CALIBRATION OF THE AIR FORCE AERO PROPULSION LABORATORY 120-INCH HYPERSONIC SHOCK TUNNEL FOR 1.0-INCH DIAMETER NOZZLE THROAT.

Abstract : A shock tunnel with a 120-inch diameter test section was installed and calibrated for the Air Force Aero Propulsion Laboratory, Wright-Patterson Air Force Base, Ohio. Calibration of the tunnel was performed utilizing a 1.0-inch diameter throat, with helium driver pressures from 3000 to 20,000 psia at the tailored condition. The uniformity of the test flow and the test core diameter at one axial station were determined at the various driver pressures by means of a total pressure rake spanning the tunnel. The measurements indicated that a test flow of Mach number 18.38, with a minimum test core of 108 inches, was established. To confirm the validity of the measured Mach number, a conical calibration model with pressure and heat transfer instrumentation along the surface was tested in the tunnel. Existing theory was used to predict the pressure and heat transfer rate distributions along the surface of the cone, and the measured results were then compared to theory. The pressure results indicate the existence of an axial Mach number gradient of 0.26 per foot. The heat transfer measurements were found to be in close agreement with theory as computed from the measured pressure distribution. (Author)