干凝胶粒子物性对空心玻璃微球炉内成球过程的影响

Effects of gel particle properties on fabrication process of hollow glass microspheres in drop-tower furnace by dried gel method

为实现干凝胶法制备惯性约束聚变靶用空心玻璃微球(HGM)炉内成球工艺过程的有效控制,从数值模拟和工艺实验两个方面研究了干凝胶粒子直径、比热容、发泡剂质量分数和辐射吸收系数对干凝胶粒子炉内成球过程及最终HGM性能参数的影响。结果表明,随着干凝胶粒子直径和/或比热容的增大,干凝胶粒子在吸热封装阶段的升温速率显著降低,在炉内成球过程各工艺阶段的停留时间快速下降,尤其是在精炼阶段的停留时间急剧缩短。降低干凝胶粒子的比热容和/或提高干凝胶粒子的发泡剂质量分数,HGM的直径和壁厚均匀性增大,高质量空心球的比例也相应提高。干凝胶粒子的辐射吸收系数变化对炉内成球过程几乎没有影响。

To fabricate high quality hollow glass microsphere（HGM） for inertial confinement fusion targets by dried gel method,effects of gel particle diameter,specific heat,blowing agent concentration and thermal radiation absorption coefficient on the transformation process from gel particle to HGMs and the resulting quality of HGMs were investigated by numerical simulation and experiments.The results show that with the increase of diameter and/or specific heat of dried-gel particles,heating-up rate of gel particle in heating and encapsulating stages is significantly reduced,and the residence time in various stages of the transformation process is sharply shortened,especially for the residence time in refining stage.The velocity of particle/microsphere increases remarkably with decreasing the blowing agent concentration in gel particles.With more blowing agent in gel particles,higher yield and larger HGMs can be obtained.The transformation process from gel particles to HGMs and the resulting quality of HGMs changes slightly with the change of thermal radiation absorption coefficient.