加压喷动床中细颗粒喷动特性

在内径分别为 186mm和 80mm的加压喷动床中 ,以空气为喷动介质 ,在 10 1～ 70 0kPa的压力范围内考察了几种不同粒度的细颗粒在加压下的喷动特性 .研究结果表明在不同的Re_t 内压力对最小喷动速度的影响不同 .实验还发现 ,随着压力的升高 ,喷动区直径增大 ,稳定操作区域增大 ,加压可明显改善喷动床的操作稳定性

SPOUTING OF FINE PARTICLES AT ELEVATED PRESSURE

The hydrodynamics of fine particles in pressurized air-spouted beds with internal diameter of 186 and 80mm, respectively, was studied using alumina and silicon gel particles of the size ranging from 0.26 to 1.7mm at the operating pressure up to 700kPa.A model for the minimum spouting velocity( U _ms )has been established through a series of experiments.There are three different cases in the relationship between the operating pressure and U ms . U _ms increases in a way for a Re _t<2 range, decreases in a way for a Re _t=2-500 range and decreases evidently for a Re _t>500 range with the increase of the operating pressure.The experimental results showed that the spouting stability could be significantly improved by increasing operating pressure.The maximum spouted bed height and spout diameter increase with the increase in bed pressure.It was also found that the fountain height in the bed almost keeps constant with the increase in the operating pressure.