At different time, particles with different sizes can hit different locations on the wall, which are mainly at the connective part of shell and nozzle and out the convergent section of nozzle.

在不同的时间下，不同尺寸的颗粒会撞击壁面不同的位置，但主要集中在壳体与喷管的相接部分和喷管的收敛段。

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There will be great stress concentration appearing nearby the junction of nozzle and shell of pressure vessels with big openings, so reinforcement is absolutely necessary.

大开孔压力容器在开孔接管部位有很大的应力集中，必须进行补强。

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