ENHANCEMENT OF FLOW-JET COMBINED BOILING HEAT TRANSFER OF FC-72 OVER MICRO-PIN-FINNED SURFACES

摘要

For highly efficient solving of the power dissipation problem of electronic components with high heat flux, experimental study of the flow-jet combined boiling heat transfer on silicon chips was conducted. Micro-pin-fins with dimensions of 30×60 μm~2 and 30×120 μm~2 (thickness x height) were fabricated on the chip surfaces by the dry etching technique. The experiments were made at three different cross-flow velocities V_c (0.5,1.0,1.5 m/s) and different jet velocities V_j (0-2 m/s) with two liquid subcooling ΔT_(sub) (25℃ and 35℃). A smooth surface was also tested for comparison. The micro-pin-fins showed a considerable heat transfer enhancement due to an increase in effective heat transfer surface area caused by micro-convection around micro-pin-fins. The maximum allowable heat flux q_(max) is increased and the wall superheat is decreased greatly. For a given V_c, the heat transfer enhancement is more significant as V_j increases, but the q_(max) increment decreases as V_c increases. The fin efficiency decreases as V_c or/and V_j increases or the heat flux q increases. The maximum q_(max) can reach 161 W/cm~2 at V_c = 1.5 m/s, V_j = 2 m/s, ΔT_(sub) = 35℃ for chip PF30-120.