Modeling studies of electron transpiration cooling at high-speed flows.

We present preliminary numerical results exploring the concept of electron transpiration cooling using a caesiated tungsten surface and a cesium-air plasma layer. For the reaction kinetics, a one-dimensional model is used together with reaction kinetics reflecting anticipated cesium and air plasma chemistry. The model predicts predominant charge species, electron emission current densities, and electric field effects as well as threshold temperatures for effective electron transpiration cooling. Extension to a fluid model for a 1 cm radius of curvature leading edge at Mach 10, 50,000 ft altitude with assumed ideal thermionic electron emission for wall temperature from 1000K to 1500K indicates that significant electron and cesium evaporation cooling is possible, and that an ignited plasma will likely be formed close to the surface due to strong charge nonequilibrium.