Measurement and Analysis of Gas Bubbles Near a Reference Electrode in Aqueous Solutions
Phongikaroon, Supathorn
Herrmann, Steve
Li, Shelly
Simpson, Michael
United States. Office of the Assistant Secretary for Nuclear Energy.
Idaho National Laboratory
2005-10-01
English
Bubble size distributions (BSDs) near a reference electrode (RE) in aqueous glycerol solutions of an electrolyte NaCl have been investigated under various gas superficial velocities (U{sub S}). BSD and voltage reading of the solution were measured by using a high-speed digital camera and a pH/voltage meter, respectively. The results show that bubble size (b) increases with liquid viscosity ({mu}{sub c}) and U{sub S}. Self-similarity is seen and can be described by the log-normal form of the continuous number frequency distribution. The result shows that b controls the voltage reading in each solution. As b increases, the voltage increases because of gas bubbles interrupting their electrolyte paths in the solutions. An analysis of bubble rising velocity reveals that Stokes Law should be used cautiously to describe the system. The fundamental equation for bubble formation was developed via Newton's second law of motion and shown to be the function of three dimensionless groups--Weber number, Bond number, and Capillary number. After linking an electrochemical principle in the practical application, the result indicates that the critical bubble size is {approx}177 {micro}m. Further analysis suggests that there may be 3000 to 70,000 bubbles generated on the anode surface depending on the size of initial bubbles and provides the potential cause of the efficiency drop observed in the practical application.
Cameras
11 - Nuclear Fuel Cycle And Fuel Materials
Anodes
Electrodes
Electrolytes
Viscosity
Efficiency
Aqueous Solutions
Glycerol
Bubbles
Velocity
Stokes Law
Distribution
AIChE Annual Conference 2005,Cincinnati, Ohio,10/30/2005,11/04/2005
Article
Text
rep-no: INL/CON-05-00458
grantno: DE-AC07-99ID-13727
osti: 911755
https://digital.library.unt.edu/ark:/67531/metadc888649/
ark: ark:/67531/metadc888649