Numerical investigation of surface wettability effects on pool boiling properties of different nanofluids

Recently, some novel techniques such as surface vibration, surface roughness, coatings as well as nanoparticles have been introduced to improve the performance of boiling heat transfer in multiphase systems. Accordingly, pool boiling of different water-based nanofluids in a cylindrical chamber is investigated numerically in the present study. For this purpose, the incompressible and transient two-phase flow is simulated using the Eulerian – Eulerian scheme and the k-ε turbulence model. Three different sets of nanoparticles including SiO 2 , Al 2 O 3 , and ZrO 2 at three specific concentrations of 0.001 %, 0.01 %, and 0.1 % volumes are added to the base fluid to study the impact of nanofluid type and concentration on pool boiling characteristics such as boiling curve, bubble dynamics, void fraction, and nanofluid velocity. Results show that increasing the nanofluids concentration (0.001 %–0.1 % vol) gives rise to increase in the boiling curve slope and faster growth of the vapor mass. Nanofluids of different types and concentrations decrease the heat transfer coefficient (HTC) compared to water. The relative rate of decrease for the best case i.e., Al 2 O 3 /water nanofluid at 0.1 % volumetric concentration and 300 k W m 2 of flux is 39 %. Furthermore, ZrO 2 /water nanofluid encompasses higher nucleation site density in comparison to other types of nanofluids.