不同倾角下管流中超临界CO₂对流换热特性的数值研究
Numerical Study on Convective Heat Transfer Characteristics of Supercritical CO₂ in Tube Flow at Different Inclinations

针对高超声速飞行器面临的严苛工作环境，近年来利用超临界CO₂作为冷却介质对飞行器进行传热保护成为一种很有发展前景的方法，本文结合高超声速飞行器飞行过程中有可能出现的不同迎角，采用了一种基于k-ω SST模型的湍流Prt模型(TWL模型)，选择9个特殊角度(0？ ≤ θ ≤ 180？)，定义流动方向和重力方向相同时倾斜角为0？，对加热管内超临界CO₂的流动传热进行了数值模拟。研究结果表明：相同工况下，流动方向对超临界CO₂与壁面间的换热特性影响较大，当倾斜角大于90？时将伴随传热恶化现象，且随着倾斜角的增大传热恶化现象愈发明显；当倾斜角小于等于90？时将强化传热，但并非随着角度的减小传热现象持续改善，在30？时获得最佳的传热表现而非0？，所以重力是影响超临界CO₂传热的重要因素，但并非唯一因素。
In view of the harsh working environment faced by hypersonic aircraft, in recent years, the use of supercritical CO₂ as a cooling medium for heat transfer protection of aircraft has become a promising method. This paper combines the different angles of attack that may occur during the flight of hypersonic aircraft, adopts a turbulence Prt model (TWL model) based on the k-ω SST model, selects 9 special angles (0？ ≤ θ ≤ 180？), defines the flow direction and gravity direction at the same time the tilt angle is 0？. The flow heat transfer of supercritical CO₂ in the heating tube is numerically simulated. The results show that under the same working conditions, the flow direction has a greater influence on the heat transfer characteristics between supercritical CO₂ and the wall surface; when the inclination angle is greater than 90？, it will be accompanied by heat transfer deterioration, and with the increase of the inclination angle, the heat transfer deterioration phenomenon will become more and more obvious; when the inclination angle is less than or equal to 90？, the heat transfer phenomenon will be strengthened, but not with the reduction of the angle; the best heat transfer performance is obtained at 30？, so gravity is an important factor affecting supercritical CO₂ heat transfer, but it is not the only factor.