准东煤旋风燃烧的数值模拟

Numerical Simulation on the Cyclone Combustion of Zhundong Coal

为掌握准东煤在液态排渣旋风炉中的燃烧特性,对准东煤旋风燃烧过程进行了数值模拟。通过建立传热传质模型求解熔渣层的热物性参数,并作为边界条件代入燃烧CFD模拟中构建联合迭代算法。结果表明,迭代收敛后火焰温度与热电偶测量值基本吻合,误差小于4%。大于10μm的飞灰颗粒与熔渣层碰撞并被黏附,颗粒沉积可简化为一次碰撞。熔渣层厚度沿筒长方向呈非均匀分布,最大厚度约为2 mm,可近似为牛顿流体的流动边界层。排渣口处熔渣温度大于黏度25 Pa·s对应的温度,能够实现稳定液态排渣。立式旋风炉捕渣率大于0.6,捕渣率分布主要受配风方式的影响。

To understand the combustion characteristics of Zhundong coal in the cyclone furnace with liquid slagging,numerical simulation of cyclone combustion process of Zhundong coal was conducted.The heat and mass transfer models were established to solve the thermophysical parameters of the slag film,and the parameters were introduced into the combustion CFD model as the boundary condition.The results show that the calculated flame temperature is consistent with the measured value of thermocouple,and the maximum error is less than 4%.The ash particles larger than 10μm may collide with the slag film and be adhered to the slag,and the particle deposition can be simplified to a single collision.The slag film thickness is non-uniformly distributed along the cyclone furnace length,and the maximum thickness is about 2 mm.The slag film can be approximated as the flow boundary layer of Newtonian fluid.The slag temperature in the slagging outlet is higher than the temperature corresponding to the one with a viscosity of 250 Pa·s,and the liquid slagging is stable.The slag capture rate of vertical cyclone furnace is higher than 0.6,and its distribution is influenced mainly by the air supply mode.