| This paper mainly discussed about the research on microbubbles generation by metal microporous tube,it is a new method of bubble formation.The air inside the tube is impelled to run off the tube by the impetus which is provided by the difference of pressure inside and outside the tube.The microbubbles formation based on an overall force balance of surface tension force , buoyancy force , inertia force and so on. The microbubbles are taken away by high speed liqulid cross-flow outside the tube, the mixture of water and microbubbles are formed.The factors affect the size and the number of microbubbles are also discussed ,such as the difference of pressure inside and outside the tube, air-water ratio.At last , the disposal efficiency of the microbubbles is presented.A analysis on the system of bubble formation was made after measured the amount of air precipitation and the bubble size in this paper. The measuring method of air precipitation is based on measuring the precipitated air volume with a batch system,which is more accurate and easier. On the other hand ,the bubble size is measured by micro-video system. The distribution of the microbubbles diameter can be determinde by picking up the images on the mixture of water and microbubbles. Experimental results show that the diameter of micro-bubble between 20 and 70μm,and the number density between1.3×103and 8.2×103/mm3.The bubble diameter is decreased when the difference of pressure inside and outside of the tube is increased,the mean bubble diameter decreased from 53μm to 40μm with increasing... |
