Hypersonic flow diagnostic studies in a large arc-heated wind tunnel

Abstract

This study consisted of the experimental investigation of test flow in an arc-heated hypersonic wind tunnel. These tests utilized a high-voltage d.c. arc heater which operated at input powers in excess of 50 Mw and provided reservoir pressures ranging from 100 to 1500 psi and bulk enthalpies from 1500 to 4000 Btu/lb. Local freestream measurements of Pitot pressure, mass flux, stagnation point heat-transfer rate, and wall static pressures were obtained at the exit of a nominal 2-ft-diam conical nozzle. Stagnation enthalpy profiles at the nozzle exit became peaked at high stagnation pressures. From these data, center line enthalpies as high as 6500 Btu/lb were indicated in the flow. Selective comparisons between theory and experiment are presented. At a reservoir enthalpy of approximately 2500 Btu/lb and for stagnation pressures in excess of 500 psi, the expanded flow data were in good agreement with equilibrium expansion theory. However, below 500 psi, the data compared more closely with nonequilibrium theory with the flow frozen downstream of the nozzle throat.