Abstract:
Turbulent jets of miscible
uids of di erent densities are commonly observed in natural
and industrial
ows. In these type of
ows, the di erence in densities causes a buoyancy
driven convection along with the momentum driven
ow. In the case of miscible
uids,
the mixing causes variations in density and a ects the properties of the jet. Understanding
the behaviour of buoyant jet
ows and mixing in con ned space would help in the
design of buildings in improving natural ventilation, especially during re or gas leakage.
Understanding the
ow and mixing patterns and enhancing the natural ventilation would
help in cases like re or gas leakage as power shut-down during emergencies would stop
forced ventilation.
The present work aims at studying the patterns of
ow and mixing through experiments
in a con ned space with a jet source of unsteady buoyancy
ux. The experiments
were conducted in simple con nements that replicate a wall or roof opening. Approximately
50
ow visualization experiments were conducted on scaled models of a room
with a jet source of buoyancy and
ow outlets that resemble windows or roof openings.
The air-smoke pair was replaced by water-salt solution pair to scale down the dimensions
of the experiment set up. The con nement is located at the near- eld of the jet. The
results from the project may be used in optimizing the ventilation design to maintain
su cient oxygen levels inside buildings for safe evacuation and prevent su ocation from
smoke caused by re.
The experiments were conducted using synchronized Particle Image Velocimetry (PIV)
and Planar Laser Induced Fluorescence (PLIF) techniques to get the high resolution, simultaneous,
velocity and concentration elds. The design of the experiment set up,
instrumentation, experiment techniques and analysis methods are discussed in the report.
Di erent sets of experiments by varying the
ow rate and the position of outlet
have been conducted using simultaneous PIV-PLIF technique. A detailed description of
velocity and density pro les along the
ow are presented.
