Sieve plate hole pressure fluctuations: Bubble formation in aerated reactors

Abstract The influence of small changes to water hardness on the nonlinear behaviour of liquid penetration into a capillary and the resulting air pressure fluctuations during air bubble formation are examined in this paper. Experiments were undertaken in which bubbles were generated both in water having a surface tensile force of σ = 72.2 mN/m and in an aqueous solution of calcium carbonate having a surface tensile force of σ = 75.4 mN/m, each contained in a glass capillary with an internal diameter of 1 mm. It is shown that both the maximum value of liquid penetration into the capillary and bubble growth time are affected by perturbations to the water hardness. The time it takes for the bubble to depart the capillary was estimated using the following nonlinear data analysis methods: time delay (τ), attractor reconstructions, correlation dimension (D), and largest Lyapunov exponent (λ). All estimates demonstrate that the pressure fluctuations in the c-c aqueous solutions and extent of liquid solution penetration into the capillary during the time between subsequent bubble departures behave chaotically.

Download Full-text

AN EXPERIMENTAL STUDY OF BUBBLE FORMATION TRANSITIONS AT SIEVE PLATE SPARGERS

Chemical Engineering Communications ◽

10.1080/00986449308936160 ◽

1993 ◽

Vol 122 (1) ◽

pp. 245-261 ◽

Cited By ~ 3

Author(s):

ROBERT RAINBOLT ◽

LARRY A. GLASGOW

Keyword(s):

Experimental Study ◽

Bubble Formation ◽

Sieve Plate

Download Full-text

Statistical pressure characteristics in modelling of gas-liquid reactors

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19790056 ◽

1979 ◽

Vol 44 (1) ◽

pp. 56-68 ◽

Cited By ~ 3

Author(s):

Jan Čermák ◽

František Kaštánek ◽

Antonín Havlíček

Keyword(s):

Gas Flow ◽

Pressure Fluctuations ◽

Liquid System ◽

Considerable Effect ◽

Tube Formation ◽

Venturi Tube ◽

Sieve Plate ◽

Average Porosity ◽

Integral Characteristics ◽

The Given

The integral characteristics (average porosity and product kLa) and the fluctuating component of static pressure inside the gas-liquid system were measured in two types of column reactors with different gas distributors. It has been determined that at the same gas velocity in the reactor with a Venturi tube as the gas distributor the mean porosities are about 1.5 times greater than with the sieve plate reactor. To this corresponds, especially, at small gas flow rates even higher ratio of coefficients kLa. Standard deviation of pressure fluctuations becomes with the Venturi tube reactor for orders of magnitude greater then with the sieve plate reactor. The analysis of pressure fluctuations has demonstrated that in the reactor with the Venturi tube the decisive portion of fluctuation output corresponds to frequencies within the band 10-30 Hz, while in the reactor with the given type of the sieve plate to the band 0-10 Hz. In the reactor with the Venturi tube formation of surface waving has no considerable effect on flow of the gas phase, though the amplitudes in both types of reactors are comparable.

Download Full-text

Direct observations of radiation-enhanced transformations in glass

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075543 ◽

1983 ◽

Vol 41 ◽

pp. 354-355

Author(s):

J. F. DeNatale ◽

D. G. Howitt

Keyword(s):

Glass Matrix ◽

Diffusion Mechanism ◽

Bubble Formation ◽

Silicate Glasses ◽

Phase Decomposition ◽

Direct Observations ◽

Thin Foils ◽

Oxygen Bubble ◽

Electron Energy Loss ◽

Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Download Full-text