Numerical Analysis of the Thermal Environment of Rail-Based Hot Launch Systems

This paper investigates the surface thermal environment of a rail-based launch system subjected to missile plume impingement flow during hot launch. This study established a computational model for missile plume impingement on a rail-based launch system based on the three-dimensional Navier–Stokes equations and the realizable k−ε turbulence model. CFD simulations were performed for the flow field impacting the launch system with varying deflector heights under different missile flight altitudes. The results demonstrate that when the missile flight altitude H is within 20 m, the launch system experiences a severe thermal environment, the maximum gas temperature on the deflector surface can reach as high as 3200 K, the maximum gas temperature on the surface of the carriage bottom will also exceed 2600 K. Higher deflector heights improve the thermal conditions for facilities beneath the launch vehicle, such as the rail track components and sleepers, it can reduce the maximum surface temperature of the carriage bottom by up to 22.3%, but simultaneously deteriorate the thermal environment on the upper surface of the launch vehicle and the deflector itself. Furthermore, the position where the barrel shock of the engine plume impinges on the deflector alters the gas temperature distribution pattern on the deflector surface. This demonstrates that even a slight variation in the engine’s position relative to the deflector can induce dramatic changes in the gas temperature distribution morphology across the deflector surface. Research demonstrates that during rail-based launch system operations, employing deflectors with optimized heights can significantly improve the thermal environment across critical components. For deflectors of a given height, the current engineering practice of using discrete computational conditions (e.g., H = 0 m, 2 m, and 10 m) requires finer parametric refinement. This is essential to resolve the phenomenon where minor variations in engine-deflector standoff distance induce significant morphological changes in surface gas temperature distribution, thereby enabling further optimization of the launch system’s thermal protection design. The “thermal environment” in this paper only provides the surface gas temperature as a reference.