高密度循环流化床出口结构对床内流动特性的影响

Influence of the Outlet Structure of a High Density Circulating Fluidized Bed on the Flow Characteristics Inside the Bed

在Φ0.205 m×7 m高密度循环流化床冷态实验台上,对3种出口结构(C型光滑出口、L型和T型突变出口)在不同循环流率和不同表观气速下分别对主床轴向颗粒浓度分布的影响进行研究。高密度循环的研究主要针对C型出口,最大循环流率G s为220 kg/(m2·s),底部3 m以下区域颗粒浓度大于0.1进行的。实验结果表明:C型出口使床内颗粒浓度呈现指数衰减规律;L型、T型出口效应对整个床高轴向颗粒浓度分布均有影响,T型出口增浓效果高于L型,且离出口中心线2 m区域出现局部增浓现象。

On a Φ0. 205 m × 7 m high density circulating fluidized bed cold-state test rig,studied was the influence of three types of outlet structure( C type smooth outlet,L type and T type abrupt change outlet) on the main bed axial particle concentration distribution under different circulating flow rates and apparent air speeds respectively. The high density circulation research work was mainly performed on the C type outlet with the maximum circulating flow rate Gs being 220 kg /( m2·s) and the particle concentration in the area of the bottom below 3 m being greater than 0. 1. The test results show that the C type outlet can make the particle concentration inside the bed assume an exponential attenuation law and the L and T type outlet can both exercise their influence on the axial particle concentration distribution in the whole bed height. The concentration enhancement effectiveness of the T type outlet is better than that of L type and a local concentration enhancement phenomenon emerges in the zone 2 meters away from the centerline of the outlet.