This study focuses on the effect of a weak jet of a porous plate on the aerodynamic heating of high-speed vehicles. By using a variable nozzle to form different weak air jets through a uniformly distributed porous plate in a shock tunnel, the heat flux distribution on the surface of the porous plate near the ejection area under different Mach numbers, attack angles, and jet velocities is studied. The main results show that the uniformly distributed pore structure increases the wall roughness and promotes transition during heating, the jet velocity has a remarkable impact on the heat transfer characteristics of the plate, and the heat flux on the plate as well as the cooling effect increase with the attack angle.

No abstract

The use of magnesium alloys in aerospace is relatively restricted by their poor ignition resistance performance. A continuous heating test was conducted to investigate the ignition resistance of pure Mg, ZM5, and ZM6 magnesium alloys with different alloying elements. It was found that alloying elements greatly influenced the ignition resistance of magnesium alloys. With about 2% addition of Nd rare earth element, ZM6 had a higher ignition temperature than pure Mg. In comparison, the ignition temperature of ZM5, which contains mainly about 8% Al alloying element, was lower than that of pure Mg. Analysis of high-temperature surface oxide film reveals that the higher ignition temperature of ZM6 resulted from a protective Nd2O3 oxide film formed on the oxidized surface. Alloying with rare earths can improve the ignition resistance of magnesium alloys.