Analytical two-phase flow void prediction method

Huq, Reazul; Loth, John L.

doi:10.2514/3.329

Cited by 51 publications

(13 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Some of the correlations are proprietary of which no information was given while the others were collected from the open literature. Some of the correlations considered in the analysis that passed the limiting void fraction criteria, for x = 0, e = 0 and x = 1, e = 1, and were considered in our comparison are Huq and Loth (1992), Kowalczewski (Isbin and Biddle, 1979), Smith (1969), the Loscher and Reinhardt correlation reported by Friedel (1977), Rouhani and Axelsson (1970) and Premoli et al (1970).…”

Section: Horizontal/vertical Upward Comparisonmentioning

confidence: 99%

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Woldesemayat

Ghajar

2007

International Journal of Multiphase Flow

411

229

View full text Add to dashboard Cite

Section: Horizontal/vertical Upward Comparisonmentioning

confidence: 99%

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Woldesemayat

Ghajar

2007

International Journal of Multiphase Flow

411

229

View full text Add to dashboard Cite

“…Their measurements agree qualitatively with those from our facility and, therefore, they are adopted to derive the limits of the slip at very low and very high qualities. They also validate the theoretical boundary conditions for non-dissipative two-phase flows, formulated by Huq and Loth [13] in Eq. (13) (11) at the inlet of the corner valve, equipped with and without disk, as a function of quality for flows of air and water, as well as for those of air and aqueous solutions of glycerin.…”

Section: Comparison With Vertical Co-current Pipe Flowsmentioning

confidence: 73%

“…(5) suggest that the void fraction may be affected not only by both densities and by the liquid viscosity, l L , but also by the quality of the mixture, the total mass flux, G, the surface tension, r, and though to a lesser extent, also by the inlet cross-sectional diameter, d in . In alternative to the correlation of Rouhani, Diener and Friedel [10] recommended the void fraction model of Huq and Loth [13] in Eq. (6) for total mass fluxes above 100 kg/(m 2 s):…”

Section: Literature Surveymentioning

confidence: 99%

Influence of the Liquid Phase Physical Properties on the Void Fraction at the Inlet of a Full‐Lift Safety Valve

Moncalvo¹,

Friedel

2009

Chem Eng & Technol

View full text Add to dashboard Cite

This work studies the influence of the physical properties of a liquid on the void fraction at the inlet of a corner valve resembling a full-lift safety valve. The test media are mixtures of air and aqueous solutions of glycerin. Our own measurements evince a reduction in the void fraction when the relative weight of glycerin in the solution is increased. If the effects of density, viscosity, and surface tension on the void fraction are accounted for by increasing the relative weight of glycerin in the solution, it results that the observed reduction of the void fraction is primarily a consequence of the enhancement of viscosity. On the other hand, the increment of the liquid density is responsible for a modest increase in the void fraction and the effect of the reduction in the surface tension is almost negligible. The enhancement of either the density or the viscosity of the liquid phase increases the relative velocity of the gas in the two-phase mixture and, therefore, the slip. The impact of the liquid properties on the void fraction in co-current vertical pipe flows is similar to that at the inlet of the corner valve. Among the most common correlations for pipe flows, the formulation of Rouhani and the homogeneous void fraction accurately reproduce the void fraction at the inlet of the valve only for two-phase flows with liquids of low viscosity. A new void fraction correlation is proposed here, which reproduces all measurements very well and correctly predicts the impact of the liquid phase properties. Despite numerical coefficients, which can be fitted to additional sets of measurements, the structure of the new correlation is also applicable outside the range of two-phase flows for which it has been explicitly validated. Introduction and PurposeFull-lift safety valves -here the definition of full-lift safety valve is in agreement with ISO 4126-1 -are installed on top of pressurized vessels to avoid human injuries and financial losses following the collapse of the units due to external fire or runaway reactions. Both accidents cause an abnormal heat inflow, leading to a partial evaporation of the liquid and a disengagement of the dissolved gaseous phases. The released gases and vapors increase the pressure in the vessel until the set pressure is reached and the safety valve opens [1]. If the liquid phase is very viscous, some gas or vapor cannot disengage and it remains entrapped in the liquid. The entrapped gas or vapor enhances the volume of the liquid that much to eventually make it swell to the top of the vessel. In that case, a two-phase discharge would pass through the safety valve. The amount of discharged mass and the duration of the two-phase release are strongly affected by the viscosity of the liquid [2].The gas content in the two-phase mixture at the inlet of the safety valve is expressed in terms of mass and volume, respectively, with the quality, _ x 1) , and the void fraction, a. On the base of the research on the two-phase discharge from pressurized vessels, the amount of gas in the mixtur...

show abstract

“…Over the years, many studies have been conducted on the modeling of void fractions, and can be divided into several groups Dalkilic and Wongwises [24]: slip ratio void fraction models [2,[25][26][27][28][29][30][31][32][33][34][35], Lockhart and Martinelli parameter based void fraction models [36][37][38][39][40][41][42][43][44], flow regime based void fraction models [45][46][47], ka H parameter based void fractions [48][49][50], and general void fraction models [51][52][53][54][55][56][57].…”

Section: Void Fractionmentioning

confidence: 99%

Condensation pressure drop of R22, R134a and R410A in a single circular microtube

Son

2012

Heat Mass Transfer

View full text Add to dashboard Cite

The condensation pressure drop characteristics for pure refrigerants R22, R134a, and a binary refrigerant mixture R410A without lubricating oil in a single circular microtube were investigated experimentally. The test section consists of 1,220 mm length with horizontal copper tube of 3.38 mm outer diameter and 1.77 mm inner diameter. The experiments were conducted at refrigerant mass flux of 450-1,050 kg/m 2 s, and saturation temperature of 40°C. The main experimental results showed that the condensation pressure drop of R134a is higher than that of R22 and R410A for the same mass flux. The experimental data were compared against 14 two-phase pressure drop correlations. A new pressure drop model that is based on a superposition model for refrigerants condensing in the single circular tube is presented.

show abstract

Analytical two-phase flow void prediction method

Cited by 51 publications

References 3 publications

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Comparison of void fraction correlations for different flow patterns in horizontal and upward inclined pipes

Influence of the Liquid Phase Physical Properties on the Void Fraction at the Inlet of a Full‐Lift Safety Valve

Condensation pressure drop of R22, R134a and R410A in a single circular microtube

Contact Info

Product

Resources

About