SCI和EI收录∣中国化工学会会刊

›› 2017, Vol. 25 ›› Issue (6): 712-721.DOI: 10.1016/j.cjche.2016.11.016

• Fluid Dynamics and Transport Phenomena • 上一篇    下一篇

Thermophoresis effects on gas-particle phases flow behaviors in entrained flow coal gasifier using Eulerian model

Chao Dai, Fan Gu   

  1. School of Energy and Environment, Southeast University, Nanjing 210096, China
  • 收稿日期:2016-03-30 修回日期:2016-11-28 出版日期:2017-06-28 发布日期:2017-08-02
  • 通讯作者: Fan Gu,E-mail address:power_engine@163.com

Thermophoresis effects on gas-particle phases flow behaviors in entrained flow coal gasifier using Eulerian model

Chao Dai, Fan Gu   

  1. School of Energy and Environment, Southeast University, Nanjing 210096, China
  • Received:2016-03-30 Revised:2016-11-28 Online:2017-06-28 Published:2017-08-02

摘要: A numerical model based on the Eulerian-Eulerian two-fluid approach is used to simulate the gasification of coal char inside an entrained flow gasifier. In this model, effects of thermophoresis of coal char particles are thoroughly investigated. The thermophoresis is due to the gas temperature gradient caused by absorpted heat of coal char gasification. This work, firstly, calculates the gas temperature gradient and thermophoretic force at 1100℃,1200℃,1300℃ and 1400℃ wall temperatures. Then, the changes of particle volume fraction and velocity in the gasifier are studied in the simulation with thermophoresis or not. The results indicate that considering the particle thermophoresis has some effects on the calculation of particle volume fraction in the gasifier, especially at wall temperature of 1400℃, and the maximum particle volume fraction variance ratio reaches up to 1.38% on wall surface of the gasifier. These effects are mainly caused by large gas temperature gradient along the radial direction of the gasifier. For the particle velocity, the changes are small but can be observable along radial direction of the gasifier, which has good agreement with the distributions of radial gas temperature gradient and thermophoretic force. These changes above may have certain effects on gasification reaction rates in this Eulerian model. So the change of gasification reaction rates in the simulation with thermophoresis or not is studied finally.

关键词: Gasification, Thermophoresis, Eulerian model, Two-phase flow

Abstract: A numerical model based on the Eulerian-Eulerian two-fluid approach is used to simulate the gasification of coal char inside an entrained flow gasifier. In this model, effects of thermophoresis of coal char particles are thoroughly investigated. The thermophoresis is due to the gas temperature gradient caused by absorpted heat of coal char gasification. This work, firstly, calculates the gas temperature gradient and thermophoretic force at 1100℃,1200℃,1300℃ and 1400℃ wall temperatures. Then, the changes of particle volume fraction and velocity in the gasifier are studied in the simulation with thermophoresis or not. The results indicate that considering the particle thermophoresis has some effects on the calculation of particle volume fraction in the gasifier, especially at wall temperature of 1400℃, and the maximum particle volume fraction variance ratio reaches up to 1.38% on wall surface of the gasifier. These effects are mainly caused by large gas temperature gradient along the radial direction of the gasifier. For the particle velocity, the changes are small but can be observable along radial direction of the gasifier, which has good agreement with the distributions of radial gas temperature gradient and thermophoretic force. These changes above may have certain effects on gasification reaction rates in this Eulerian model. So the change of gasification reaction rates in the simulation with thermophoresis or not is studied finally.

Key words: Gasification, Thermophoresis, Eulerian model, Two-phase flow