

	Mechanics På svenska

Project

Computing the two-phase flow in gas-evolving, electrochemical cells.

Research Area:

Fluid mechanics

Project Members:

Dahlkild, A. A.

Wedin, R.

Sponsor:

Faxén Laboratoriet

Project Description

This work aims at develop computational tools for flow in electrochemical reactors with gas-evolving electrodes. Focus is on the effect of the gas bubbles on the process, which are used to force a circulating convective flow of the electrolyte in the reactor. Two-phase flow models are applied compute bubble concentrations and flow velocities in different parts of the reactor. First, a global model is formulated for the whole reactor, where available two-phase flow models of the commercial software CFX is used. An important question to answer is e.g. to predict the flow distribution of electrolyte through the various channels of the electrode packet depending on reactor design. Secondly, a more detailed model of the flow between an electrode pair is developed. A source of bubbles appear on the surface of a gas-evolving electrode. Since the hydrogen bubbles studied are very small, the transport of bubbles away from the electrode in laminar flow conditions is obtained from available models of hydrodynamic diffusion of small Reynolds number-particles.

Publications related to the project

Year	Title
2001	Modelling the two-phase flow and current distribution along a vertical gas-evolving electrode. J. Fluid Mech. 428 249-272 (Published)
2001	Experiments and Modelling on Electrochemically generated bubbly flows. Proceedings of the 4th ICMF, New Orleans 2001. (Accepted)
2001	On the transport of small bubbles under developing channel flow in a buoyant gas-evolving electrochemical cell. Ind. Eng. Chem. Res. (Accepted)
2001	A hydrodynamical model for the dispersal of small bubbles under developing channel flow. J. Appl Electrochem. (Submitted)
2001	Modelling the mass transport and two-phase flow in a gas-evolving electrochemical cell. Journal of the Electrochemical Society (Submitted)
2000	A Mono-Modal Fiber-Optics Velocimeter for Electrochemically Generated Bubbles Proceedings of Tenth International Symposium on Applications of Laser Techniques to Fluid Dynamics, Lisbon, 2000 (Published)
1999	A numerical and analytical hydrodynamic two-phase study of an industrial gas-lift chlorate reactor. Computational technologies for fluid/thermal/structural/chemical systems with industrial applications 1 125-136 (Published)
1997	Hydrodynamic Diffusion of small Bubbles produced at a vertical electrode under Laminar flow conditions. Proceedings of 3:rd Int. Conf, on transfer phenomena on Magnetohydrodynamic & Electroconducting flows. (Published)

Internal Reports related to the project

Year	Title	Document Type
2001	Two-Phase Flows in Gas-Evolving Electrochemical Applications	Doctoral thesis
2000	Modelling the current distribution and two-phase flow along a vertical gas-evolving hydrogen electrode	Technical report
1999	Numerical studies of two-phase flows in gas evolving electrochemical applications.	Licentiate thesis