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中文核心期刊

液粒凝固过程的动力学理论

the dynamics theory on the solidification of liquid droplets

  • 摘要: 在平均场的概念下对液态粒子的凝固过程提出了一个简化的液-固-气-雾(LSGF)数学模型,并在小过冷度的条件下,求出了有关初值问题的一致有效渐近解. 结果表明:整个动力学过程可以分为两个相互联结的时间阶段. (1) 液粒初始温度分布的瞬态过渡阶段. 在这个阶段,凝固尚未正式启动,只是系统内的温度从任意给定的初始分布迅速调整到某一特定空间分布. (2)液粒向固粒转变阶段. 在这一阶段,液-固两相开始分离,相界面逐渐向液粒中心传播,直至液相完全消失. 进而以铜为例,讨论了液态粒子在不同生长条件与物理参数下的凝固时间与凝固过程中的温度分布的演化规律.

     

    Abstract: The present paper develops a simplifiedLiquid-Solid-Gas-Fog (LSGF) model in the solidification of dispersed liquiddroplets on the basis of mean field concept to obtain the uniformly validasymptotic solution of the initial value problem at small supercooling. Theresults show that the whole dynamics process can be divided into two stages,the transient transition stage and the solidification stage. In thetransient stage without phase transition, the initial temperaturedistribution prescribed in the system is quickly to be special spatial. Inthe solidification stage, there is the solid/liquid phase conversion processtill to the vanish of the liquid phase. In addition, the case of the liquidcopper droplets is simulated to obtain the duration and the temperaturedistribution of the solidification under various growth conditions.

     

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