, a wind tunnel test for the reduced-scale container crane model is performed according to the wind direction using an Eiffel-type atmospheric boundary-layer wind tunnel. Next, FSI analysis for a full-scale container crane is conducted using ANSYS and CFX. Then, the uplift force obtained from FSI analysis is compared with that yielded by the wind tunnel test. Finally, a formula is suggested to compensate the difference between FSI analysis and the wind tunnel test.     

基于PLC的LT风洞内三维高精度探针定位系统

机翼模型受力试验是飞机翼型设计必不可少的关键环节,风洞是进行空气动力学试验的必备装置。该文介绍了基于LT(低湍流)风洞的探针三维高精度位移测控系统的组成,详细分析了LT风洞现场实验条件及应满足的控制要求,在此基础上,论述了系统的总体设计方案,硬件结构和触摸屏的组态过程,重点论述了PLC的硬件配置及控制软件的设计。运行实践证明,该系统满足设计要求,运行可靠。有效地解决了翼型实验研究中探针在风洞中准确定位控制的难题。     

Influence of thermal insulation and wind velocity on the SMA actuator for morphing applications

This paper presents the modeling and simulation of shape memory alloy (SMA) wire actuators for morphing micro air vehicles (MAVs) when exposed to high-velocity wind during flight. The specific operating conditions include thermal insulation, varying convective heat-transfer coefficients due to wind velocity, aerodynamic loads, and operation from MAV battery. Application-oriented modeling parameters were determined from a flyable morphing MAV. The simulation could dynamically generate the morphing angle as a function of the electrical input pulse duty cycle. The model showed that compared with 10 % duty cycle, a 25 % duty cycle achieves an energy saving of 33 % and an increase in actuation speed of 3.7 times. Further, increasing the duty cycle has a negligible improvement in energy saving, but the actuation rate is increased by 15.8 times. The SIMULINK® model, which was validated through the ground test, would help in the design of SMA actuators and controllers for aerospace vehicles and automobiles.

     

亚音速可调气流温度风洞试验台设计

设计研究的气流模拟试验台是一座小型开口高速风洞,可以对试验段温度进行调节。在气动热力方案设计和计算的基础上,采用软件Fluent对风洞收缩段设计参数进行优化设计并进行了试验段流场的模拟计算,模拟计算流场及温度场结果表明设计合理。在优化设计的基础上加工制作了一座风洞,实际测量表明该风洞的流场品质优良,试验段温度符合设计要求。     

超空化航行体原理试验模型结构设计

设计并研制了通气超空化航行体水洞试验模型,给出了航行体空化器、航行主体、控制舵的设计原理与方案。利用该模型在西北工业大学水洞实验室实现了航行体超空化状态的形成原理与过程、航行体超空化状态下力的平衡原理、航行控制原理与实现方法等演示验证试验。实验结果表明,该模型设计原理与方案是正确的,模型的研制是成功的。     

基于Fluent的MAF风洞标准实验模型研究

基于相似原理,设计适合于MAF风洞的弹丸模型,应用Fluent软件进行仿真模拟,得出的模拟数据与风洞实验数据进行对比,为制作实验模型累积标准实验数据,为开设风洞测试基础技术研究实验提供理论参考.     

Experimental investigation of the effects of leading edge bluntness on supersonic flow over a double compression ramp

Understanding the flow characteristics over a double compression ramp is crucial for high-speed vehicle design. Leading edge bluntness is a key factor influencing the formation of a separation region on a double compression ramp flow. In the present study, the effect of bluntness on a double compression ramp is investigated experimentally at a nominal Mach number of 4. The test model has 13° and 40° inclinations with respect to the freestream. Five different levels of leading-edge radius, varying from 0.0 to 2.0 mm, were subjected to supersonic wind tunnel tests. Shadowgraph and infrared thermography techniques were employed to visualize the flow features of the double ramp model. Measurements of surface heat-transfer along the centerline of the test model were obtained from the acquired infrared images. It is shown that the leading-edge radius alters the separation characteristics as well as the surface heat-transfer. Possible reasons for such flow characteristics are discussed.

     

驻室抽气压缩机及其与风洞性能相关性研究

为了研究驻室抽气压缩机及其与风洞性能的相关性,对E71-3离心压缩机进行了性能试验,并进行了驻室抽气性能测试。试验结果表明:(1)E71-3离心压缩机实测最高压比4.516,设计点多变效率81.8%,达到了设计要求。(2)风洞运行总压升高,压缩机多变效率降低。(3)风洞试验段Ma=0.9~1.1时,驻室抽气量对风洞模型区梯度的影响不大,但驻室抽气量超过4%后风洞马赫数均方根偏差明显增大;压缩机稳定在中等转速、适量抽气量的工况,且入口流量调节阀全开,风洞流场品质较好,运行成本最低。