Review of the effect of foldability and working fluid on the performance of flexible pulsating heat pipe for foldable applications

Abstract

Pulsating Heat Pipe (PHP) is the most successful device used for thermal management in different application areas. Although it is having complex thermo-hydrodynamics, many researchers carried out theoretical as well as experimental investigations and reported important information regarding its operational phenomenon like a start-up, flow pattern, thermal performance, etc. To date, the majority of PHPs are built with rigid materials such as aluminum, glass, steel, and copper because of the simplicity of fabrication, high thermal conductivity, and of course good workability. However, foldable electronic devices have recently seen an increase in demand due to their flexibility, confined space, lesser weight, and also durability, where rigid PHP may not be compatible. This in turn leads to develop a PHP that fulfills the demand for foldability. Therefore, the present paper attempts to review the developments of flexible PHPs especially made of polymer materials over the last decade. Moreover, this paper also highlights the problems associated with flexible PHPs like flexibility limitation, the high gas permeability of base material, and reduced thermal performance. The paper also tried to suggest possible solutions to such problems. The present paper will help future researchers to fabricate and design flexible thermal management systems for foldable applications.