Accession Number : AD0625253

Title :   OBSERVED SUPERSATURATION IN THE ARL 20-INCH HYPERSONIC WIND TUNNEL.

Descriptive Note : Technical rept.,

Corporate Author : AEROSPACE RESEARCH LABS OFFICE OF AEROSPACE RESEARCH WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Goddard,Richard T.

Report Date : OCT 1965

Pagination or Media Count : 28

Abstract : An experimental investigation of the condensation of air in a hypersonic wind tunnel was carried out. The experimental work was conducted in the ARL 20-inch hypersonic wind tunnel which utilizes a contoured nozzle to expand the flow to Mach 14 with stagnation temperatures up to 2100R at free stream Reynolds of 300,000 per foot to 1,000,000 per foot. Pitot probe surveys were made at the nozzle exit and at axial locations upstream of the nozzle exit. Surveys at the nozzle exit showed that the only indication of apparent condensation was a slight change in the slope of the pitot pressure versus free stream temperature curve. However, upstream surveys indicated a slight increase in pitot pressure at the critical temperature with the per cent of increase becoming greater at higher stagnation pressures. Therefore, it was concluded that the relaxation time (axial location) and the Reynolds number (variance of stagnation pressure) are the primary factors contributing to the pitot pressure sensitivity at the onset of condensation. The report also presents the experimentally determined operating regime of the ARL 20-inch hypersonic tunnel. (Author)

Descriptors :   (*HYPERSONIC WIND TUNNELS, CONDENSATION), (*CONDENSATION, AIR), RELAXATION TIME, NUCLEATION, WATER VAPOR, STAGNATION POINT, HYPERSONIC NOZZLES

Subject Categories : Test Facilities, Equipment and Methods
      Fluid Mechanics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE