地下水源热泵回灌的生物堵塞机理研究

China is promoting renewable energy application, of which the groundwater-source-heat-pump engineering is developing very fast，while facing the energy shortage and grim situation of increasingly high building energy consumption. Clogging problems in heat pump system make artificial recharge difficult to take. It will bring serious negative effect on groundwater and ecological environment. Based on typical groundwater source heat pump engineering in Wuhan city, we plan to study biological clogging mechanism in heat pump artificial recharge system as the key point of research. Firstly, the mesoscopic biological obstruction experiment, monitoring date from injection/rejection well in heat pump recharge system, are used to establish mechanism model of biological film on recharge well sidewall and sand layer microbial migration clogging model, in which the hydraulic/thermal/chemical effects on the biological processes are fully taken into consideration in coupling manner. And then the coupled hydraulic/thermal field evolution involving biological/physical clogging will be analysed. Finally, fully coupled THBC (thermal-hydro-biological-chemical) model and numerical codes are going to be established. It will provide ability of analysis and simulation on biological clogging and hydraulic/thermal performance. Research achievements are expected to provide strong theoretical guidance and countermeasures technical support to solve the difficult problem of groundwater recharge. Further more, it could contribute to large-scale application of groundwater source heat pump in China, and to ensure long-term healthy and sustainable development of renewable energy.

面对能源短缺和建筑能耗日益高企的严峻形势，我国大力推广可再生能源应用，其中地下水源热泵工程发展非常迅速。热泵系统中各种堵塞问题造成取用水的回灌困难，将对地下水乃至生态环境造成严重负面影响。本项目依托武汉地区典型地下水源热泵工程，以热泵回灌系统中生物堵塞机理为重点开展研究。首先，基于室内细观生物阻塞试验、抽灌井与砂层钻孔现场监测数据，充分考虑热泵回灌系统中渗流/温度/化学因素对生物过程的耦合影响，建立回灌井壁生物成膜机制模型与含水砂层微生物迁移阻塞模型。然后在研究受到生物/物理堵塞影响的渗流/温度场演化规律的基础上，综合形成全耦合THBC（温度-渗流-生物-化学）模型，并发展计算方法与程序，解决热泵工程条件下生物堵塞的机理分析和模拟问题。预期研究成果将为解决地下水回灌困难问题提供有力的理论指导和对策技术支撑，有利于我国地下水源热泵技术的大规模推广应用，促进可再生能源利用的长期健康发展。

面对能源短缺和建筑能耗日益高企的严峻形势，我国大力推广可再生能源应用，其中地下水源热泵工程发展非常迅速。热泵系统中各种堵塞问题造成取用水的回灌困难，将对地下水乃至生态环境造成严重负面影响。本项目依托武汉地区典型地下水源热泵工程，以热泵回灌系统中生物堵塞机理为重点开展研究。首先，通过观测和采样实验，研究了水体/湿地中微生物的群落特征及生物膜的演化规律；同时基于室内砂箱细观颗粒阻塞试验、抽灌井现场监测数据，研究了含水砂层中颗粒的迁移、阻塞、脱离过程，建立颗粒物阻塞模型；考虑热泵回灌系统中渗流/温度/化学因素对生物过程的耦合影响，建立回灌井壁生物成膜机制模型与含水砂层微生物迁移阻塞模型。以浅层地热利用的地源热泵系统为背景，建立含水砂层介质中的THMBC（温度-渗流-变形-生物-化学）全耦合模型，解决热泵工程条件下生物堵塞的机理分析和耦合模拟问题。鉴于观测数据对耦合模型研究的重要性，项目还研发了围岩内部应力和变形观测技术和长期监测一体化系统，为耦合分析提供必要数据支持。研究成果可为解决地下水回灌困难问题提供有力的理论指导和对策技术支撑， 有利于我国地下水源热泵技术的大规模推广应用，促进可再生能源利用的长期健康发展。