Coupling characteristics of the bowed micro-tubes for precooled heat exchangers under different inflow speeds

The micro-channel heat exchanger is extensively employed in the field of heat exchange, including aerospace precooling technology. This paper takes the bowed heat exchange tubes used in the precooler of aerospace vehicles as the research object and has studied and analyzed the flow and heat transfer characteristics of the tubes under different inflow speeds. In addition, the fluid–structure interaction numerical method based on parametric design language programming is proposed, which is verified by the vibration experiment of bowed tubes. Furthermore, by using the methods, the reliability of the micro-tube structure have been analyzed. The conclusions can be gotten as: (1) With operating conditions of the coolant helium unchanged, the heat exchange effect of the heat exchange tube bundle is greatly affected by the air flow rate. As the speed of the inflow hot air increase, the heat transfer coefficient decreases significantly. (2) The losses caused by wall shear stress near the heat exchange tubes account for the main part. After the air flows through the tubes, vortices are formed, causing disturbances to the tubes. (3) Furthermore, the flow–structure coupling analysis for the heat exchange tubes was conducted. As inflow velocity rises, the vibration displacement also decreases by 5.89%, which is predominantly localized at the middle position of tube bundles, gradually decreasing toward both sides. (4) Concurrently, it is evident that the support plate plays a role in concentrating the various rows of tube bundles. If the support plate is fixed, the vibration displacement of the tube bundle can be reduced.