600MW机组锅炉管排偏斜引起的磨损模拟分析

Simulation analysis of tubes erosion induced by bundle deflexion in 600 MW boiler

以商用软件Fluent为平台,运用用户自定义函数(UDF)模拟分析600 MW机组锅炉低温再热器管排发生偏斜对气固两相流场分布、飞灰运动轨迹、碰撞速度等的影响,进一步研究飞灰碰撞造成的管束磨损分布。研究结果表明:当管排偏斜角从1.6°增加到6.5°,管排通道内最大气流速度由16 m/s增至20 m/s,最大飞灰质量浓度由5.8 g/m3增至6.8 g/m3。同时颗粒平均碰撞速度增大,较多颗粒平均碰撞角集中于最大磨损发生角附近,造成偏斜管束年磨损量有较大增加。

The influences of bundle deflexion of a 600 MW boiler low-pressure reheater on the distribution of gas-solid two-phase flow fields,moving tracks and impact velocities of fly ash particles were simulated and analyzed using commercial software package Fluent and user defined function（UDF）.The tubes erosion caused by impingement of ash particles was further studied.The results show that the maximum flow velocity in the channel between tube bundles increases from 16 m/s to 20 m/s,the maximum particle mass concentration increases from 5.8 g/m3 to 6.8 g/m3.Meanwhile,the average impingement velocity of particles increases and the average impingement angels of most particles are close to the maximum erosion angle,resulting in a relatively large erosion rate of boiler tubes.