具有偏流块的弯管文丘里管组合浓淡燃烧器数值分析

Numerical analysis of elbow and Venturi tube combination bias burner with a bias block

研究了一种新型煤粉燃烧器,该燃烧器是由偏流块、弯管和文丘里管组合而成。通过数值计算的方法研究了这种特殊燃烧器的浓度分布特性,分析内部的气固两相流动特性,并通过改变偏流块角度和对比有无文丘流管的情况,研究偏流块角度和文丘里管对燃烧器出口浓淡分离效果的影响。采用RNGk-ε模型和Eu ler多相流模型研究气固两相流动。结果表明:偏流块有助于加强弯管对煤粉的浓淡分离作用,随着偏流块角度逐渐增大,浓淡分离效果越来越明显,沿程阻力也随之增加;文丘里管可以实现煤粉高浓度区域不贴壁,出口煤粉浓相的位置积聚在出口的中上部,该组合结构有利于减少燃烧器出口结焦;改变文丘里管渐扩段的长度可以对浓淡分离效果进行调节。

Investigates a new pulverized coal burner which consists of bias block,elbow and Venturi tube.The concentration distribution characteristics of the special burner have been studied by numerical method and gas-solid flow characteristics have been analyzed.Through changing the angle of bias block and compared with the case without Venturi tube,the effects of bias block angle and Venturi tube on burner rich-lean separation have been researched.RNG k-ε model and Euler multiphase flow model were used to investigate gas-solid flow.The results show that bias block contributes to enhancing elbow′s effects on the rich-lean separation of coal.With the angle of bias block increasing,the rich-lean separation of coal becomes more and more obvious and the resistance along the way increases.With Venturi tube,the high concentration area of pulverized coal can be away from the wall and at outlet,the dense phase of pulverized coal accumulates in the upper of the export.The composite structure helps to reduce coke at the outlet of burner.The rich-lean separation ability of burner can be adjusted by changing the angle of bias block.