气固两相流绕流H型翅片管流动及积灰特性的数值模拟

Numerical simulation of flow and ash deposition property on gas-solid flow around an H-finned tube

为评价锅炉尾部烟道烟气流过H型翅片管省煤器时的积灰特性,使用Fluent软件对气固两相流绕流H型翅片管进行了冷态数值模拟。对颗粒相的计算采用单向耦合模型,忽略固相对气相的作用,在给定进口速度及烟气颗粒相质量浓度条件下,得到绕流流场。计算结果表明:颗粒速度在H型翅片管迎风面呈M型分布;背风面呈W型分布。H型翅片管开缝既可提高迎风面驻点附近速度,增强轴向吹扫分流,又可增大背风面的回流扰动。这种速度分布特点使H型翅片管不易积灰。在此基础上,模拟了不同入口流速和颗粒质量浓度时的工况,计算结果表明H型翅片管在高速高质量浓度下工作效果同样较好。

In order to assess the ash deposition performance of flue gas flowing through the H-type finned tube economizer, a cold numerical simulation was carried out. The unidirectional coupling model was adopted to solve the gas parti- cle flow by ignoring the influence of the solid phase on the gas phase. The flow field was obtained and thoroughly analyzed under the condition of given inlet velocity and particle mass concentration. Results showed that the velocity profile was M-type on the windward side and W-type on the leeward side of the H-type finned tube. The seams of the H-finned tube had an axial sweep effect at the stagnant point on the windward side and could enhance the backflow turbulence on the leeward side, which could be helpful to alleviate ash deposition on the H-type finned tube. In addition, simulations under different inlet velocities and paxticle mass concentrations were carried out. Calculation results indicated that the Hfinned tube had excellent anti-deposition performance under higher inlet velocity and particle mass concentration.