Investigation on Heat Flux Measurements in Plasma Ground Test Facilities for Aerospace Heating Applications

摘要

This investigation studied the effects of velocity gradient on stagnation point heat flux in a high-enthalpy, incompressible plasma facility at the University of Vermont. This was done by measuring heat flux with slug calorimeters of various body geometries (which is a parameter directly influencing velocity gradient). As the slug was made of copper, it was important to investigate the effects of oxidation on the slug surface. This was done to assure that variations in heat flux measurements were mostly due to changes in velocity gradient. It was found that the oxidation layer developed very quickly and had little discernable effect on the heat flux of the slug. This allowed for further tests to single out the stagnation point velocity gradient as the only contributor to the change in heat flux. Tests were then conducted analyzing the effect the stagnation point velocity gradient had on the heat flux into various slug calorimeter geometries. The results obtained from the varying calorimeter body geometries provide a suitable investigation into the study of isolating the sensitivity of heat flux to the velocity gradient, . Comparative studies using the same calorimeter body geometries at the similarly scaled NASA Langley HYMETS facility will provide a good follow up to this research to identify the similarities between compressible and non-compressible flows.