Three-Dimensional Simulation of Turbulent Flow in 3-Sub Channels of a VVER-1000 Reactor


1 Department of Mechanical Engineering,Sharif University of Technology

2 Department of Mechanical Engineering,BUET


In this study, the
uid dynamics and convective heat transfer for turbulent
ows through
a 3-sub channel of a rod bundle, which is representative of those used in VVER-1000, are examined.
The rod bundle is constructed from parallel rods in a hexagonal array. The rods are on constant pitch
by spacer grids spaced axially along the rod bundle. The geometry details of the bundle and heat
from the fuel rod are similar to that of the Iranian nuclear reactor under construction. A numerical
study using Computational Fluid Dynamics (CFD) was carried out to estimate the
ow eld, pressure
loss and heat transfer coecients in spacer grids and rod bundles. Turbulence has been modeled using the
k ???? " turbulence model. At a distance of 2Dh from the beginning of the spacer grids, in the direction of

ow, because
uid enthalpy and Nusselt numbers have maximum and minimum values, respectively, the
probability of nucleate boiling (PNB) is much higher, and a two phase
ow will occur. Predicted results
are found to be in close agreement with those of the experimental results reported in the literature.