地埋管群换热系统传热机制及耦合作用关系

Heat Transfer Mechanism and Coupled Action Relations of Buried Pipe Heat Exchange System

摘要: 地埋管群换热系统的布管设计还没有形成标准化的方法体系，制约着其能效和可靠性。通过现场试验、数值模拟和理论分析等方法，构建精细化的三维有限元数值分析模型，捕捉地埋管群换热系统的温度场演化特征和换热功率变化过程，揭示布管形式和埋管间距对换热系统传热过程的作用机制和耦合关系。结果显示：以地埋管为中心，地埋管群换热系统在横向断面上形成温度极值区，在纵向断面上形成温度极值条带和温度异常区；相较于顺序排列地埋管群，交叉排列地埋管群的温度极值区、极值条带更容易发生连通，温度异常区更发育；随着埋管间距的增加，地埋管群的温度极值区、极值条带更独立，温度异常区更不发育。确定了布管形式和埋管间距对地埋管群换热功率的耦合作用关系：布管形式对不同埋管间距条件下换热功率的差距产生显著的影响；埋管间距会导致不同布管形式条件下换热功率的差异发生明显的变化。研究成果对于地埋管群换热系统设计方法体系的建设具有重要价值。

Abstract: There is no standard method system for pipe arrangement design of ground pipe group heat exchange system (GPG-HES), which has restricted the energy efficiency and reliability of GPG-HES. Elaborative 3-dimensional finite element numerical analysis model of GPG-HES was structed, temperature evolution features and heat exchange power changing process of GPH-HES was captured, and action mechanism and coupled action relations of pipe arrange pattern and pipe spacing to the heat transfer process of GPG-HES was revealed, based on in-site test, numerical simulation and theoretical analysis. Results shown: Temperature extremum regions was formed on transverse section of GPG-HES, temperature extremum strips and temperature abnormal area were formed on longitudinal section of GPG-HES, centered on buried piles; compared with sequenced buried pipe group, temperature extremum regions and strips of interleaved buried pipe group are more likely to connected, and temperature abnormal area are more active; as the pipe spacing increases, temperature extremum regions and strips are more isolated, and temperature abnormal area is less active. Coupled action relations of pipe arrangement pattern and buried pipe spacing to GPG-HES was ascertained: pipe arrangement pattern markedly affects the difference of heat exchange power under different pipe spacing; pipe spacing causes obvious change to difference of heat exchange power under different pipe arrangement pattern. Study fruit is of great value to the design method system of GPG-HES.