On the Flashing Flow of Saturated Water Through Horizontal Pipes

Abstract

The energy equation for a single-phase flow is usually applied to predict the pressure drop of the flashing flow of steam water mixtures. This energy equation must be solved in such a way that the solution may not only give the relations among the pressure drop, the mass flow rate and other factors, but also be applicable without discrepancy to the critical flow. In this paper, a new correction factor ψ_m for friction loss is introduced to satisfy the above mentioned requirements and is determined by experiment. The factor ψ_m is the ratio of the true coefficient of friction for the flashing flow to the calculated coefficient of friction for a homogeneous flow. An empirical formula for ψ_m is determined from the experiments over a pressure range from about 3.5 to 8 ata, a range of the length of horizontal pipe line from 1 to 10 m, and a range of the internal diameter of pipe 10.0, 6.2 and 4.1 mm. The equation ε for critical flow rates is also developed by using the empirical formula of ψ_m.