Description and Preliminary Calibration of a Low-Density, Hypervelocity Wind Tunnel

Abstract

A small, low-density, hypervelocity, continuous wind tunnel operating at total temperatures from 2000 to 4000 0 K is described, and initial experiments designed to determine the characteristics of the flow are discussed. Effects of low Reynolds numbers on impact-pressure probes and static-pressure probes are shown. Preliminary work with a probe for measuring local mass-flow rate is outlined, and results are shown to be in agreement with impact and static pressure measurements. Axial and transverse surveys of flow in the nozzle are presented to illustrate the extent of boundary-layer growth and the useable core of flow. A diffuser is proved to be advantageous, even though very low Reynolds numbers are typical of the tunnel. A comparison of data on drag of spheres, including measurements from the new wind tunnel, is presented.

Drag of Spheres in Rarefied Hypervelocity Flow

“…7) of the von Kerman Gas Dynamics Facility (,VIC), Arnold Engineering Development Center (AEDC), Air Force Systems Command (AFSC), US Air Force, has been used to extend previous experimental studies of drag of spheres in low-density flow. Using the LDH Tunnel, drag data have been taken under hypersonic, cold-wall (r., << [r) support-free conditions which are described later.…”

“…A description of the facility is contained in Ref. 7. Briefly, the tunnel consists of a d-c arc-heater, stilling chamber, conical nozzle of 15-deg half angle, test chamber with instrumentation, diffuser, and pumping system.…”

“…7, but the points now have been shifted slightly because of the use of a new source (Ref. 19) for viscosity of nitrogen at high temperatures.…”

Snap 19 Capsule Low Reynolds Number Force Test.

“…On the basis of the test results, the following recommendations are made: (1) For future tests on the capsule, the test objectives should be expanded to include a smooth face model to more fully determine the effects of the notches on the pitching moment.…”

A Calorimetric Investigation of Some Problems Associated With a Low-Density Hypervelocity Wind Tunnel

“…A description of this tunnel, commonly referred to as the LDH tunnel, and the results of a preliminary calibration program have been presented in Ref. 1. Briefly, the tunnel consists of: (1) a direct-current, electric arc heater, (2) a stilling chamber, (3) a conical expansion nozzle of 15-deg half angle*, (4) a test section with model and probe traversing mechanism, (5) a vacuum pumping system, and (6) necessary instrumentation.…”