垂直弯管段高压密相煤粉气力输送特性的数值模拟  

Numerical Simulation on High-pressure Dense-phase Pneumatic Conveying of Pulverized Coal in Vertical Elbow

作　　者：裴宇[1] 熊源泉[1] 周海军[1] 

机构地区：[1]东南大学能源热转换及其过程测控教育部重点实验室,南京210096

出　　处：《动力工程学报》2015年第9期760-767,共8页Journal of Chinese Society of Power Engineering

基　　金：国家高技术研究发展计划资助项目(2011AA05A201);国家重点基础研究发展计划资助项目(2010CB227002-02)

摘　　要：基于以氮气为输送介质的高压密相煤粉气力输送,在现有壁面模型和颗粒动力学基础上,充分考虑弯管中对气固两相流动特性起主要作用的摩擦应力的影响,建立了高压密相煤粉气力输送一体化管道(垂直管、弯管和水平管连在一起)的多相流新模型.采用该新模型模拟垂直向上转水平弯管内的气固两相流动特性,分析了补充风体积流量对弯管内固相速度、体积分数、湍动能分布以及垂直弯管压降的影响.结果表明:考虑摩擦应力后模拟所得弯管压降与试验值的误差减小至20%以内,验证了该模型的正确性;随着补充风体积流量的增大,垂直弯管压降先增大后减小,表观气速增大,垂直弯管壁面外侧煤粉堆积减少,低体积分数区范围增大,固相湍动能和固相拟温度均有所增大,当补充风体积流量达到1.0m3/h时,固相湍动能和固相拟温度均减小.Based on existing wall surface model and particle kinetics, a new model of multiphase flow was set up for high-pressure dense-phase pneumatic conveying of pulverized coal in an integrated pipe （vertical pipe, elbow and horizontal pipe connected together） with nitrogen as the carrying medium, by adequately considering the impact of friction stress on the gas-solid two-phase flow. The model was used to simulate the flow characteristics of gas-solid two-phase flow in an integrated pipe, so as analyze the effects of sup plementary air flow on the solid-phase velocity, concentration and distribution of turbulent kinetic energy as well as the elbow pressure drop. Results show that the error of elbow pressure drop between simulation results and experimental data is reduced to be less than 20 %, verifying the correctness of the model; with the rise of supplementary air flow, the elbow pressure drop increases first and decreases later on, resulting in increased superficial gas velocity, reduced accumulation of pulverized coal on outer side of elbow sur- face, increased low density area, and increased solid-phase turbulent kinetic energy and granular tempera- ture; when the supplementary air flow gets up to 1.0 ma/h, both the solid-phase turbulent kinetic energy and the granular temperature reduce.

关 键 词：垂直弯管 气力输送 摩擦应力 数值模拟 

分 类 号：TK224[动力工程及工程热物理—动力机械及工程]