Thermal Effects on the Wall Surfaces of Transonic Evacuated Tube Maglev Transportation
Thermal Effects on the Wall Surfaces of Transonic Evacuated Tube Maglev Transportation
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DOI：
10.1016/j.applthermaleng.2022.119876
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发表时间：
2022-12
影响因子：
6.4
通讯作者：
Qiujun Yu;Xiaofeng Yang;J. Niu;Yang Sui;Yanxia Du;Yanping Yuan
中科院分区：
文献类型：
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作者：
Qiujun Yu;Xiaofeng Yang;J. Niu;Yang Sui;Yanxia Du;Yanping Yuan
跨音速真空管磁悬浮列车（ETMT）在复杂流场中产生的激波和膨胀扇结构，形成了独特的热环境，增加了列车和管道壁面的气动加热，并可能导致结构损伤。在这项研究中，对跨音速ETMT壁面上的热效应进行了数值研究，使用基于密度的计算流体动力学（CFD）求解器。计算结果表明，管内流动的阻流和非阻流的热效应是不同的。对于列车而言，在阻流区更容易出现表面非均匀分布的极热或极冷环境。对于该管，在阻塞流中，在超声速下对壁的瞬时热冲击是严重的，在马赫数1.5时达到最大值43.2 kW/m2，阻塞比为0.2。将管壁热流脉动的频谱分为由正激波或弓形激波引起的低频带（主频率）和由下游反射激波串引起的次频带。此外，由于膨胀风扇和激波之间的相互作用，在边界层上交替作用，在管上积聚的热量是微不足道的。采用这些研究结果，包括热控制技术和热冲击的耐材料，为不同的ETMT系统，可以促进高效率和低冗余的热保护系统的设计。
Shock waves and expansion fan hierarchies in complex flows induced by transonic evacuated tube maglev transportation (ETMT) cause a unique thermal environment, which can increase the aerodynamic heating on the wall surfaces of the train and tube with the possibility of structural damage. In this study, the thermal effects on the wall surfaces of transonic ETMT were numerically investigated using a density-based computational fluid dynamics (CFD) solver. The results show different thermal effects for choked and unchoked flows in the tube. For the train, the extreme hot or cold environment, which is non-uniformly distributed on the surface, occurs more easily in the choked flow. For the tube, the instantaneous thermal impact is severe on the wall at supersonic speeds in the choked flow, reaching a maximum of 43.2 kW/m2at Mach 1.5 with a blockage ratio of 0.2. The spectrum of the heat flux fluctuation on the tube wall is divided into the low-frequency band (main frequency) subjected to the normal or bow shock wave and secondary-frequency band induced by the downstream reflected shock trains. In addition, the amount of heat accumulated on the tube is insignificant owing to the interaction between the expansion fans and shock waves with alternating action on the boundary layer. Adoption of these findings, including the thermal control techniques and thermal-impact-resistant materials, for different ETMT systems can promote high-efficiency and low-redundancy designs of thermal protection systems.