LAMINAR MIXING AND HEAT TRANSFER PHENOMENA BETWEEN A PARTIALLY IONIZED GAS AND A GASEOUS COOLANT

Mixing and heat transfer characteristics of a laminar subsonic argon arcjet issuing into a stagnant atmosphere of room-temperature helium were investigated by a combined analytical-experimental approach. The analysis was based on classical continuum theory utilizing the boundarylayer approximation. Good correlation between theory and experiment was observed. Although the departure from equilibrium between the electrons and the heavy particles was estimated to be sufficiently small when considering the overall mixing process, it was shown analytically that this equilibrium probably did not exist in the regions of highest temperature gradient. It was, therefore, decided to explore the nature of this departure in the high-density (one atmosphere) collision-dominated, partly-ionized gas by the use of a cooled electrostatic probe. The theory for such a probe was formulated, and it appears to provide the capability for measuring both electron concentrations and electron temperatures.