The Effect of Rheological Complexities on Bubble Size in an Agitated Vessel

Research Project

Project/Area Number	02044018
Research Category	Grant-in-Aid for international Scientific Research
Allocation Type	Single-year Grants
Section	Joint Research
Research Institution	Yamagata University
Principal Investigator	KONNO Hirotaka Yamagata University, Faculty of Engineering, 工学部, 教授 (70005247)
Co-Investigator(Kenkyū-buntansha)	TAKAHASHI Koji Yamagata University, Faculty of Engineering, 工学部, 助教授 (00134023) ニーナウアルビン・W・バーミンカ゛ム大学, 工学部(英国), 教授 NIENOW Alvin Birmingham University, Faculty of Engineering
Project Period (FY)	1990
Project Status	Completed (Fiscal Year 1990)
Budget Amount *help	¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 1990: ¥1,000,000 (Direct Cost: ¥1,000,000)
Keywords	Bioreactor / Aerated Vessel / Bubble Size / Scale-Up / Phtographical Method
Research Abstract	Gas dispersion in agitated vessels is a common operation in the chemical and fermentation industries, one of the main purposes being gas-liquid mass transfer and chemical reaction. In such processes, knowledge of the total surface area of gas bubbles is important especially in the impeller region where most of the mass transfer is considered to occure. We have reported the bubble sizes and size distributions in a 0.61m vessel agitated by a Rushton turbine (Proceedings of European Conference on Mixing, Toulouse, France (1985)). In this year, the bubble size in the impeller region in the vessel of 0.49m diameter agitated by a 6-bladed Rushton turbine were measured by using flash photography incorporating a twin flash unit and a camera with a very short depth of focus developed by us (Proceedings of European Conference on Mixing, Toulouse, France (1985)) in order to investigate the scale-up relationship on bubble size. After the assembling of the instrument for enlargements of negatives, the bubble dimaeters will be determined. We also discussed about the bubble sizes at several positions in an aerated vessel of 0.61 diameter and the coalescence rate during passage of the bubbles from the impeller to the vessel wall, on the basis of the data obtained before. The results will be reported in the 7th European Conference on Mixing this autumn. The effect of shear rate on bubble size was also investigated.