层流假设在型腔充填过程数值模拟中的适用性

根据Ｊ．Ｃａｍｐｂｅｌ的基准实险，采用层流假设和紊流模型对其充填过程中的流动现象进行三维数值模拟，进而逐步改变其直浇道高度，用上述２种方法进行数值模拟实验对比．根据所得结果的比较，提出了一个浇注系统最小断面处的临界雷诺数，该处的雷诺数小于此值时，采用层流假设进行模拟是合适的；而大于此值时，应采用紊流模型．

Suitability of Laminar Flow Assumption for Numerical Simulation of Mold Filling

According to the benchmark tests performed by J. Campbell,the three dimensional numerical simulation of fluid flow during mold filling has been carried out by using laminar flow assumption and turbulence model.By comparing the obtained results,a critical Reynolds number at the choke condition of the gating system is proposed.If the Reynolds number is less than critical, the laminar flow assumption could be used for the numerical simulation of mold filling. Otherwise, the turbulence model must be used.