The two-phase flow structure of an air-water, bubbly, upward flow in a 20 cm diameter pipe is presented with particular emphasis on the local interfacial area concentration. The radial distribution of void fraction, bubble velocity, bubble size, bubble frequency, and interfacial area concentration were measured using a local dual-optical probe. The experimental results showed that the saddle-type distribution of void fraction and interfacial area concentration, which are common for bubbly flow in small diameter pipes, only appeared in the present experiments under conditions of very low area-averaged void fraction ( < 0.04). The values for the interfacial area concentration were higher in large diameter pipes when compared with data obtained under the same flow conditions in small pipes. The area-averaged void fraction data were correlated using the drift-flux model.
On decrit la structure d'ecoulement biphasique d'un ecoulement air-eau bouillonnant ascendant dans une conduite de 20 cm de diametre en mettant l'accent sur la concentration de surface interfaciale locale. La distribution radiale de la fraction de vide, la vitesse, la taille et la frequence des bulles ainsi que la concentration de surface interfaciale ont ete mesurees a l'aide d'une sonde optique double locale. Les resultats experimentaux montrent que la distribution en forme de selle de la fraction de vide et de la concentration de surface interfaciale, qui sont courantes avec l'ecoulement bouillonnant dans des conduites de petits diametres, apparaissent seulement, dans les presentes experiences, dans des conditions de tres faibles fractions de vide moyennees en surface ( < 0,04). Les valeurs de la concentration de surface interfaciale sont plus grandes dans des conduites de gros diametre en comparaison avec les donnees obtenues dans les memes conditions d'ecoulement dans des conduites de petit diametre. Les donnees de fraction de vide moyennee en surface sont correlees a l'aide d'un modele a derive de flux.
[1]
Kataoka Isao,et al.
Drift flux model for large diameter pipe and new correlation for pool void fraction
,
1987
.
[2]
Mamoru Ishii,et al.
Local interfacial area measurement in bubbly flow
,
1992
.
[3]
N. Zuber,et al.
Average volumetric concentration in two-phase flow systems
,
1965
.
[4]
Edward Ihab Gerges.
TWO-PHASE BUBBLY FLOW STRUCTURE IN LARGE DIAMETER PIPES
,
1999
.
[5]
G. Kocamustafaogullari,et al.
An experimental study on local interfacial parameters in a horizontal bubbly two-phase flow
,
1991
.
[6]
Mamoru Ishii,et al.
Experimental study on interfacial area transport in bubbly two-phase flows
,
1999
.
[7]
S. G. Bankoff,et al.
Structure of air-water bubbly flow in a vertical pipe—II. Void fraction, bubble velocity and bubble size distribution
,
1993
.
[8]
J. H. Hills.
The behaviour of a bubble column at high throughputs: II. radial voidage profiles
,
1993
.
[9]
Mamoru Ishii,et al.
Local formulation and measurements of interfacial area concentration in two-phase flow
,
1986
.
[10]
B. Stankovic.
AN EXPERIMENTAL STUDY ON THE LOCAL VOID FRACTION MEASUREMENTS IN LARGE-DIAMETER VERTICAL PIPES USING OPTICAL FIBER PROBES
,
1997
.
[11]
Mamoru Ishii,et al.
Axial development of interfacial area and void concentration profiles measured by double-sensor probe method
,
1995
.