Flash Evaporation Phenomena in Actively Cooled Wing Leading Edge of Re-Entry Vehicles

Abstract

An innovative “active” cooling system of a wing leading edge of a hypersonic re-entry vehicle making use of water is studied. In particular, a steady model is developed to analyze the critical discharge of the cooling water into a very low pressure ambient simulating the outlet conditions of both the re-entry and wind tunnel environments. Due to the strongly subcooled operating conditions of the fluid, the model predicts no-flashing within the duct connecting the outlet (hot) manifold to the vacuum ambient. For a fixed water mass flow rate, the pressure within the outlet manifold is determined, giving that flow rate in connection with the proper head losses. The exit section (critical) pressure is determined as well. These findings are confirmed by unsteady numerical simulations of the system start-up.