第三类边界条件下长圆柱对流融化过程的分阶段求解

Periodic Solution for the Melting Convection Process of Length Cylinder under the Third Boundary Condition

为了研究圆柱融化各个传热阶段的特性,以第三类边界条件下一维长圆柱对流融化过程为研究对象,同时考虑融化后的相变材料被周围流体及时带走,按照圆柱内部温度分布特性把传热过程分成3个阶段,并采用三次多项式热平衡积分方法对各阶段进行近似求解,以长冰柱对流融化过程为计算对象,分析了各控制参数对于相界面移动规律的影响。通过分析得到结论如下:当Bi≦3(T_m-T_0)/(θ_0-T_m)时长圆柱传热过程分为两个阶段,当Bi>3(T_m-T_0)/(θ_0-T_m)时分为三个阶段;不同控制参数条件下,相界面均随时间约呈线性变化规律;随着对流换热系数、冰柱初始温度及水流温度的增大,相界面随时间变化率越大。不同冰柱直径条件下,相界面随时间变化率基本相同。

In order to study the characteristics of each melting heat conduction process of the length cylinder,this paper concerned the one-dimensional convective melting process of a length cylinder under the third boundary condition and considered the phase change material that would be took away by the surrounding fluid in time after melting.The heat transfer process was divided into three stages according to the temperature distribution inside the cylinder.A cubic heat balance integral method was used in solving the approximate solution of each stage.Taking the convective melting process of the length cylinder as the calculating object to analyze the change impacted by each governs parameter of the moving regulation of phase change interface,some conclusions could be got as follow：The heat transfer process of the length cylinder could be divided into 2 phases in the condition of Bi ≦3（Tm-T0）/（θ0-Tm）,on the contrary Bi〉3（Tm-T0）/（θ0-Tm）,it could be divided into 3 phases.In the condition of different control parameters,the phase change interface varied in a linear manner with time.With the increase of the initial temperature of the icicle,the temperature of water fluid and convective heat transfer parameter,the variation rate of phase change interface with time also increased.In the condition of different icicle＇s diameter,the variation rate of phase change interface almost maintained the same value with time.