炉内成球法制备PVA涂层理论模拟研究

 根据炉内成球法制备PVA涂层原理，建立了炉内成球法在PS微球表面制备PVA涂层的数学模型，并利用数值方法进行了求解，研究了初始PS壁厚和直径、载气种类、炉内温度、PVA含量等实验条件的影响。计算结果表明，包裹PS微球的PVA水溶液复合微球在下落过程中速度迅速增加，短时间内达到最大值后又逐渐降低；复合微球的PVA水溶液涂层厚度逐渐减少，微球表观密度降低；炉内温度较低时，PVA涂层不易烘干；空气和纯Ar做炉内气氛时，微球烘干时间延长，而在He和Ar混合气体中，随着He含量增加，微球烘干时间缩短；小直径PS微球及高含量PVA溶液有利于制备厚的PVA涂层。

Theoretical simulation of PVA coating using drop-tower technique

Polyvinyl alcohol(PVA) capsule layer,as a gas barrier,were developed for the inertial confinement fusion(ICF) program.This paper presented the simulation study on fabrication of PVA coating using drop-tower technique.Based on the heat,mass and momentum transfer of the transformation process,a physical model was established and the related mathematic model was developed.The influence of processing parameters on the transformation was simulated.The key processing parameters that greatly affected the gel-to-shell transformation and the resulting PVA properties had been found to be initial PVA concentration,PS diameter,furnace temperature profile and thermal conductivity of the furnace gas.