【摘要】 由于新研制的3 GPa熔融盐固体介质高温高压三轴实验系统改进了高压容器的装样方式以及样品的尺寸,需要对新装置的压力容器进行温度标定,为此采用多个NiCr-NiSi热电偶,在围压为0.5 GPa时对样品内部和周围的温度分布进行了研究。实验结果表明,样品外侧相对于样品中心上1/3位置热电偶监测到的温度与其它位置监测到的温度之间具有良好的线性关系,它们之间的斜率大小可以直接反映出温度的高低。样品外侧相对于样品中心上1/3位置与下1/3位置监测温度基本相同,也可以作为实验控制温度;样品中心温度比样品外侧相对于样品中心上1/3位置和下1/3位置监测温度低4%;样品底部温度比样品中心温度低5%;样品内部相对于样品中心下1/4位置温度比样品中心低2%。样品的温度从中间向两端对称式递减,在样品尺寸范围内,样品的垂直温度梯度恒定(900℃为16℃/mm)。本设备样品温度分布和温度控制精度与国际同类型实验设备相类似,达到了国际同类设备的水平。更多还原

【Abstract】 A triaxial deformation apparatus with 3 GPa molten salt medium pressure vessel was developed to study the mechanical behavior of the rock under high temperature and ultra-high pressure.It is based on the conventional Griggs design and the molten salt cell concept is after the concept of Green and Borch(1989) and Rybacki et al(1998).The pressure vessel is improved with respect to systems described previously by the use of different salt mixtures with low eutectic temperatures,and by a mechanically stable arrangement of the thermocouples.In this study,we focus on the temperatures distribution around the sample under confined pressure of 500 MPa.The experimental results show that there is a good linear correlation between temperatures monitored by the upper thermocouple(at the upper 1/3 position of the sample center,outside the sample) and others.Based on the linear slopes,we can identify temperature difference in positions of sample.The temperature difference between the upper and the lower thermocouple(at the lower 1/3 positon of the sample center,outside the sample) is so small that both of them can be used as temperature controller for the heating system.The temperature in the center of the sample is by 4% lower than the ones monitored by the upper thermocouple.The temperature in the bottom of the sample is by 5% lower than that in the center of the sample.The temperature in the lower quarter of the sample is by 2% lower than that in the center of the sample.The temperature distribution in the sample show that vertical temperature gradient in the sample is constant(16 ℃/mm at 900 ℃).The temperature controlling resolution and temperature distribution in the pressure vessel are similar to the same type apparatuses in other laboratories of the world.更多还原