On the heat-flux/exit-quality type correlation of chf of forced convection boiling in uniformly heated vertical tubes

Abstract In this paper, it is attempted to use generalized correlation equations of CHF proposed recently by the author for predicting the well-known relation which appears between critical heat flux qc and exit quality χex when tube length l and inlet subcooling enthalpy ΔHi are varied for fixed pressure p, mass velocity G and tube diameter d. Numerical calculation is made for water under the conditions of p = 29.5–196 bar, G = 750–4000 kg/m2s, d = 0.008 m, l d = 10–793 , and ΔHi = 0–400 kJ/kg. Then, the result is compared with the standard table of qc — χex published recently by Heat Mass Transfer Section, Academy of Sciences, U.S.S.R., for water in uniformly heated tubes of d = 0.008 m, and thereby the characteristics of qc — χex type correlation are discussed.