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http://dx.doi.org/10.3795/KSME-B.2015.39.3.223

Enhancement of Performance of Shell and Tube Heat Exchanger Using Pertinent Leakage Flow Between Baffle and Tube Bundles  

Nguyen, Van Hap (School of Mechanical Engineering, Univ. of Ulsan)
Lee, Geun Sik (School of Mechanical Engineering, Univ. of Ulsan)
Publication Information
Transactions of the Korean Society of Mechanical Engineers B / v.39, no.3, 2015 , pp. 223-229 More about this Journal
Abstract
In this study, the effects of the leakage flow between the baffle and tube bundles on the performance of a shell and tube heat exchanger (STHE) were examined using the commercial software ANSYS FLUENT v.14. A computational fluid dynamics model was developed for a small STHE with five different cases for the ratio of the leakage cross-sectional area to the baffle cross-sectional area, ranging from 0 to 40%, in order to determine the optimum leakage flow corresponding to the maximum outlet temperature. Using fixed tube wall and inlet temperatures for the shell side of the STHE, the flow and temperature fields were calculated by increasing the Reynolds number from 4952 to 14858. The present results showed that the outlet temperature, pressure drop, and heat transfer coefficient were strongly affected by the leakage flow, as well as the Reynolds number. In contrast with a previous researcher's finding that the leakage flow led to simultaneous decreases in the pressure drop and heat transfer rate, the present study found that the pertinent leakage flow provided momentum in the recirculation zone near the baffle plate and thus led to the maximum outlet temperature, a small pressure drop, and the highest heat transfer rate. The optimum leakage flow was shown in the case with a ratio of 20% among the five different cases.
Keywords
Leakage Flow; Shell-and-Tube Heat Exchanger; Baffle; Heat Transfer; Pressure Drop; Performance Enhancement;
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