Development of nickel bi-porous wicks for miniature loop heat pipe applications

Abstract

PurposeMiniature loop heat pipes (MLHPs) are highly efficient passive heat transfer devices, which have considerable advantages over conventional heat pipes. Currently, miniature LHPs with ammonia and water as working fluids have been developed and utilized in electronics cooling within temperature range of 50°C-70°C at any orientation in 1-g conditions.Design/methodology/approachThe authors studied the standard procedure for the development of bi-porous nickel wicks and their characterization. Three different shaped nickel powders were studied, and best fitting nickel powder for electronics cooling application was reported. The manufacturing of bi-porous wick structures was analyzed with parameters such as porosity, permeability, capillary pressure and effective thermal conductivity for efficient performance of MLHP.FindingsThe study investigated the sintering process for number of samples to identify effective sample for the particular application. It is found that carbonyl nickel powder (type 287) with particle size of 2.6-3.3 µm gives promising results. Permeability and porosity were found to be highest in this case.Originality/valueIt is found that carbonyl nickel powder type with particle size gives promising results. Permeability and porosity was found to be highest in this case.