Air-side condensate management: Drainage channels in heat exchangers

Condensate;Automotive;Evaporator;Drainage;Channels;Louver-fin

Gupta, Deep ; Jacobi ; Anthony M.

关键词: Condensate;    Automotive;    Evaporator;    Drainage;    Channels;    Louver-fin;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/16954/1_Gupta_Deep.pdf?sequence=3&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Condensate onthe air-side surface of flat-tube air-cooling heat exchangers can resultin several adverseeffectsontheoverallthermal-hydraulicperformance.Inordertoimprovethe performance of compact heat exchangers under wet-surface conditions, promotingthe drainage of condensed water is critical. Drainage channels ontube walls might provide a robust solution topromotecondensatedrainagefromcompactheatexchangers. Aquantitativeandqualitative evaluation of the effectiveness of drainage channels on the condensate retention characteristics of compactflat-tubelouver-finheatexchangersispresented.Variousgeometriesofdrainage channelsare engraved onsurrogatetubesin contact withfinstock. Twofin designsaretested using a dynamic dip testing method, and four designs are tested in a small wind tunnel apparatus. Datafromthequantitativeresultsandthevisualizationtestsshowthatthedrainagechannels reducethe condensate retention for allthe fin designstested, except one. Fin structure plays an important role in determining the condensate retention behavior and hence the effect of drainage channels. Otherimportant parameters, such as fin gap andlouver gap, which have an effect on thecondensateretentionbehaviorareidentified. Theresultsincludeacomparisonofdrainage channel geometry and dimensions, over a range ofincoming air velocity and relative humidity, and at different sample inclinations. The maximum effect obtained is a 27% reduction in steady-stateretention.Amethodtoimplementdrainagechannelsinfull-sizeheatexchangersis suggested and an analysis suggests heat transfer can be improved by 12% while pressure drop is reduced by 9%.