Research On Heat Dissipation For Jet Impact And Tiny Channels

Since mankind steps into the era of microelectronics,the measurement scale of electronic devices began to change from "meter" to "millimeter" or even "nanometer ".When the miniaturization of electronic products bring convenience to our lives,the problems of high-density heat dissipation become unavoidable.The cooling technology of conventional air convection is gradually replaced by air forced convection or even liquid convection cooling technology,but need for mass heat dissipation of large scale integrated circuits still can’t fully be met.When use jet impact cooling technology,extremely high heat transfer effect can be produced in the local range.In the meantime,few requirements of space position is needed and mute performance is good.Especially when the multi-beam impact jet work together,a very low temperature range on the heat transfer surface can be maintained and good temperature uniformity can be achieved.And because of the high surface-to-volume ratio of the micro channel,it is one of the best cooling technology for heat dissipation.With the progress of micro-processing technology and packaging technology,the leakage problem of liquid-cooled technology has been solved.Therefore,the technology of liquid jet impact and micro-channel liquid cooling come to be research hotspots in the field of heat dissipation.At present,human beings have a preliminary understanding of the flow distribution and heat transfer distribution of jet impact,but there are different views about the influence of the various parameters on the jet impact cooling.As we know,the most important characteristic of jet impact is the high local heat transfer coefficient.However,in the past experiments,the characteristics of the mass and heat transfer of the jet impact are not accurately described and the flow field becomes more difficult to measure especially for the multi-beam jet impact,due to the low density of points and the imperfect measurement methods.Starting from this,in this paper,the numerical simulation method is used to study the flow field distribution of single and multiple jet impacts,and the geometrical parameters and external parameters which affect the heat transfer efficiency of impact target surface are discussed.In order to obtain higher heat transfer efficiency,based on the analysis of jet impact cooling,the technology of the jet impact and micro-channel liquid cooling are combined to study the factors influencing the cooling efficiency of this composite structure,such as the depth of perforation,micro-channel aspect ratio,impact angle and outlet arrangement,etc.And then calculate the weight ratio of each part in the total convective heat transfer.Finally,a kind of array jet micro-channel radiator with the combination of the two is put forward.Meanwhile,the model is processed and experimentally verified.The study results show that the center of the jet has a high heat transfer effect,and the heat transfer coefficient is closely related to the impact space and the pore size.Due to the influence of the impact flow field,there are some different phenomena between the porous jet and the single jet.In general,the porous jet is more uniform than the single-beam jet heat transfer.The combination of impact jet and micro-channel can take advantage of the both to achieve better heat transfer effect and temperature uniformity.