Title:
Analysis of Binary Fluid Heat and Mass Transfer in Ammonia-Water Absorption

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dc.contributor.advisor Garimella, Srinivas
dc.contributor.author Bohra, Lalit Kumar en_US
dc.contributor.committeeMember Bergin, Michael
dc.contributor.committeeMember Frederick, James
dc.contributor.committeeMember Graham, Samuel
dc.contributor.committeeMember Wepfer, William
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2008-02-07T18:36:48Z
dc.date.available 2008-02-07T18:36:48Z
dc.date.issued 2007-07-24 en_US
dc.description.abstract An investigation of binary fluid heat and mass transfer in ammonia-water absorption was conducted. Experiments were conducted on a horizontal-tube falling-film absorber consisting of four columns of six 9.5 mm (3/8 in) nominal OD, 0.292 m (11.5 in) long tubes, installed in an absorption heat pump. Measurements were recorded at both system and local levels within the absorber for a wide range of operating conditions (nominally, desorber solution outlet concentrations of 5 - 40% for three nominal absorber pressures of 150, 345 and 500 kPa, for solution flow rates of 0.019 - 0.034 kg/s.). Local measurements were supplemented by high-speed, high-resolution visualization of the flow over the tube banks. Using the measurements and observations from videos, heat and mass transfer rates, heat and vapor mass transfer coefficients for each test condition were determined at the component and local levels. For the range of experiments conducted, the overall film heat transfer coefficient varied from 923 to 2857 W/m<sup>2</sup>-K while the vapor and liquid mass transfer coefficients varied from 0.0026 to 0.25 m/s and from 5.51×10<sup>-6</sup> to 3.31×10<sup>-5</sup> m/s, respectively. Local measurements and insights from the video frames were used to obtain the contributions of falling-film and droplet modes to the total absorption rates. The local heat transfer coefficients varied from 78 to 6116 W/m<sup>2</sup>-K, while the local vapor and liquid mass transfer coefficients varied from -0.04 to 2.8 m/s and from -3.59×10<sup>-5</sup> (indicating local desorption in some cases) to 8.96×10<sup>-5</sup> m/s, respectively. The heat transfer coefficient was found to increase with solution Reynolds number, while the mass transfer coefficient was found to be primarily determined by the vapor and solution properties. Based on the observed trends, correlations were developed to predict heat and mass transfer coefficients valid for the range of experimental conditions tested. These correlations can be used to design horizontal tube falling-film absorbers for ammonia-water absorption systems. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/19780
dc.publisher Georgia Institute of Technology en_US
dc.subject Ammonia/water en_US
dc.subject Absorption en_US
dc.subject Heat and mass transfer correlations en_US
dc.subject Flow visualization en_US
dc.subject Local variation of absorption rates en_US
dc.subject.lcsh Ammonia Absorption and adsorption
dc.subject.lcsh Mass transfer
dc.subject.lcsh Heat transfer
dc.subject.lcsh Thermal desorption
dc.subject.lcsh Heat pumps
dc.title Analysis of Binary Fluid Heat and Mass Transfer in Ammonia-Water Absorption en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Garimella, Srinivas
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication 7c74399b-6962-4814-9d2a-51f8b9c41e1f
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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