Abstract:
There are still some unknown aspects of nanofluids
regarding simulations. Pool boiling flows are complicated in
terms of numerical modelling and presence of particles can
noticeably expand this complexity. Two-dimensional pool
boiling flow with nanoparticles is numerically solved around a
horizontal cylinder for validation purposes. For further study, a
tube bundle with four tubes is considered with nanofluid pool
boiling. Unsteady Eulerian two-fluid model in ANSYS-Fluent
is used to simulate the liquid and vapour flows in the
computational domain. On the other hand, the particles are
injected and tracked in the domain in the Lagrangian frame via
the discrete model. Coupling between two frames is carried out
through some user defined functions and the effects of final
outcomes appear as thermos-physical properties. It means that
nanofluid mixture properties are a function of local volume
fraction. Superheat temperature and heat transfer coefficient
from modelling are compared with experimental measurements.
The good agreement is found and further discussion regarding
particles migration and deposition are presented. Since the real
fluctuation of the surface roughness cannot be introduced, an
estimation of deposition predicted by the discrete model is
presented. It is found that the percentage of deposition depend
on heat flux and a weak function of particle concentration.
Description:
Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .