The Design Of Micro-channel Radiator And Numerical Investigation Of Flow Field Distribution And Heat Transfer Characteristics

With the rapid development of microelectronics technology,the development of electronic components gradually tends to miniaturization,integration and intelligence,and the power density of chip has also risen sharply.In order to ensure the normal operation of the system,the heat dissipation capacity of high-power micro devices is put forward higher requirements.Compact,lightweight and efficient microchannel radiator technology has become an effective way to solve the heat dissipation of microelectronic devices.Guided by the heat dissipation requirements of electronic chips,this paper designed the geometric structure of micro-channel radiator with different fin spacing and different combinations of ribs and holes in the channel.Water is used as the cooling medium.The internal flow field distribution and heat transfer performance of the micro-channel radiator were numerically simulated in the range of 0.25lpm～1.5lpm volume flow rate and 325W heating power at the inlet.The internal flow field of different radiator structures and its influence on the overall heat transfer performance of the radiator were analyzed.The main research contents and achievements include:（1）Based on the micro-channel radiator structure used in the model verification and control experiment,the number of fins of the micro-channel radiator is determined to be 28,the height ratio of rectangular section is 3mm,the channel interval is 1mm,the area of the contact between the upsurge and the chip is 28.7mm×28.7mm,and the geometric parameters of the inlet,outlet and upper and lower container are determined.Thus,the overall geometry of the micro-channel radiator is determined to meet the heat dissipation performance requirements of the chip.（2）Based on the accuracy and reliability of the simulation results of laminar flow model verified by FLUENT solver,the internal flow field and the change of heat transfer characteristics of the micro-channel radiator were explored in the volume flow interval between 0.25lpm and 1.5lpm at the inlet,and the flow rate of each channel,maximum and average temperature of the bottom plate,heat transfer and pressure distribution were obtained.Then,the variation of the parameters of unequal distribution factor（MF）,thermal resistance(R_th)and total pressure drop were analyzed.The results show that the MF is in the range of1.2～1.8,the average temperature of the bottom surface of the radiator is in the range of317K～334K,the maximum temperature is in the range of 321K～339K,the thermal resistance is in the range of 0.060K/W～0.095K/W,and the pressure drop of the radiator is in the range of 80 Pa～2020 Pa under different inlet volume flow.The channel flow rate in the middle area of the radiator is larger than that on both sides of the channel.The change law of heat transfer and Nu in each channel is similar to the change trend of the flow rate.（3）By designing seven different types of fin widths and channel widths,the uniform distribution of internal flow field is simulated.It is found that the design idea of structure D,E and F is more conducive to the uniform distribution of internal flow field by using smaller channels with the same width increasing successively from the middle channel to both sides in the middle channel（C10-C18）.The fin width and channel width in structure E are the best configuration for the uniform distribution of the internal flow field of the radiator.By designing five different structure types of ribbed columns and holes in the channel,the heat transfer performance and channel pressure drop were simulated.It is found that the structureⅡhad higher heat transfer performance while maintaining lower pump pressure and interface average temperature.（4）Based on the original structure of micro-channel radiator,the channel and fin width of structure E are combined with the rib column and hole design of structureⅡto construct a new microchannel radiator structure.The laws of channel mass flow rate,channel pressure drop,channel heat transfer,channel Nu value,uneven flow distribution molecular MF,thermal resistance R_th,base temperature,overall pressure drop and other physical quantities are summarized.The effects of changing channel and fin width size,adding rib column and hole design on the flow field and heat transfer characteristics of heat sink was analyzed.The results show that under different inlet volume flows（0.25LPM～1.5LPM）,the difference between the maximum and minimum mass flows in each channel of the new micro-channel radiator structure is only 1×10~4kg/s,which is 1/8 of the initial structure,and the MF value is9%～56.4%of the initial structure.The maximum temperature of the base decreases by6.4～8.8℃.The average temperature of the substrate decreases by 7.1～10.1℃,and the R_thvalue is 74%～93%of the initial structure.The results show that the new microchannel radiator has better performance and uniform distribution of internal flow field due to the optimization of fin width and spacing and the increase of heat transfer area between the fluid and the radiator.