为研究水汽循环作用下红层泥岩的强度、变形及损伤的演化规律,对红层泥岩开展了水汽循环试验。通过单轴压缩试验、巴西劈裂试验以及声发射与三维数字图像相关(three-dimensional digital image correlation,简称DIC-3D)技术,研究了不同...为研究水汽循环作用下红层泥岩的强度、变形及损伤的演化规律,对红层泥岩开展了水汽循环试验。通过单轴压缩试验、巴西劈裂试验以及声发射与三维数字图像相关(three-dimensional digital image correlation,简称DIC-3D)技术,研究了不同水汽循环次数下红层泥岩强度、变形及损伤特性的演化规律。研究结果表明:随着水汽循环次数的增加,泥岩含水率和体积将产生不可逆累积,泥岩的水汽平衡时间延长;水汽循环作用将导致泥岩抗压强度、抗拉强度、弹性模量和剪切模量的衰减,由此提出了红层泥岩的指数型劣化模型;在经历不同水汽循环次数后的单轴加载过程中,泥岩的破裂形态随循环次数的增加由整体剪切破坏逐步发展为局部弥散裂纹发展破坏的模式,演化规律的特征表现为裂隙闭合点推迟、起裂应力和损伤应力点提前、岩石的压密过程延长、线弹性变形阶段缩短以及岩石抵抗变形的能力降低。展开更多
Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). ...Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). The pressure fluctuations of the reversible pump turbine at three different water heads(with non-dimensional values being 0.48, 0.71 and 0.90) are measured and compared based on the pressure data recorded in the whole flow passage of the turbine. Furthermore, effects of monitoring points and load variations on the impeller-induced unstable behavior(e.g. blade passing frequency and its harmonics) are quantitatively discussed. Our findings reveal that water head variations play a significant role on the pressure fluctuations and their propagation mechanisms inside the reversible pump turbine.展开更多
文摘为研究水汽循环作用下红层泥岩的强度、变形及损伤的演化规律,对红层泥岩开展了水汽循环试验。通过单轴压缩试验、巴西劈裂试验以及声发射与三维数字图像相关(three-dimensional digital image correlation,简称DIC-3D)技术,研究了不同水汽循环次数下红层泥岩强度、变形及损伤特性的演化规律。研究结果表明:随着水汽循环次数的增加,泥岩含水率和体积将产生不可逆累积,泥岩的水汽平衡时间延长;水汽循环作用将导致泥岩抗压强度、抗拉强度、弹性模量和剪切模量的衰减,由此提出了红层泥岩的指数型劣化模型;在经历不同水汽循环次数后的单轴加载过程中,泥岩的破裂形态随循环次数的增加由整体剪切破坏逐步发展为局部弥散裂纹发展破坏的模式,演化规律的特征表现为裂隙闭合点推迟、起裂应力和损伤应力点提前、岩石的压密过程延长、线弹性变形阶段缩短以及岩石抵抗变形的能力降低。
基金supported by the National Natural Science Foundation of China(Grant No.51506051)the Fundamental Research Funds for the Central Universities(Grant No.JB2015RCY04)+2 种基金the Open Research Fund Program of Key Laboratory of Fluid and Power Machinery(Xihua University)Ministry of Education(Grant No.szjj-2017-100-1-001)the Open Research Fund Program of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(Grant No.LAPS16014)
文摘Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). The pressure fluctuations of the reversible pump turbine at three different water heads(with non-dimensional values being 0.48, 0.71 and 0.90) are measured and compared based on the pressure data recorded in the whole flow passage of the turbine. Furthermore, effects of monitoring points and load variations on the impeller-induced unstable behavior(e.g. blade passing frequency and its harmonics) are quantitatively discussed. Our findings reveal that water head variations play a significant role on the pressure fluctuations and their propagation mechanisms inside the reversible pump turbine.
