Natural Convection Flows and Associated Heat Transfer Processes in Room Fires.
Natural Convection Flows and Associated Heat Transfer
Processes in Room Fires.
(210154 K)
Sargent, W. S.
NBS GCR 83-447; 525 p. October 1983.
Sponsor:
National Bureau of Standards, Gaithersburg, MD
Available from:
National Technical Information Service
Order number: PB84-171172
Keywords:
compartment fires; convective flow; doors; heat
transfer; room fires; windows
Abstract:
This report presents the results of experimental
investigations of natural convection flows and
associated heat transfer processes produced by small
fires in rooms with a single door or window opening.
Calculation procedures have been developed to model the
major aspects of these flows. Two distinct sets of
experiments were undertaken. First, in a roughly 1/4
scale facility, a slightly dense solution of brine was
allowed to flow into a tank of fresh water. The
resulting density difference produced a flow which
simulated a very small fire in a room with adiabatic
walls. Second, in an approximately 1/2 scale test room,
a nearly stoichiometric mixture of air and natural gas
was burned at flow level to model moderate strength
fires. In this later facility, we directly measured the
heat conducted through the walls, in addition to
determining the gas temperature and composition
throughout the room. The computed results both for the
average floor and ceiling zone gas temperatures and for
the convective heat transfer in the ceiling jet agreed
reasonably well with our experimental data. This
agreement suggests that our computational procedures can
be applied to answer practical questions, such as
whether the convective heat flux from a given fire in a
real room would be sufficient to trigger sprinklers or
other detection systems in a given amount of time.
