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Study of droplet entrainment from bubbling surface in a bubble column; Etude de l`entrainement de gouttelettes a la surface libre du liquide dans une colonne a bulles

Abstract

In a bubble column droplets are ejected from the free surface by bubble bursting or splashing. Depending on their size, the droplets are partly carried away by the streaming gas or fall back to the bubbling surface by gravity force. Experiments have been carried out to determine the void fraction in the column by means of an optical probe. In the interfacial zone the bubble bursting process was captured with a high-speed video camera. Simultaneous measurements were made of size and velocity of droplets at several distances from the bubbling surface with a Phase-Doppler Anemometry. The bubble column can be divided into three regions: A lower zone with a flat profile of the local void fraction, a central zone where the flow regime is steady and an upper zone where the local void fraction grows rapidly. A two-parameter log-normal distribution function was proposed in order to describe the polydisperse distribution of droplet-size. Results were obtained concerning the entrainment, concentration, volume fraction and interfacial area of droplets. Finally, it was found that the turbulence intensity affects the droplet terminal velocity for droplets smaller than the Kolmogorov microscale.
Publication Date:
May 01, 1991
Product Type:
Thesis/Dissertation
Report Number:
FRCEA-TH-351
Reference Number:
SCA: 420400; PA: FRD-91:003751; SN: 92000621305
Resource Relation:
Other Information: TH: These (D. es Sc.)Thesis; PBD: May 1991
Subject:
42 ENGINEERING; TWO-PHASE FLOW; DROPLETS; VOID FRACTION; ENTRAINMENT; PARTICLE SIZE; BUBBLES; DRAG; TURBULENT FLOW; OPTICAL SYSTEMS; 420400; HEAT TRANSFER AND FLUID FLOW
OSTI ID:
10104515
Research Organizations:
CEA Centre d`Etudes de Grenoble, 38 (France); Grenoble-1 Univ., 38 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
Other: ON: DE92743657; TRN: FR9103751
Availability:
OSTI; NTIS (US Sales Only)
Submitting Site:
FRN
Size:
358 p.
Announcement Date:
Jun 30, 2005

Citation Formats

Ramirez de Santiago, M. Study of droplet entrainment from bubbling surface in a bubble column; Etude de l`entrainement de gouttelettes a la surface libre du liquide dans une colonne a bulles. France: N. p., 1991. Web.
Ramirez de Santiago, M. Study of droplet entrainment from bubbling surface in a bubble column; Etude de l`entrainement de gouttelettes a la surface libre du liquide dans une colonne a bulles. France.
Ramirez de Santiago, M. 1991. "Study of droplet entrainment from bubbling surface in a bubble column; Etude de l`entrainement de gouttelettes a la surface libre du liquide dans une colonne a bulles." France.
@misc{etde_10104515,
title = {Study of droplet entrainment from bubbling surface in a bubble column; Etude de l`entrainement de gouttelettes a la surface libre du liquide dans une colonne a bulles}
author = {Ramirez de Santiago, M}
abstractNote = {In a bubble column droplets are ejected from the free surface by bubble bursting or splashing. Depending on their size, the droplets are partly carried away by the streaming gas or fall back to the bubbling surface by gravity force. Experiments have been carried out to determine the void fraction in the column by means of an optical probe. In the interfacial zone the bubble bursting process was captured with a high-speed video camera. Simultaneous measurements were made of size and velocity of droplets at several distances from the bubbling surface with a Phase-Doppler Anemometry. The bubble column can be divided into three regions: A lower zone with a flat profile of the local void fraction, a central zone where the flow regime is steady and an upper zone where the local void fraction grows rapidly. A two-parameter log-normal distribution function was proposed in order to describe the polydisperse distribution of droplet-size. Results were obtained concerning the entrainment, concentration, volume fraction and interfacial area of droplets. Finally, it was found that the turbulence intensity affects the droplet terminal velocity for droplets smaller than the Kolmogorov microscale.}
place = {France}
year = {1991}
month = {May}
}