The Effect of Bubble Shape on Dynamic Surface Tension Profiles－A theoretical Simulation

• Main Author: 鄭長森
• Other Authors: Shi Yow, Lin
• Format: Others
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/87882367131706059708

碩士 === 國立臺灣科技大學 === 化學工程系 === 92 === A finite element method was applied for simulating the relaxation of surface tension due to the adsorption of surfactant onto a fresh air-water interface of a pendant bubble. A comparison with the results from the simulation assuming a spherical interface was presented in this work. The effects of adsorption depth, mesh element number, size of needle, and bubble shape were studied systematically. This simulation was performed theoretically, but an illustration example was also given for the case of C12E4 at 25 oC. The Langmuir adsorption isotherm was assumed and only the process of diffusion limited adsorption was considered here. The results of theoretical simulation show that (1) an adsorption depth with 30 times of saturated adsorption at the air-water interface is needed; (2) a mesh element number of 7000 is required; and (3) the needle effect is significant when the pendant bubble is small.