气升式内环流浆态床流动特性实验及数值模拟

为实现1,3-丙二胺系列精细化工产品的连续化生产,研发一种气升式内环流浆态床,从实验和数值模拟计算两个方面对设备内部流体动力学特性开展研究。实验结果表明,表观气速由0.007增至0.028 m/s,4种固含率工况下,气含率均呈线性增加,增大固相浓度会降低同等操作条件下升液管的气含率,并增大流型转变气速。压力对气含率和流型转变气速影响较小,因压力引起的气泡特性变化是产生差异的主要原因。采用三欧拉法及RNG k-ε湍流模型建立环流浆态床的数值模型,模型计算结果与实验数据吻合较好,最大气含率偏差8.9%,流型转变气速偏差5.0%。模拟结果表明,在表观气速0.007~0.028 m/s范围内,增大固相浓度会降低同等操作条件下降液管中液相循环速率,压力对液相循环速率的影响很小。

Introduction and evaluation of a novel hybrid brattice for improved dust control in underground mining faces: A computational study

A proper control and management of dust dispersion is essential to ensure safe and productive underground working environment. Brattice installation to direct the flow from main shaft to the mining face was found to be the most effective method to disperse dust particle away from the mining face. However,it limits the movement and disturbs the flexibility of the mining fleets and operators at the tunnel. This study proposes a hybrid brattice system- a combination of a physical brattice together with suitable and flexible directed and located air curtains- to mitigate dust dispersion from the mining face and reduce dust concentration to a safe level for the working operators. A validated three-dimensional computational fluid dynamic model utilizing Eulerian–Lagrangian approach is employed to track the dispersion of dust particle. Several possible hybrid brattice scenarios are evaluated with the objective to improve dust management in underground mine. The results suggest that implementation of hybrid brattice is beneficial for the mining operation: up to three times lower dust concentration is achieved as compared to that of the physical brattice without air curtain.