The omega method for discharge rate evolution

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:255386

Leung, J C ^[1]

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1. Leung Inc., Darien, IL (United States)

In 1986 the present author published a generalized correlation for one-component homogeneous equilibrium flashing choked flow (where the lines represent best-fit to the eleven fluids tested). Since then no fewer than ten publications have appeared, extending the methodology (or correlations) to cover non-flashing two-phase flow, flashing flow with noncondensables, two-phase flow in pipes with elevation change, subcooled inlet flashing flow, multicomponent systems, and safety relief valve sizing. Such a methodology has come to be known as the {open_quotes}omega{close_quotes} method since an {omega} parameter comprising of dimensionless physical property groups was introduced to successfully characterize a wide range of fluid conditions. This paper serves to review its evolution as well as update its recent developments. Relative to a single-phase system, two-phase flow has two additional degrees of freedom - one due to thermal non-equilibrium effect, and the other due to mechanical non-equilibrium resulting in slip between phases. It has been generally accepted that for high momentum discharges of a two-phase system, both thermal equilibrium and mechanical equilibrium can be assumed. This is the classical homogeneous (i.e. no slip) equilibrium flow model (HEM). Evaluation of this HEM usually involves a lengthy procedure and requires detailed thermodynamic property tabulation. The {omega} method was hence proposed as an alternative and has the attribute of bringing out key physical parameters in connection with the compressible nature of a two-phase flow system. 22 refs., 15 figs.

• OSTI ID: 255386
• Report Number(s): CONF-9508216--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
42 ENGINEERING
CALCULATION METHODS
CHEMICAL EXPLOSIONS
CHEMICAL EXPLOSIVES
FLASHING
FLOW RATE
NOZZLES
PIPES
RELIEF VALVES
TWO-PHASE FLOW