Study Of Forming Defects In Bending Micro-heat Pipe With Micro-grooves

As the microelectronics, optoelectronics chip heat flux increase rapidly, and the space for heat dissipation growing small, power-driven grooves micro heat pipe with high thermal conductivity, high reliability, fast thermal response and no extra features has become a ideal and widely used thermal components for aviation and optoelectronics. However, the micro heat pipe limited by incapacious and complex space in practice, so it must be bended to adapt to different working environments.As the micro-grooves heat pipe has thin wall and many tiny grooves, and can not use mandril when bending it, etc, it is difficult to process by conventional tube pipe bending process. This paper analyzes the mechanism of heat pipe bending deformation, based on comparison of different methods commonly used in pipe bending on the pros and cons of such a condition. And focuses on the forming defects, identify the defects has greatest impact, and to analyze the forming mechanism in order to eliminate such defects to guide the implementation of process and the quality control of pipe bending.First of all, compare the pipe bending methods on the pros and cons of such a condition and analyze the mechanism of micro-grooved heat pipe bending deformation based on some experiments, then analysis the micro heat pipe bending process with three-dimensional finite element numerical simulation, and attempt to establish a wrinkling model based on experimental study and finite element simulation to guide the implementation and quality control of micro heat pipe bending. Main contents and results are as follows:(1) Compare and analyze the advantages and disadvantages of some common bending methods, and select the most appropriate method for such specific conditions;(2) Develop a heat transfer performance test platform for heat pipe, to study influence to the heat pipe performance of the bending defects, and defines the acceptable defects, as well as the most influential type of defect;(3) Perform the experimental study the rotary draw bending process, analyze the forming limit, the defect shaping-law, and the relationship of the defects occur on inside and outside of the wall;(4) Based on the experimental study and three-dimensional numerical simulation of bending, strain, stress state and formation mechanism of thin-walled micro-grooved heat pipe bending process are analyzed;(5) Base on the experimental study and simulation results of thin-walled micro-grooved heat pipe bending, and the thin plate buckling theory, the mathematical model of wrinkling has been founded to make up for weakness in analyzing the wrinkling of finite element simulation;(6) Proposed an improvement of heat pipe bending process, based on experimental studies, three-dimensional finite element simulation and theoretical analysis results.