Experimental Aerodynamic Data Concerning Vortex Flow and the Gas Velocity in a Small C-C Arc Heater Operated With Argon

Abstract

The performance characteristics of a small d-c arc heater of the Gerdien type are analyzed with and without a vortex flow in the nozzle. Moreover, total pressure profiles taken in the plasma and static pres-•sure distributions along the nozzle are presented and used to indicate the effects produced by the vortex in the nozzle. Injecting the working medium (argon) tangentially into the arc chamber was found to be an ineffective !lleans for producing gas dynamic swirl due to the effects from heat addition in the nozzle. The data were obtained at chamber pressures from 1. 72 to 5. 15 atm and exhausting to atmosphere with power levels up to 22 kw. Two basically different methods are used to calculctte the "bulk" gas temperature, which is required to calculate the gas velocity. The first method makes use of several measured quantities to perform an energy balance on the arc heater. The second method makes use of the conventional weight-flow equation for sonic flow. The total pressure and total temperature at the sonic point (nozzle exit) were obtained from the Rayleigh heat-addition equations. A comparison of the velocities calculated by the two methods reveals agreement within ten percent at the nozzle exit. PUBLICATION REVIEW This report has been reviewed and publication is approved.