Cocurrent Gas-liquid Flow Research Articles

Turbulent Co-Current Gas-Liquid Flow in a Tube With and Without Swirl

The fluid dynamic effects of swirl generation on boiling flow in a tube were simulated experimentally by the flow of a water film surrounding a core of air down the interior of a vertical tube. Each of the two fluids could be injected with swirl. Water injection with swirl thickened the subregion of the film not contacted by the air-water interface. Air injection with swirl reduced interfacial disturbances. Transitional phenomena were identified. No transition was correlated with the appearance of dry patches on the test section inner wall. Models for estimating mean film thickness and axial pressure gradient were evaluated.

Mass transfer into laminar gas streams in wetted-wall columns. Cocurrent gas-liquid flow with circulation in gas phase.

Mass transfer into laminar gas streams in wetted-wall columns. Cocurrent gas-liquid flow with circulation in gas phase.

Mass transfer in cocurrent gas-liquid flow: Gas side mass transfer coefficients in upflow, interfacial areas and mass transfer coefficient in gas and liquid in downflow

A comparison of the values of interfacial area in cocurrent downward flow of gas and liquid with those obtained in upward flow revealed very little difference. Volumetric as well as true liquid side mass transfer coefficients in downflow were found to be several times lower than in upflow. Only in the smallest 10 mm tube a dependence of the mass transfer coefficient on the gas flow rate could be detected, no effect of the gas velocity was observed in the 15 and 20 mm tubes. A correlation for the liquid side mass transfer coefficient was obtained in terms of the Reynolds number of the film. The volumetric gas side mass transfer coefficient in upflow was generally independent on the liquid flow rate, except at high gas velocities in the two smaller tubes. Correlations were obtained for the volumetric mass transfer coefficient in terms of the specific rate of energy dissipation, and of the true mass transfer coefficient in terms of dimensionless groups. Much lower values were obtained for the gas side mass transfer coefficient in downflow. Only the data for the 10 mm tube could be correlated with some success by the formulas proposed for upflow.

Effect of tube size on liquid side mass transfer in co-current gas-liquid upward flow

Liquid side mass transfer in cocurrent upward gas-liquid flow in empty tubes of three different sizes, viz. 10, 15 and 20 mm has been studied by absorbing carbon dioxide from a mixture with air into a buffer solution of sodium carbonate and sodium-bicarbonate. A method for predicting the partial liquid side mass transfer coefficients, based on the Levich model of damped turbulence at the gas liquid interface, has been proposed for the case of annular flow.

On the concentration boundary layer theory at a moving interface

We present a theoretical investigation of the diffusion process in boundary layers at a moving interface for a cocurrent gas-liquid flow regime. The exact solution of the problem using a computer shows the dependence of the mass flux on the solubility of the exchanged substance. The results of a perturbation calculation are in good agreement with the exact solution. The interface concentration was found to remain constant along the boundary length under consideration.

The stability of gas-flow over a stagnant liquid in a pipe and the onset of slugging

A theoretical and experimental study is made of the stability of a cocurrent gas—liquid flow on the curved portion of a pipe traversing hilly terrain. For small values of the dimensionless stability parameter, experimental agreement with inviscid theory is excellent. For larger values, ripples and friction account for the discrepancy between theory and observation.

Laminar boundary layers of co-current gas-liquid stratified flows—II. Velocity measurements

An experimental investigation of the velocity distribution in the laminar boundary layer at a moving interface in co-current gas-liquid flow has been made. The velocity profiles were measured by hot wire technique at different distances from the initial phase interaction location. The experimental results compare well with theoretical predictions which are solutions of the Prandtl's equations.

Mass transfer into laminar gas streams in wetted-wall columns with cocurrent gas-liquid flow.

The effect of the gas and liquid flow rates on the mass transfer rate in laminar gas streams in wetted-wall columns with cocurrent gas-liquid flow was studied. An analytical solution was obtained for the average gas-phase Sherwood number as a function of the gas-phase Graetz number and the dimensionless interfacial gas velocity. Experiments were carried out on the absorption of ammonia into sulfuric acid solution and of methanol vapor into water, using three columns of different dimensions. The agreement between the experimental and the predicted effects of both gas and liquid flow rates on the gas-phase mass transfer rate was found to be fairly good.

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Axial Liquid Dispersion in Gas-Liquid Co-current Flow through Packed Beds

Axial Liquid Dispersion in Gas-Liquid Co-current Flow through Packed Beds

A comparison of some void-fraction relationships for co-current gas-liquid flow

A comparison of some void-fraction relationships for co-current gas-liquid flow

Radial Liquid Dispersion in Gas-Liquid Cocurrent Flow through Packed Beds

Radial Liquid Dispersion in Gas-Liquid Cocurrent Flow through Packed Beds

Two-phase flow—IV. Gas and liquid side mass transfer coefficients

Mass transfer coefficients in gas and liquid have been obtained for the case of cocurrent gas—liquid flow through a vertical tube 6 mm i.d. by absorbing sulphur dioxide into sodium hydroxide solution and carbon dioxide into sodium carbonate—sodium bicarbonate solution respectively. The liquid side mass transfer coefficient was found to increase with the gas velocity but showed a maximum when plotted against the liquid velocity. A model based on the analogy between momentum and mass transfer has been proposed for the rate of mass transfer in the liquid phase. The mass transfer coefficient in the gas phase increases with the gas velocity but the liquid velocity has an opposite effect. A correlation in terms of dimensionless groups is presented for the gas side mass transfer coefficient.

Cocurrent gas—liquid flow in packed columns

A model is proposed for cocurrent gas liquid flow through a packed bed. For a given packing, gas and liquid flow rates, we proposed that (i) liquid holdup is a function only of pressure gradient and liquid flow rate and (ii) pressure gradient is only a function of liquid holdup and gas flow rate. Equations are presented which permit the prediction of pressure gradient and liquid holdup for cocurrent upflow and cocurrent downflow in a packed bed. Predictions from the model are shown to be in reasonable agreement with the experimental observations of Turpin and Huntington.

Two-phase flow — III. Interfacial area in cocurrent gas—liquid flow

Specific interfacial areas for cocurrent gas—liquid flow through a vertical tube 6 mm i.d. and 1524 mm long have been obtained by absorbing carbon dioxide from air into aqueous sodium hydroxide. The interfacial area was found to increase with the liquid flow rate but a maximum was observed on the interfacial area vs gas flow rate curves. The position of the maximum is virtually independent of the liquid flow rate. A correlation is presented in terms of the rate of creation of the interfacial area V L a/α L against the pressure drop.

GAS HOLDUP AND PRESSURE DROP IN A MULTISTAGE VIBRATING DISK COLUMN WITH COCURRENT GAS-LIOUID FLOW

The gas holdup and pressure drop of a multistage vibrating disk column with cocurrent gas-liquid flow are measured and the effects of column geometry and operating variables are determined for the evaluation of column performance. Among the operating variables, the vibrating speed of the disks Av (amplitude A multipled by vibrating frequency v) has a definite effect on the gas holdup and pressure drop at speeds higher than a certain critical speed Avr. At speeds lower than Avc, disk vibration has little effect on gas holdup and pressure drop. The gas holdup and pressure drop are correlated successfully by the addition of increased values due to disk vibration to those in the absence of vibration.

Mass transfer in upwards co-current gas-liquid annular flow

The absorption of carbon dioxide in water has been studied in gas-liquid annular flow in a vertical tube. New types of probes have been developed to al

One-Dimensional Two-Phase Flow. BY G. B. WALLIS. McGraw Hill, 1969. 408pp. £7. 18s. Cocurrent Gas-Liquid Flow. Edited by E. RHODES AND D. S. SCOTT. Plenum Press, 1969. 698 pp. $27.50.

One-Dimensional Two-Phase Flow. BY G. B. WALLIS. McGraw Hill, 1969. 408pp. £7. 18s. Cocurrent Gas-Liquid Flow. Edited by E. RHODES AND D. S. SCOTT. Plenum Press, 1969. 698 pp. $27.50. - Volume 42 Issue 2

Pressure Drop in Horizontal and Vertical Cocurrent Gas-Liquid Flow

Pressure Drop in Horizontal and Vertical Cocurrent Gas-Liquid Flow