用CFD研究潜流人工湿地集水区对其水力学性能的影响_范立维

第58卷第12期化工学报Vol.58No.122007年12月JournalofChemicalIndustryandEngineering(China)December2007研究论文用CFD研究潜流人工湿地集水区对其水力学性能的影响范立维,海热提,卢泽湘(北京化工大学化学工程学院,北京100029)摘要:采用计算流体力学(CFD)软件Fluent(FluentInc.,Version6.2.16)中的多孔介质模型对潜流人工湿地进行了模拟,并引入颗粒轨道模型讨论了潜流人工湿地层式和护管式两种集水区结构对其水力学性能的影响。模拟结果表明,在考察条件下,平均停留时间相差不大,散度成为人工湿地水力学效能的主要影响因素。集水区为层式结构时,净化区与集水区阻力比越小,其变化对湿地水力学效能影响越大;集水区高度增加,水流散度增大,湿地水力学效能减小。集水区为护管式结构时,减小集水区宽度有利于提高湿地水力学效能和明显减小阻力比对湿地水力学效能的影响;集水区高度的增加对湿地水力学效能影响不大。与层式集水区结构相比,护管式集水区结构的潜流人工湿地水力学效能更高,而且可以通过减小集水区宽度显著提高湿地水力学效能和逐步减小阻力比对其水力学效能的影响,因此护管式集水区结构优于层式结构。关键词:集水区;潜流人工湿地;水力学性能;水力学效能中图分类号:X505文献标识码:A文章编号:0438-1157(2007)12-3024-09CFDstudyoneffectofcatchmentareaonhydraulicperformanceofsubsurfaceflowconstructedwetlandFANLiwei,HAIReti,LUZexiang(CollegeofChemicalEngineering,BeijingUniversityofChemicalTechnology,Beijing100029,China)Abstract:Thesubsurfaceflowwetlandwassimulatedbyusingacommercialcomputationalfluiddynamiccode,Fluent(FluentInc.,Version6.2.16).Themediaconstructedinthewetlandwasmodeledbytheporousmediaandtheparticletrajectorymodelwasintroducedtodiscusstheeffectoftwotypesofcatchmentarea,thelayerpatternandprotectorpatternonthehydraulicperformanceofthewetland.Thesimulationresultsconfirmedthatdispersionwasanimportantfactorforhydraulicefficiencywhilemeanresidencetimechangedlittleinallreviewedcases.Forthetypeoflayerpattern,thesmallertheratioofmediaresistanceofpurgeandcatchmentarea,thebiggertheeffectoftheirchangesonhydraulicefficiency.Withtheincreaseofcatchmentheight,thedispersionofflowincreasedandthehydraulicefficiencyofthewetlanddecreasedaccordingly.Forthetypeofprotectorpattern,withthedecreaseofcatchmentbreadth,hydraulicefficiencycouldbeimprovedandtheeffectofresistanceratioonhydraulicefficiencycouldbeweakened.Theeffectofcatchmentheightontheperformanceofthewetlandwasslightandwiththeincreaseofcatchmentheight,hydraulicefficiencywasimprovedslightlyandwhentheheightincreasedtothetopofthewetland,theeffectofresistanceratioonhydraulicefficiencydecreasedfurther.Ascomparedwiththelayerpatterncatchmenta