Arabian Journal of Chemistry - 18 (2) - Coal Dust Particle Size and Explosion Flame Characteristics in Hartmann Tube

Aug 26, 2026

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Coal dust explosions in coal mines cause severe casualties and major property losses, making prevention and control a high-priority safety challenge. This study examines how coal dust particle size influences explosion flame structure and propagation in a Hartmann tube using theoretical analysis and experiments. High-speed and schlieren cameras capture flame evolution temporally and spatially from tube position and outlet perspectives. Results show particle size strongly modulates flame morphology, combustion regions, turbulence-driven vacancies, wall adhesion, and changes to the preheating zone thickness, informing explosion mitigation strategies.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages9

Reading Time23 min

AccessFree to download

Introduction

Related influencing factors on coal dust explosions

Methods and experimental approach

Theoretical analysis and camera-based observation

Results and discussion

Flame morphology and propagation characteristics

Combustion regions, turbulence, wall adhesion, and preheating zone

[https://arabjchem.org](https://arabjchem.org) Arabian Journal of Chemistry 2025 18 (2) 902024 Original Article Study on the influence of coal dust particle size on the structure and propagation characteristics of explosion flame in Hartmann tube Zemiao Yang, Ke Gao*, Yujiao Liu Department of College of Safety Science and Engineering, Liaoning Technical University, Longwannan 188, Huludao, 125105, China | A R T I C L E I N F O
Keywords:
Coal dust explosion
Coal dust particle size Flame dynamics Propagation mechanism | A B S T R A C T
Coal dust explosions in coal mines can result in numerous casualties and substantial property damage. This study investigates the flame propagation characteristics of coal dust explosions in a Hartmann tube through theoretical analysis and experimentation. The flame propagation characteristics during coal dust explosions with varying particle sizes were investigated using high-speed cameras and schlieren cameras to simultaneously capture the temporal and spatial development of flames from two perspectives: tube position and outlet. The results indicate that particle size significantly affects flame propagation. Flames produced from burning small particles of coal dust are densely packed and compact, while flames from larger particles exhibit more irregular shapes, suggesting that a more intense reaction leads to brighter light radiation on the flame surface. These morphological variations correspond to distinct combustion regions and mechanisms. In addition, during the formation of coal dust clouds, turbulence-induced phenomena create vacancies within the flames as they propagate. This results in coal dust adhering to and agglomerating on the tube wall, leading to an absence of flames near both sides of the wall. Furthermore, increasing coal dust particle size contributes to a thicker preheating zone for flames. Specifically, for particles smaller than 53 μm, this thickness measures approximately 5 mm. Clustered flames with irregular fronts characterize the combustion behavior within micron-sized coal dust particles. A comprehensive understanding of these variations in particle size, along with the spatial evolution characteristics of flames, is essential for developing effective prevention and control measures against coal dust explosions from a theoretical perspective. | | | --- | --- | --- | | 1. Introduction
Coal dust is a major contributor to explosion accidents, and 80% of gas explosion accidents have coal dust involved. In recent years, coal dust and gas accidents have become one of the key issues that the country attaches great importance to. Once an explosion occurs, it often causes significant casualties and property damage [1-3]. Coal dust explosions make the safety situation of coal mines still deplorable [4]. Therefore, macro- and micro-level experimental studies on the factors influencing coal dust explosions are of great practical significance for realizing explosion prevention measures and energy control.
To effectively prevent coal dust explosion accidents, numerous scholars from both domestic and international backgrounds have conducted in-depth research on the influencing factors of coal dust explosions. These factors include coal dust concentration [5,6], volatile content [7], particle size of the coal dust [8,9], minimum ignition energy [10], explosion limit [11], and maximum explosion pressure. Wang et al. [12] found that an increase in ignition delay time leads to an initial increase and subsequent decrease in the rate of pressure rise and the maximum explosion pressure value. Azam S and Mishra D P [13] have shown that the decrease in coal dust particle size and the increase of rock dust particle size lead to an increase in the proportion of rock powder during the inerting of coal dust explosion. Li et al. | | [14-16] revealed the influence of ignition delay time and particle size of coal dust cloud explosion on flame height in the Hartmann

FAQs

What variable is the study focusing on regarding coal dust explosions?

The study focuses on coal dust particle size and how it affects the structure and propagation characteristics of explosion flames in a Hartmann tube.

How were flame behaviors observed in the experiments?

Flame evolution was captured using high-speed cameras and schlieren cameras simultaneously, viewing temporal and spatial development from tube position and outlet perspectives.

What do the results indicate about smaller versus larger coal dust particles?

Smaller particles produce densely packed, compact flames, while larger particles form more irregular flame shapes with differences linked to more intense reaction and distinct combustion regions.

How does particle size influence the preheating zone before flame propagation?

Increasing particle size thickens the preheating zone; for particles smaller than 53 μm, the preheating zone thickness is about 5 mm.

Aug 26, 2026

Upload by Skyler