Sj. Yoo et al., POSTCRITICAL HEAT-FLUX SWIRL FLOW HEAT-TRANSFER WITH 2 REFRIGERANTS AND WATER, Journal of thermophysics and heat transfer, 11(2), 1997, pp. 189-195
Boiling heat transfer in the post-critical heat flux (post-CHF) regime
was studied experimentally under steady-state swirl flow conditions w
ith low superheat temperatures of the heated surface. Experiments were
performed with the vertical flow of refrigerant-113 (R-113) in a tube
with an i.d. 7.75 mm and with a heated length of 3.66 m over the mass
flux range of 375-535 kg/m(2) s at a pressure of 0.184 MPa. The use o
f R-113 as the boiling fluid significantly extended the property range
s of available post-CHF swirl-flow data. The swirl flow was generated
in the refrigerant tube by the use of four twisted metal tapes with ta
pe-twist ratios ranging from 2.5 to 93. Liquid heating produced the lo
w-wall superheat (below 50 degrees C) in the post-CHF region, that was
stable at steady state, and that was typical of the operation of many
heat exchangers. Superheated vapor measured at the test section exit
in most tests ensured that the entire post-CBF region was included. R-
113 data were compared with data for water and refrigerant-12. A form
of an existing correlation for post-CHF swirl flow heat transfer was g
eneralized, resulting in good predictions of both magnitudes and trend
s of the data of all three fluids.