An Evaluation of Existing Two-Phase Flow Correlations for Use With ASME Sharp Edge Metering Orifices

1977 ◽  
Vol 99 (3) ◽  
pp. 343-347 ◽  
Author(s):  
L. T. Smith ◽  
J. W. Murdock ◽  
R. S. Applebaum

The two-phase flow correlations developed by Murdock, James, Marriott, and Smith and Leang are evaluated for the case of flow through sharp edge measuring orifices which physically meet ASME standards for flow measurement. The evaluation is based on two sets of consistent orifice flow data. The first data base consists of 34 test points for the flow of steam-water mixtures. The second data base consists of 81 data points for the flow of air-water, natural gas-water, natural gas-salt water, and natural gas-distillate mixtures. The root mean square fractional deviation of each correlation is used to determine its predictive reliability. Computed root mean square fraction deviations for steam-water flows are: James, ±0.081; Marriott, ±0.114; Murdock, ±0.141; Smith and Leang, ±0.218. For the case of gas-liquid flows, the values are: Murdock, ±0.074; James, ±0.178; Smith and Leang, ±0.183; Marriott, ±0.458.

1962 ◽  
Vol 84 (4) ◽  
pp. 419-432 ◽  
Author(s):  
J. W. Murdock

This paper presents a practical method for computing two-phase flow rates through AGA-ASME stamdard orifice meters to a tolerance of 1.5 per cent. A rational equation is developed modifying the present single-phase metering equation by the introduction of one experimentally determined constant and permitting the use of data already contained in the ASME Fluid Meters Research Committee publications. Equations are also given for computing the two-phase flow of natural gas using the American Gas Association Report No. 3. No additional data are needed for the solution of two-phase flow metering problems. The experimental constant is derived from the analysis of 90 test points for two phase flow of steam-water, air-water, natural gas-water, natural gas-salt water, and natural gas-distillate combinations. Three separate test series are described for orifices equipped with radius, flange, and pipe tap locations in 2 1/2, 3, and 4-inch pipe with beta ratios ranging from 0.25 to 0.50. Pressures ranged from atmospheric to 920 psia, differentials from 10 to 500 inches of water, and liquid weight fractions from 2 to 89 per cent. Temperatures were from 50 to 500 F and Reynolds numbers for the liquid from 50 to 50,000 and for the gas from 15,000 to 1,000,000. These data were correlated to a standard deviation of 0.75 per cent. The areas where further research is needed to increase the universality of the two-phase metering equation are delineated.


Author(s):  
Aurelia Chenu ◽  
Konstantin Mikityuk ◽  
Rakesh Chawla

In the framework of PSI’s FAST code system, the TRACE thermal-hydraulics code is being extended for representation of sodium two-phase flow. As the currently available version (v.5) is limited to the simulation of only single-phase sodium flow, its applicability range is not enough to study the behavior of a Sodium-cooled Fast Reactor (SFR) during a transient in which boiling is anticipated. The work reported here concerns the extension of the two-fluid models, which are available in TRACE for steam-water, to sodium two-phase flow simulation. The conventional correlations for ordinary gas-liquid flows are used as basis, with optional correlations specific to liquid metal when necessary. A number of new models for representation of the constitutive equations specific to sodium, with a particular emphasis on the interfacial transfer mechanisms, have been implemented and compared with the original closure models. As a first application, the extended TRACE code has been used to model experiments that simulate a loss-of-flow (LOF) accident in a SFR. The comparison of the computed results, with both the experimental data and SIMMER-III code predictions, has enabled validation of the capability of the modified TRACE code to predict sodium boiling onset, flow regimes, dryout, flow reversal, etc. The performed study is a first-of-a-kind application of the TRACE code to two-phase sodium flow. Other integral experiments are planned to be simulated to further develop and validate the two-phase sodium flow methodology.


Author(s):  
Dieter Mewes ◽  
Dirk Schmitz

Pressurized chemical reactors or storage vessels are often partly filled with liquid mixtures of reacting components. In case of an unexpected and uncontrolled exothermic reaction the temperature might increase. By this the pressure follows and would exceed a critical maximum value if there would be no mechanism to decrease the pressure and the temperature in a very short period of time. A sudden venting by the opening of a safety valve or a rupture disc causes a rapid vaporization of the reacting liquid mixture. A two-phase flow will pass the ventline. Since two-phase gas-liquid flows cause high pressure losses and give rise to limited mass flows leaving the reactor, single-phase gas flows are preferred. This is emphasized by a periodic venting mechanism of the pressurized vessel. Each time the two-phase flow from the bubbling-up liquid inside the vessel reaches a certain cross-section close the entrance of the ventline. The outlet-valve is closed. Inside the vessel the increasing pressure stops the two-phase flow and only single phase flow is leaving the vessel. The two-phase bubbly flow inside the vessel is detected by a tomographic measurement device during the venting process. Experimental results for local and time dependant phase void fractions as well as pressures are compared with those obtained by numerical calculations of the instationary bubble swarm behavior inside the vessel.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Baojin Wang ◽  
Zhongyang Wang ◽  
Liuci Wang ◽  
Pengyu Sun

Natural gas hydrate (NGH) is a kind of new type green energy source with giant reserves which has been thought of highly by energy explorers in the world. However, NGH breaks down to produce some natural gas that enters the annulus and flows together with the drilling fluid. The gas-liquid two-phase flow can have an impact on the work of the drill string. Therefore, it is important to study gas-liquid two-phase flow in the annulus on the dynamic characteristics of the drill string. In this article, taking a single drill string as the research object, a fluid-structure coupled finite element mathematical model of two-phase flow in the annulus and drill string is established based on computational fluid dynamics and computational structural dynamics theory. The finite element numerical simulation method is used to analyze the influence of drilling fluid and natural gas in the annulus on the dynamic characteristics of the drill string. The simulation analysis shows the following: (1) The motion of drilling fluid or natural gas in the annulus will reduce the natural frequency of the drill string, and the drilling fluid has a greater impact on the natural frequency of the drill string. (2) When single-phase drilling fluid flows in the annulus, the displacement peak in different directions, maximum equivalent stress, and strain of the drill string increase with the increase of the drilling fluid flow velocity or pressure, and the drilling fluid pressure has a more significant effect. (3) When the gas-liquid two-phase fluid flows in the annulus, the displacement peak, maximum equivalent stress, velocity amplitude, and acceleration amplitude of the drill string all increase with the natural gas flow velocity and natural gas content increase, and the natural gas flow velocity has a more significant effect.


Author(s):  
Djimako Bongo ◽  
Alexis Mouangué Nanimina ◽  
Nandiguim Lamai ◽  
Togdjim Jonas ◽  
Bonaventure Danoumbe ◽  
...  

The aim of this study is to determine the phase indicator functions of a two-phase flow in an air-lift vacuum column. The outcome of this study is to master the hydrodynamics in a vertical column when determining the size, the velocities of the bubbles and the void rate then the gas-liquid interphase. The functions are the vacuum rate, the interface speed and bubble size, the flow rate and the speed of the liquid phase. The vacuum lift air column that is the subject of this study is based on the principle of air lift and flotation, all under vacuum. In its operation, the column combines hydraulic pumping, solute transfer and particle phase separation functions, which has the particularity of minimizing energy costs. The process of air-lift columns under the vacuum is still at the development stage and the experimental study of its hydrodynamics is one of the determining axes in the course of the exploration with a assessment to optimizing its design and functioning. The experiments were carried out on a vertical column composed of two concentric plexiglas tubes connected to a water recirculation tank and to a vacuum pump. For all experiments performed, demineralized water and salt water are used and the flow rate is measured using a flow meter. The experimental analysis is done using two-phase instrumentation consisting of a bi-probe and the use of experimental techniques has enabled a better understanding of the hydrodynamics of the two-phase flow.


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