Liquid film flow-rate measurement at elevated pressures

A knowledge of liquid film flow-rates is important for design purposes when accurate predictions are required of the conditions under which "dry out" heat flux occurs in nuclear-reactors and boilers. Liquid film flow-rates were measured for a steam-water mixture in cocurrent, upward, annular flow in a tube at pressures of 1,000 and 1,200 psia. Sinters located at the test section exit were used to extract the liquid film after the method of the Harwell group. Sinter lengths of 2-, 1- and 1/2-in. were employed to investigate the effect of length on the extracted liquid flow rates. The test section as a stainless steel pipe of inside diameter 0.493 in., approximately 200 diameters in length. The total mass flux ranged from 0.2--0.7 x 106 lbm/hr.ft2 and the quality varied from 0.3 to 0.92.;The experimental film flow-rates were found to increase with decreasing mass flux and decreasing, quality. Film flow-rates were consistently higher thin the theoretical predictions using Levy's model with deviations as high as 64%. However, at the same total mass flux and quality, there was better agreement with Levy's model for the 1/2 in. sinter data. This suggests that the larger sinters may be extracting liquid from the main core. The experimental results were also compared with predictions from Minh's model. Deviations as large as +200% were obtained.