Vertical two‐phase flow part I. Flow pattern correlations

Abstract

Two‐phase gas‐liquid flow has been investigated in a 1‐inch internal diameter vertical tube coil containing two risers and a downcomer all connected by “U” bends. Flow pattern data were obtained in the three vertical tubes, each 17.30 ft. long, for five different air‐liquid systems at about 25 psia over flow ranges of 0–700 lbm air/min‐ft2 and 140–25300 lbm liquid/min‐ft2. Liquid phase viscosities ranged from 1 to 12 cp. A flow pattern classification with six regimes including coring‐bubble, bubbly‐slug, falling film, falling bubbly‐film, froth and annular flow regimes was established for downflow. Flow patterns in the bends were also classified. Data from the present investigation were used to formulate an empirical flow pattern graphical correlation for both upflow and downflow which is based upon the coordinates (Rv)1/2 and FrTP/A, where Rv is the delivered gas‐to‐liquid volume ratio, FrTP is the mixture Froude number, and A = μs/(SLσs3)1/4 in which μs, SL, σs are specific viscosity, specific density and specific surface tension respectively of the liquid with reference to water. The correlation was satisfactorily tested with independent literature data for upflow systems, including air‐water, steam‐water at various pressures, nitrogen‐mercury and air‐heptane, and data from flowing gas‐oil wells. No independent literature data appear to be available for testing the correlation for downflow systems, but it is anticipated that the correlation will prove to be generally applicable. The coring phenomenon in downward bubble flow was examined by means of high speed motion photography and is explained by the development of a lift force on a bubble.

A critical review of flow maps for gas-liquid flows in vertical pipes and annuli

“…These approaches attempt to account for the effect of factors such as fluid density, viscosity, surface tension, and pipe geometry within their proposed flow map systems [15][16][17][18][19][20][21][22].…”

Shear-Induced Microbubble Generation at High Pressures

“…The void fraction and the system temperature are chosen to be α=0.016 and T=298.2 K, respectively, throughout this study. Under such a low void fraction, the flow regime of the methane-water mixture is considered to be bubbly in the entire domain of the current flow loop (Mandhane et al, 1974;Oshinowo and Charles, 1974;Taitel et al, 1980), except for the pump flow at high pressure in which a transition from bubbly to jetting may be possible. More detail about the pump flow regime is addressed in Section 3.4.…”

Liquid film thickness behaviour within a large diameter vertical 180° return bend

“…Abdulkadir et al (2012) concluded that the average film fraction is higher in straight pipes than in bends. And that the condition for which the liquid goes to the outside or inside of the bend can be identified based on a modified form of Froude number, a proposal first made by Oshinowo and Charles (1974). It is worth mentioning that the averaging effect of the conductance rings can result in differences in the time-varying data, as some details of the asymmetric nature of the liquid film thickness profiles can be affected.…”