CN-116011069-B - Efficient numerical calculation method for heat extraction of buried pipe of filling mining working face

CN116011069BCN 116011069 BCN116011069 BCN 116011069BCN-116011069-B

Abstract

The invention discloses a high-efficiency numerical calculation method for heat extraction of buried pipes of a filling mining working face, which comprises the steps of obtaining thermal physical performance parameters of a top-bottom coal rock mass, determining a calculation area range, establishing a numerical calculation model comprising a filling body, heat exchange pipes arranged in the filling body and surrounding rocks of the top-bottom coal rock mass, dividing grids by the model, setting symmetrical boundary conditions in the established numerical calculation model, setting initial conditions and boundary conditions of the model according to heat extraction conditions, operating the calculation model, determining the number of representative heat exchange pipes in the calculation model according to heat exchange characteristics of buried pipes at different positions, and calculating the heat extraction performance of the buried pipes of the whole filling working face. The method is simple in operation, convenient, quick, accurate and reliable in calculating the heat-taking performance of the whole filling space, evaluates the heat-taking performance of the filling mining working face, improves the calculation efficiency, saves the calculation cost, effectively solves the problem of simulating the calculation speed of underground large-scale filling space buried pipe heat-taking, and provides a reference for efficient calculation of underground space geothermal heat extraction.

Inventors

LI BAIYI
ZHANG JIXIONG
Ding Luwei
LI ZHONGKAI
JIN XUELIANG
SUN ZHIHUI
MA JIAYUAN

Assignees

中国矿业大学
淮北矿业股份有限公司

Dates

Publication Date: 20260505
Application Date: 20221226

Claims (6)

1. A high-efficiency numerical calculation method for heat extraction of buried pipes of a filling mining working face is characterized by comprising the following steps: s1, firstly, acquiring thermal physical performance parameters of a top-bottom coal rock mass according to collected filling coal face engineering geological conditions and rock performance indoor experiments, and determining a calculation area range; S2, establishing a numerical calculation model according to the heat extraction technical characteristics of the buried pipes of the filling working face, wherein the numerical calculation model comprises a filling body, heat exchange pipes and top and bottom plate surrounding rocks, the heat exchange pipes are divided into 1A type pipe at a boundary, 2C type pipes at the middle part of the model and 2C type pipes close to a symmetrical boundary according to positions, and 4 heat exchange pipes are initially arranged at equal intervals; S3, meshing the model, setting symmetrical boundary conditions in the established numerical calculation model, and setting initial conditions and boundary conditions of the model according to the heat-taking working condition, wherein the initial conditions comprise water flow temperature, water flow speed and initial surrounding rock temperature; s4, running a calculation model, simulating and analyzing the outlet water temperature of each heat exchange tube and the distribution condition of the temperature around the tube, and determining the number N of the representative heat exchange tubes in the calculation model by gradually increasing the number of the heat exchange tubes in the filling body in the model until the heat exchange tube heat-taking performance is consistent with that of the previous heat exchange tube; and S5, finally, calculating the heat-taking performance of the buried pipe of the whole filling working face according to the heat-taking characteristics of the representative heat exchange pipes at different positions.
2. The method for efficient numerical calculation of heat extraction from buried pipes at a filling and mining face according to claim 1, wherein in the step S2, the initial equidistant l is set to a range of 1-10 m.
3. The method for efficiently calculating the heat extraction value of the buried pipe of the filling mining working face according to claim 1, wherein in the step S3, the grid around the heat exchange pipe is thinner during the grid division of the model, the grid division at a position far from the heat exchange pipe is relatively thicker, and the calculation efficiency is improved on the premise of not affecting the calculation precision.
4. The method for calculating the heat extraction efficiency of the buried pipe of the filling and mining working face according to claim 1, wherein in the step S4, the representative heat exchange pipe can represent the heat extraction performance of all the heat exchange pipes of the whole filling and mining working face, and the determination criterion of the number N is that the heat extraction performance of 2C-type pipes is consistent.
5. The method for calculating the heat extraction efficiency of the buried pipes of the filling and mining working face according to claim 1, wherein in the step S5, the heat extraction performance of the C-type pipe is used as the heat extraction performance of the heat exchange pipe in the middle of the whole filling and mining working face, and the heat extraction quantity Etot of all the buried pipes of the whole filling and mining working face L is calculated, and the calculation expression is as follows:
6. The method for calculating the heat extraction efficiency of the buried pipe on the filling mining working face according to claim 5, wherein the heat extraction quantity E of each heat exchange pipe is calculated according to the outlet water temperature obtained by simulation.

Description

Efficient numerical calculation method for heat extraction of buried pipe of filling mining working face Technical Field The invention relates to the technical field of mine geothermal development and utilization, in particular to a high-efficiency numerical calculation method for heat extraction of buried pipes of a filling mining working face. Background The energy endowment characteristics of rich coal, lean oil and less gas in China determine the energy status of coal as a main body in China, along with the high-intensity exploitation of coal resources, shallow coal resources mainly in an eastern mine are gradually exhausted, the exploitation depth of the mine is gradually increased, the surrounding rock temperature of a working face is gradually increased and gradually increased under the influence of a ground temperature gradient, and a high-temperature environment facing the exploitation of deep coal resources also becomes a normal state of coal exploitation. Meanwhile, mine exploitation creates a convenient condition for obtaining geothermal resources of underground space, so that geothermal energy is gradually focused and valued in deep coal resource development. The related scholars propose the collaborative development of the deep mine geothermal and the coal resources, namely, the mine geothermal is regarded as the resources which are as important as the coal, and the deep geothermal and the coal resources are explored, planned and developed together, so that the comprehensive development and utilization of the geothermal and the coal resources are realized. Filling buried pipe heat extraction is taken as a typical geothermal and coal resource collaborative development technology, heat in Wen Weiyan can be transferred to a heat exchange pipe through a filling body to be extracted to the ground for use by arranging the heat exchange pipe in a goaf of a coal stope face and then filling the filling body with high heat conduction. The heat extraction effect of the filling buried pipe is a key for determining whether the technology can be widely applied, and the most effective underground space heat transfer calculation method is numerical simulation calculation at present due to the complex heat transfer process of an underground space structure. The heat-collecting performance of the heat-collecting pipes at different positions in the filling body is affected by the position relation, so that the calculation result is inaccurate when the heat-collecting performance of the heat-collecting pipes at different positions in the filling body is simulated to represent the heat-collecting capacity of the whole filling surface of all the heat-collecting pipes, but the grid division and the calculation speed are faced with great challenges when the heat-collecting performance of all the heat-collecting pipes of the whole filling working surface is simulated and analyzed due to the huge scale of underground space, and the calculation is difficult to realize. Therefore, developing a high-efficiency numerical calculation method for heat extraction of buried pipes of a filling and mining working face becomes a great difficulty to be solved urgently, and has important significance for conveniently, rapidly and accurately evaluating heat extraction capacity of buried pipes of underground filling space and guiding collaborative development of hot coal of underground space. Disclosure of Invention Aiming at the technical defects, the invention aims to provide the high-efficiency numerical calculation method for the heat extraction of the buried pipe of the filling and mining working face, which is simple in operation, convenient, quick, accurate and reliable in calculating the heat extraction performance of the whole filling space, evaluating the heat extraction performance of the filling and mining working face, improving the calculation efficiency, saving the calculation cost, effectively solving the problem of the thermal simulation calculation speed of the buried pipe of the underground large-scale filling space and providing reference for the high-efficiency calculation of the underground space geothermal extraction. In order to solve the technical problems, the invention adopts the following technical scheme: The invention provides a high-efficiency numerical calculation method for heat extraction of buried pipes of a filling mining working face, which comprises the following steps: s1, firstly, acquiring thermal physical performance parameters of a top-bottom coal rock mass according to collected filling coal face engineering geological conditions and rock performance indoor experiments, and determining a calculation area range; S2, establishing a numerical calculation model according to the heat extraction technical characteristics of the buried pipes of the filling working face, wherein the numerical calculation model comprises a filling body, heat exchange pipes and top and bottom plate surrounding rocks,