Study Of Bionic Topology Optimization Design Technology For Heat Transfer Structure Heat Flow Tree

With the reduction in size and the increase of integration in the electronic devices,the accumulation of the heat generated under the working conditions leads to temperature rise in the devices and surroundings.In order to simultaneously meet the requirements of efficiency,space and cost,material,through which heat is conducted to external environment and then dissipated,with high thermal conductivity coefficient is inserted into the substrate of the devices.Reasonable distribution of the material can effectively improve the conduction efficiency and further reduce the temperature of the equipment.Therefore,the distribution optimization design is necessary.Since imperfect conduction efficiency and difficulty in manufacture in existing design method,the bionic topology optimization design method is applied by the natural branch systems to design ideal heat transfer structure.Adaptive growth method is a bionic optimization method based on the idea of nature branch system,in which parallel channels may appear due to element dependence.In response to this problem,sensitivity filtering considering density gradient information is combined with the original method to form hierarchical adaptive growth method.The hierarchical method can suppress the parallel channel in four numerical examples with different boundary conditions.In the meantime,heat transfer efficiency is improved in comparison with the original method.The design results of the hierarchical method with different filtering demonstrate the advantage of the sensitivity filtering considering density gradient information.Synthesizing the morphological characteristics and growth laws of the natural branch systems and design claims,heat flow tree method is suggested.In this method,each heat channel has uniform geometry defined by the start point,the end point and the width.The design process of the method is divided into the principal channel design step,whose completion condition is obtained by the hierarchical growth of the leaf vein,and the lateral channel design step.The space colonization algorithm considering temperature information is applied in the principal channel design,and the law of the minimal thermal resistance is applied in the lateral channel design.During the process,the modified Murray’s law controls the widths of all the channels.Reasonable heat transfer structures with better heat performances are obtained by the heat flow tree method in three numerical examples with different boundary conditions in comparison with the traditional method.Reasonable parameter selection suggestion based on the natural branch systems including the number of the principal channel and bifurcation exponent is proposed through analysis of the design results with different parameters.The experiment platform is built and the heat transfer structure is designed and made based on heat flow tree method to verify heat transfer efficiency.The temperature distribution monitored by the infrared thermal imager demonstrates the advantage of heat flow tree method.