Calorimetric and Visual Measurements of R123 Pool Boiling on Four Enhanced Surfaces.
Calorimetric and Visual Measurements of R123 Pool
Boiling on Four Enhanced Surfaces.
(3121 K)
Kedzierski, M. A.
NISTIR 5732; 59 p. November 1995.
Sponsor:
Department of Energy, Washington, DC
Available from:
National Technical Information Service
Order number: PB96-128129
Keywords:
building technology; electric resistance heating;
enhanced heat transfer; fluid heating; GEWA-K(TM);
GEWA-T(TM); high-flux(TM); porous surface; T-fin;
trapezoidal-fin; R123; pool boiling; Turbo-BII(TM)
Abstract:
Pool boiling of R123 on four commercial enhanced
surfaces was investigated both calorimetrically and
visually. The four surfaces were: (1) Turbo-BII(TM)
(2) High-Flux(TM) (3) GEWA-K(TM), and (4) GEWA-T(TM).
The surfaces were either machined or soldered onto a
flat thick oxygen-free high-conductivity copper plate.
This permitted 20 sheathed thermocouples to be embedded
in the copper for accurate heat transfer measurements.
The difference between electric resistance and fluid
heating was investigated. The fluid heating condition
results in heat fluxes that are as much as 32% greater
than those obtained by electric resistance heating.
Hysterisis effects near the onset of nucleate boiling
were also investigated. The boiling was visually
recorded with 16 mm high speed film. Mechanistic
descriptions of the boiling activity are given for each
surface.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899