文档介绍：A generalized correlation for heat transfer with forced flow boiling of cryogenic liquids
(nitrogen, hydrogen and neon) in tubes is presented. The correlation describes, with a
+ 35% accuracy, all known experimental data for vertical and horizontal channels
(without stratified regimes) in the pressure range - 22 bar, mass flow rates from 20
to 2200 kg m -2 s -1 , and heat fluxes from 400 to 210 000 W m -2. The boundary line
between channels of a large and a small diameter has been established; a simple method
of taking into account the higher heat transfer intensity in capillaries has been suggested.
Heat transfer intensity at forced flow boiling of
cryogenic liquids in tubes
. Klimenko
Key words: cryogenic, heat transfer, forced flow boiling
Nomenclature R u mean surface roughness
a thermal diffusivity (pcX)w
S dimensionless parameter --
A Philippov's thermodynamic similarity (pcX)'
criterion, equation (5)
At. Archimedes number, gb 3 (p, _ p,,)/p2 T temperature
x quality
b Laplace constant, (o/(o'- p,,)g)l/2
Be boiling number, q/rG a heat transfer coefficient
Be. modified boiling number, rG[1 + x(p'/p"- 1)]/q o surface tension
Cp heat capacity at constant pressure X thermal conductivity
d diameter p dynamic viscosity
g acceleration of body forces rr reduced pressure, P/Pcr
G mass flow rate r reduced