In this paper, numerical investigation of upward two phase flow of air-water has been studied. Different conditions of flow regimes including annular, wispy annular, slug, churn and bubbly are simulated based on Hewitt and Roberts map, and a good agreement between the experimental data of the map and the numerical simulation has been observed. Accordingly, a proper CFD model in CFD software of ...

The annular foam breaker is one which uses the vacuum and shear force generated by the Coanda effect to break foam. The pressure distribution directly affects its performance. So an investigation on the flow characteristics inside the annular foam breaker is important to optimize its structure. In this paper, the computational fluid dynamics (CFD) code, FLUENT, is employed to simulate the flow ...

the flow of fluids in annular conduits has been studied for over sixty years, however the resulted data are very scattered. in this paper the problem is analytically solved, starting out with navier-stokes equations. a computer solution is used to determine the shape of velocity profiles, the discharge and the friction factor in a large number of concentric and eccentric annular conduits. the e...

The study on the flow behave inside of a ball valve is important for heavy crude oil transportation. Owe to the fast progress of the numerical technique, it becomes an effective way to observe the flows inside a valve and to analyze the flow structure of the oil-water core annular flow. In the present study, the simulation of the oil-water core annular flowing through the valve is conducted...

Molecular dynamics simulation of annular flow boiling in a nanochannel with 70000 particles is numerically investigated. In this research, an annular flow model is developed to predict the superheated flow boiling heat transfer characteristics in a nanochannel. To characterize the forced annular boiling flow in a nanochannel, an external driving force ext F ranging from 1to12PN (PN= Pico Newton...

Flow visualization of two phase flow pattern of steam during condensation process in separate horizontal quartz micro-tubes with inner diameter ranging from 70-675 m was conducted. Two main kinds of flow patterns were observed: annular flow and slug flow, which both were nearly symmetrical. The annular flow also can be divided into two kinds: annular flow and annular-wave flow. The effects of t...

OBJECTIVE To test the hypothesis that diastolic mitral annular motion velocity, as determined by Doppler tissue imaging and left ventricular diastolic flow propagation velocity, is related to the histological degree of heart transplant rejection according to the International Society of Heart and Lung Transplantation (ISHLT). METHODS In 41 heart transplant recipients undergoing 151 myocardial...

gas-lift pumps are devices for lifting liquid phase incorporating the gas phase to be injected in the bottom of liquid column. they are widely used in various industrial applications such as oil extracting in petroleum industries. gas-liquid flow being the main part of the flow through these systems, flowing in vertical pipes of gas-lift pumps has different regimes namely bubbly, slug, churn an...

Gas-lift pumps are devices for lifting liquid phase incorporating the gas phase to be injected in the bottom of liquid column. They are widely used in various industrial applications such as oil extracting in petroleum industries. Gas-liquid flow being the main part of the flow through these systems, flowing in vertical pipes of gas-lift pumps has different regimes namely bubbly, slug, chur...

A theoretical investigation has been made of core-annular flow: the flow of a high-viscosity liquid core surrounded by a low-viscosity liquid annular layer through a horizontal pipe. Special attention is paid to the question of how the buoyancy force on the core, caused by a density difference between the core and the annular layer, is counterbalanced. From earlier studies it is known that at t...