Using staircase walls to improve heat and mass transfer inside a micro flat plate heat pipe cell: A molecular dynamics simulation study

Abstract

Heat pipes (HPs) dissipate heat generated or transfer heat linearly efficiently. In equipment such as electronic processors, managing the heat generated is effective in their optimal performance and survival. Micro HPs have been able to perform this task well. However, improving their thermal performance can help develop the electronics industry. In this research, staircase walls have been proposed and studied to improve a flat plate micro HP performance. Considering the dimensions of each cell (90 × 220 × 1050 Å³), the molecular dynamics (MD) method has been used for simulations. Aluminum (Al), copper (Cu), and platinum (Pt) have been used as wall metals, and ethanol (EtOH), water (H₂O), and argon (Ar) as working fluids. The results show that Cu and EtOH result in the best condensation rates. The lowest and the highest condensation rates are related to Pt-H₂O (62 %) and Cu-EtOH (72 %). Among all working fluids, the lowest evaporation rate is achieved using H₂O. For Pt and Cu, the highest evaporation rate is obtained using EtOH (75 %). The highest evaporation rate for Al is obtained using Ar (75 %). Among all wall materials, the highest mass transfer rate improvement is related to Al (4 % for Al-Ar and 3 % for Al-H₂O). In all cases, H₂O results in the lowest mass transfer rate. The highest mass transfer rate experienced corresponds to Al-Ar and equals 38 %. The lowest and highest heat flux experienced are related to Pt-Ar and Cu-H₂O and are 1599 and 1833 W/cm², respectively. Cu has the highest heat flux compared to the other two metals. In all cases, the staircase walls improve the heat flux. The highest improvement is also equal to 3.1 % and is related to EtOH.