HEAT TRANSFER COEFFICIENT BY WATER JETS IMPINGING ON A HOT SURFACE
This paper deals with experimental determination
of the heat transfer coefficient of water
jets impinging perpendicularly on a hot surface.
In the experiments, a method involving a transient
heat flow through the specimen is applied,
and the heat transfer coefficient is evaluated from
the respons of a thermocouple beneath the surface
of specimen. Heat transfer coefficient is determined
for single jet, for arrays of jets, for several
configuration of jet versus surface, and for
different impulses of the jet.
The heat transfer coefficient for single jet
is shown to increase monotonously with increasing
surface temperature. The heat transfer coefficient
for arrays of jets is shown to have an optimum value
at a certain velocity of jets. It is explained
by the interference of spouted droplets with adjacent
jets which thereby are losing impulse pressure
on the surface.