Abstract: To improve the cooling efficiency of the chip by using the high-efficiency heat transfer technology and ensure the normal operation of the chip, the flow and boiling heat transfer characteristics of four kinds of chips with the microfin surfaces immersed in saturated FC-72 were investigated, with the microfin dimensions (thickness ×height) of 50 μm ×190μm, 50μm ×250 μm, 100 μm ×150 μm and 100 μm ×300 μm, respectively.The effect of FC-72 subcooling on the boilingheat transfer was also investigated, with the results compared to those of a chip withsmooth surface.The experimental results show that, with the increasing of FC-72 subcooling, the critical heat flux (CHF) increases for all the tested chips.For chips with microfin surfaces, the wall temperature corresponding to the CHF is less than 85 ℃, while for those with smooth surfaces, it is more than 85 ℃.It is also shown that, with the same FC-72 subcooling, the maximum allowable heat flux for chips with microfin surfaces are 7～ 9 times that of those with smooth surfaces, which proves that the microfin can obviously enhance the boiling heat transfer of FC-72.

Key words: chip, microfin, enhancement , FC-72, boiling heat transfer