熔池热焓最小值原理

Principle of Minimum Enthalpy for Molten Pool

在焊接过程中稳定的焊接条件下 ,熔池尺寸是确定的 ,当焊接条件变化时熔池尺寸随之要发生变化 ,并经过一定时间后达到一个新的稳定值 ,那么熔池尺寸确定及变化的热动力学的机理是什么 ?熔池热焓最小值原理就是回答这个问题的。在给定热输入与边界条件下 ,熔池有一种自动改变其尺寸 ,自动调节其热输出使其热焓 (热容量 )保持最小值的特性 ,即稳态下熔池的热焓具有最小值。应用这个原理可以解释焊接过程中出现的一些基本物理现象 。

The molten pool size has a certain value when the welding condition is stable in the arc welding process. It correspondingly alters if the condition changes, and it will reach a new stabilization value after some time. The mechanism of the thermodynamics about the pool size change is described by the principle of minimum enthalpy for the molten pool. The minimum enthalpy value by automatically changing its size and adjusting its enthalpy under the given heat input and boundary condition, namely the molten pool has a minimum enthalpy value. The principle can be used to explain some basic physical phenomena in arc welding process.