dimentional numerical simulation of spontaneous combustion in goaf of fully mechanized top-coal caving longwall

2016 ◽  
Vol 9 (1) ◽  
pp. 47-54
Author(s):  
Jing Shen ◽  
Mingran Chang

One of the main reasons for coal mine fire is spontaneous combustion of residual coal in gob. As the difference of compaction degree of coal and rock, the underground gob can be considered as a porous medium and divided into “three zones” in accordance with the criteria. The “three zones” are “heat dissipation zone”, “oxidation zone” and “choking zone”, respectively. Temperature programming experiments are taken and numerical simulation with obtained experimental data is utilized to analyze the distribution of “three zones” in this paper. Different width and depth of “oxidation zone” are obtained when the inlet air velocity is changed. As the nitrogen injection has inhibition effect on spontaneous combustion of residual coal in gob, nitrogen is injected into the gob. The widths of “oxidation zone” are compared before and after nitrogen injection. And ultimately the optimum location and volume of nitrogen injection are found out.


2019 ◽  
Vol 98 (2) ◽  
pp. 616-624
Author(s):  
Ruizhi Chu ◽  
Minglei Wang ◽  
Xianliang Meng ◽  
Peng Liu ◽  
Zhenyi Liu ◽  
...  

2018 ◽  
Vol 175 ◽  
pp. 03014
Author(s):  
Xin-jian Li ◽  
Jun Yang ◽  
Bing-qiang Yan ◽  
Xiao Zheng

A mathematical model of electrified insulated cable was established to calculate temperature of insulating layer. The insulating layer temperature is determined as a function of the current intensity, time, insulation layer thickness, etc. A widely used polyvinyl chloride (PVC) cable with sectional area of 4 mm2 was selected as example and its insulating layer temperature was simulated using ANSYS. The simulation revealed the evolution of insulating layer temperature with time, and also along radius after a certain time when the cable was applied with 40A and 60A constant current respectively. The analysis method has practical significance to prevent electrical fire and can be applied to analyze spontaneous combustion accident of insulated cable.


2012 ◽  
Vol 524-527 ◽  
pp. 317-320
Author(s):  
Bo Tan ◽  
Yuan Gang Jiang ◽  
Chao Nan He ◽  
Jing Chang ◽  
Ya Qi Luo

This paper aimed at fire control in thick seam large-scale top-carving region. On the basis of coal and oxygen compounding theory, theoretical analysis, numerical simulation and experiment are combined, and a coal spontaneous combustion process model is built according to fluid mechanics and control theory. By studying and testing on top-carving coal spontaneous combustion process, conclusion is drawn that spontaneous combustion area is the largest in partly-closed region, followed by unclosed region. A totally closed baffle leads to the smallest spontaneous combustion area and the smallest possibility of fire. With local materials in a certain condition, new, cheap backfilling materials are developed. Thus provide theoretical basis for study on the forecasting and prevention of thick seam large-scale top-carving coal spontaneous combustion.


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