循环流化床锅炉炉内过渡区磨损机理数值模拟的研究

Numerical Study on Abrasion Mechanism in the Transition Area of a Circulating Fluidized Bed Boiler

采用欧拉-欧拉双流体模型,对某大型循环流化床锅炉炉膛内过渡区的磨损机理进行数值模拟研究。模拟结果表明,密稀相过渡区存在大摆动及由其引起的大涡流,是引起过渡区磨损的主因。通过揭示的大摆动与大涡流的本质在于炉膛内沿密稀相过渡区高度上气固两相流的不稳定性来表明,这一结论与以往所认识的磨损机理的重要区别在于,以往的研究中,把这一区域的磨损机理仅仅简单地看作稳定流动下的涡流现象。研究深化了对循环流化床过渡区磨损机理的理论认识。

Numerical simulation, which adopting a multi-fluid Eulerian - Eulerian model, was conducted to probe the abrasion mechanism in transition area inside a large-scale circulating fluidized bed （CFB） boiler. The simulation results indicate that the main reasons for abrasion in the transition area are big waves as well as big vortexes which are led by the big waves in the transition zone of dense-phase and dilute-phase. We conclude that the essence of big waves and big vortexes is the instability of the gas-solid flow in the transition area, while previous studies on abrasion mechanism simply regard it as the result of vortexes which are produced by stable flow. This research provides a deeper sense of abrasion mechanism in the transition area of the CFB boiler.