Design,Processing And Performance Optimization Of Thermal Manipulation Devices Based On Laser-induced Graphene

With the further integration and miniaturization of electronic devices,scaled heat accumulation occurs in electronic devices,resulting in obvious thermal crosstalk and uneven heat distribution,which seriously affects the performance and service life of electronic devices.The current heat treatment solutions are difficult to solve such problems.Therefore,electronic device packaging needs a more refined heat treatment solution to achieve more scientific and efficient heat dissipation.The emergence of thermal metamaterials has promoted the rapid development of thermally functional device structures,making it possible to manipulate heat flow.In this thesis,based on the core coordinate transformation principle of transformation thermotics,theoretical modeling and analysis of thermal manipulation devices are carried out.It is confirmed that only thermal metamaterials have differentiated thermal conductivity in the tangential and radial directions,and heat flow can be achieved in the thermal superstructure nonlinear conduction in the thermal metadevice.In order to overcome the severe challenges such as cumbersome processing,low precision,and difficulty in large-scale application caused by the necessary anisotropic thermal conductivity of thermal metadevices,this thesis proposes and processes a flexible thermal cloak based on laser-induced graphene concentric circles achieving thermal protection of heat-sensitive areas.By establishing a simulation model,the main factors affecting the protection effect of the device on the thermally sensitive area are studied.Based on this,an experimental platform for laser processing thermal manipulation devices is built.Through the infrared camera test,it is confirmed that after entering the thermal cloak,the heat flow bypasses the thermal protection area for transmission,which is consistent with the simulation results,with an error of only 0.62℃;and the thermal shielding rate of the thermal cloak is as high as 70%.The temperature of the thermal protection area is almost unaffected by the external temperature,and its temperature gradient is maintained at only about 0.18℃/mm,which achieves a high-precision thermal protection effect.In addition,this thesis proposes and manufactures a thermal concentrator composed of two wedge-shaped materials alternately arranged in the angular direction,which realizes the heat collection in thermal concentrated area.By establishing a simulation model,the main factors affecting the thermal collection effect of the device on the heat concentration area are studied.It is found that the thermal conductivity of laser-induced graphene is the key factor affecting its heat concentration effect.And in order to increase the anisotropy of thermal metamaterials in the device,this thesis uses magnetron sputtering technology to coat a lay of wedge copper material on the substrate through a mask made of laser processing,so that it and the laser-induced graphene wedge material are alternately arranged in the angular direction to form a new thermal concentrator,thereby enhancing the thermal concentration effect.It has been verified by experiment that the concentration efficiency of the optimized thermal concentrator is as high as 149%,17% higher than before optimization;and its temperature gradient is raised to about 0.48 ℃/mm.This proves that the optimized thermal concentrator can collect heat more efficiently and increase the temperature gradient in the thermal concentration area.In summary,this thesis proposes and fabricates two kinds of thermal metadevice based on laser-induced graphene with unique capabilities for manipulating heat flow,which provides a new solution for artificially manipulating thermodynamic phenomena,especially in the field of thermal management of electronic devices has great application potential.