研究RHCM模具的三维有限元瞬态传热建模,分析进入稳态工作状态的模具和熔体之间的耦合传热过程,提出了模具和熔体接触热阻计算模型。案例对比分析发现:三维模型可克服目前简化二维模型存在的加热时间预测偏短,精密模具型腔边缘与模具中心温差误差大的问题;接触热阻导致热传导效率大大降低,冷却时间增长,可通过减小热阻来解决;减少加热时间可避免冷却阶段初期型腔壁面温度继续上升。
The 3D finite-element modeling of transient heat transfer in RHCM mould was studied. The coupled heat transfer between the mould and melt of being in steady working state was analyzed. A calculating model of thermal contact resistance between the mould and the melt was proposed. Through analysis and comparison, it is found that 3D model can solve the problems of shorter predicted heating time and large deviation in tempera- ture difference between the edge and center of precision mould cavity in existing simpli- fied 2D model. The phenomenon of heat transfer efficiency greatly reduced and cooling time lengthened because of the thermal contact resistance can be avoided through reducing the thermal contact resistance. The temperature of cavity surface will not increase at the beginning of cooling period by shortening the heating time.