隧道衬砌换热器的传热特性及其热交换管与衬砌相互力学作用研究

Buried pipe heat exchanger is a series of heat lines with heat pump installed in tunnel lining in certain depth. The heat exchanger can solve two major obstacles, land occupation and high cost in traditionally vertical and horizontal ground heat exchanger system. With thermal response characteristics of buried pipe heat exchanger as the object and with theory analysis → numerical simulation→ experimental verification → depth analysis as the method, the research was carried out as follows. Heat transfer model and boundary conditions of buried pipe heat exchanger were established with considering ventilation and groundwater seepage. Solving method of the model was determined and was verified or modified by utilizing the heat response test of long cycle. Thermodynamic model and solution method of lining structure with heat exchange pipes were studied on the above basis. Based on numerical simulation and field test, the influence of design parameters, wind speed and groundwater seepage of heat exchange pipe on the long run effect of heat exchanger was studied, and the recovery characteristics of ground temperature under different ratios of heat storage and intermittent operation were also researched. The effect of heat exchange on the lining stress state and the effect of lining structure on heat pipe service were both discussed. The analysis and calculation model of heat transfer and mechanics was finally established to rich the heat transfer theory and calculation model of buried pipe heat exchanger. It has important theory value and practical guiding significance to promote the technology.

隧道衬砌换热器是将地源热泵热交换管路安装于一定埋深下的隧道初衬和防水板之间的新型地埋管换热器，能解除传统垂直和水平地埋管换热器占地和成本高两大主要障碍。以隧道衬砌换热器在通风和地下水共同作用下的热响应为研究对象，运用理论分析、现场试验和数值模拟相结合的研究手段，采取试验→分析→建模→验证的研究思路，开展如下关键内容：①基于"长周期"热响应试验的隧道衬砌换热器传热机理研究；②建立通风和地下水渗流作用下的衬砌换热器的传热模型及求解方法；③分析研究热交换管设计参数、围岩热物理性、风速、地下水流速和水位变化对换热器长期运行效果的影响，以及不均衡冷热负荷和运行间歇下的地温恢复特性；④计算分析衬砌劣化和热交换管冷热循环作用下的衬砌结构力学性态和热交换管的服役性。项目成果可建立更符合实际工况的隧道衬砌换热器的传热和力学模型，丰富地埋管换热器的传热理论，对推广应用该技术具有重要的理论价值和实际指导意义。

隧道衬砌换热器是将地源热泵热交换管路安装于一定埋深下的隧道初衬和防水板之间的新型地埋管换热器，能解除传统垂直和水平地埋管换热器占地和成本高两大主要障碍。本课题综合运用理论分析、数值计算、模型试验和现场试验等研究方法，对隧道衬砌热交换器传热及其热交换管与结构相互作用开展系统研究，取得如下成果如下：.(1) 开展了隧道自然通风条件下的隧道衬砌热响应现场试验、通风和地下渗流共同作用下的隧道衬砌热响应模型试验，系统研究通风和地下水渗流两大典型不确定性因素对隧道衬砌热交换器传热的双重影响，揭示了通风和地下水渗流共同作用下的隧道衬砌热交换器传热机理；.(2) 理论推导气-固界面传热数学模型，建立了隧道衬砌与洞内空气耦合传热模型和隧道围岩温度场-渗流场耦合模型，并提出了其求解方法；.(3)分析研究了通风和地下渗流共同作用下的隧道衬砌热交换器长期运行效果和地温恢复特性； .(4)研究了热交换管对隧道衬砌承载力的影响，运营引起的温度应力对衬砌承载力影响，隧道初衬变形对热交换管的影响，为隧道衬砌热交换器设计提供指导。.课题研究成果成功指导了博牙高速公路地源热泵型隧道防冻加热系统的设计和实施，具有重要的工程指导意义，推广应用前景广阔。