Abstract:
This paper discusses numerical simulations of sub-cooled
nucleate boiling in a duct using Reynolds Stress Model (RSM)
and conjugate heat transfer (CHT). The predictions of flow
characteristics and distributions of interfacial area
concentration (IAC), Sauter mean diameter (SMD),
temperature of liquid and void fraction of gas are investigated
using the above methods. The RSM turbulence model is used in
the simulations to incorporate anisotropic turbulence, which has
been reported in experimental studies, where it has been
observed that the flow is affected by the drag of bubbles
nucleating at a heater block. The heat flux, which leads to phase
change of the fluid, has been applied in two different ways. One
implementation involves the fluid-only domain with a
particular boundary providing constant heat flux, whereas, in
the other case, the solid duct has been made part of the
computational domain and the fluid has been heated via CHT.
The study first focuses on investigating the mean and
fluctuating velocity components over the heated section of the
domain. It is found that the bubbly layer is predicted thinner in
the solid-fluid case than the fluid-only case. Amount of heat
flux added to the coolant is higher in the case where the
computational domain is limited to the fluid only. This results
in a relatively larger amount of void fraction directly above the
heated section.
Description:
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.
