Abstract:

The subsurface flow wetland was simulated by using a commercial computational fluid dynamic code，Fluent（Fluent Inc. ,Version 6. 2. 16）. The media constructed in the wetland was modeled by the porous media and the particle trajectory model was introduced to discuss the effect of two types of catchment area，the layer pattern and protector pattern on the hydraulic performance of the wetland. The simulation results confirmed that dispersion was an important factor for hydraulic efficiency while mean residence time changed little in all reviewed cases. For the type of layer pattern，the smaller the ratio of media resistance of purge and catchment area，the bigger the effect of their changes on hydraulic efficiency. With the increase of catchment height，the dispersion of flow increased and the hydraulic efficiency of the wetland decreased accordingly. For the type of protector pattern，with the decrease of catchment breadth，hydraulic efficiency could be improved and the effect of resistance ratio on hydraulic efficiency could be weakened. The effect of catchment height on the performance of the wetland was slight and with the increase of catchment height，hydraulic efficiency was improved slightly and when the height increased to the top of the wetland，the effect of resistance ratio on hydraulic efficiency decreased further. As compared with the layer pattern catchment area，the wetland with the protector pattern catchment area had high hydraulic efficiency and by decreasing [JP+4]catchment breadth，hydraulic efficiency could be improved and the effect of resistance ratio on hydraulic efficiency could be weakened. Therefore，the protector pattern catchment area was better than the layer pattern.

摘要：

采用计算流体力学（CFD）软件Fluent（Fluent Inc. ，Version 6. 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。