摘要
利用Eulerian-Lagrangian模型耦合飞灰沉积模型对一台化工废液焚烧卧式余热锅炉的飞灰沉积和分布进行数值模拟。Realizable k-模型计算炉膛内部的气相湍流,离散坐标法求解包括飞灰粒子的辐射换热和散射影响的辐射换热过程。基于经验黏附模型和临界动能理论,建立了适用于废液焚烧飞灰粒子的沉积模型,对飞灰粒子黏附/反弹和已沉积粒子的脱落过程进行数值预测。结果表明,粒子尺寸是影响沉积率以及沉积分布的主要因素。大粒子在惯性作用下主要沉积于凝渣管排迎风侧,而小粒子由于热泳、湍流波动的影响能够沉积于换热管的迎风和背风侧。此外,随着管表面温度升高,沉积率逐渐增大。通过对一台废液焚烧卧式余热回收锅炉现场测量表明,模拟结果与实际测量结果吻合较好。
Numerical study of characteristics of ash deposition and distribution in an industrial wastewater incineration heat recovery steam generator was performed using Eulerian-Lagrangian gas-solid two-phase flow model coupled with the deposition model. The Realizable κ-ε model was used to calculate turbulent flow and radiative heat transfer including the ash particle effect was modeled by discrete ordinates model. Based on viscosity-based empirical model and critical momentum theory, a numerical deposition model combined with discrete random walk model was developed to predict ash sticking/rebounding and detachment of deposited particles from the surface. The results show that particle size plays important role in particle deposition and distribution on different tube surfaces. Large particles subjected to inertial impaction mainly deposit on the windward side of tube surface, while small particles can deposit on both windward and leeward sides. Strong deposition propensity of large particles on the windward side should be responsible for the formation of serious fouling deposits near the entrance of the furnace. In addition, rate of deposition of ash particles increases with increased tube-surface temperature. The results are in good agreement with the experimental data.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2012年第29期30-37,I0005,共9页
Proceedings of the CSEE
关键词
余热锅炉
气固两相流
飞灰粒子沉积
沉积率
数值模拟
heat recovery steam generator
gas-particletwo-phase flow
ash deposition
deposition rate
numericalsimulation
