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过程工程学报 ›› 2019, Vol. 19 ›› Issue (3): 492-499.DOI: 10.12034/j.issn.1009-606X.218239

• 流动与传递 • 上一篇    下一篇

转炉蒸发冷却器换热效率数值模拟

李海英， 刘东*， 张春奇， 刘良旭， 王晓波   

  1. 华北理工大学冶金与能源学院，现代冶金技术教育部重点实验室，河北 唐山 063210
  • 收稿日期:2018-07-02 修回日期:2018-10-12 出版日期:2019-06-22 发布日期:2019-06-20
  • 通讯作者: 刘东 silvermaster7@outlook.com
  • 基金资助:
    河北省科技计划资助项目

Numerical simulation of heat exchange efficiency of evaporative cooler

Haiying LI, Dong LIU*, Chunqi ZHANG, Liangxu LIU, Xiaobo WANG   

  1. Key Laboratory of Ministry of Education for Modern Metallurgy Technology, College of Metallurgy and Energy, North China University of Science and Technology, Tangshan, Hebei 063210, China
  • Received:2018-07-02 Revised:2018-10-12 Online:2019-06-22 Published:2019-06-20

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摘要： 基于国内某钢厂65 t转炉蒸发冷却器运行参数，采用CFD方法的离散相模型模拟了蒸发冷却器内雾化液滴与高温烟气间的换热效率，考察了单个液滴粒径、雾化液滴粒径分布对换热效率的影响。结果表明，模拟结果与实际运行参数吻合较好，计算的出口温度为468 K，实际为483 K，相对误差为3.1%，模型可靠。粒径小于300 μm的雾滴均能在0.62 s内蒸发完全，不同粒径的雾滴完全蒸发所需时间最高相差20多倍。液滴与高温烟气的换热效率受粒径分布影响较大，中位粒径d50=340 ?m和d50=95 ?m的雾滴在同一截面的平均温度可相差70 K。烟气温度下降先快后慢，最后趋于平稳，烟气主要降温区域为喷嘴下游3.5 m内。

关键词: 蒸发冷却器, 数值模拟, 液滴, 蒸发特性, 粒径分布

Abstract: In Lurgi?Thyssen dedusting system of steelmaking converter, the evaporative cooler represented a crucial operating unit, in which the hot dust-laden flue gas had to be cooled by saturation with water. The cooling process of the gas consisted of gas?liquid two phase flow and interphase heat and mass transfer. In this work, k?? standard equation and Lagrange discrete phase model were employed to describe the gas turbulent flow and the heat/mass transfer with droplet evaporation individually. The computational fluid dynamics (CFD) simulation for practical engineering project showed that the large-flux cooling gas was commonly constructed in a nonuniform flow caused by the sharp turnings at the inlet and outlet channels. The simulation results of the model were in good agreement with the actual working condition parameters of the evaporative cooler. The relative error of flue gas outlet temperature was 3.1%, the simulation results were reliable. The smaller the size of atomized droplet was, the shorter the time was required to reach the critical evaporation temperature and complete evaporation. The droplet with a particle size of less than 300 ?m could evaporate completely within 0.62 s. The main temperature drop of flue gas was within 3.5 m downstream of the nozzle. The heat transfer efficiency of droplet and high temperature flue gas was greatly affected by particle size distribution. The mean temperature of the same section corresponding of droplets with d50=340 ?m and d50=95 ?m can differ by 70 K. Using rosin-rammler distribution function to describe droplet size distribution, the effect of particle size distribution on the cooling efficiency of flue gas was studied. The droplet size should not be too large or too small. The particle size was too small to make a reasonable use of evaporative cooler space. The temperature of flue gas dropped unevenly and the droplet evaporation was incomplete due to the large particle size, resulting in wet bottom or wall hanging of the device.

Key words: evaporative cooler, numerical simulation, droplet, evaporation characteristics, particle size distribution