含瓦斯煤热流固耦合三轴伺服渗流装置的研制及应用

介绍自主研发的含瓦斯煤热流固耦合三轴伺服渗流装置,该装置主要由伺服加载系统、三轴压力室、水域恒温系统、孔压控制系统、数据测量系统以及辅助系统等6个部分组成,其最大轴压为100MPa、最大围压为10MPa、最高加热稳定温度为100℃,试件尺寸为φ50mm×100mm。该装置具有如下特点:(1)所进行的试验能反映地应力、瓦斯压力、温度等对含瓦斯煤渗透率的综合影响;(2)实现伺服液压控制加载功能,能进行多种形式的加载;(3)实现"面充气",更加逼真地反映实际煤层瓦斯源的情况;(4)设计有导向装置,实现加压活塞杆和支撑轴的对位,避免在加压过程中产生晃动,使得试件受压均匀而稳定;(5)数据采集使用更加灵敏、精确度更高的各类传感器;(6)设计有大型水域恒温系统,并安装有水域循环水泵,加热过程更加均匀;(7)具有研究含瓦斯煤渗透性、变形特性等多种功能。采用该装置进行含瓦斯煤在不同围压、不同温度条件下的渗透试验,结果表明含瓦斯煤变形存在4个阶段,其抗压强度随着围压的增加而增大;含瓦斯煤渗流流量在应力–应变过程中存在阶段性变化且随着温度的升高呈现总体减小的趋势。该装置可用于含瓦斯煤热流固耦合渗流领域的研究,为进一步深层次揭示煤层瓦斯运移规律和研究煤层瓦斯抽采技术提供理论基础。

DEVELOPMENT AND APPLICATION OF TRIAXIAL SERVO-CONTROLLED SEEPAGE EQUIPMENT FOR THERMO-FLUID-SOLID COUPLING OF COAL CONTAINING METHANE

A self-developed triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing methane is introduced. It is composed of servo-controlled loading system，triaxial compression chamber，water bath with thermostatic control system，interstitial pressure control system，data measuring system and supporting system. The maximum axial pressure is 100 MPa；and the maximum confining pressure is 10 MPa. The heating temperature can reach as high as 100 ℃；and the dimensions of tested cylinder samples are f50 mm×100 mm. There are some advantages of the seepage equipment：(1) Tests performed on this equipment can show the comprehensive influence of geostress，gas pressure and temperature up on permeability of coal containing methane. (2) Many kinds of load forms can be completed on this servo-controlled system. (3) Plane-charging can be carried out for the coal sample，which reflects the actual gas source situation of coal bed. (4) An orientation system is designed to insure the accuracy of the data achieved in the tests. (5) By using the sensors，the data are more sensitive and accurate. (6) A large-scale water bath with thermostat-controlled system is designed；and a water circulating pump is also installed. (7) It can be used to study permeability and deformation characteristics of coal containing methane. Experiments on coal containing methane with different confining pressures and different temperatures in the seepage equipment demonstrate that the deformation of coal containing methane has four stages；and the compressive strength increases with the increase of confining pressure. Moreover，the seepage discharge is different in each stage and declines with the increasing of temperature in general. The seepage equipment can be used to study certain scientific law of thermo-fluid-solid coupling seepage of coal containing methane，which can provide fundamental basis for studying gas movement in underground coal seam and gas suction technology.