Radiative transfer in the electrode region of an arc heater
Radiation from hot gases in the electrode region of an arc heater are discussed. Major original contributions are made: (1) an analytical expression for the radiative heat flux, for an axisymmetric geometry and a grey reflecting wall, is derived, (2) the expression is rendered analytically differentiable/integrable by using appropriate techniques to remove the singularities, and (3), finally a two band model is devised to compute the radiative heat load at the walls in NASA Ames' jet facility. The advantage of using these techniques is that the time taken for the numerical integration is considerably reduced and computation of a 39 x 39 axisymmetric geometry becomes manageable. Fluid equations, representative of a high current arc heater, are numerically solved for an axisymmetric geometry. The computed average heat load of 400 Watts/sq cm using the two band model agrees well with the experimental estimates made at NASA Ames' facility.