Design, simulation and fabrication of a silicon micro flat heat pipe with axial triangle grooves

The design, numerical simulation and fabrication process of a silicon micro flat heat pipe with axially micromachining triangle grooves are discussed. In this paper the structure of a silicon micro flat heat pipe is presented firstly. Then numerical simulation is undertaken to evaluate the thermal performance of micro flat heat pipe. Using MATLAB a one-dimensional model is developed and solved numerically to investigate the flow of liquid and vapor in triangle grooves. The effect of interfacial and vapor shear stress is considered in the model. The results obtained from this simulation contain axial variation of pressure difference between vapor and liquid, velocity of liquid and vapor and film thickness. In addition maximum heat transport capacity of MHP is calculated. The results predicted by the model are compared with the published results in literature and show good agreement. These numerical results are used to determine the structural parameters of final prototypes. Finally a silicon/methanol prototype was fabricated to demonstrate the feasibility of heat spreading using this type of MHP. The MHP grooves capped by a glass wafer were fabricated by using bulk micromachining and anode bonding techniques. Detailed fabrication process of a silicon micro flat heat pipe with axial triangle grooves is presented.