Penetrative Convection of a Plane Turbulent Wall Jet in a Two-Layer Thermally Stable Environment: A Problem in Enclosure Fires.
Penetrative Convection of a Plane Turbulent Wall Jet in
a Two-Layer Thermally Stable Environment: A Problem in
Kapoor, K.; Jaluria, Y.
International Journal of Heat and Mass Transfer, Vol.
36, No. 1, 155-167, 1993.
Sponsor:National Institute of Standards and Technology,
enclosures; turbulent jets; flow fields; heat transfer;
flow visualization; penetration
An experimental investigation has been carried out on
the penetrative characteristics of a heated,
two-dimensional, turbulent wall jet discharged downward
into a two-layer thermally stable environment. Such
flows, with opposing buoyancy effects, are frequently
encountered in heat rejection processes and in enclosure
fires. The discharge temperature of the jet is taken as
higher than the upper layer temperature so that the jet
is negatively buoyant in both layers. Of particular
interest is the penetration of the jet into the lower
layer. The conditions for which it fails to penetrate
the interface between the two layers are also
determined. The penetration distance of the jet is
measured and related to the inflow conditions,
particularly to the temperature and the velocity at the
discharge. The thermal field is studied in detail to
determine the basic characteristics of such flows. The
mass flow rate penetrating downward as well as that
rising upward due to thermal buoyancy are obtained and
compared with the jet inlet mass flow rate. The heat
transfer to the surface is measured for several wall
temperatures and considered in terms of the penetrative
flow. Flow visualization with smoke is also undertaken
in order to obtain further insight into the basic nature
of the flow.