Migration Properties of TiO2 Nanoparticles during the Pool Boiling of Nanorefrigerants

Nanofluid is a promising fluid due to its enhanced heat transfer properties. Nanorefrigerant is a kind of nanofluid that uses a refrigerant as the base fluid. It can enhance the energy and cooling performance of refrigeration and air-conditioning systems. The objective of this paper is to study the migration properties of nanoparticles during the pool boiling of the nanorefrigerant. The effects of different parameters including heat flux, liquid level height, vessel size, insulation, and lubricating oil on the migration of nanosized particles have been investigated. TiO2 particles with average diameters of 40 nm were used with R141b refrigerant. The experimental results show that the migrated mass of nanoparticles increases with augmenting the initial mass of nanoparticles as well as the applied heat flux. Besides, particle departure from the liquid to vapor augments by increasing the lubricating oil concentration and adding insulation to the container. However, the migration of nanoparticles decreases with the increase of initial liquid level height and boiling vessel size. Therefore, migration properties of nanoparticles during the pool boiling of nanorefrigerants have a distinct relationship with the distribution of nanosized particles.