Based on thermoelectric generators (TEGs), an aerodynamic heat energy recovery system for vehicle is proposed. A mathematical model describing the energy conversion law of the system is established, and the integrated calculation method which combined aerodynamic heating and thermoelectric (TE) conversion is given. Furthermore, the influences of the typical flight Mach number, flight altitudes and the length of TE legs on the energy conversion behavior of energy recovery systems are investigated. The performance of the energy recovery system is analyzed and evaluated. The results show that, the decrease of flight altitude and the increase of Mach number will obviously improve the performance of the heat energy recovery system with TEGs. The increase of leg length will increase the temperature of the hot end of TEGs and reduce the heat absorbed at the hot end. When the external load, Mach number and flight altitude is fixed, there exists an optimal length of legs corresponding to the maximum output power and maximum conversion efficiency of the system. The results will have significant positive impact on thermal protection and management of supersonic/hypersonic vehicles.

Jet mill is an apparatus that produces superfine powder and is widely used in various industries. In this work, a new supersonic target jet mill based on aerodynamic theory is presented according to the flow field of a traditional jet mill. An annular supersonic flow produced by an annular converging–diverging nozzle is used to entrain the central particle flow by the shear mechanism in this new supersonic target jet mill. Then, the particle beam concentrating in the flow center impacts the target with high kinetic energy after the entrainment of the supersonic flow. An apparatus of the annular supersonic target jet mill was created to validate the theoretical design. Two types of experiments were implemented to estimate its performance. The validation experiments confirmed that the gas speed in the collision chamber was approximately 600 m/s and the supersonic flow could deliver a kinetic energy of approximately 180 J/s to the particles. The particle size reduction of boroncarbide (B₄C) and silica (Si) in the collision tests showed that the accelerated particles concentrated in the supersonic flow center collided on the targets precisely with high collision energy.

The transition characteristics of a modified RAE5243 airfoil were investigated using a wind tunnel test and numerical simulations. Transition detection is of great significance for the assessment of drag reduction. In wind tunnel tests, transition location can be detected by infrared thermography. However, in subsonic and transonic wind tunnel tests, the temperature difference between the laminar flow region and turbulent flow region is small. Moreover, the test models are usually made of metals, which make the transition location hard to identify. Combined with infrared thermography, a carbon nanotube heating coating powered by electricity was used to detect the transition location of a modified RAE5243 airfoil wing. The effects of heating power, angle of attack (AOA), and Mach number were studied. The results show that heating power has no impact on transition location. As the AOA increases, the transition location moves forward. With an increase in Mach number, the transition location moves forward first and then backward, and it reaches its most forward point at Ma = 0.75. The results of our numerical simulations indicate that, at Ma$\ge$ 0.75, a shock wave appears on the wing, and the transition is closely related to the shock wave rather than the adverse pressure gradient.

本文描述了一种用于生成时间相关的三维可压缩湍流边界层数据的数值方法. 该方法最早始于Lund的应用于不可压缩湍流边界层的Rescale方法, 后来Urbin, Stolz等人又分别将该方法推广到了可压缩湍流边界层. 其基本思想是将下游提取的边界层数据通过van Driest变换和修正Crocco关系式来建立湍流边界层内外层的速度和温度相似律, 根据该相似律分别构建入口处内外层的流动参数, 然后将内外层参数通过权函数加权合成为入口条件. Sagaut指出, Urbin和Stolz提出的Rescale方法存在着边界层漂移问题, 入口处的Re数无法固定的缺点. 本文直接给定入口处的名义厚度和动量损失厚度来固定入口处的来流Re数, 为了解决相应的入口条件超定问题, 首先采用动量损失厚度来无量纲化边界层外层法向距离, 然后将权函数中的常数设置为一个优化变量, 通过对该变量的设计将内外层参数加权合成为入口剖面, 使得生成的入口边界条件同时满足给定的名义厚度和动量损失厚度. 最后, 将该方法成功应用于M∞=3的可压缩湍流边界层数据的生成, 计算结果和DNS结果保持一致, 充分说明了方法的可行性和适用性.