The effect of channel aspect ratio on flow boiling characteristics within rectangular micro-passages

In the present paper, a fundamental analysis on effect of channel aspect ratio bubble dynamics and heat transfer characteristics for early transient stages growth within confined microchannels rectangular cross-section, under saturated flow boiling conditions, is conducted, utilising high resolution, 3D, transient, conjugate simulations. The open-source toolbox OpenFOAM applied simulations, custom, user-enhanced, diabatic Volume OF Fluid (VOF) solver. Two different series numerical simulations are performed, focused single nucleation event from site multiple, arbitrarily located, sites, respectively. each series, three values considered, corresponding to narrow, square, wide microchannel. For first performed low, medium, value flux mass flux. second only lower used ratio, since this constitutes worst-case scenario overall performance point view, amongst cases examined in micro-passage has significant generated during onset nucleate regime, as bubbles grow liquid crossflow. This alteration interfacial dynamics, effect, regulates size position contact areas with microchannel walls, direct individual contribution therefore, balance between line film evaporation mechanisms. Moreover, work presents quantification solid domain thermal inertia whole process particular local Nusselt numbers. It evident that considering compulsory order predict physical processes correct form.