LOW DENSITY BOUNDARY LAYER CONTROL BY LIQUID HYDROGEN CRYOPUMPING

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.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1965
Accession Number
AD0467446

Entities

People

  • B. H. Shirley
  • R. E. Dix
  • W. N. Macdermott

Organizations

  • Arnold Engineering Development Complex

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Air Force
  • Boundaries
  • Boundary Layer
  • Boundary Layer Flow
  • Contracts
  • Cooling
  • Cryopumping
  • Flow
  • Fluid Flow
  • Liquid Hydrogen
  • Low Density
  • Mean Free Path
  • Nozzles
  • Pumping
  • Static Pressure
  • Test Facilities
  • Wind Tunnels

Fields of Study

  • Physics

Readers

  • Combustion and Flow Dynamics.
  • Fluid Dynamics.

Technology Areas

  • Hypersonics
  • Hypersonics - Hypersonic Boundary Layers
  • Hypersonics - Hypersonic Flow