| Nowadays,the human society is transitioning to the information age,and the comprehensive advent of the new 5nm process era can greatly reduce the volume of all kinds of electronic equipment,and the high heat loss caused by the miniaturization and integration of various components has gradually become a problem that cannot be ignored.Based on the above background,the physical model of cylindrical cavity with internal heating block was established by using CFD numerical simulation technology and by simplifying the actual engineering conditions,The conjugated heat transfer of fluid-structure coupling in closed cylindrical cavity and open cylindrical cavity with built-in constant heat flux heating block was numerically simulated,and the temperature field,velocity field,heat flux density on each wall surface and air velocity on the open surface were monitored,The effect of flow heat transfer is analyzed,and the influences of the spacing,height,sequence and power of the heating block on the heat dissipation effect of the cylindrical cavity are discussed.The research conclusions are as follows:Firstly,the actual equipment is simplified,and a physical model with two heating blocks inside a cylindrical cavity is established,and the structure of the cylindrical cavity is compared with that of the rectangular cavity.The conclusions are as follows:(1)for two different hot piece of spacing of three kinds of conditions are simulated and the smoke visualization experiments,the yz section velocity vector chart:the cylindrical cavity body wall surface more smooth than rectangular cavity flow,change the heating block spacing effect on top averaged wall heat flux is lesser,a greater influence on the average heat flux density of the wall surface;When the heat block spacing d=75mm,the temperature distribution in the cavity is the most uniform,the average heat flux on the wall is the highest,and the heat transfer effect is the best.(2)Numerical simulation was carried out for three working conditions with different height ratios of the two heating blocks.The average heat flux of each wall surface was the highest and the heat transfer effect was the best when the height ratio was 1:2.Secondly,the case of four heating blocks inside the closed cylindrical cavity is analyzed,and the conclusions are as follows:(1)Four typical working conditions were set according to the four heating blocks with different heights arranged in different order.The average heat flux of each wall surface was the highest and the heat transfer effect was the best in working conditionⅣ(heating blocks with different heights arranged in sequence);working condition ⅱ(the height of the heating block is 20 mm,40mm,10 mm and 30 mm from left to right),the wall heat flow density will decrease,that is,the heat is difficult to disperse in time,which should be avoided in practical engineering.(2)Four typical working conditions are set for the four heating blocks with different powers in different order.The heat transfer effect is the best in working condition ⅱ(from left to right,the power ratio is 2:4:1:3 in order),and the homogenization of the heating block is the best.Finally,in view of the fact that the surface thermal conductivity of cylindrical cavity is not superior in practical engineering,this paper chooses the single-side open cylindrical cavity heating block model to carry out numerical simulation,The change of temperature field and flow field in the cavity was analyzed,the average heat flow density of each wall surface and the average air flow velocity of the opening surface were monitored,and the change of the total heat transfer in the cavity with time was quantitatively calculated,by comparing the percentage of heat transfer of each wall surface and opening surface in the total heat transfer,the conclusions are as follows:(1)After the heating block is heated,the opening cross section will form a heat transfer mode in which hot air rapidly flows out of a small area on the upper wall and cold air flows into a large area below the cross section.(2)The distance between a single heating block and the opening surface was changed,and the three working conditions were compared.When D =100mm,the total heat transfer was the highest,and the proportion of heat transfer from the opening surface was the highest,which could effectively reduce the temperature rise burden caused by the high heat flux on the wall surface,which was the best working condition for natural convection heat transfer.(3)The Angle between the cylindrical cavity and the xz section is changed,and the three working conditions are compared.When φ=60°,the cold and hot air exchange rate inside and outside the cavity is the fastest,the heat transfer rate is the highest,and the proportion of heat transfer through the opening surface is the highest,which is the best working condition of natural convection heat transfer.(4)When the height ratio of heating blocks in the cylindrical cavity and the relative position of heating blocks at different heights to the opening surface are changed,the total heat transfer is the highest,the heat transfer ratio of the opening surface is the best,and the heat dissipation is the best under the working condition ⅰ(the height ratio of the two heating blocks from left to right is 1:2).(5)When the power ratio of the two heating blocks in the cylindrical cavity and the relative position of the high-power heating block and the opening surface are changed,the total heat transfer in condition ⅱ(the power ratio of the two heating blocks from left to right is 1:2 in order)is the highest,the heat transfer ratio in the opening surface is the highest after the full air flow,and the heat dissipation is the best.In this paper,the fluid-structure coupling heat transfer numerical simulation of cylindrical cavity natural convection is carried out from the above three aspects,which provides a theoretical basis for the enhanced heat transfer design of various electronic equipment with cylindrical structure. |
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