A thermo-fluidic model for the analysis of deformed, multi-source heat pipes

This study details a computationally efficient heat conduction based thermo-fluidic model for the analysis of deformed, multi-source heat pipes. The numerical model was validated against existing experimental and numerical work, as well as with new data collected within this study, giving excellent agreement (within 8 % and 7.5 % for thermal resistance and maximum heat transfer capacity respectively). Moreover, a semi-empirical methodology was developed to implement the effects of bending on the internal wick structure into the numerical model, enabling a large number of bend configurations to be examined. A parametric study investigating the combined effects of parameters relating to the thermal load distribution and bend implementation was carried out. It was concluded that significant increases in maximum heat transfer capacity (77.5 %) can be achieved through the redistribution of thermal loads towards the condenser. However, the addition of heat sources adjacent to the condenser decreases (−10 %) the maximum heat transfer capacity from the most distant source. Bending was found to decrease wick permeability by up to 85 % within the deformed section, degrading maximum heat transport capacity by up to 26.7 %. Moreover, the position of a bend in multi-source configurations was found to influence this performance degradation due to the variation in mass flow rate of working fluid along the length of the heat pipe. Therefore, to achieve maximum heat pipe performance, it is suggested that bend severity be limited, particularly in close proximity to the condenser where maximum mass flow rates occur.