A Numerical Study on Condensation Heat Transfer Characteristics of R134a in Microchannel Under Varying Gravity Conditions

A large amount of heat can be dissipated more efficiently by utilizing the latent heat than the sensible heat of coolant using condensation technique. In addition, cooling by microchannel is found as a promising method to dissipate more heat than the conventional channel. The application of condensation in a microchannel under different gravity conditions becomes very important due to rising demand in space technology, where compact high-performance electronic devices experience rise in temperature beyond the tolerable limit. The present numerical model explores the effect of different gravity conditions on the fluid flow and heat transfer characteristics of R134a condensation in a two-dimensional microchannel with a diameter of 100 µm. The gravity condition is varied from zero to normal gravity as g = 0, 0.1, 0.5, 1 and 9.81 m/s2. Moreover, the effects of subcooled wall temperature, mass flux and vapour quality on two phase flow regimes, flow characteristics, temperature distribution, local and average Nusselt number behaviour are also investigated. The flow regime is significantly influenced by the gravity, wall temperature, mass flux and vapour quality and accordingly, different flow regimes are observed. The flow behaviour and temperature contour are also prominently dependent on the working parameters. The gravity condition has found to insignificantly affect the average condensation heat transfer properties in the considered microchannel.