利用“材料边界”的概念 ,构造了伴有相变的热传导问题的泛函 ,建立了相变热传导问题的变分原理 .在此基础上 ,采用有限元等效热容法求解温度场 ,并对相变单元的潜热、相界面位置的确定提出了处理方法 .最后通过数值算例说明了方法的有效性 By using the concept of “material boundary”, the functional of the heat conduction problem with phase transition is constructed and the variational principle of the phase transition heat conduction problem is established. Based on this, the finite element equivalent heat capacity method is used to solve the temperature field The method to deal with the latent heat and phase interface of phase change unit is put forward.Finally, numerical examples are given to illustrate the effectiveness of the method