循环高温作用下花岗岩裂缝渗流–传热特性试验研究  

Experimental study on seepage and heat transfer characteristics of single fracture granite under high-temperature cycle conditions

作　　者：黄长松 梁卫国[1,2] 陈跃都 廖涛 HUANG Changsong;LIANG Weiguo;CHEN Yuedu;LIAO Tao(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of Insitu Property-improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]太原理工大学原位改性采矿教育部重点实验室,山西太原030024

出　　处：《岩石力学与工程学报》2023年第9期2253-2265,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家杰出青年科学基金资助项目(51225404);山西省基础研究计划面上项目(202203021211166);山西省回国留学人员科研资助项目(2022–057)。

摘　　要：在利用注水热交换方式进行高温岩体地热开发过程中,热交换对流通道周围高温岩体会反复经历降升温循环作用,循环温度作用下高温岩体裂缝壁面变形、裂缝导流与岩体传热特性都会受到一定影响。为揭示这一复杂过程中花岗岩裂缝渗流特性及强制对流换热规律,在实验室进行降–升温循环(300℃→250℃→200℃→150℃→300℃)作用下流体渗流换热试验,结果表明:(1)低温水注入会诱发高温花岗岩裂隙面损伤破裂,裂缝面粗糙度系数JRC由初始的14.51变化至作用后的21.03,粗糙裂缝面轮廓最大高差ξ由2.2 mm增至3.21 mm,高温岩体导流裂缝随温度变化而变得更为曲折、粗糙度增大。(2)岩体温度由300℃递减至150℃时,裂缝渗透率呈指数型下降,由初始1.63达西降至0.53达西;而岩体温度由150℃增至300℃后,由于岩石基质热膨胀导致裂缝闭合,渗透率进一步降低;随着降–升温循环次数增加,裂缝渗透率整体呈一定程度波动变化,最终使得渗透率明显降低。(3)岩石初始温度高、提高热交换注入水压力,有利于高温花岗岩裂缝对流换热效果;然而随着降–升温循环次数增加,对流热交换作用效果变弱。研究对高温岩体地热高效开发及对流热交换控制技术具有一定的指导意义与价值。In the process of utilizing water injection heat exchange for the geothermal development of hightemperature rock mass,the surrounding high-temperature rock mass of the convective channel in the heat exchange will experience repeated cycles of cooling and heating.Under the cyclic temperature effect,the deformation of the fracture wall surface,fracture flow,and heat transfer characteristics of the high-temperature rock mass will be affected to a certain extent.To reveal the granite fracture seepage characteristics and forced convection heat transfer law in this complex process,the water seepage and heat transfer experiments were carried out in the laboratory under the cyclic cooling-heating process(300℃→250℃→200℃→150℃→300℃).The results showed that:(1)the injection of low-temperature water could induce damage and fracture of the high-temperature granite fracture surface.The roughness coefficient JRC of the fracture surface changed from the initial 14.51 to 21.03 after the cyclic process,and the maximum height difference ξ of the fracture surface profile increased from 2.2 mm to 3.21 mm.The flow-conducting fracture of the high-temperature rock mass became more tortuous and the roughness increased with the temperature change.(2)When the rock temperature decreased from 300℃to 150℃,the fracture permeability decreased exponentially from the initial 1.63 Darcy to 0.53 Darcy.However,when the rock temperature increased from 150℃to 300℃,the fracture closed due to the thermal expansion of the rock matrix,and the permeability further decreased.With the increase of the cooling-heating cycles,the overall fracture permeability fluctuated to a certain extent,eventually leading to a significant decrease in permeability.(3)A higher initial rock temperature and an increase in the injection water pressure for heat exchange were beneficial to the forced convection heat exchange effect of the high-temperature granite fracture.However,with the increase of the cooling-heating cycles,the effect of convection heat

关 键 词：岩石力学 高温岩体 地热开采 高温循环作用 裂缝渗流 传热特性 

分 类 号：TU45[建筑科学—岩土工程]