An experimental investigation of single-phase forced convection in microchannels

Investigation of heat transfer in rectangular microchannels

“…As seen in Fig. 7(c), the experimental Nusselt numbers are generally higher in this turbulent region than predictions from correlations in [15,16,28]. Predictions from the Petukhov and Dittus-Boelter [25] correlations, on the other hand, are seen to lie above the experimental data, possibly because they were proposed for fully turbulent flow (Re > 3000), while results obtained in the present study cover more of a transitional regime.…”

“…Based on comparison with these conventional correlations, various conclusions have been drawn regarding their applicability to microchannel heat transfer [1,12,13,14,15,[29][30][31][32][33][34][35][36][37]. Table 4 summarizes the conditions considered in these past microchannel studies, the conventional correlations against which results were compared, the conclusions that were drawn regarding applicability of conventional correlations, and any new correlations that were proposed.…”

“…Adams et al [15] investigated single-phase forced convection of water in circular microchannels of diameter 0.76 and 1.09 mm. Their experimental Nusselt numbers were significantly higher than those predicted by traditional large-channel correlations, such as the Gnielinski [16] correlation.…”

Thermal analysis of a solar collector absorber plate with microchannels

“…Since then, heat transfer in micro-channels has been extensively studied, however, published results are still inconsistent; some studies have found the average Nusselt number to be Reynolds number dependent in the laminar regime [10][11][12], some recorded lower Nusselt numbers [13][14][15] while some recorded higher Nusselt numbers [16][17][18]. Reviews on experimental and numerical studies of heat transfer in microchannels published by Mokrani, Bourouga, Castelain and Peerhossaini [19], Hetsroni, Mosyak, Pogrebnyak and Yarin [20], Rosa, Karayiannis and Collins [21] and Sobhan and Garimella [22] confirm the very large scatter in published results and attribute this to "scaling effects", which arise from neglecting phenomenon which are insignificant in conventional sized channels but become significant with the high channel wall surface to fluid volume ratio in microchannel flow.…”

The significance of scaling effects in a solar absorber plate with micro-channels

“…Tuckerman and Pease [17] pioneered the study of heat transfer in microchannels in 1981. Inconsistent results have been published from the extensive study in this field; some studies have found the average Nusselt number to be Reynolds number dependent in the laminar regime [18][19][20], some recorded lower Nusselt numbers [21][22][23] while some recorded higher Nusselt numbers [24][25][26][27]. Reviews on experimental and numerical studies of heat transfer in micro-channels published by Morini [28], Hetsroni, et al [29], Rosa, et al [30] and Sobhan and Garimella [31] confirm the very large scatter in published results and attribute this to "scaling effects".…”