A numerical modeling for the steady-state performance of a micro heat pipe using thin liquid film theory

A numerical analysis on heat and mass transfer in a micro heat pipe was performed in this work. Mass, energy, and momentum equations were applied to vapor and liquid phases under steady-state operation in the numerical model. As a result, the trends in mass flow, pressure distribution, and temperature distribution for the working fluid circulating inside the micro heat pipe were obtained for vapor and liquid, respectively. In particular, the vapor-liquid interface shape obtained with a thin liquid film through augmented Young-Laplace equation and areas for heat and mass transfer of liquid and vapor from the vapor-liquid interface thickness were predicted. These areas were applied to solution on the governing equations for vapor and liquid. The numerical model was validated by experimental results. The errors between the experimental and numerical results for the average temperature difference of the evaporator and condenser were found to be less than 1 °C. The errors for thermal resistance had maximum and minimum values of 15.2% and 3.8%, respectively.