米尺度裂隙岩体模型水流-传热试验的数值模拟分析  

Numerical modeling of water flow and heat transfer in a meter-scale physical model of fractured rocks

作　　者：刘学艳[1] 项彦勇[1] 

机构地区：[1]北京交通大学土木建筑学院,北京100044

出　　处：《岩土力学》2012年第1期287-294,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.50778014)

摘　　要：为了研究高放射性核废物地下处置库近场的水流-传热耦合问题,采用国内高放废物地下处置库预选场址——甘肃北山地区的花岗岩石块体,加工组合成米尺度的规则裂隙岩体模型,设置边界热源和裂隙水流,试验模拟裂隙水水流与传热之间的相互作用。作为该室内模型试验的前期理论研究,采用等效孔隙介质数值模型,着重分析了裂隙开度、裂隙流量和热源功率对流场和温度场的影响。在设定条件下,计算分析表明:热传导和裂隙水水流由热源作用初期的不耦合很快转化为耦合;不流动的裂隙水主要表现为热存储和热传导,而流动的裂隙水还引起流动传热和水与岩石之间的对流换热,使岩体温度场明显不同于单纯热传导的情况;如果保持裂隙水流量不变,则裂隙开度的变化对水流-传热影响不大;如果保持裂隙水流速不变,则裂隙开度的变化对水流-传热影响显著;热源功率越大,通过裂隙水的热流量越大,裂隙水压强越大,而当温度超过100℃时,裂隙水会因汽化而压强显著增大;加热7 d时,热量的输入和输出几乎相等,裂隙水流带走的热量接近热源供给的热量,模型系统基本达到了热平衡。In order to study coupled groundwater flow and heat transfer in the near-field of high-level nuclear waste repositories, a meter-scale physical model with regular fractures has been constructed, using rock blocks taken from the preliminary potential Beishan site in China＇s Gansu province, to conduct experiments of fracture water flow and heat transfer. As a preliminary theoretical study of the physical modeling, this paper presents a numerical modeling analysis of the fractured rock physical model using an equivalent continuum model. Under the prescribed conditions, the calculations reveal： heat conduction and fracture water flow au-n quickly from uncorrelated in the early phase of heating to fully coupled at later times; while the standstill fracture water essentially behaves through heat storage and conduction, the fracture water flow can induce heat convection between water and the rock matrix as well as heat advection; if the fracture water flux is kept constant, then variation of the fracture aperture would exert little influence on the system; if the fracture water velocity is kept constant, then the effect of the variation of the fracture aperture would be significant; higher heat intensity would cause more convection heat transfer from fracture water flow and larger water pressure increase, and the latter effect would be much more significant when the temperature exceeds 100℃; the model system approaches to steady state after about 7 days of heating, with the amount of heat flushed out due to fracture flow equaling the effective heat input.

关 键 词：核废物处置库 裂隙岩体 地下水流动 传热 等效孔隙介质模型 数值模拟 

分 类 号：TU452[建筑科学—岩土工程]