| With the rapid development of modern technology,electronic components have become more and more miniaturized and functionalized,followed by a significant increase in the heat flux density of components,if the heat can not be lost in time,it will lead to the failure of electronic components due to excessive temperature,so it is very important to find efficient and reliable cooling technology.Among them,jet impact cooling has high heat transfer efficiency,good heat transfer uniformity,large heat exchange area of micro channels,and micro channels with jet combine the advantages of both,which is considered to be an effective way to solve the bottleneck problem of heat dissipation of electronic components.In this paper,water is used as the medium to study the jet impact and its heat transfer method combined with the micro channel.The flow and heat transfer of jet impinging on convex heat sources with different shapes are studied by numerical simulation.The results show that under the open boundary,when Reynolds number and impact distance increase,the fluid sucked in from the outside also increases,and it will not be affected when the shape of convex heat sources changes.Among the three kinds of convex heat sources,the triangular convex heat source has a very high heat transfer efficiency at the stagnation point,while the rectangular heat source has the best comprehensive heat transfer effect,followed by the triangular heat source,and the circular arc heat source has the worst comprehensive heat transfer effect.The average Nusselt number of three kinds of convex heat sources increases with the increase of Reynolds number.From the analysis of system thermal resistance and pump power consumed,the rectangular heat source with impact distance of 1mm has the best performance.The micro-channel evaporator with jet impingement-was numerically studied,and the influence of various parameters on the heat transfer of the micro-evaporator was analyzed.It was found that the narrower the micro-channel,the stronger the heat transfer effect,but the more pump power was needed.The smaller the impact distance,the better the heat transfer performance of the micro-evaporator,but when the impact distance is within 1mm,with the decrease of the impact distance,the required pump power will increase in series.Increasing the number of jet holes would make the heat transfer more uniform,but with the increase of the number of holes,the more pump power was consumed.The inserted micro-evaporator could effectively improve the adverse effect of constant current on the multi-hole impinging jet,thus improving the heat transfer effect,Finally,the heat transfer correlation of micro evaporator with good performance is obtained by least square method.In order to further improve the heat transfer performance of micro-evaporator,this paper designs a jet micro-channel structure with ribbed columns,analyzes the heat transfer advantages of ribbed columns to micro-evaporator,and obtains the microevaporator with the best heat transfer performance by changing the structure of ribbed columns.The results show that ribbed columns increase the disturbance of fluid and contribute to the heat transfer of the system.Increasing the number of ribbed columns can further improve the heat transfer efficiency,but it will require more pumping work.If the height of the rib column is increased to the same height as the microchannel,the heat transfer will deteriorate,and its heat transfer coefficient is smaller than that of the ordinary microchannel structure with jet.When Reynolds number is in a small range,long ribs are more conducive to heat transfer,but when Reynolds number is large,the conclusion is just the opposite.Finally,the heat transfer correlation of the optimal structure is obtained.Through research,it is found that the jet impingement cooling method has good heat transfer performance because of the excellent synergy between velocity field and temperature field.By combining with micro-channels,the heat transfer area is increased,which will further improve the heat transfer effect of the system and have great development potential. |
