Parametric Studies on the Processing Parameters of a Thermally Wicking Material using Image Analysis

A heat pipe is a device that transports heat against gravity using a wicking material and evaporation-condensation cycle..In these systems a thermal wick moves fluid from the cool region of a heat pipe to the hot region, where evaporative cooling occurs. Due to the operating demands of a thermal wick, several microstructural features are integral to the performance of the wick: capillary radii, specific surface area and permeability. Measuring these properties of a thermal wick (capillary radii, specific surface area and permeability) is difficult, therefore image analysis methods of quantification of the critical properties of a thermal wick has been developed . However, the microstructure of a thermal wick contains semicontinuous pores, therefore connectivity of pores cannot be assumed during quantification of the critical properties.. Two processing parameters, sacrificial template particle size and sintering temperature, were varied during the thermal wick synthesis. Quantification of the critical properties of the thermal wick was performed using the newly developed method. The newly developed method was able to detect the an increase in the pore connectivity as the sintering temperature decreased, and an increase in the connectivity as the sacrificial template particle size decreased. The newly developed method was also able to describe the size distribution of individual pores as well as the hydraulic resistance and orientation of individual pores as well as estimate the porosity and true specific surface area of the different samples.