Bubble coalescence in electrolytes: effect of bubble approach velocity-

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985858%3A_____%2F21%3A00525219" target="_blank" >RIV/67985858:_____/21:00525219 - isvavai.cz</a>

Result on the web

<a href="http://hdl.handle.net/11104/0311268" target="_blank" >http://hdl.handle.net/11104/0311268</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.cej.2020.125926" target="_blank" >10.1016/j.cej.2020.125926</a>

Result language

angličtina

Original language name

Bubble coalescence in electrolytes: effect of bubble approach velocity-

Original language description

The coalescence of air bubbles in aqueous solutions of electrolytes was studied experimentally. The bubbles were produced from two vertical parallel capillaries in a still liquid and video recorded. Several quantities were evaluated: bubble shape and size, bubble distance, bubble expansion rate, time of the first touch, time of bubble merger, time of bubble detachment. The three state variables were: bubble coalescence efficiency E, transition electrolyte concentration Ct, bubble contact time - coalescence time T. The effect of four control parameters was investigated: electrolyte type (3 inorganic salts: NaCl, Na2SO4, CaCl2), electrolyte concentration C (5 values sparsely covering a broad interval, 0.001 - 2 mol/L), bubble approach velocity V (9 values, from 0.03 to 40 mm/s), bubble diameter D (2 values, 1 and 1.5 mm). The following results were obtained. Coalescence efficiency E decreases with both C and V. Transition concentration Ct is not a material property but depends on the hydrodynamic conditions, Ct decreases with V. Contact time T decreases with V, as T ∼ V-1, and increases with C, roughly as T ∼ C1.9. Bubble approach velocity V plays a dual role: it reduces the coalescence region but accelerates the coalescence process. The transition from coalescence to noncoalescence proceeds via a minimum in the T(V) graphs. Bubble size D reduces the value of Ct, whence the extent of the coalescence region. The three electrolytes behave in a similar way. A scale-estimates model was developed to describe the results. The effect of electrolytes on the coalescence is similar to the effect of liquid viscosity.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

20402 - Chemical process engineering

Project

<a href="/en/project/GA19-09518S" target="_blank" >GA19-09518S: Dynamics of unsteady phenomena in gas-liquid systems</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2021

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chemical Engineering Journal

ISSN

1385-8947

e-ISSN

1873-3212

Volume of the periodical

460

Issue of the periodical within the volume

FEB 2021

Country of publishing house

NL - THE KINGDOM OF THE NETHERLANDS

Number of pages

18

Pages from-to

125926

UT code for WoS article

000603567400002

EID of the result in the Scopus database

2-s2.0-85090584841