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Title: Theoretical and empirical study of single-substance, upward two-phase flow in a constant-diameter adiabatic pipe

Technical Report ·
DOI:https://doi.org/10.2172/5780270· OSTI ID:5780270

A Scheme is developed to describe the upward flow of a two-phase mixture of a single substance in a vertical adiabatic constant area pipe. The scheme is based on dividing the mixture into a homogeneous core surrounded by a liquid film. This core may be a mixture of bubbles in a contiguous liquid phase, or a mixture of droplets in a contiguous vapor phase. Emphasis is placed upon the latter case since the range of experimental measurements of pressure, temperature, and void fraction collected in this study fall in the slug-churn''- annular'' flow regimes. The core is turbulent, whereas the liquid film may be laminar or turbulent. Turbulent stresses are modeled by using Prandtl's mixing-length theory. The working fluid is Dichlorotetrafluoroethane CCIF{sub 2}-CCIF{sub 2} known as refrigerant 114 (R-114); the two-phase mixture is generated from the single phase substance by the process of flashing. In this study, the effect of the Froude and Reynolds numbers on the liquid film characteristics is examined. The compressibility is accounted for through the acceleration pressure gradient of the core and not directly through the Mach number. An expression for an interfacial friction coefficient between the turbulent core and the liquid film is developed; it is similar to Darcy's friction coefficient for a single phase flow in a rough pipe. Finally, an actual steam-water geothermal well is simulated; it is based on actual field data from New Zealand. A similarity theory is used to predict the steam-water mixture pressure and temperature starting with laboratory measurements on the flow of R-114.

Research Organization:
Brown Univ., Providence, RI (United States). Div. of Engineering
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC03-85SF15548
OSTI ID:
5780270
Report Number(s):
DOE/SF/15548-T14; ON: DE92006628
Country of Publication:
United States
Language:
English