摘要
利用计算流体动力学(CFD)技术,以浸没板式膜生物反应器(MBR)中曝气槽内的流体为研究对象,将固相和液相视作"假想的均一混合相",将气、液、固三相流简化为"气-液两相流"问题。选用FLUENT软件中的多项流Eu-lerian模型,对曝气槽的内部流场的流态进行了模拟分析。结果得到包括气液两相多个截面的速度场及局部气含率分布等信息。模拟结果显示浸没板式MBR具有较好的水力条件,在一定的曝气强度条件下,在获得较大的升流区上升流速的同时,也获得了较大的膜面剪切力;一定的曝气条件会在曝气槽中产生固定的影响微生物生长的缺氧区,通过改变曝气强度可以解决这一问题。以上模拟结果能够合理解释实际工况中存在的膜污染等现象,证明了CFD技术在膜生物反应器中应用的可行性。数值求解结果可以为MBR的实际工程设计提供理论依据。
In cognizance of membrane fouling and the membrane hole-jam of the submerged flat type MBR （Membrane bioreactor）, the fluids in the aerator tank of submerged flat type MBR were studied with CFD （Computational fluid dynamics） technology, taking solid-liquid two-phase as hypothetical homogeneous phase, and simplifying the flow of gas-liquid-solid three-phase to gas-liquid two-phase. The simulation analysis was carried out on the flow regime of the internal flow field in the aeration tank by the Eulerian module of multiphase model designed by the software FLUENT. Therefore it showed the information of gas-liquid two-phase various sections of velocity field and distribution of gas-up and so on. This simulation result revealed that the submerged flat type MBR had preferably water power condition, in the same strength of aeration, comparatively big air lift flow velocities were obtained, at the same time, larger shear stress was obtained near the surface of the membrane too. In addition, the simulation found that certain conditions aeration in the aeration tank would have a fixed hypoxia impacting on the growth of microorganisms, which could be resolved by changing the strength of aeration. The simulation result could rationally explain the membrane fouling and other phenomena in practical situation, and proved the feasibility of CFD technology applied in MBR. Numerical solution result could provide a theoretical basis for the actual engineering design of this type reactor.
出处
《化学与生物工程》
CAS
2008年第11期44-47,共4页
Chemistry & Bioengineering
基金
国家自然科学基金资助项目(30671026)
辽宁省企业项目博士后基金资助项目(BSH-2004921023)
