Studies of confined high-pressure discharges in an electrothermal capillary

Experimental measurements and numerical analyses for a series of capillary discharge tests are reported. The tests are conducted in a high-pressure vessel with an instrumented polyethylene-lined capillary that injects into a small, constant-volume and pressure-instrumented chamber. A sequence of tests in which the capillary radius is varied by a factor of 5 and in which the capillary power dissipation levels are varied is discussed. The results obtained show that significant radial temperature gradients can be expected at high power levels or for low flow rates from the capillary. The results show that the use of blackbody heat fluxes based on the plasma core temperature should not be used to estimate wall heat fluxes in an electrothermal chemical system