Analytical and experimental investigation on the operational characteristics and the thermal optimization of a miniature heat pipe with a grooved wick structure
Sung Jin Kim, Joung Ki Seo, Kyu Hyung Do
Abstract
A mathematical model for heat and mass transfer in a miniature heat pipe with a grooved wick structure is developed and solved analytically to yield the maximum heat transport rate and the overall thermal resistance under steady-state conditions. The effects of the liquid–vapor interfacial shear stress, the contact angle, and the amount of initial liquid charge have been considered in the proposed model. In particular, a novel method called a modified Shah method is suggested and validated; this method is an essential feature of the proposed model and accounts for the effect of the liquid–vapor interfacial shear stress. In order to verify the model, experiments for measuring the maximum heat transport rate and the overall thermal resistance are conducted. The analytical results for the maximum heat transport rate and the total thermal resistance based on the proposed model are shown to be in close agreement with the experimental results. From the proposed model, numerical optimization is performed to enhance the thermal performance of the miniature heat pipe. It is estimated that the maximum heat transport rate of outer diameter 3 and 4 mm heat pipes can be enhanced up to 48% and 73%, respectively, when the groove wick structure is optimized from the existing configurations. Similarly, the total thermal resistance of these heat pipes can be reduced by 7% and 11%, respectively, as
a result of optimization.
Analysis of Thermal Performance in a Micro Flat Heat Pipe with Axially Trapezoidal Groove
Jeong-Se Suh* and Young Sik Park
Abstract
Numerical analysis is made on the thermal performance of micro heat pipe in a axial flat grooved channel. The flow of liquid and vapor is investigated in trapezoidal grooves and the effect of variable shear stress along the interface of the liquid and vapor considered. The results from this study are obtained in the axial variation of pressure difference between vapor and liquid, contact angle, velocity of liquid and vapor and so forth. In addition, maximum heat transport capacity of micro-heat pipe is provided by varying the operation temperature, and compared with that from Schneider and Devos’s model in which
the interfacial shear stress is neglected.
Key Words: Micro-Heat Pipe, Micro-Channel, Liquid, Vapor, Trapezoidal Groove, Maximum Heat Transport Capacity
