ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
A technique employing the impulse plate principle was developed whereby the ratio of the average vapor-to-liquid velocities (slip ratio) for flowing two-phase mixtures could be measured accurately at high vapor volume fractions. Data were collected for steam-water mixtures flowing adiabatically in a horizontal ½-in. tube. Flow conditions were in the spray annular and dispersed flow regimes and covered a pressure range of 30 to 80 lb.f/sq.in.abs., flow rates of 200 to 800 lb.m/(sec.)(sq.ft.), and steam qualities of 0.02 to 0.8. The experimental slip ratios, ranging between 1 and 3.5, decreased with increasing quality and pressure and increased with increasing mass velocity and pressure gradient.A theoretical analysis in which an idealized dispersed flow model was used indicated that the observed average slip ratios were caused largely by local slip between vapor and entrained droplets and that high local slip ratios may be attained near critical flow rates due to the simultaneously occurring steep pressure gradients.The total pressure gradients, computed by adding the Martinelli-Nelson frictional pressure drop prediction to the acceleration pressure gradients calculated by the use of an empirical correlation of the slip ratio data, deviated from the experimental values by an average of only 14%.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690110628
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