Accession Number : AD0668251

Title :   THERMO-MOLECULAR PRESSURE EFFECTS IN TUBES AND AT ORIFICES,

Corporate Author : ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT PARIS (FRANCE)

Personal Author(s) : Kinslow,Max ; Arney,George D. , Jr

Report Date : AUG 1967

Pagination or Media Count : 66

Abstract : An investigation of the errors arising from thermal nonequilibrium in systems measuring gas pressures is presented. The errors are attributed to a phenomenon referred to as thermo-molecular pressure. This effect is investigated both theoretically and experimentally at sensing orifices and in tubes. A thorough review of the literature is given and a theory is developed for the error introduced in the limiting case of a very small sensing orifice with heat flux to the orifice surface. The theory takes into account the effect of arbitrary thermal accommodation coefficient at the orifice surface. Experimental data are presented separately for thermo-molecular pressures in tubes and at orifices. In addition, results of heat-transfer measurements in the transitional flow regime between flat plates are presented as a basis for correlating the orifice data. Finally, methods are given, with examples, for the correction of thermo-molecular effects both at orifices and in circular tubes. (Author)

Descriptors :   (*PRESSURE GAGES, ERRORS), (*RAREFIED GAS DYNAMICS, PRESSURE GAGES), MOLECULAR PROPERTIES, THERMAL PROPERTIES, PRESSURE, PIPES, ORIFICES, KNUDSEN NUMBER, HEAT FLUX, HEAT TRANSFER

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

Distribution Statement : APPROVED FOR PUBLIC RELEASE