THERMO-MOLECULAR PRESSURE EFFECTS IN TUBES AND AT ORIFICES,
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1967
- Accession Number
- AD0668251
Entities
People
- George D. Arney Jr.
- Max Kinslow
Organizations
- AGARD