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oai:www.ideals.illinois.edu:2142/83874 2023-07-11 col_2142_5131 col_2142_14787 com_2142_5130 com_2142_9630 com_2142_234

Jacobi, Anthony M. Park, Young-Gil 2015-09-25T21:12:32Z 2015-09-25T21:12:32Z 10000-01-01 2007 2007 A simple area-partitioning method for analyzing the wind-tunnel data is developed for flat-tube heat exchangers under partially wet conditions, and new air-side performance correlations are presented for both dry- and wet-surface conditions. Correlations between the Colbum j or f factors and the Reynolds numbers are developed in the conventional way and compared to multivariate non-parametric regressions. The conventional correlations significantly extend prior work by expanding the parameter space and establishing a physical basis for the form of the fits. However, it is found that multivariate non-parametric regressions can dramatically reduce the RMS errors if a large, well-structured dataset is used. Furthermore, this method provides statistical indicators that can be used to prevent over-fitting when the dataset is limited. Important condensate retention and drainage mechanisms are identified and modeled using analytical and numerical methods. When condensate obstructs the louver gap, boundary layer re-starting does not occur, and the most important heat transfer enhancement mechanism in these flows lost. It is shown that surface tension can maintain inter-louver condensate bridges against gravity and flow-generated shear and pressure forces, even at air-side Reynolds numbers much higher than are typical to the applications of interest. Thus, maintaining wet-surface heat transfer performance depends on avoiding the initial formation of inter-louver bridges. Made available in DSpace on 2015-09-25T21:12:32Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3270001.pdf: 4610207 bytes, checksum: e645a7fa0313d2d021d8782c4270c639 (MD5) Previous issue date: 2007 Embargo set by: Seth Robbins for item 85155 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 191 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007. http://hdl.handle.net/2142/83874 (MiAaPQ)AAI3270001 eng Engineering, Mechanical Predicting the Air-Side Thermal -Hydraulic Performance Characteristics of Flat-Tube Louver-Fin Heat Exchangers Under Dry and Wet Conditions text Mechanical Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.