Accession Number : AD0467446


Title :   LOW DENSITY BOUNDARY LAYER CONTROL BY LIQUID HYDROGEN CRYOPUMPING


Descriptive Note : Rept. for Aug 1963-Jun 1964


Corporate Author : ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN


Personal Author(s) : MacDermott, W N ; Dix, R E ; Shirley, B H


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/467446.pdf


Report Date : Aug 1965


Pagination or Media Count : 30


Abstract : Boundary layers in a low density wind tunnel nozzle have been reduced by applying suction on the diverging walls of the nozzle and by cryogenically pumping the boundary layer gas directly to the wall. The experimental apparatus used in this study incorporates a 12-in.-diam hypersonic nozzle and a 16-in. primary liquid hydrogen cryopump with a pumping speed of 200,000 liters/sec. Comparison of pitot and static pressures measured in this nozzle with nitrogen at 300 K indicates a supersaturated isentropic flow regime bounded on the low pressure end by a merged boundary layer. In a typical operating condition (upstream temperature of 300 K) a merged boundary layer flow at M = 9.50, Re = 256/cm, and a mean free path of 0.06 cm was converted to a 4-in. core flow with M =15.7, Re = 40/cm, and a mean free path of 0.6 cm by cooling the nozzle walls sufficiently for cryopumping. The wall cryopumping retains effectiveness at supply temperatures at least as high as 4000 K.


Descriptors :   *BOUNDARY LAYER CONTROL , *CRYOPUMPING , CRYOGENICS , HIGH TEMPERATURE , HYDROGEN , HYPERSONIC FLOW , HYPERSONIC NOZZLES , LIQUEFIED GASES , STAGNATION POINT , WIND TUNNELS


Subject Categories : Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE