水平铜板表面液滴冻结过程的数值模拟

Numerical simulation of droplet freezing on horizontalcopper plate surface

为了探究水平铜板表面温度和液滴体积大小对液滴冻结过程的影响规律,以及冻结过程中液滴内部固液相界面变化和温度场分布,文中基于能量守恒原理,建立了单个静止液滴冻结的数值模型进行模拟研究。研究结果表明:液滴冻结过程中,固液相界面呈凹型状态;随着液滴冻结的进行,固液相界面推进速度呈先快后慢的变化趋势,模拟结果和对应的实验数据吻合良好;冻结完成后,液滴内部温度场呈弧形对称分布,同一水平面上,液滴中心温度要高于液滴两侧温度;水平铜板表面温度越低,固相体积分数和液滴中心温度随冻结时间变化越快,完成冻结所需时间越短;对于体积大小不同的液滴,体积越小,固相体积分数和液滴中心温度变化越快,完成冻结越快。

To explore the influence of surface temperature and droplet size on droplet freezing process,as well as the change of solid-liquid interface and temperature field distribution in the droplet during freezing process,a numerical model of single static droplet freezing was established based on the principle of energy conservation.The results show that the solid-liquid interface is concave in the droplet freezing process.With the whole process of droplet freezing,the solid-liquid interface advancing speed is first fast and then slow,and the experimental and simulation data are in good agreement.After freezing,the temperature field inside the droplet is distributed symmetrically in an arc shape,and the center temperature of the droplet is higher than the boundary temperature of the droplet on the same horizontal plane.The lower the surface temperature of the horizontal copper plate,the faster the change of solid volume fraction and droplet internal temperature with freezing time and the shorter the time required to complete freezing.For droplets with different volume,the smaller the volume,the faster the change of solid volume fraction and droplet internal temperature,and the faster the completion of freezing.