省煤器输灰管道结构优化

Structure Optimization of Ash Conveying Pipe of Economizer

对省煤器输灰主管道进行优化,利用CFD软件Fluent,选择k-e标准型湍流模型和mixture两相流模型,分析输送速度为6 m/s,对比光滑管道与旋流管的输送性能及参数分布,对不同导叶角度α,导叶高度h,导叶数目和旋流段前长度l进行分析,并计算输送顺畅度β。得出结论:增加导叶段之后,输送顺畅程度β明显提高,叶片数和角度存在最佳值,叶片数6和α=15°,旋流段靠近入口,颗粒过早沉降,靠后产生较大高浓度颗粒区域,导叶高度在18~36 cm之间流场变化较小,当其增加至42 cm时产生颗粒贴壁流并沉降。设有旋流管道输送性能明显提高,颗粒沉降减少。

Main pipe of economizer pneumatic conveying was studied by using software Fluent,and two-phase flow model of mixture and the turbulent model of k-e standard were selected,in order to analyze ash conveying of economizer with conveying speed of 6 m/s.The conveying performance and parameter distribution of pipe and swirl pipe were compared.The guide vane anglesα,guide vane height h,number of blade and the length in front of swirl section l were analyzed.The smoothness of particles transportationβwas calculated.The conclusion was made that the smoothness of particles transportationβincreased after the swirl flow.The number 6 and angle of bladesα=15 showed a better performance.The particle settle too early when the swirling part was designed near the entrance,however it would make a high particle concentration when it was designed in the posterior part.The flow fields change slightly when the height of blade change from 18 cm to 36 cm.When the height of blade increased to 42 cm,the particles moved close to the wall and settled,the transportation performance of swirl pipe was batter but the particle settlement was reduced.