碳化硅增强相变充填体热力学性能研究  

Thermodynamic properties of silicon carbide-enhanced phase change backfills

作　　者：乔兰[1,2] 尹雅 李庆文[1,2] 苗淼 QIAO Lan;YIN Ya;LI Qing-wen;MIAO Miao(Beijing Key Laboratory of Urban Underground Space Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学城市地下空间工程北京市重点实验室,北京100083 [2]北京科技大学土木与资源工程学院,北京100083

出　　处：《岩土力学》2024年第12期3624-3634,3644,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.52274107,No.52374113,No.52204091);中央高校优秀青年团队培育项目(No.FRF-EYIT-23-01);北京市科技新星计划资助(No.20230484242)。

摘　　要：矿山蓄热储能功能性充填实现了深地矿床-地热协同共采,研发具有适宜相变参数和物化性能优良的功能充填材料迫在眉睫。针对相变材料微胶囊(microencapsulated phase change materials,Micro PCM)导致充填体抗压强度、导热系数下降的现状,开展预试验探究相变充填体的强度特征和热学性能,基于获取的较佳MicroPCM添加量,进一步探究不同碳化硅(SiC)添加量(质量百分率为0%、2%、4%、6%、8%)对相变充填体抗压强度、导热系数、比热容的影响,并测试了其密度、泌水率与流动度,同时结合扫描电子显微镜-能量分散谱仪(scanning electron microscope-energy dispersive spectrometer,SEM-EDS)观测其微观形貌,开展能谱扫描分析解释宏观试验现象,探究其在高低温交变循环下的蓄热储能稳定性。得到了以下结论:MicroPCM添加量为5%时,相变充填体的比热容达到最大,为1.75 MJ/(m^(3)·K);充填体的密度在SiC添加量为2%时达到最大,为1.67 g/cm^(3);充填体的流动性和泌水性随SiC添加量的增加逐渐增强;充填体的抗压强度和导热系数随SiC添加量的增加不断增长,添加量达到4%时,其增幅分别为10.1%和21.7%,达到6.64 MPa和1.12 W/(m·K),随后增长趋势逐渐减缓;相变充填体的比热容随SiC添加量的增加呈现先增长后衰减趋势,但是波动幅度较小,在4%添加量时,比热容达到最大值,为2.32 MJ/(m^(3)·K),因此推荐SiC添加量为4%;500次高低温交变循环后,相变充填体的抗压强度得到增强,且SiC添加量越高增长幅度越大,而导热系数与比热容均有所降低,下降幅度逐渐减小。研究为实际工程中蓄热储能充填提供了数据参考。Functional filling of mine thermal storage has achieved the synergy of deep underground ore deposits and geothermal energy extraction.It is urgent to develop functional filling materials with suitable phase change parameters and excellent physicochemical properties.Aiming at the current situation that microencapsulated phase change materials(MicroPCM)lead to the decrease of compressive strength and thermal conductivity of the backfill,this study carries out pre-experiments to investigate the strength characteristics and thermal properties of the phase change backfill.After determining an optimal MicroPCM additive amount,the study further investigated the effects of various silicon carbide(SiC)additions(ranging from 0%to 8%by mass)on the compressive strength,thermal conductivity,and specific heat capacity of the phase change backfill.The density,water secretion rate,and fluidity of the backfill were also tested.At the same time,scanning electron microscope-energy dispersive spectrometer(SEM-EDS)was used to observe its micro-morphology,and energy spectrum analysis was carried out to explain the macro-experimental phenomena,to explore its thermal energy storage stability under alternating high and low temperature cycles.The following conclusions were obtained that the specific heat capacity of the phase change backfill reached a maximum of 1.75 MJ/(m^(3)·K)at 5%MicroPCM addition.The maximum density of the backfill,1.67 g/cm^(3),occurred at 2%SiC addition.As SiC content increases,both fluidity and water secretion of the backfill gradually rised.The compressive strength and thermal conductivity of the backfill increased continuously with the increase of SiC addition,and the increase was 10.1%and 21.7%,respectively,to 6.64 MPa and 1.12 W/(m·K)at 4%addition,and then the growth trend decelerated.The specific heat capacity of the phase change backfill exhibited a trend of initial growth followed by decay with increasing SiC addition.The fluctuation amplitude remained small.The maximum specific heat capacity of 2.32 MJ/(

关 键 词：矿-热共采 相变充填体 蓄热储能 碳化硅 高低温交变循环 

分 类 号：TB34[一般工业技术—材料科学与工程]