高热通量芯片干冰冷却降温性能的理论分析

Theoretical analysis on the cooling performance of high heat flux chip with dry ice

针对高热通量芯片的冷却散热问题,利用具有巨大升华潜热以及极低初始温度的干冰作为散热流体,通过建立干冰冷却的散热器模型,对散热器散热空间内干冰冷却降温过程的热流场进行模拟仿真,对干冰冷却的芯片降温特性进行分析,得出:干冰入口半径为6 mm,散热器针柱直径为2 mm、11×11均匀分布的散热效果最好。随着干冰流速逐渐增大,芯片温度达到稳定时间越快,流速为0.20 m/s时稳定温度为15.49℃,远低于芯片结温,0.06 m/s的流速即可达到芯片安全温度。干冰流速为0.20 m/s,在10 s时散热空间内已充满干冰,降温效果更好。功率为125 W时,干冰冷却也可将芯片中心测点(A点)温度稳定控制在49.47℃之下。此外,对比分析了P0=65 W下的水冷式冷却降温与P0=95 W下的干冰冷却降温性能,得出水冷式冷却稳定后的温度停留在74.2℃,干冰冷却稳定后的温度为15.49℃,干冰冷却降温的芯片整体温度分布更均匀,冷却效果更好。研究结果为进一步深入研究高热通量芯片干冰冷却降温系统打下基础。

This paper aims at the heat dissipation and cooling of high heat flux chips,dry ice with huge sublimation latent heat and extremely low initial temperature is used as heat dissipation fluid.By establishing the model of dry ice cooling radiator,the heat flow fields of dry ice cooling process in the cooling space of radiator are simulated,and the characteristics of the dry ice cooling chip are analyzed.The results show that the best heat dissipation effect is that the radius of dry ice inlet is 6 mm,and the pin diameter of radiator is 2 mm and 11×11 is evenly distributed.With the increase of dry ice flow rate,it takes less time for the chip temperature to reach stability.When the flow rate is 0.20 m/s,the temperature of stability is 15.49℃,which is far lower than the junction temperature of the chip.The safe temperature of the chip can be obtained when the flow rate is 0.06 m/s.When the flow rate of dry ice is0.20 m/s,the cooling space is filled with dry ice in only 10 s,so that better cooling effect can be obtained.When the power is 125 W,dry ice cooling can also stably control the temperature of the central measuring point(point A)of the chip below 49.47℃.Moreover,the cooling performance of water-cooled at P0=65 W and dry ice-cooled at P0=95 W are compared and analyzed.It is concluded that the stabilized temperature of water-cooled cooling chip is74.2℃,and that of dry ice cooling chip is 15.49℃.The overall temperature distribution of the chip cooled by dry ice is more uniform and the cooling effect is better.The research results lay the foundation for further research on the dry ice cooling system of high heat flux chips.