| With the rapid growth of the heat flux of the electronic packages, traditional coolingapproaches using fans or fins may not meet the increasing cooling demand. The heatdissipation issue will prevent the further development of electronic products. Microchannelheat sinks will be an efficient way to solve this problem. The goal of this study is todissipate the heat flux20W/cm2within heat surface20×40×0.5mm while maintainingthe wall temperature below60°C.Due to the large specific surface area of the porous medium, this thesis numericallyinvestigates the flow and heat transfer characteristics in a micro-channel filled with porousmedia and ribs. A three dimension (3-D) mathematical model, consisting ofNavier–Stokes(N-S) equations and energy conservation, the conjugate heat transferbetween the channel wall and the coolant, and local thermal non-equilibrium conditions inporous media as well, is solved numerically. It is found that due to the addition of the fin,the convective heat transfer is enhanced by enhancing the heat conduction in the directionof heat flux. The effect of the number of fin columns on the performance of thecompounded miniature channel is also investigated. It is found that for the same porousmedium, the averaged Nusselt (Nu) value increases rapidly with the increase of number ofrib columns, while the pressure drop slightly decrease firstly and the increases graduallywith the increasing of number of columns.. Better uniformity of temperature field and lowerheat sink temperature can effectively reduce the thermal stress, which is of greatimportance to the reliability of the electronic devices.At the same time, the thesis has changed the fin parameters and the effect of ribthickness on the heat transfer performance is also investigated. It is found that there is arelationship between rib thickness and heat transfer performance. In this article, the thickerthe fin is, the better the performance will be for a given lower rate. However, there will bean optimal value of thickness for a given higher flow rate. In this paper, the effects ofdifferent arrangements of fin on compounded micro channel are also studied. Thesimulation results show that for the compounded micro channel, the offset arrangement isbetter than the aligned arrangement and the double-inclined is also better than the alignedarrangement. This results show that, for the micro scale, the offset structure and the double- inclined structure results are the same as that of macro scale. Finally, in the article thesimulation of the r staggered row of fins of rib is also investigated. Simulation data andconclusions of this article provide a certain reference for further micro channel heat sinkdesign. |
