Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10385787 | Chemical Engineering Research and Design | 2005 | 12 Pages |
Abstract
The paper describes tests boiling R 113 at atmospheric pressure in upward flow over a 17 row column of square pitched electrically heated tubes. Uniform heat fluxes of 10-65 kW m-2 and maximum Reynolds numbers, Remax, between 7800 and 27 000 were used. The data at the lower heat fluxes of 10 and 20 kW m-2 consistently exhibited a linear increase of heat transfer coefficient, h, with quality, the slope lower at 20 kW m-2, so that h at 10 kW m-2 exceeded that at 20 kW m-2 and both reached h at 40 kW m-2 for the maximum quality tested. At the higher heat fluxes a nucleate boiling controlled region was observed at low quality, with h equal to the value at the same heat flux as observed with an isolated tube in a pool, followed by a rise in h at higher quality. The results were compared with the work of other researchers. Heat transfer coefficients for q ⥠40 kW m-2 were predicted to an average r.m.s. deviation of 7%, using the asymptotic flow boiling model. However, the sensitivity of h to change of quality and flow rate predicted was much lower than measured and in some cases exhibited opposite trends.
Keywords
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Filtration and Separation
Authors
B.M. Burnside, N.F. Shire,