Fluid flow and heat transfer characteristics of low temperature two-phase micro-channel heat sinks – Part 2. Subcooled boiling pressure drop and heat transfer

Flow boiling performance of Ω-shaped reentrant copper microchannels with different channel sizes

“…For sample RCM1 with small channel size, the bubbles cannot grow to an ideally large size before they were washed away by the incoming liquid, and it facilitated an early and rapid coalescence of bubbles due to the restriction of the limited space inside the small microchannels. It induced strong confinement effects on the bubble growth, and early transition from bubbly to slug and annular flow commenced at low heat fluxes [12,26]. This suppressed the nucleate boiling activities and resulted in small heat transfer rates.…”

“…Lee et al [25] highlighted the important role of microchannel height on nucleation-site activities and bubble dynamics using rectangular silicon microchannels with the widths ranging from 150 to 9000 lm and heights ranging from 5 to 510 lm. Lee and Mudawar [26] found that boiling heat transfer in rectangular copper microchannels increased with the hydraulic diameters increasing from 175.7 lm to 334.1 lm, while it deteriorated apparently when the size increased further to 415.9 lm. Moreover, the critical role of channel cross-section geometry of silicon microchannels on boiling performance was systemically examined by Harirchian and Garimella [27,28].…”

“…In conventional microchannels, the microchannel size has been found to play a critical role on the flow boiling performance by many researcher groups [22][23][24][25][26][27][28]. A number of research efforts have been devoted to examine the tube diameter effects on the two-phase flow boiling behaviors of microtubes, such as Saitoh et al [22], Huo et al [23], Dupont and Thome [24].…”

A Critical Review of Recent Investigations on Flow Pattern and Heat Transfer During Flow Boiling in Micro-Channels

“…The effect of the saturation pressure on the heat transfer coefficient was obvious for R-236fa. Lee and M udawar (2008) HFE 7100 G = 670-6730 q = 0-7500 P out = 113. At high heat flux region, the heat transfer coefficient was nearly independent with heat flux.…”

“…According to the comparisons based on di fferent experimental conditions, they concluded that R-245fa provided heat transfer performance slightly higher than that for R-236fa. Lee and M udawar (2008) carried out experiments to investigate flow boiling in four d ifferent rectangular micro-channels. The heat transfer coefficient did not monotonously increase with the decrease in hydraulic diameter.…”