Research On The Heat Tranfer And Flow Performance Of Water Cooling Heat Sink Filled With Packing

With the develop vigorouslyof electronic technique, the solidity of the electronic devicesis minishing along with the power density is increasing gradually. So the effect of the heatsink is definitive to its development.As dispersion effects and ribwork effects of porous media can result in strong transversemixing for liquid, so the flow is more complex and heat transfer can be obviously enhanced inporous media. The water cooling technologyis improved used in this experiment based on themechanism of heat transfer enhancement inside porous media. The water cooling heat sink ischanged to be a packed heat sink by filling the snake-like flow channel with various balls. Theheat transfer and flow performance of the heat sink were carried out in an experimental setupby measuring the volume flow, inlet and outlet temperature and temperature of exterior wallof heat sink, in which water was used as the cooling medium and various balls were packed.Based on evaluation of the experimental uncertainty, the uncertainties ofα,f,Nu,PECare obtained. The uncertainty ofαis 7.83% and the uncertainty of f is 5.70%, besides the uncertainties of Nu and PEC are 7.84% and 8.79% respectivelyin the experimental setup.Over the range of experiment, the cooling effect of improved heat sink is much better.Besides the intensifing effect is more notable when the power is increasing. At the samepower and fill porosity, the heat sink packed with stainless steel balls is much better than thatof packed with glass balls and the Nusselt number of packed with steel balls is 1.2~1.5 timesthan that of packed with glass balls. The results show that heat transfer and flow performanceof heat sink are becoming better with the increasing of the diameter of bearing balls. Whenthe fill porosity is 0.75, the cooling effect is best. And when the fill porosity is minimum, thecooling effect is worst. The pressure drop is increasing with fill porosity decrease. Theanalysed results show the overall performance of packed heat sink is decreasing when the Reis increasing and it is best when the diameter of filling is 3mm. The next are packing of thediameterФ4mm andФ2mm. Besides when the fill porosity is 0.75, the overall performanceof packed heat sink is best. Therefore when the diameter is 3mm and the fill porosity is 0.75,filling steel balls will help to improve the heat transfer and flow performance of packed heatsink.