ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
HEAT TRANSFER AND FLOW CHARACTERISTICS OF JETS IMPINGING ON A CONCAVE HEMISPHERICAL PLATE
Abstrakt
Measurements of velocity profiles and static
pressure distribution have been carried out on jets
impinging on a concave hemispherical plate (CHP).
In comparison with the flat plate (FP), the boundary
layer at the stagnation point appears to be unchanged,
but the potential core length is slightly
shorter, while in the wall-jet region the inner
boundary layer is thinner, and the velocity profile
is somewhat steeper farther away from the plate. A
formula has been derived for the maximum wall-jet
velocity decay that agrees well with the experimental
data. Heat transfer at the stagnation point is
on CHP adversely affected by the presence of curvature,
which also tends to make flow there more turbulent,
as observed for the smaller diameter jets.
The average heat transfer is independent of the nozzle-
to-target spacing, in both the measured and the
calculated version. The total heat transfer on a
CHP is higher, caeteris paribus, than that corresponding
to a FP, because of a larger surface area
for the same diameter, for close target to nozzle
spacings. It appears that the use of CHP of relatively
small diameter as a target plate would enhance
heat transfer from impinging jets.