“Air movement and mixing can control the transport of surface-reactive pollutants from bulk air to surfaces. To further understand pollutant transport, the efficacy of measuring mass-transfer coefficients (MTC) utilizing sublimation or evaporation from a coated microbalance sensor was evaluated. For practical utility, this sensor must project from the wall surface. Therefore, the broad goal of this research is to recommend a design for the sensor enclosure that minimizes the influence of enclosure shape on the measurement itself. Analyses were performed for enclosures with rectangular, parabolic and other cross-sections. A computational fluid dynamics package was used to determine the shear stress and the heat-transfer coefficient for the enclosure and for the wall with no enclosure. The corresponding mass transfer coefficient values were estimated using a transport analogy suggested by Chilton and Colburn. The result from the parabolic enclosure simulation deviated by about 6-8% from the flat wall value for 0.1m s-1 mean air velocity while the deviation for the results from rectangular enclosure was 3-8%. These simulations led us to the conclusion that the parabolic enclosure experiences the smallest range of deviation over a variety of environmental conditions. We also compared the “whole-wall” mean value of the MTC with the results from a parabolic enclosure where a 20 cm and 100 cm diameter section is coated. The mean MTC for a flat wall deviates by about 140% and 40% respectively for the 20 cm and 100 cm diameter coatings. The simulated MTC values for the parabolic enclosure at a typical indoor velocity of 0.1 m s-1 was found to be around 0.05 cm s-1 which is in good agreement with the literature central value of 0.04 cm s-1“--Abstract, page iii.
Isaac, Kakkattukuzhy M.
Civil, Architectural and Environmental Engineering
M.S. in Environmental Engineering
University of Missouri--Rolla
x, 57 pages
© 2005 Anjana Srirama, All rights reserved.
Thesis - Restricted Access
FLUENT (Computer file)
Indoor air pollution -- Analysis
Hazardous substances -- Analysis
Fluid dynamics -- Data processing
Mass transfer -- Mathematical models
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Electronic access to the full-text of this document is restricted to Missouri S&T users. Otherwise, request this publication directly from Missouri S&T Library or contact your local library.http://merlin.lib.umsystem.edu/record=b5475917~S5
Srirama, Anjana, "Geometric design of a mass transfer sensor for indoor environments using computational fluid dynamics" (2005). Masters Theses. 5814.
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