Falling-film evaporation over horizontal rectangular tubes

Bustamante, John Gabriel

Title:

Falling-film evaporation over horizontal rectangular tubes

dc.contributor.advisor	Garimella, Srinivas
dc.contributor.author	Bustamante, John Gabriel
dc.contributor.committeeMember	Ghiaasiaan, S. Mostafa
dc.contributor.committeeMember	Kumar, Satish
dc.contributor.committeeMember	Fuller, Thomas
dc.contributor.committeeMember	Jacobs, Laurence
dc.contributor.department	Mechanical Engineering
dc.date.accessioned	2014-08-27T13:41:06Z
dc.date.available	2014-08-27T13:41:06Z
dc.date.created	2014-08
dc.date.issued	2014-07-07
dc.date.submitted	August 2014
dc.date.updated	2014-08-27T13:41:06Z
dc.description.abstract	The present study is the first investigation of falling-film evaporation over horizontal rectangular tubes. This geometry is representative of the external profile of microchannel tubes. Incorporating these designs into shell-and-tube heat exchangers has the potential to provide compact, high-performance components for a wide range of applications. This fluid flow was investigated experimentally, targeting three areas: measurements of heat transfer coefficients, quantification of flow characteristics, and the performance of flow distributors. Falling-film evaporation experiments were conducted using water on a rectangular test section with dimensions of 203 × 1.42 × 27.4 mm (length × width × height), measuring heat transfer coefficients over a range of saturation temperatures, test section spacings, heat fluxes, and film Reynolds numbers. This was supported by a flow visualization study that quantified droplet and wave parameters using image analysis of high speed videos. Finally, the performance of eight liquid distributors, which are used to establish falling-film flows, was quantified and the size of the generated droplets and jets was measured. Three models were developed to predict the flow regime, wetted tube area, and heat transfer coefficient. The flow regime model is based on a thermodynamic analysis, while the wetted tube area is found with a hydrodynamic model based on idealized flow assumptions. Finally, the heat transfer model relies on a relationship with the classic Nusselt (1916) film theory. Each of these models demonstrated good agreement with the experimental data, as well as trends in the literature. The increased understanding of falling-film evaporation gained in this study will enable the accurate design of shell-and-tube heat exchangers with microchannel tubes.
dc.description.degree	Ph.D.
dc.format.mimetype	application/pdf
dc.identifier.uri	http://hdl.handle.net/1853/52296
dc.language.iso	en_US
dc.publisher	Georgia Institute of Technology
dc.subject	Heat transfer
dc.subject	Flow visualization
dc.subject	Falling film
dc.subject	Evaporation
dc.subject	Water
dc.subject	Distributor
dc.subject	Heat exchanger
dc.subject	Microchannel
dc.title	Falling-film evaporation over horizontal rectangular tubes
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
thesis.degree.level	Doctoral