Air Pressure Measurement in the Rarefied Gas Transition Region
Report Number: AFFDL TR 65-101
Author(s): Brunschwig, Fred S.
Corporate Author(s): The Boeing Company
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1965-08
Pages: 87
Contract: AF 33(615)-1793
DoD Project: 1469
DoD Task: 146907
Identifier: AD0473766
Abstract:
Presented are parameters and pressure corrections for a low air pressure (1-100 p.s.f.a.) measurement system consisting of a pressure transducer and tubing ported to a hot surface at temperatures to 2800 F. Included are results of laboratory measurements with argon and air under conditions of both thermal creep and slip flow occurring together in a pressure transmission tube under temperature gradients. Both temperature functions, thermal creep and slip flow, were found to affect the system pressure. Dynamically, the temperature dependance of slip flow affects time response for tubes since it has the temperature dependancy of gas viscosity. Integration of the tubular time constant, modified for slip flow along the tube's temperature gradient, is carried out and compared to measurements; fair agreement is shown. Work reported includes calibration of a commerical airborne alpha emission pressure transducer; also data is presented on adsorption/oxidation at temperature for pressure tubing material.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Brunschwig, Fred S.
Corporate Author(s): The Boeing Company
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1965-08
Pages: 87
Contract: AF 33(615)-1793
DoD Project: 1469
DoD Task: 146907
Identifier: AD0473766
Abstract:
Presented are parameters and pressure corrections for a low air pressure (1-100 p.s.f.a.) measurement system consisting of a pressure transducer and tubing ported to a hot surface at temperatures to 2800 F. Included are results of laboratory measurements with argon and air under conditions of both thermal creep and slip flow occurring together in a pressure transmission tube under temperature gradients. Both temperature functions, thermal creep and slip flow, were found to affect the system pressure. Dynamically, the temperature dependance of slip flow affects time response for tubes since it has the temperature dependancy of gas viscosity. Integration of the tubular time constant, modified for slip flow along the tube's temperature gradient, is carried out and compared to measurements; fair agreement is shown. Work reported includes calibration of a commerical airborne alpha emission pressure transducer; also data is presented on adsorption/oxidation at temperature for pressure tubing material.
Provenance: Lockheed Martin Missiles & Fire Control