Research On The Screw-pneumatic Reclaimer's Separation Principle

Transport grain in bulk has generally been used as an advanced transportation mode and it became the main mean to raise competing power of countries for world market. As China enters for the WTO and the incorporating of international commerce, the advanced mode that transport grain in bulk has influenced China's grain enterprises and China's grain circulation domain, which especially has greateffect on the main undertaker of grain's circulation and transfer——the ports. It hasthe follow characteristics: low circulating capital which reduces 30-60% transportation capital, high efficiency to load and unload and grain's odds is much less than other transportation modes. While transport grain in bulk has widely used in America, Japan, Canada, France and Australia, it also has been used more and more in China in this decade.Unload in bulk is a significant component of transport grain in bulk—load in bulk, transport in bulk, unload in bulk, deposit in bulk. Its efficiency has directly effect on the development of transport grain in bulk.This paper was a study on screw-pneumatic reclaimer—a new reclaimer. My study was on the basis of other schoolmen's and researchers' some work has done before that the function of the air movement followed the helix has been established and the equation of materiel's plumb velocity and radial distributing of airflow's velocity has been set up.Following are the main tasks and the main methods used in the paper:First, the mathematical mode was under the condition of has known the material separation interface's boundary conditions, based on the velocity distribution of rotational flow and the corresponding assumptions of the gas-solid two-phase flow has made. So a critical particle diameter's mathematical model was built which supplies an effective engineer method in theory for reclaimer's frame size, screw rotate velocity and airflow's velocity (or wind quantity parameters).Second, through visual curve, the relationship between various parameters and critical particle diameter, and it has analyzed of various parameters on critical particle diameter could easily been worked out. Cycle speed of air has been estimated.Third, adopting orthogonal table, the experimental project of the mathematical model has been set up. The analogical ratio between scale models and their prototypes are provided by the dimensional analysis. The velocity of the gas-solid two-phase flow and the diameter of critical particle in the experiments had been put forward, also the metrology equipment's characteristics use method and the range of its application had been illustrated.Given all that, a critical particle diameter's mathematical model which supplies an effective engineer method in theory for screw-pneumatic reclaimer has been established in this paper and how it influences by reclaimer's frame size, screw rotate velocity and airflow's velocity (or wind quantity parameters) has been found out, where a design theories and methods has been supplied for screw-pneumatic reclaimer.