Dryout characteristics of R1234yf in a uniformly heated vertical mini-channel
2013 (English)In: UK Heat Transfer Conference, 2013Conference paper (Refereed)
Two phase heat transfer in small channels has many practical applications like, miniature heatexchangers, high powered electronics, miniature refrigeration system. Flow boiling in these compactchannels offers many potential advantages like, cope with high heat flux, less fluid inventory,compactness in size. It is well known that two phase heat transfer is drastically reduced when theheater surface becomes partially dry, for any reason. Moving beyond the point where this happensresults in a sharp increase in the temperature of the heated surface and eventually leads towardsburnout. So the upper operational limit (from safety and efficiency point of view) is extremelyimportant to be able to predict.Experimental findings on dryout of Isobutane in a uniformly heated, vertical, stainless steel testsection (1.6 mm inside diameter and 245mm heated length) are reported in this article. Experimentswere conducted at two saturation pressures corresponding to temperatures of 27 and 32 oC, with fivemass fluxes in the range 50-350 kg/m2s and with vapor fractions at the outlet up till dryout conditions.Analysis showed that the dryout heat flux increased with increasing mass flux, while no effect ofvarying the operating pressure was observed. Experimental results were compared with differentcorrelations from the literature, Wu , Mikielewicz , Callizo  and Katto-Ohno  correlationsquite satisfactorily predicted the data.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:kth:diva-136075OAI: oai:DiVA.org:kth-136075DiVA: diva2:670485
13th UK Heat Transfer Conference
QC 201502032013-12-032013-12-032015-02-03Bibliographically approved