辐射废锅入口结构对流场及颗粒分布的影响

Numerical Study on Effects of Inlet Structure of Radiant Syngas Cooler on Flow Field and Particle Concentration

为优化结构设计,合理布置水冷壁,对辐射废锅接口、入口结构及内筒水冷壁组成的系统进行模拟研究。采用组分输运模型计算气体组分扩散过程,通过Realizable-湍流模型计算炉内流场,利用随机轨道模型跟踪灰渣颗粒运动轨迹,并考虑了气固相间耦合。利用灰气体加权和模型和P1辐射模型计算炉内辐射传热过程,且考虑了灰渣颗粒的热辐射特性。结果表明:炉体入口存在中心射流区,流速与宽度和入口结构有很大关系,且周围存在明显回流区;灰渣颗粒主要集中在中心流道,但由于卷吸回流的作用,回流区内部分细小颗粒富集;缩口结构使灰渣颗粒更集中于中心流道,扩口结构则起一定的导流作用,使卷吸作用减弱。

In order to optimize structural design and rationalize arrangement of water-wall, the system composed of the connection combining the gasifier and the radiant syngas cooler （RSC）, inlet structure and the inner cylinder water-wall was established. The syngas multi-component diffusion was calculated with the species transport model. The gas phase flow field was calculated by realizable κ-εmodel while the discrete random walk was applied to trace the particles, and the interaction between gas and particles was considered. The radiation heat transfer was simulated with the P1 radiation model include the particles＇ radiation, and the radiative properties of syngas mixture were calculated by weighted-sum-of-gray-gases model （WSGGM）. The results show that there is a central jet at the entrance area, and the inlet structure has a great influence on the velocity and the width of the jet. Recirculation regions appear around the jet. The majority of ash particles gather in the center flow, but litter small particles gather in the recirculation region due to the entrainment. The convergent section makes the ash particles gather in the center flow much more, and the diffuser section played a role of diversion to weaken the entrainment.