Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process

The heterogeneous spatial distribution of bulk material stockyards is one of the key factors constraining the accurate prediction of spontaneous combustion behavior in storage systems such as grain silos and coal piles. In order to overcome the limitations of the homogeneous parameter assumption in...

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Main Authors: Shuanglin SONG, Yuntao LIANG, Qi LIN, Kun LI, Hongyang YANG, Cheng WANG
Format: Article
Language:zho
Published: Editorial Department of Coal Science and Technology 2025-07-01
Series:Meitan kexue jishu
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Online Access:http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-0709
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author Shuanglin SONG
Yuntao LIANG
Qi LIN
Kun LI
Hongyang YANG
Cheng WANG
author_facet Shuanglin SONG
Yuntao LIANG
Qi LIN
Kun LI
Hongyang YANG
Cheng WANG
author_sort Shuanglin SONG
collection DOAJ
description The heterogeneous spatial distribution of bulk material stockyards is one of the key factors constraining the accurate prediction of spontaneous combustion behavior in storage systems such as grain silos and coal piles. In order to overcome the limitations of the homogeneous parameter assumption in existing research on self-heating of bulk materials and to improve the accuracy of spontaneous combustion prediction in bulk storage systems, this paper focuses on the spatial distribution of porosity within the bulk material. By considering the formation process of “falling-collision-accumulation” in bulk materials, a numerical reconstruction approach using the discrete element method to simulate the formation of bulk materials is proposed. Based on this, the paper studies the distribution law of non-uniform porosity within the bulk material under different particle sizes and dumping heights, discusses the influence of equivalent particle size and falling height on the distribution law of non-uniform porosity within the bulk material, quantitatively characterizes the distribution characteristics of porosity within the bulk material, and compares the impact of the homogeneous assumption on the spontaneous combustion law of coal piles. The results show that: ① The overall porosity of the bulk material slightly increases with the increase of dumping height, but the influence of dumping height on the distribution law of porosity within the bulk material is not significant. The average change in porosity when the dumping height increases from 0.55 m to 0.95 m is only 5.1%. ② Influenced by the gravity and compression of particles above, the porosity within the bulk material gradually decreases from high to low along the vertical direction, but the porosity of large particles near the ground will increase, reaching the lowest value at a height of about 3 cm above the ground. ③ The porosity within the bulk material is approximately uniformly distributed along the horizontal direction, with an average value of about 0.45. ④ The homogeneous assumption has no significant effect on the natural ignition period, but after adopting the homogeneous bulk material assumption, the center of the self-heating zone migrates 0.3 m towards the surface of the bulk material, and the length of the self-heating zone is shortened from 10.2 m to 3.1 m, significantly underestimating the risk and concealment of coal self-heating. This study provides a new research idea and direction for the analysis of typical heterogeneous structures in bulk storage systems, and is expected to break through the prediction deviation of coal self-heating caused by the difficulty in characterizing the heterogeneity inside large coal piles at the current stage, greatly improving the prediction accuracy of spontaneous combustion processes in bulk porous systems and making coal self-heating prevention measures more targeted.
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spelling doaj-art-5b869536ee1f44249ec93e82b8d03e9e2025-08-20T02:59:39ZzhoEditorial Department of Coal Science and TechnologyMeitan kexue jishu0253-23362025-07-0153714615510.12438/cst.2024-07092024-0709Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion processShuanglin SONG0Yuntao LIANG1Qi LIN2Kun LI3Hongyang YANG4Cheng WANG5State Key Laboratory of Coal Mine Safety Technology, CCTEG Shenyang Research Institute, Shenfu Demonstration Zone 113122, ChinaChinese Institute of Coal Science, Beijing 100013, ChinaSchool of Energy and Environment, Anhui University of Technology, Ma’anshan 243002, ChinaSchool of Energy and Environment, Anhui University of Technology, Ma’anshan 243002, ChinaSchool of Energy and Environment, Anhui University of Technology, Ma’anshan 243002, ChinaSchool of Energy and Environment, Anhui University of Technology, Ma’anshan 243002, ChinaThe heterogeneous spatial distribution of bulk material stockyards is one of the key factors constraining the accurate prediction of spontaneous combustion behavior in storage systems such as grain silos and coal piles. In order to overcome the limitations of the homogeneous parameter assumption in existing research on self-heating of bulk materials and to improve the accuracy of spontaneous combustion prediction in bulk storage systems, this paper focuses on the spatial distribution of porosity within the bulk material. By considering the formation process of “falling-collision-accumulation” in bulk materials, a numerical reconstruction approach using the discrete element method to simulate the formation of bulk materials is proposed. Based on this, the paper studies the distribution law of non-uniform porosity within the bulk material under different particle sizes and dumping heights, discusses the influence of equivalent particle size and falling height on the distribution law of non-uniform porosity within the bulk material, quantitatively characterizes the distribution characteristics of porosity within the bulk material, and compares the impact of the homogeneous assumption on the spontaneous combustion law of coal piles. The results show that: ① The overall porosity of the bulk material slightly increases with the increase of dumping height, but the influence of dumping height on the distribution law of porosity within the bulk material is not significant. The average change in porosity when the dumping height increases from 0.55 m to 0.95 m is only 5.1%. ② Influenced by the gravity and compression of particles above, the porosity within the bulk material gradually decreases from high to low along the vertical direction, but the porosity of large particles near the ground will increase, reaching the lowest value at a height of about 3 cm above the ground. ③ The porosity within the bulk material is approximately uniformly distributed along the horizontal direction, with an average value of about 0.45. ④ The homogeneous assumption has no significant effect on the natural ignition period, but after adopting the homogeneous bulk material assumption, the center of the self-heating zone migrates 0.3 m towards the surface of the bulk material, and the length of the self-heating zone is shortened from 10.2 m to 3.1 m, significantly underestimating the risk and concealment of coal self-heating. This study provides a new research idea and direction for the analysis of typical heterogeneous structures in bulk storage systems, and is expected to break through the prediction deviation of coal self-heating caused by the difficulty in characterizing the heterogeneity inside large coal piles at the current stage, greatly improving the prediction accuracy of spontaneous combustion processes in bulk porous systems and making coal self-heating prevention measures more targeted.http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-0709stockpile systemdiscrete element simulationheterogeneous characteristicscoal spontaneous combustionvoid fraction
spellingShingle Shuanglin SONG
Yuntao LIANG
Qi LIN
Kun LI
Hongyang YANG
Cheng WANG
Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
Meitan kexue jishu
stockpile system
discrete element simulation
heterogeneous characteristics
coal spontaneous combustion
void fraction
title Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
title_full Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
title_fullStr Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
title_full_unstemmed Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
title_short Heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
title_sort heterogeneous geometric characteristics of coal piles based on numericalreconstruction and its spontaneous combustion process
topic stockpile system
discrete element simulation
heterogeneous characteristics
coal spontaneous combustion
void fraction
url http://www.mtkxjs.com.cn/article/doi/10.12438/cst.2024-0709
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AT yuntaoliang heterogeneousgeometriccharacteristicsofcoalpilesbasedonnumericalreconstructionanditsspontaneouscombustionprocess
AT qilin heterogeneousgeometriccharacteristicsofcoalpilesbasedonnumericalreconstructionanditsspontaneouscombustionprocess
AT kunli heterogeneousgeometriccharacteristicsofcoalpilesbasedonnumericalreconstructionanditsspontaneouscombustionprocess
AT hongyangyang heterogeneousgeometriccharacteristicsofcoalpilesbasedonnumericalreconstructionanditsspontaneouscombustionprocess
AT chengwang heterogeneousgeometriccharacteristicsofcoalpilesbasedonnumericalreconstructionanditsspontaneouscombustionprocess