垂直管煤粉高压密相气力输送特性的模拟研究

Numerical Simulation of Hydrodynamic Properties of Dense Pneumatic Conveying of Pulverized Coal in Vertical Pipe at High Pressure

基于颗粒动力学理论,采用k-ε-kp-εp湍流模式,对垂直管内高压密相上升流的三维流动行为进行了数值模拟,其颗粒浓度高达30%,并对部分模拟结果进行了实验验证。模拟过程中考虑了气固两相之间的湍流相互作用,得到了两相速度分布、浓度分布和湍流强度分布,考察了表观气速、输送压力和煤粉粒径对流动行为的影响。模拟结果显示:表观气速的增加导致压降梯度先减小后增加,导致煤粉浓度减小;输送压力的减小导致压降梯度减小;煤粉粒径的增加导致压降梯度增加。通过实验得到了表观气速和输送压力对压降梯度的影响。数值模拟结果与实验结果吻合较好。

A κ-ε-κp-εp two fluid model was introduced to study three dimensional flow behaviors of dense phase pneumatic conveying of pulverized coal in vertical pipe on the basis of the kinetic theory of granular flow, taking into account the turbulent interaction between gas phase and particle phase. The results of influence of superficial velocity, transport pressure and particle diameter were reported. The results indicate that as the superficial velocity increases pressure gradient decreases first then increases; as the transport pressure decreases pressure gradient declines and an increase in particle size leads to increment in pressure gradient. The simulation results on pressure gradient were validated by the experimental data.