Flow boiling in micro-scale channels – Synthesized literature review

• Published in: International journal of refrigeration 2013-03, Vol.36 (2), p.301-324
• Main Authors: Tibiriçá, Cristiano Bigonha, Ribatski, Gherhardt
• Format: Article
• Language: English
• Subjects: Applied sciences; CHF; configuration de l’écoulement; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Flow boiling; Flow pattern; flux thermique critique; Heat transfer; microcanaux; Microchannels; Refrigerating engineering; Refrigerating engineering. Cryogenics. Food conservation; taux de vide; Theoretical studies. Data and constants. Metering; Transition; Void fraction; ébullition libre
• ISSN: 0140-7007; 1879-2081
• DOI: 10.1016/j.ijrefrig.2012.11.019

This paper presents a synthesized review on the recent literature concerning micro-scale flow boiling. The topics covered are macro- to micro-scale transition, flow patterns, pressure drop, heat transfer coefficient, critical heat flux, superficial void fraction and liquid entrainment. The analyses revealed some characteristics common to micro-scale two-phase flow, i.e. absence of stratified flow, predominance of annular flow over all saturated region, uniform liquid film thickness during horizontal flows, reduced liquid entrainment, high heat transfer coefficients and pressure drops. Despite the importance of liquid entrainment and void fraction in predictive methods, there is a lack of experimental results for these parameters in the micro-scale literature. Important accomplishments concerning the investigation of micro-scale flow boiling have been obtained over the last two decades, but some aspects, including local physical mechanisms related to heat transfer, onset of dryout and flow boiling instabilities still remain unclear. ► A broad and synthesized review of micro-scale flow boiling is presented. ► Unique characteristics of micro-scale two-phase flow were described. ► The majority of void fraction micro-scale experimental results are for air–water. ► Flow boiling liquid entrainment experiments should be performed for microchannels. ► Physical mechanisms related to heat transfer, onset of dryout still remain unclear.