水平浓淡煤粉燃烧器内气固两相流的数值模拟

Numerical Simulation of Gas-Solid Two-phase Flow in Horizontal Rich/Lean Pulverized Coal Burners

为了揭示煤粉气流在带有弯管、方圆接头、可调浓淡煤粉分离装置及喷口前直管段内的运动轨迹及分离机理,将新型可调水平浓淡煤粉椭圆锥燃烧器喷口前弯管、方圆接头、可调浓淡煤粉分离装置及直管段作为整体,采用RNGK ε模型和随机轨道模型,通过颗粒与流体耦合的PISC算法,对管内气固两相流进行了数值模拟。模拟结果表明弯管是一种经济而有效的煤粉分离装置,可调浓淡煤粉分离装置可调节燃烧器向火侧和背火侧的煤粉浓度,为其进一步完善和广泛应用提供了理论依据。

In order to ensure stable combustion at low-load, reduction of NOx emission, avoid slagging and high temperature corrosion in the combustion chamber, as well as to improve boiler combustion efficiency, many pulverized-coal boilers in large power plants have adopted the horizontal rich/lean pulverized-coal combustion technology. In order to unveil the track as well as separation mechanism of pulverized coal, the bend, the square-circle tie-in, the adjustable rich/lean pulverized coal separation contrivance and the straight section in front of the newly developed adjustable rich/ lean pulverized coal ellipsoidal cone shaped burner are considered as an entity for simulating the gas-solid two-phase flow in the topping straight pipe sections. Adopting the RNG K-ε and the stochastic track model, the gas-solid two phase flow in pipes is numerically simulated with the help of PISC arithmetic for coupling particles and fluid. Study results show that pipe bends are economic and effective separation contraptions. The adjustable rich/lean pulverized coal separation device can adjust the concentration of pulverized coal in the burner, facing as well as backing the fire. This provides some theoretical foundation for the burner's further improvement and application.