Abstract
The boiling convective heat transfer of dielectric fluid of FC-72 in a microchannel with etched micro fins is experimentally studied. The microchannel test surface is a square of 10 mm size with a height of 100 μm. The surface of the microchannel is covered with parallel-nucleated fins of a cubic size of 100 μm. The fins are nucleated with the central pore size of 60 μm and an opening of 45 μm. The fins are arranged in the equal space of 400 μm. There is a planar electrical element below the microchannel, which produces an adjustable surface heat flux below the channel. The dielectric liquid enters the test microchannel and flows over the test surface and the fins. In the experiments, the mass velocity (94–275 kg/m2 s) and heat flux (0–6 W/cm2) are tested with a saturation temperature of either 35 or 50 °C. The heat transfer, the outlet vapor quality, and the pressure drop across the microchannel are measured and reported. The boiling behavior of FC-72 over the etched fins is also investigated using photos. The results show that the liquid first go through some superheat states and then the boiling phase change starts. When the boiling heat transfer occurs, a significant pressure-drop can be observed across the microchannel, but the surface temperature difference would also drop significantly. In the case of very low mass velocity of 94 kg/m2 s, the minimum superheat temperature-difference of 4.7 °C is observed.
Original language | English |
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Pages (from-to) | 390-400 |
Number of pages | 11 |
Journal | International Journal of Heat and Mass Transfer |
Volume | 138 |
DOIs | |
State | Published - 08 2019 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2019 Elsevier Ltd
Keywords
- Dielectric fluid
- Flow boiling
- Microchannel
- Parallel nucleate micro-pin-fin