Void fractions in two‐phase flow

Abstract

AbstractVoid fractions (fraction of the flow cross‐sectional area occupied by the gas phase) have been measured for steam‐water flows in an adiabatic, horizontal test section of 0.484 in. I.D. at 400, 600, 800, and 1,000 1b./sq. in. gauge. A comprehensive survey of void data for two‐phase concurrent flow is included in the paper, and the data, including the Martinelli and homogeneous flow model predictions, are compared. System characteristics, involving one‐ and two‐component flows in horizontal and vertical test sections with and without heat transfer over a range of flow ratios, total flow rates, and pressure, are too complex, and the data available are neither extensive nor precise enough to warrant the generation of over‐all correlations. Use of the void data in correlating two‐phase frictional pressure drops is discussed. A model has been presented for the prediction of critical flows based upon the void data, and calculations have been made for steam‐water critical flows over a range of critical pressures from 15 to 2,000 1b./sq. in. abs.