疏水管道局部损伤的仿真模拟研究

Analogue Simulation for Local Damage of Drain Pipe

电厂疏水管路中过渡管段(大小头)因减薄而引起泄漏,汽蚀及流体冲刷的协同作用是重要的影响因素。利用计算流体动力学软件对某电厂疏水管道的局部减薄进行了仿真模拟,得到了大小头处损伤的分布规律。计算结果表明:阀门后大小头的小径端静压出现最小值,并低于汽化压强,从而产生汽蚀;另外,此处流体剪切应力达到最大值,加速了流体对材料的冲刷。针对以上现象,文中提出了控制疏水管道局部损伤的防护措施。

For the leakage of variable diameter drain pipe caused by local thinned area, the synergism of cavitation and erosion is regarded as the main factor. In order to obtain the distribution of damage, CFD code was used. The calculated result shows that static pressure reaches its minimum at the small-end of conical pipe behind the valve and is lower than the vaporization pressure, which will cause the cavitation, and maximum of shear stress appears at the same position, which accelerates the erosion effect of fluid. Furthermore, corresponding proposals are put forward to prevent the conical drain pipe from local damage.