Ashutosh Yadav (Advisor: Prof. S. Roy)
Hydrodynamic Investigations in Boiling Flows
0400-0430 pm (20+10 mins)
Boiling flow is of great importance to nuclear reactors, specifically
for Boiling Water Reactors (BWR) used in the nuclear industry. In BWRs,
the heat of nuclear fission is extracted by either forced or preferably
natural circulation of boiling water around the fuel rods. Such flow is
characterized by several flow regimes depending on local flow and heat
transfer conditions. Prior studies reported in the open literature
indicate variation of vapor holdup in axial and radial direction affects
the liquid velocity distribution and flow regime transition. Void
fraction measurements employing Gamma Ray Densitometry (GDT) have been
performed on an experimental setup having single heating rod as well as
on multiple heated rod arrangement, which closely resembles the flow
behavior in BWR. The experimental setup consisting of multiple heating
rods is based on single calandria of Advanced Heavy Water Reactor (AHWR)
design (patented design of Bhabha Atomic Research Centre, India).
Different arrangements of heating rods correspond to different flow
patterns and thus different void fraction profiles are observed.
In order to determine local liquid velocity distribution and flow
pattern within the liquid phase fraction, Radioactive Particle Tracking
(RPT) technique is implemented. Several modifications have been done in
the conventional position reconstruction method used in the RPT to make
it more robust and fast. Work is in progress on this front and some
initial results will be presented, and challenges in RPT implementation
in boiling flows will be highlighted.