摘要
基于对干凝胶粒子在干凝胶炉内吸热、封装、发泡、精炼和冷却过程的传热、传质和运动分析,建立了空心玻璃微球炉内成球过程的数学模型,并模拟了干凝胶粒子在炉内自由下落过程中温度、速度和直径的变化、粒子/微球与载气之间的温差及热传递系数在成球过程中的变化趋势.结果表明,在吸热封装阶段,干凝胶粒子表面升温速率非常高(1000～2000℃/s),能在很短时间(<1s)和距离(<4.5cm)内完成封装过程.提高载气的传热性能并不能显著增大液态玻璃微球的降温速率,提高制备炉冷却区的轴向温度梯度是增加其降温速率以提高空心玻璃微球几何对称性和表面粗糙度的关键.实验与模拟结果基本一致.
Based on the analysis of heat, mass and momentum transfer in the transformation process from dried gel particles to hollow glass microspheres, a mathematic model was established to simulate the temperature, mass, velocity and diameter of particle/microsphere in the transformation process. The temperature difference and heat transfer coefficient between furnace and particle/microsphere was also investigated. The results show that in the heating and encapsulating stages, the surface of dried gel particles have extremely high heating-up rate （1000-2000 ℃/s）, and consequently the encapsulation process can be completed in very short time （〈1 s） and distance （〈4.5 cm）. The cooling rate of liquid glass microspheres can not be improved by increasing the heat transfer rate of furnace atmosphere, since the cooling rate of liquid glass microspheres depends on the axial temperature gradient of cooling zone of drop-tower furnace. The simulation results agree well with the experimental results.
出处
《过程工程学报》
CAS
CSCD
北大核心
2010年第1期109-114,共6页
The Chinese Journal of Process Engineering
基金
国防科技重点实验室基金资助项目(编号:91400C680603090C68)
关键词
干凝胶法
空心玻璃微球
惯性约束聚变
靶制备
模拟
sol-gel technology
hollow glass microspheres
inertial confinement fusion
target fabrication
modeling
