Performance evaluation of air-cooled heat exchangers

Makhema, Thabo (2000-12)

Thesis (MEng)--Stellenbosch University, 2000.

Thesis

ENGLISH ABSTRACT: The main objective of this study to determine the air-side heat transfer and pressure drop performance characteristics of commercially available round and elliptical fined tubes. A . computer code to compare the performance of industrial forced and induced draught aircooled heat exchangers (henceforth referred to as f\CHE's) commonly found in the petrochemical industry is also developed. The comparison is extended to include both round and elliptical finned tubes. From the tests conducted, it is found that there is generally an increase in the heat transfer parameter with a decrease in the fin pitch. The decrease in the fin pitch however also results in an increase in the pressure drop across the tube bundle. The performance of the tubes is compared with round reference tubes having circular or plate fins for which performance correlations are available in the literature. The fan power required by an induced draught aircooled heat exchanger is found to be higher than that required by a forced draught heat exchanger rejecting the same amount of heat.

AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie studie is om die werksverrigting van industriële geforseerde trek -- en geinduseerde trek lugverkoelde warmteruilers (LVWR) soos algemeen aangetref in die petrochemiese nywerheid te vergelyk. Warmteruiier bundels word gewoonlik opgebou uit ronde vinbuise. Die werksverrigting van laasgenoemde word vergelyk met die werksverrigting van warmteruiier bundels wat gebruik maak van elliptiese vinbuise. Die werksverrigting van 'n reeks kommersieël verkrygbare ronde en elliptiese vinbuise word deur middel van toetsing bepaal. In die algemeen word 'n toename in die warmteoordrag-parameter waargeneem met In afname in die vinsteek. 'n Toename in die vinsteek gaan egter gepaard met" 'n toename in die drukverlies oor die bundel. Die werksverrigting van hierdie buise word vergelyk met bestaande korrelasies vir die werksverrigting van ronde verwysingsbuise wat gebruik maak van ronde of plaatvinne. Daar is bevind dat die drywing wat benodig word deur 'n waaier vir 'n geinduseerde trek lugverkoelde warmteruiler, heelwat hoër is as in die geval van 'n geforseerde trek lugverkoelde warmteruiler, vir dieselfde hoeveelheid hitte verwydering

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/51872
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