不同进水方式对污泥床膨胀的影响

Impact of different water inflow on expansion of sludge bed

为了探究不同进水方式对污泥膨胀床性能的影响,设计一种侧向进水物理模型和四种不同进水夹角的底部进水口的数值模型,对比分析计算流体力学的三维模拟与实物模型的运行状态。结果表明:侧向进水方式污泥床在进水时膨胀速率比底部进水方式快19%;进水流量对两种进水方式的污泥膨胀高度及死区面积的减少有显著影响,在模拟中倾角为15°时,流量提升2.7倍,死区面积减少87%;底部圆锥倾角的变化,对死区产生显著的影响;侧向进水时,流场分为左右两部分,未有明显的优先流,底部进水则存在沿中轴线前进的主流,两侧的速度场分布梯度较小。

This paper aims to investigate the impact of different water inflow on the performance of sludge bed expansion.The study involves designing a lateral water inflow physical model and four numerical models with different bottom inflow angles;and comparing and analyzing the actual operating status of three-dimensional computational fluid dynamics simulations and the physical models.The results show that the expansion rate of the sludge bed with lateral water inflow is faster by 19%than that with bottom water inflow.The two inflow rates significantly affec the sludge expansion height and the reduction of dead zone areas.In the simulation,the flow rate increases by 2.7 times at an inclination angle of 15°,and the dead zone area can be reduced by 87%.The changes of the bottom conical inclination significantly influence the formation of dead zones.With lateral inflow,the flow field is divided into two parts without a noticeable preferential flow,whereas bottom inflow exhibits a main flow along the central axis with a smaller velocity field gradient on both sides.