考虑液面凹陷时金属熔化与蒸发的数值研究

Numerical analysis of metal melting and evaporating with liquid surface depression

将关于液面凹陷的Young Laplace方程与关于金属溶池的流体力学方程组及关于金属蒸发的BGK方程联立求解 ,在给定的电子枪加热条件下 ,获得了熔池流场和温度场图像及金属蒸气密度、速度和温度分布 .数值计算结果表明 ,随电子枪功率增加 ,金属的蒸发速率增加 ,蒸气的密度增大、温度降低而速度升高 .与假设液面为平面的情况相比 ,考虑液面凹陷后求得的液面温度较低 ,金属的蒸发速率较小 ,并且这种差别随电子枪功率的增加而扩大 .因此对于高功率电子枪加热金属蒸发 。

A metal molten pool is described by the Navier Stokes and energy equations and the depressed liquid surface is described by the Young Laplace equations,and the metal evaporation is described by the BGK equation. The velocity and temperature distributions of the pool and the vapor heated by an electron gun are solved by the finite difference method. The numerical results show the evaporation rate of the metal increases with the power of the electron gun, so the vapor density increases and the vapor temperature decreases and the vapor velocity increases. The surface temperature of the pool with the depressed surface is less than the one of the pool with the plane surface, so is the metal evaporation rate. The difference of the evaporation rate between them increases with the power of the electron gun, so the liquid surface depression should be taken into consideration for a high power electron gun.