Laminar filmwise condensation of vapor in presence of multi-component mixture of non-condensable gases
2007 (English)In: Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12, 2007Conference paper (Refereed)
Degradation of heat transfer during water vapour free convection condensation in the presence of two noncondesable gases with significant difference in molecular weights is investigated in this paper. Ternary diffusivity coefficients are derived from the Maxwell-Stefan equation and the boundary layer approximation, both for liquid and gas sides, is formulated and, with appropriate boundary and interface conditions, numerically solved. The similarity method has been used in order to simplify partial differential equations to the system of ordinary differential equations. The new model has been validated against experimental data for free convection condensation of water vapour in presence of air. Numerical results show good agreement with experimental data. The same model has been applied to study the condensation of water vapour in presence of two noncondensable gases with significantly different molecular weights. It has been observed that addition of even small amount of the light gas into the initial binary mixture of water vapour with a heavy species creates significant resistance to the heat transfer process. It has been concluded that both the diffusivity of the lighter gas as well as the buoyancy effects close to the film-mixture interface are the major contributors to the increase of the heat transfer resistance. Finally, the conditions that can lead to the accumulation of the lighter gas are discussed.
Place, publisher, year, edition, pages
Condensation, Noncondensable gas, Ternary mixture
IdentifiersURN: urn:nbn:se:kth:diva-7456ScopusID: 2-s2.0-44349158431ISBN: 978-089448058-4OAI: oai:DiVA.org:kth-7456DiVA: diva2:12486
12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12; Pittsburgh, PA; United States; 30 September 2007 through 4 October 2007
QC 201006232007-09-102007-09-102014-11-06Bibliographically approved