New Approach to Ventilation Measurements in Enclosure Fires.
New Approach to Ventilation Measurements in Enclosure
Bryant, R. A.
Interflam 2007. (Interflam '07). International
Interflam Conference, 11th Proceedings. September 3-5,
2007, London, England, 453-463 pp, 2007.
ventilation; enclosures; standards; heat release;
experiments; tempeature measurements; velocity fields;
probes; doorways; differential pressure; thermocouples
The application of Stereoscopic Particle Image
Velocimetry (SPIV) is a new approach to quantifying the
ventilation in enclosure fires. Stereoscopic PIV is a
non-intrusive optical measurement technique which
measures the displacement of tracer particles in a flow.
The technique is completely independent of temperature
and differential pressure measurements typically applied
to quantify ventilation in enclosure fires. Stereoscopic
PIV is capable of performing thousands of measurements
over large planar regions and resolving the flow
velocity into its three components, (v<,vpvz). Using the
International Organization for Standards (ISO) 9705 room
and a natural gas burner to generate conditions similar
to the developing stages of an enclosure fire, SPIV was
applied to measure the complete velocity vector field of
the flow of air supplied to the room through a doorway.
Two separate SPIV configurations were performed to
measure the particle displacements normal to the doorway
plane. Very good agreement was achieved for the velocity
results from the two SPIV configurations, therefore
permitting greater confidence in the SPIV results.
Conventional measurements of temperature and
differential pressure were also performed in the doorway
using bare bead thermocouples and bi-directional probes,
respectively. This allowed for a comparison of
bi-directional probe velocity measurements to an
independent method of measuring flow velocity in real
fire conditions. There was a wide range of discrepancy
between the velocity inferred from the physical probe
measurements and the velocity measured with SPIV. The
results suggest that flow field characteristics playa
significant role in interpreting the measurements from
the bi-directional probes.