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Trains of Taylor Bubbles over Hot Nano-Textured Mini-Channel Surface

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journal contribution
posted on 10.03.2018, 00:00 by M Freystein, F Kolberg, L Spiegel, S Sinha-Ray, RP Sahu, AL Yarin, T Gambaryan-Roisman, P Stephan
To enhance heat transfer in forced convective boiling the mini-channel bottom was amended by nano-textured structures – periodic rectangular mats of electrospun polymer nanofibers. The fibers were about several hundreds of nanometer in diameter. The test fluid was FC-72. The flow in mini-channels contained trains of the Taylor bubbles. The role of the nanofibers was to retain the warm mini-channel bottom wetted, to prevent dry-out and thus to enhance the heat removal rate. In the present experiments the time-average heat flux at the nanofiber-coated domains was found to be 1.6 times higher than that at the uncoated ones. Accordingly, a significant decrease (by 5–8 K) in the superheat was observed. The heat transfer coefficient at the nanofiber mat-coated domains was found to be an order of magnitude higher than that at the uncoated domains. Such significant enhancement of heat transfer results from the fact that nanofiber mats facilitate wetting of the surface under the passing Taylor bubbles, thus delaying formation of vapor layer at the channel bottom.


A.L.Y., S.S.-R. and R.P.S. were supported by NASA (Grant No. NNX13AQ77G). T.G.-R. acknowledges the financial support of European Community through the Marie Curie Initial Training Network ‘‘Complex Wetting Phenomena” (CoWet), Grant Agreement No. 607861. This work has been done under the umbrella of COST Action MP1106.


Publisher Statement

This is the author’s version of a work that was accepted for publication in International Journal of Heat and Mass Transfer. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in International Journal of Heat and Mass Transfer, International Journal of Heat and Mass Transfer. 2016. 93: 827-833. DOI: 10.1016/j.ijheatmasstransfer.2015.10.054.





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