Wick parameters (particle size, porosity and contact angle) and performances of a U-shaped heat pipe: experimental, analytical and numerical

Abstract

ABSTRACT In the current investigation, wick parameters of the sintered copper powder in a U-shaped heat pipe, such as particle size, porosity, and contact angle were analysed. The investigations were conducted by cutting the U-shaped heat pipe in axial and radial directions. Then the wick parameters characterisations were conducted that consist of Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive X-Ray (EDX), and 3D optical microscope. The values of particle size, porosity, and contact angle were then used as parameters in the analytical model to calculate the heat pipe performances. Numerical models were developed to analyse the temperature distribution on the U-shaped heat pipes and validated using the experiments. Based on the analyses, the wick parameters used in the U-shaped heat pipe were obtained: average particles of 70 µm, porosity of 0.16, and contact angle of 20° (day 1). The numerical model shows a good agreement with the experiments. The experimental results suggested that the lowest thermal resistances were 0.21°C/W (natural convection) and 0.11°C/W (forced convection).