Research And Preparation Of Adaptive Microchannel Cooling System

With the development of electronic systems to miniaturization,the integration of devices used to build electronic systems is getting higher.Such as passive components,microelectronic device chips,and high-power optoelectronic devices.These devices are facing new challenges: high heat flux density,miniaturization,and arraying.This trend has led to higher power density and tighter temperature limits in integrated circuit design.Thanks to the large heat exchange area of microchannel,the micro-channel radiator can achieve a heat transfer coefficient several times or even orders of magnitude higher than that of the traditional water-cooled radiator,which helps to solve the heat dissipation problem of high heat flux density of high-power devices and chips.Micro-channel heat sinks often require an external cooling fluid drive source during operation.When the cooling fluid flow is constant,the heat dissipation capacity is fixed,and the heat dissipation capacity cannot be actively adjusted according to the working conditions of the heat source chip.But in practical application,the power of power chip is not constant,and the heat generated will change accordingly;the external environment temperature will also affect its working temperature.Therefore,it is difficult for the power chip to maintain a constant working temperature,and even burn the chip if the local temperature is too high.Therefore,adaptive cooling is of great significance for power chips.The cooling capacity can be adjusted according to the actual working conditions of the chip to make the chip work at a stable and appropriate temperature.In view of the above shortcomings of the existing microchannel cooling technology,this paper proposes an adaptive cooling system based on microchannel radiator.The system includes microchannel radiator,piezoelectric micropump,integrated temperature sensor,data acquisition module,driver module and adaptive control program.Among them,the microchannel radiator,adaptive control program and the construction of adaptive cooling system are studied.Through the integrated temperature sensor on the microchannel radiator,the temperature information on the radiator can be obtained in real time,and the output flow of the piezoelectric micropump can be adjusted accordingly,so as to adjust the heat dissipation capacity of the microchannel radiator,realize the accurate control of the temperature of the power chip and the stability of the working temperature under different working conditions.The specific research work is as follows:(1)The simulation analysis and experimental preparation of microchannel radiator are carried out.Based on the finite element model of single-layer microchannel radiator and double-layer microchannel radiator,their heat dissipation capacity and temperature distribution were studied under the same heat source power.It is found that the heat dissipation capacity of double-layer microchannel radiator is much better than that of single-layer microchannel radiator.A single-layer microchannel radiator and a doublelayer microchannel radiator were fabricated by laser etching on a silicon wafer with a thickness of 800 ? M.The length of microchannel is 9m m,the width is 50 ? m and the depth is 500 ? M.(2)The heat dissipation capacity of microchannel radiator was tested.The test results show that the heat dissipation effect of microchannel radiator is good.When the coolant flow rate is more than 1.68ml/min,the cooling capacity of the double-layer microchannel radiator reaches a temperature drop of 45 ?.And for the double-layer microchannel radiator,when the heat source is in the middle of the two-layer microchannel,the heat dissipation capacity is very prominent.YF structure(the heat source is between the twolayer microchannels,and the flow direction of coolant in the two-layer microchannels is opposite)has the best temperature uniformity and the difference between Tmax and Tmin is within 2 ? under the condition of ensuring superior heat dissipation performance.(3)An adaptive cooling system based on microchannel radiator is built.The adaptive heat dissipation ability of the system is tested from two aspects: when the target temperature is set,the power of the heat source is changed,and the automatic control temperature of the system is basically unchanged;when the power of the heat source is set,the target temperature is changed,and the system automatically controls the temperature change to the target temperature.Under the two test methods,the chip level adaptive cooling system works stably and the adaptive cooling effect is good.For example,when the power of the heat source increases from 0.5W to 0.9W,the working temperature of the heat source rises from 21.4 ? to 24.1 ? within 10s;under the same condition,when the adaptive cooling system controls,the working temperature of the heat source rises from 21.4 ? to 21.6 ? within 10 s,which is basically stable.