Flow boiling in micro and mini channels – A review

Flow boiling in micro/mini channels in recent years has found to be a very dominating area of research. The problem of high heat flux generation in electronic devices and nuclear energy systems is substantially seeking attentions. The flow boiling two phase heat transfer in micro and mini channels covers the wide range of operating conditions in heat flux dissipation. This literature comprehensively covers the arena of flow boiling in micro channels. Unlike conventional flow channel in micro and mini channels the flow pattern is considerably different and in case of two phase flow it is very much deviated. This paper covers the basic operating regimes of flow boiling in micro and mini channels i.e from subbcooled entry of fluid to subcooled boiling, saturated boiling, film boiling and partial dry out etc. The parametric study presented here is performed on various working fluids also on some low pressure refrigerants. In this review various boiling regimes, flow boiling instabilities and their proposed solutions are discusses, moreover flow boiling in some practical devices is also discussed here like micro pin fin heat sinks etc. The most concerning phenomenon during flow boiling is the occurrence of instabilities. Several studies are performed on the flow boiling instabilities and some promising solutions also have been presented. These instabilities may be in various forms like temperature and pressure fluctuations, early critical heat flux, early dry out, flow reversal etc. The flow boiling instabilities greatly depends upon the flow properties like working fluid, inlet subcooling, and bubble dynamics, geometrical features etc. Now a days concerned focus is given to the instabilities study in microchannel flow boiling, hence a major portion of micro channel flow boiling consist of study of flow boiling instabilities.