鼓泡流化床风室及分布板区域流动特性的数值模拟

Numerical Simulation of Flow Characteristics of the Wind Chamber and Distributor Perforated Area of a Bubbling Fluidized Bed

采用计算流体力学(CFD)软件对采用切向进风和垂直进风情况下不同开孔率气体分布板的鼓泡流化床流态化特性进行研究,模拟风室及分布板区域的气体流动轨迹及其速度分布变化。结果表明:气体在切向进风形式下接近层流运动的上升状态,与垂直进风形式所产生的无序湍流上升状态相比,垂直进风形式下气体速度在空间分布更加均匀,受边界条件影响所导致的风室内局部风速过高情况较少;分布板开孔率在0.15%～1.0%变化时,随开孔率增大,气体压降逐渐减小,气体均匀性逐渐稳定;气体分布板开孔率为0.5%时,气体分布均匀性和分布板压降较合理。

Computational Fluid Dynamics （CFD） software was used to simulate the fluidization characteristics of a bubbling fluidized bed with a tangential air inlet pattern and a vertical air inlet pattern at different perforated ratios of the flow distributor. The flow trajectory and flow distribution on the change of the wind chamber and the distribution plate were investigated. The results showed that the rising gas flow was almost laminar with the tangential air inlet whereas it was fully developed turbulent with the vertical air inlet. Therefore, with the vertical air inlet pattern, the flow distribution was more uniform, and the effect of boundary conditions by local high gas speed was smaller. In the range of opening area 0.15% to 1% of the flow distributor, the flow uniformity was gradually stabilized, and the pressure drop decreased with the increase of the perforated rate. The gas distribution uniformity and pressure drop on the distributor were at reasonable values when the perforated rate was 0.5%.