超临界循环流化床锅炉进风系统数值模拟分析与比较

CFD Simulation and Analysis for the Air Flow in the Primary Air Chamber of a Supper-Critical Circulating Fluidized Bed

本文针对超临界循环流化床锅炉一次风风箱系统内部的空气流动特性,包括进气管、风箱内部及一次风通过布风板的流动特性,基于FLUENT计算平台结合多孔介质模型进行了数值模拟。针对三种不同进风结构,即底部进风、侧面进风和后侧进风模式进行了分析比较。为准确模拟布风板压降损失同时又减少计算量,利用多孔介质模型模拟一次风通过布风板的压降。综合分析比较三种进风结构下流化床系统内部速度、压力和湍动能分布特性,给出了最佳进风结构。研究结果对超临界循环流化床锅炉开发设计和大型化具有一定的理论指导意义。

In this paper,CFD simulations based on FLUENT were performed for the air flow through the primary air chamber and air-distributor system in a super-critical pressure circulating fluidised bed.To reduce CFD simulation time,a simplified porous media model is used to simulate the pressure drop across the air distributor plate based user-defined function（UDF） in FLUENT.Simulations results for the air flow through the air chamber with three different air inlet supply system,i.e.,air inlet form bottom,side and real side of chamber,are given and compared.Key parameters including pressure-drop,velocity and turbulent intensity distribution and profiles in the chamber are given and compared.The optimum air supply system design for primary air chamber is given according to the simulation and analysis results.CFD simulation can be used to optimize the design and scale up for the air supply system in a supercritical pressure circulating fluidized bed.