The Two-Phase Critical Flow of One-Component Mixtures in Nozzles, Orifices, and Short Tubes

Abstract

The emergency pressure-relief theory is extended to the increasing-volatility, or "gassy" case. James E. Huff, Dow Chemical U.S.A., Midland, Mich. 48640 Runaway reactions of materials to yield more-volatile products are characterized by a rapid initial rise in pressure with a less pronounced temperature rise. If the products are very light ("gassy" reactions), the initial rate of pressure rise can be fast enough to give the appearance ofa triggered explosion. However, detailed calculation of the physical and thermochemical runaway process shows that the observed behavior will result from orderly equilibrium phenomena. These phenomena are the same regardless of the relationship between reactant and product volatilities. The distinction lies in the difference in physical-roperty parameters, and the resulting difference Another characteristic of the gassy case is the rapid composition change when the system starts to vent. This change results from preferential venting of light components with ve low heats of phase change. The net result [' such a A,,-, + B(n + C(n C(n + D(n + E,n -67000 kJ/kmol -62800 kJ/kmol The reactions are carried out in component F as a solvent. Component E is non-condensable at reaction tem-

Dynamic Modeling of the Two-Phase Leakage Process of Natural Gas Liquid Storage Tanks

“…These methods are not applicable to the two-phase NGL leakage process because the multi-component NGL is obviously inconsistent with an ideal gas hypothesis, and the NGL flow velocity cannot always reach the local sound speed as well [12]. A n-butane relief case given in Raimondi's work [17] is taken as an example to express this phenomenon.…”

“…[18,23] to calculate the outlet pressure, which accounts for the boiling delay effect of the fluid and can be regarded as an improved version of the widely used Omega method [14]. In the HNE-DS model, the outlet pressure ratio (η b ) and the non-equilibrium critical pressure ratio (η cNE ) are defined by Equations (12) and (13):…”

“…Step 5: Calculate ηb from Equation (12). If ηb ≤ ηcNEnew, set Pout = ηcNEnewPin; otherwise, set Pout = Patm.…”

Assessment of TAPINS code for application to thermal-hydraulic analysis of an integral reactor, REX-10

“…A thermal-hydraulic system code requires the critical flow model to calculate the maximum discharge rate of coolant through a broken pressure boundary. The TAP-INS employs the Henry-Fauske choked flow model [24], which requires only a knowledge of the stagnation conditions and accounts for the nonequilibrium nature of two-phase mixtures. The critical mass flux is obtained by solving the following set of equations for the choking criterion and the critical flow expression:…”

Quarterly technical report on water reactor safety programs sponsored by the Nuclear Regulatory Commission's Division of Reactor Safety Research, January--March 1975

“…The Henry choked flow model ( 8 ] was selected for the subcooled phase and the Moody (9] choked flow model (with a multiplier of 0.6) was selected for lhe saturated phase. …”