Design and Verification of Cooling System for High-Temperature Rudder Shaft

To address the thermal management challenges of the rudder shaft of hypersonic vehicles in extreme thermal environments ranging from 900 to 1100°C, this study proposes an active cooling system based on internal thread-smooth composite microchannels, which enhances cooling efficiency by intensifying phase-change heat transfer. To verify the system performance, dual experimental platforms for electrical heating (Formula: see text) and electromagnetic heating (Formula: see text) were established, and cross-scale verification was completed in combination with numerical simulation (experiment–simulation error Formula: see text). The influence of contact thermal resistance (Formula: see text) and three flow rates (5.5, 7, and 10 mL/min) on the temperature field was analyzed. Compared with smooth channels, the M1 internal-thread composite channel increases the heat transfer coefficient from 3200 to Formula: see text (18%) and reduces the rudder-shaft temperature by 44–55°C under a 1039–1043°C heat source. The pressure drop rises from 0.04 to 0.06 MPa, but the additional hydraulic power remains very small at the present flow rates, while the coolant demand is markedly reduced. In this study, the term lightweight refers to reduced coolant inventory and a compact embedded cooling architecture rather than a full vehicle-level mass audit.