曝气条件对等温层曝气器充氧性能的影响

中国环境科学2015，35(9)：2690～2697ChinaEnvironmentalScience曝气条件对等温层曝气器充氧性能的影响孙昕，刘凌炜，段飞飞，解岳(西安建筑科技大学环境与市政工程学院，陕西西安710055)摘要：分析了等温层曝气器曝气室内气泡一水接触界面的氧传质过程，确定了表征氧传质效果的各项参数，在双膜理论基础上建立了等温层曝气充氧动力学模型及其解析方法．应用本模型预测了美国Prince湖等温层曝气器的充氧效果．根据等温层曝气充氧动力学模型的预测结果，随曝气量的增加和气泡直径的减小，氧总传质系数和氧传质速率均增大；随曝气量和气泡直径的增大，曝气效率下降．在等温层曝气器结构固定的情况下，减小气泡直径和增加水深均有利于改善曝气室的充氧效果，尤其是当气泡直径达到pm级别时；当曝气量超过一定临界值0．06m／s时，曝气室的充氧效果略有削弱．根据曝气量对氧传质速率、曝气效率和单位时间内曝气室的充氧量的影响特性曲线。可确定等温层曝气器的优化运行条件．关键词：等温层曝气；溶解氧；模型曝气量；气泡直径中图分类号：X524文献标识码：A文章编号：1000—6923(2015)09—2690—08Efectsofaerationconditionsontheoxygenationperformanceofahypo~mneticaerator．SUNXin’，LIULing—wei，DUANFei-fei，XIEYue(SchoolofEnvironmentalandMunicipalEngineering，Xi’anUniversityofArchitectureandTechnology,Xi。an710055，China)．ChinaEnvironmentalScience，2015，35(9)：2690~2697Abstract：Oxygentransferprocessfromtheairbubblestothewaterwasmainlyanalyzedintheaerationchamberofahypolimneticaerator,parameterscharacterizingtheefectivenessofoxygentransferwereproperlydetermined，adynamicalmodelofoxygentransferforhypolinmeticaermionwasdevelopedbasedonthedouble-layertheory．Theefectivenessofoxygenmionwaswellpredictedusingthedevelopeddynamicalmodelofoxygentransferforhypolimneticaeration．Basedonthepredictedresultsusingthedynamicalmodelofoxygentransfer,whentheairflowrateincreasedorthebubblediameterdecreased，theoxygentransfercoeficientandtheoxygentransferrateincreased．Whentheairflowrateandbubblediameterincreased，theaerationeficiencydecreased．Underfixedconfigurationconditionsofahypolimneticaerator,decreasingthebubblediameterandincreasingthewaterdepthabovetheairdifusorswouldbehelpfultoimprovetheefectivenessofoxygenationintheaerationchamberofahypolimneticaerator,especiallywhenthebubblediameterwasofmicrometerleve1．Whentheairflowrateincreasedtoacriticalvalueof0．06m／s，theefectivenessofoxygenationintheaerationchamberwouldbecomeweaker．Judgedfromtheinfluencingcharacteristiccurvesofairflowrateontheoxygentransferrate，aerationeficiencyandoxygeninputoftheaerationchamberperunittime，theoptimizedoperationalconditi