Heat Transfer Mechanism Study And Structure Optimization Of Metal-Polymer Composite Microstructure Radiating Radiator For CPU

With the miniaturization and substantial increase of running speed, integration and frequency of the CPU, the high heating flux density and heat concentration of the CPU chip has become an irresistible trend, which make the cooling of the CPU chip become more prominent. Therefore, the manufacture of the high performance heat sink to cool the CPU chip has become a hot topic in the study of thermodynamics. Now, on the market, due to its large thermal conductivity of the metal radiator, the heat conduction of the metal radiator is far greater than the heat dissipating capacity, so that the heat is gathered in the fin. Therefore, the heat cannot be effectively distributed to the air. However, the microstructure heat exchanger has the advantage of higher heat transfer efficiency, higher heat flow, so that the heat can be efficiently distributed into the air. Therefore, the new CPU radiator based on the advantages of new materials, small size and high heat efficiency etc., will have a very large market prospects.In this paper, a novel metal-polymer composite heat exchanger was proposed. In this composite radiator structure, the efficient export and emission of heat were achieved by making use of excellent heat conduction performance of the metal substrate and excellent heat dissipation performance of the polymer microstructure. Finally, the heat transfer balance from the heat source to the environment was obtained. Based on the thermal balance mechanism of the composite radiator, the influence of factors on the heat radiating performance and overall thermodynamic performance of radiator were investigated from the aspects of material and structure of heat sink. The main research contents were as follows:1. The geometrical model of composite type radiator was established. Firstly, the effect of height on heat dissipation performance of polymer radiator was studied under different fin spacing and fin thicknes. Secondly, the comprehensive analysis of the influence of the fin spacing, height and thickness on heat dissipation performance of metal-polymer composite radiator was performed. Finally, the effect of the heating power on cooling performance of the metal-polymer composite radiator was discussed under the different fin height.2. The influences of contact surface condition between the metal and polymer, polymer substrate thickness and microstructural parameters on the performance of the composite fin were analyzed based on the research of the metal-polymer composite microstructure heat dissipation optimized structure. At the same time, the effect rule of placement of microstructure on the heat dissipation performance was evaluated.3. Based on the research of the composite radiator and composite microstructure radiating fins, the metal-polymer composite microstructure CPU radiator model was established. Based on the flat type radiator, the influence factors of the microstructure form, substrate material and microstructure placement form on heat dissipation performance of composite microstructure CPU radiator were investigated. Based on radiation type radiator, the influence of the material and heat conducting cylindrical structure on thermal performance was studied.4. In this paper, according to the simulation results, the polymer CPU radiator with the different dimensions and composite CPU radiator with three different fin structures were devised and manufactured. Moreover, the performance testing for these types radiator was conducted by using built test platform.Research results are as follows:1. For the metal-polymer composite radiator, when the fin height is 50mm, the lowest of average temperature of the heat source is achieved, which is 52.36?. The highest value of the composite surface heat transfer coefficient (32.57 and 31.93W/m2·K, respectively) is obtained, with the fin thickness and spacing of 1.5 and 2.5 mm, respectively.2. The temperature difference of contact surface with triangle combination surface structure is the smallest,0.18?. When the composite microstructure heat radiation structure is placed vertically, the heat dissipation performance is best.3. Compared with the aluminum metal CPU radiator (heat source temperature of 53.29?), the metal-polymer PPS composite microstructure CPU radiator (heat source temperature of 51.13 ?) has better heat dissipation performance. The metal-polymer composite micro-structure heat radiator can replace the metal radiator for CPU heat radiation.4. For the radiator with the fin spacing of 2mm, the fan speed should be 2680RPM.