CN-121978140-A - Loose coal rock mass multi-field coupling test system and method based on in-situ ‌ CT

CN121978140ACN 121978140 ACN121978140 ACN 121978140ACN-121978140-A

Abstract

The system comprises an in-situ reaction device, a CT device, a gas supply device, a gas analysis device and a data acquisition module, wherein the in-situ reaction device is used for filling the loose coal rock mass, a vacuum heat insulation cavity is arranged on the quartz outer wall of the in-situ reaction device, the in-situ reaction device is rotatably arranged in the CT device, the CT device is used for tomographic scanning of the loose coal rock mass and obtaining a structural image of the loose coal rock mass, and the data acquisition module is used for constructing a multi-field coupling evolution model of the loose coal rock mass based on the temperature of the loose coal rock mass, the gas product concentration of the loose coal rock mass and the three-dimensional microstructure of the loose coal rock mass. In the loose coal rock mass multi-field coupling test system and method based on the in-situ ‌ CT, the temperature isolation inside and outside the in-situ reaction device can be realized, the stable operation of the CT device is ensured, and the radiation can penetrate through the in-situ reaction device.

Inventors

LIANG YUNTAO
MENG CHENG
SUN ZUO
HU PEIYU
SU WEIWEI

Assignees

煤炭科学研究总院有限公司

Dates

Publication Date: 20260505
Application Date: 20260407

Claims (10)

1. A loose coal rock mass multi-field coupling test system based on in-situ ‌ computed tomography ‌ CT, comprising: the device comprises an in-situ reaction device, a CT device, a gas supply device, a gas analysis device and a data acquisition module; the in-situ reaction device is used for filling the loose coal rock mass, and a vacuum heat insulation chamber is arranged on the quartz outer wall of the in-situ reaction device; The in-situ reaction device is rotatably arranged in the CT device, and the CT device is used for performing fault scanning on the loose coal rock mass and obtaining a structural image of the loose coal rock mass; The gas outlet end of the gas supply device is connected with the gas inlet end of the in-situ reaction device, and the gas supply device is used for introducing oxidizing gas with preset temperature into the in-situ reaction device and gradually heating the loose coal rock mass to the target temperature; the gas inlet end of the gas analysis device is connected with the gas outlet end of the in-situ reaction device, and the gas analysis device is used for detecting the gas product concentration of the loose coal rock mass; The data acquisition module is used for acquiring rotation dynamic structure images of the loose coal rock mass in different temperature stages through the CT device, reconstructing the structure images to obtain three-dimensional microstructures of the loose coal rock mass in different temperature stages, and constructing a multi-field coupling evolution model of the loose coal rock mass based on the temperature of the loose coal rock mass, the gas product concentration of the loose coal rock mass and the three-dimensional microstructures of the loose coal rock mass.
2. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 1, wherein the in-situ reaction device comprises: a reaction chamber, a reaction vessel and a top cover; The reaction container is rotatably arranged in the CT device, the reaction container is provided with an air inlet groove, the top cover is covered on a notch of the air inlet groove and enables the air inlet groove to form an air inlet cavity, an air inlet end of the air inlet cavity is connected with an air outlet end of the air supply device, and the outer wall of the reaction container and the top cover are respectively provided with the vacuum heat insulation cavity; The reaction chamber is arranged in the air inlet cavity, the reaction chamber is provided with a reaction cavity, the reaction cavity is used for filling loose coal rock mass, the bottom of the reaction chamber is provided with a flow equalizing plate, the reaction cavity is communicated with the air inlet cavity through the flow equalizing plate, and the air outlet end of the reaction cavity is connected with the air inlet end of the gas analysis device.
3. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 2, wherein the in-situ reaction device further comprises: A heat insulation base and a heat insulation cylinder; wherein the heat insulation base is rotatably arranged in the CT device, and the reaction container is arranged on the heat insulation base; The heat insulation cylinder is sleeved on the outer sides of the reaction container and the top cover.
4. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 2, wherein the in-situ reaction device further comprises: a rotary joint and a conductive slip ring; The rotor of the rotary joint is arranged on the top cover, and is provided with a first air inlet channel, a first air outlet channel and a wire harness channel, the air outlet end of the first air inlet channel is connected with the air inlet end of the air inlet cavity, and the air inlet end of the first air outlet channel is connected with the air outlet end of the reaction cavity; The stator of the rotary joint is rotationally sleeved on the rotor of the rotary joint, the stator of the rotary joint is provided with a second air inlet channel and a second air outlet channel, the air inlet end of the second air inlet channel is connected with the air outlet end of the air supply device, the air outlet end of the second air inlet channel is arranged along the circumferential direction of the stator and is communicated with the air inlet end of the first air inlet channel, the air outlet end of the second air outlet channel is connected with the air inlet end of the gas analysis device, and the air inlet end of the second air outlet channel is arranged along the circumferential direction of the stator and is communicated with the air outlet end of the first air outlet channel; The rotor of the conductive slip ring is connected with the rotor of the rotary joint, the stator of the conductive slip ring is rotatably sleeved on the rotor of the conductive slip ring and is connected with the stator of the rotary joint, one end of the wire harness channel is communicated with the reaction cavity, and the other end of the wire harness channel penetrates to the rotor of the conductive slip ring along the axial direction of the rotor of the rotary joint.
5. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 1, wherein the gas supply device comprises: a gas supply module and a heating module; the gas outlet end of the gas supply module is connected with the gas inlet end of the in-situ reaction device, and the gas supply module is used for introducing oxidizing gas into the in-situ reaction device; the heating module is arranged between the air outlet end of the air supply module and the air inlet end of the in-situ reaction device, and is used for heating the oxidizing gas so as to gradually heat the loose coal rock mass to the target temperature.
6. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 5, wherein the air supply module comprises: the system comprises an air source, a pressure reducing valve, a mass flow controller, a one-way valve, a gas mixing tank and a first pressure sensor; The gas source is connected with the gas inlet end of the pressure reducing valve, the gas outlet end of the pressure reducing valve is connected with the gas inlet end of the mass flow controller, the gas outlet end of the mass flow controller is connected with the gas inlet end of the one-way valve, the gas outlet end of the one-way valve is connected with the gas inlet end of the gas mixing tank, the gas outlet end of the gas mixing tank is connected with the gas inlet end of the in-situ reaction device, the heating module is arranged between the gas outlet end of the gas mixing tank and the gas inlet end of the in-situ reaction device, and the detection end of the first pressure sensor is arranged at the gas outlet end of the gas mixing tank; The signal input end of the data acquisition module is respectively connected with the signal output end of the first pressure sensor and the signal output end of the mass flow controller, and the signal output end of the data acquisition module is respectively connected with the signal input end of the pressure reducing valve and the signal output end of the mass flow controller.
7. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 5, wherein the heating module comprises: a heater and a temperature sensor; The heater is arranged between the air outlet end of the air supply module and the air inlet end of the in-situ reaction device, and the detection end of the temperature sensor is arranged in the in-situ reaction device; the signal input end of the data acquisition module is connected with the signal output end of the temperature sensor, the signal output end of the data acquisition module is connected with the signal input end of the heater, and the data acquisition module is used for controlling the heater according to the temperature detected by the temperature sensor so that the oxidizing gas reaches the preset temperature.
8. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 1, wherein the CT apparatus comprises: the lead room, the rotary carrying platform, the ray source and the detector are protected; the rotary carrying platform is arranged in the protective lead room, the in-situ reaction device is arranged on the rotary carrying platform, and the rotary carrying platform is used for driving the in-situ reaction device to rotate; The radiation source and the detector are oppositely arranged and are respectively positioned at two sides of the in-situ reaction device, the signal output end of the data acquisition module is respectively connected with the signal input end of the radiation source and the signal input end of the rotary carrying platform, the signal input end of the data acquisition module is connected with the signal output end of the detector, and the data acquisition module is used for controlling the rotary carrying platform to rotate at a preset rotating speed and for scanning the loose coal rock mass by using the radiation source and the detector in a fault mode and obtaining rotary dynamic structural images of the loose coal rock mass in different temperature stages.
9. The loose coal rock mass multi-field coupling test system based on in-situ ‌ CT of claim 1, wherein the gas analysis device comprises: A heat tracing pipe, a condensing pipe, a fume hood, a gas chromatograph and a second pressure sensor; The first channel air inlet end of the heat tracing pipe is connected with the air outlet end of the in-situ reaction device, the second channel of the heat tracing pipe is filled with heat tracing fluid, the first channel air inlet end of the condensing pipe is connected with the first channel air outlet end of the heat tracing pipe, the second channel of the condensing pipe is filled with condensing fluid, and the air inlet end of the fume hood is connected with the first channel air outlet end of the heat tracing pipe; the gas chromatograph is connected with the first channel gas outlet end of the condenser pipe, the signal output end of the gas chromatograph is connected with the signal input end of the data acquisition module, and the data acquisition module is used for obtaining the gas product concentration of the loose coal rock mass through the gas chromatograph; The detection end of the second pressure sensor is arranged at the air outlet end of the first channel of the heat tracing pipe, the signal output end of the second pressure sensor is connected with the signal input end of the data acquisition module, and the data acquisition module is used for obtaining the air pressure of the air outlet end of the first channel of the heat tracing pipe through the second pressure sensor.
10. The loose coal rock mass multi-field coupling test method based on in-situ ‌ ‌ CT is characterized by comprising the following steps of: Filling the loose coal rock mass into an in-situ reaction device in a CT device, connecting an air outlet end of an air supply device with an air inlet end of the in-situ reaction device, and connecting an air inlet end of a gas analysis device with an air outlet end of the in-situ reaction device, wherein a vacuum heat insulation chamber is arranged on the quartz outer wall of the in-situ reaction device; Introducing an oxidizing gas with a preset temperature into the in-situ reaction device through the gas supply device, gradually heating the loose coal rock mass to a target temperature, detecting the gas product concentration of the loose coal rock mass through the gas analysis device, and performing fault scanning on the loose coal rock mass through the CT device to obtain a structural image of the loose coal rock mass; Reconstructing the rotating dynamic structure images of the loose coal rock mass at different temperature stages to obtain three-dimensional microstructures of the loose coal rock mass at different temperature stages, and constructing a multi-field coupling evolution model of the loose coal rock mass based on the temperature of the loose coal rock mass, the gas product concentration of the loose coal rock mass and the three-dimensional microstructures of the loose coal rock mass.

Description

Loose coal rock mass multi-field coupling test system and method based on in-situ ‌ CT Technical Field The disclosure relates to the technical field of loose coal rock mass testing, in particular to a loose coal rock mass multi-field coupling testing system and method based on in-situ ‌ CT. Background In the exploitation, storage and transportation process of coal resources, the inside of coal rock is influenced by the coupling action of a temperature field, a seepage field and a concentration field, and the flowing state of gas in the pores of the coal rock becomes a determining element of the natural ignition process of coal by influencing the heat production and heat dissipation rate of locally accumulated coal bodies. Particularly, the factors such as the porosity, permeability, heat conduction capacity and the like of the coal body become key regulation and control parameters in the processes of gas flow, oxygen diffusion and heat transfer in the coal body. Meanwhile, the increase of the ambient temperature not only can change the oxidation reaction rate of the coal body, but also can change the physical and chemical properties of the surface of the coal matrix, and further affects the pore structure and seepage field of the coal body. It is noted that this change is not a unidirectional change, and the change in the structure of the coal during the heating process also contributes to the multiple physical fields and oxidation rates. The heating process of coal inevitably damages a balance system of a seepage field, a temperature field and a concentration field in original coal rock, and induces the coupling evolution of multiple physical fields and a coal body structure. The mutual influence causes the self-heating temperature rising process of the coal body to present high nonlinear characteristics, and the difficulty of disaster mechanism analysis and prevention and control is obviously increased. Therefore, on the basis of the definition of multiple physical fields and structural rules in the heating process of coal and rock, the nonlinear dynamic change of the pore network structure of the coal body and the time-space evolution rule of the coupling physical fields in the heating oxidation process are researched, and the self-heating response of the coal caused by the multiple physical field coupling effect is analyzed, so that the method is a core problem for solving spontaneous combustion fire accidents of the coal in coal exploitation and storage. Currently, most research methods are usually based on static assumptions of the coal matrix to evaluate temperature, gas production changes under the influence of multiple physical field couplings. Because the internal components of CT cannot be exposed to the high-temperature environment exceeding 60 ℃, the current common research method can only carry out structural scanning reconstruction on the coal sample cooled to room temperature after oxidation, and can not realize dynamic scanning of structural change in the coal rock mass evolution process. Disclosure of Invention The present disclosure aims to solve, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the present disclosure to provide a loose coal rock mass multi-field coupling test system and method based on in situ ‌ CT. In order to achieve the aim, the first aspect of the disclosure provides a loose coal and rock mass multi-field coupling test system based on an in-situ ‌ CT, which comprises an in-situ reaction device, a CT device, an air supply device, a gas analysis device and a data acquisition module, wherein the in-situ reaction device is used for filling the loose coal and rock mass, a vacuum heat insulation cavity is arranged on the quartz outer wall of the in-situ reaction device, the in-situ reaction device is rotatably arranged in the CT device, the CT device is used for scanning the loose coal and rock mass in a fault mode and obtaining a structural image of the loose coal and rock mass, the air outlet end of the air supply device is connected with the air inlet end of the in-situ reaction device, the air supply device is used for introducing oxidizing gas with preset temperature into the in-situ reaction device and gradually heating the loose coal and rock mass to a target temperature, the air inlet end of the gas analysis device is connected with the air outlet end of the in-situ reaction device, the gas analysis device is used for detecting gas product concentration of the loose coal and rock mass, the data acquisition module is used for obtaining a rotating rock mass different-temperature phase coal and rock mass rotation phase structural image of the loose coal and rock mass and coal mass multi-field dynamic coal and coal mass multi-field coupling three-dimensional coupling structure based on the three-dimensional coal and coal microstructure coal and coal mass micro-phase coupling image. The in-situ reaction device co