McCray J E
International Ground Water Modeling Center, Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO 80401-1887, USA.
J Hazard Mater. 2000 Feb 25;72(2-3):237-63. doi: 10.1016/s0304-3894(99)00142-9.
A review of published mathematical models used to simulate air sparging is provided. Applicability of the models, efforts to test the models using experimental data and contributions of modeling efforts to the practice of air sparging are also discussed. Compartmentalized lumped-parameter models and multiphase flow models have dominated air-sparging modeling efforts. In essence, each class of models requires the assumption of a continuum over some model domain. Each approach has significant benefits as well as some inherent disadvantages. Based on the literature, both lumped-parameter modeling and multiphase-flow modeling have been successful in improving our theoretical understanding of the air-sparging process and in facilitating practical development of sparging systems. Lumped-parameter models are simpler to use, and can lend considerable insight to sparging operations. Multiphase flow models have the potential to offer a more realistic simulation of the airflow process, but may require a considerable amount of data collection for model input. The literature suggests that for any air-sparging model to be useful for field applications, detailed model calibration is necessary. It is recommended that models incorporate, in some fashion, the diffusion and dispersion of contaminants to macro-scale air channels, and nonequilibrium interphase mass transfer of contaminants. These mass-transfer-limited processes are frequently listed as causes for the "tailing" of vapor-extraction effluent contaminant concentrations that are frequently observed during field applications. However, time-varying mixing of relatively clean and contaminated vapors in the extraction system may also explain this tailing. Geophysical imaging techniques and inverse modeling combined with air-sparging pilot tests and measurement of traditional hydrogeologic parameters may allow for successful modeling efforts.
本文对用于模拟空气注射的已发表数学模型进行了综述。还讨论了这些模型的适用性、利用实验数据对模型进行测试的工作以及建模工作对空气注射实践的贡献。分区集总参数模型和多相流模型主导了空气注射建模工作。从本质上讲，每一类模型都需要在某个模型域上假设一个连续体。每种方法都有显著的优点以及一些固有的缺点。基于文献，集总参数建模和多相流建模在提高我们对空气注射过程的理论理解以及促进注射系统的实际开发方面都取得了成功。集总参数模型使用起来更简单，并且可以为注射操作提供相当多的见解。多相流模型有可能对气流过程提供更真实的模拟，但可能需要大量的数据收集作为模型输入。文献表明，要使任何空气注射模型对现场应用有用，详细的模型校准是必要的。建议模型以某种方式纳入污染物向宏观尺度空气通道的扩散和弥散，以及污染物的非平衡相间传质。这些传质受限过程经常被列为现场应用中经常观察到的蒸汽提取流出物污染物浓度“拖尾”的原因。然而，提取系统中相对清洁和受污染蒸汽的时变混合也可能解释这种拖尾现象。地球物理成像技术和反演建模与空气注射先导试验以及传统水文地质参数的测量相结合，可能会带来成功的建模工作。
