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Flow of steam‐water mixutures in a heated annulus and through orifices
Author(s) -
Hoopes John W.
Publication year - 1957
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690030224
Subject(s) - body orifice , annulus (botany) , pressure drop , chemistry , vaporization , mechanics , vapor quality , boiling , thermodynamics , materials science , composite material , heat transfer , physics , mechanical engineering , heat transfer coefficient , organic chemistry , engineering
Values of total pressure drop are presented for the flow of vaporizing water in an internally heated 1‐in. I.D. by 1½‐in. O.D. annulus at mass velocities of 270 to 1,440, lb./(sec.)(sq.ft.), pressures of 9 to 180 lb./sq. in., and up to 0.34 fraction by weight vaporized. The total heated length over which boiling took place was as large as 6 ft. There is no evidence of “sonic” pressure jumps at the outlet. The results for the annulus mentioned lie within +30 to −11% of the Lockhart‐Martinelli curve at higher qualities and with ±45% of the correlation at lower qualities where the actual quality is more uncertain. A simplified correlation in terms of quality and volume fraction of liquid predicted the two‐phase frictional pressure drops with an average error of 41%. It was found that the ratio of the two‐phase pressure drop through a 0.3‐in. orifice to the drop with no vaporization was approximately a linear function of the quality in the vena contracta but was only one tenth to one third as great as would be predicted if the mixture were to expand as a homogeneous fluid. Prediction of orifice presure drops is improved if slip between vapor and liquid is considered.