The best time to melt the end of the tube increases with the increase of heating area, and more importantly, the energy of con vection and radiation decreases with the increase of the wall thickness.
管端面熔化的最佳时间,是随着需要加热的面积增大而增大的,更重要的是对流和辐射传播的能量,会随着管壁厚度的增加而减小。