Study of flow boiling characteristics of a microchannel using high speed visualization
2013 (English)In: Journal of heat transfer, ISSN 0022-1481, Vol. 135, no 8, 081501- p.Article in journal (Refereed) Published
This paper presents the visualization results obtained for an experimental study of R134a during flow boiling in a horizontal microchannel. The microchannel used was a fused silica tube having an internal diameter of 781 lm, a heated length of 191mm, and was coated with a thin, transparent, and electrically conductive layer of indium-tin-oxide (ITO) on the outer surface. The operating parameters during the experiments were: mass flux 100-400 kg/m2 s, heat flux 5-45 kW/m2, saturation temperatures 25 and 30 °C, corresponding to saturation pressures of 6.65 bar and 7.70 bar and reduced pressures of 0.163 and 0.189, respectively. A high speed camera with a close up lens was used to capture the flow patterns that evolved along the channel. Flow pattern maps are presented in terms of the superficial gas and liquid velocity and in terms of the Reynolds number and vapor quality plots. The results are compared with some flow pattern maps for conventional and micro scale channels available in the literature. Rigorous boiling and increased coalescence rates were observed with an increase in the heat flux.
Place, publisher, year, edition, pages
2013. Vol. 135, no 8, 081501- p.
Bubbles, Flow boiling, Flow patterns, Heat transfer, Microchannel
IdentifiersURN: urn:nbn:se:kth:diva-133392DOI: 10.1115/1.4023879ISI: 000326167900014ScopusID: 2-s2.0-84883373886OAI: oai:DiVA.org:kth-133392DiVA: diva2:661852
QC 201311052013-11-052013-10-312013-11-27Bibliographically approved