Numerical simulation on response characteristics of coal ignition under the disturbance of fluctuating heat

Shi, Xiaoxuan; Zhang, Yutao; Chen, Xiaokun; Liu, Rui; Guo, Ruizhi; Zhao, Tenglong; Deng, Yin

doi:10.1016/j.combustflame.2021.111870

Cited by 29 publications

(8 citation statements)

References 42 publications

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“…When the time step decreases, more time steps are required to calculate the same time, which means that the actual calculation time increases. To sum up, we choose 2.5 × 10 –4 s as the time step of this paper …”

Section: Simulation Verificationmentioning

confidence: 99%

Effect of Structural Optimization of Scrubbing Cooling Rings on Vertical Falling Film Flow Characteristics

Huang

Wang

et al. 2022

ACS Omega

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In order to study the influence of the structural optimization of the scrubbing cooling ring in the scrubbing cooling chamber on the flow characteristics of the vertical falling film, the flow characteristics of the turbulent falling film in the rising section of the development region at different internal platform heights of the scrubbing cooling ring and a high Reynolds number were studied by FLUENT software. First, the correctness of the model was verified by the maximum error of simulation and experimental results of no more than 9.836%. Then, the distribution of liquid film thickness (δ), velocity ( V ), and turbulence intensity ( I z ) at 0° of the tube in the axial direction x = 0–500 mm were calculated and obtained when the platform height ( H ) was 0–30 mm and the liquid film Reynolds number ( Re l ) = 1.1541 × 10 4 –3.4623 × 10 4 . The results showed that δ in the entrance region increased sharply due to the “jet” effect with solid wall constraints formed by the structure of the water inlet pipe and the scrubbing cooling ring. On the contrary, the liquid film in the fully developed region showed a stable fluctuation trend due to the weakening of the “jet” effect. When H = 30 mm, the change of δ was relatively stable and the change of I z was small, indicating that this platform height is conducive to the stable and uniform distribution of the liquid film. In addition, when Re l < 1.1541 × 10 4 , the liquid film was unstable due to the low flow rate and insufficient cohesion of the liquid film, but V increased slightly. In addition, with the increase of Re l , δ did not change significantly along the axial direction, that is, the Plateau–Rayleigh hindered the growth of δ. Finally, the empirical formula for δ applicable to Re l = 1.1541 × 10 4 –3.4623 × 10 4 at the axial fixed position was fitted for the first time.

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Section: Simulation Verificationmentioning

confidence: 99%

Effect of Structural Optimization of Scrubbing Cooling Rings on Vertical Falling Film Flow Characteristics

Huang

Wang

et al. 2022

ACS Omega

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“…Coal is closely related to economic development and people’s lives and is a primary energy source globally . However, coal mines have long been plagued by various disasters, of which, coal mine fires are the most serious. − When a coal mine fire occurs, it not only causes massive casualties and losses but also leaves behind intractable pollution, which continues to affect the coal mining environment. , Among coal mine fires, 90% are caused by the spontaneous combustion of coal …”

Section: Introductionmentioning

confidence: 99%

Characterization and Performance Testing of an Intumescent Nanoinhibitor for Inhibiting Coal Spontaneous Combustion

et al. 2022

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Considering disadvantages such as the low thermal stability and environmental pollution of existing gel inhibitors, a green and stable intumescent nanoinhibitor (INI) was prepared and tested. First, polyacrylamide (PAM), nano-silica, and intumescent flame retardant (IFR) were selected as raw materials. The INI was prepared by nanoparticle modification and cross-linking polymerization. Then, the structure and physical properties of INI were tested by Fourier transform infrared spectroscopy, scanning electron microscopy, and rheological experiments. Meanwhile, the inhibition performance of INI was studied through thermogravimetric analysis-Fourier transfer infrared spectroscopy (TGA-FTIR) analysis. The results suggest that the nanomodification improved the dispersibility of INI particles. The addition of modified nano-silica (MNS) and IFR enhances the strength of the reticular structure, thereby improving the transport convenience and covering ability of the INI gel. At high temperatures, IFR can generate a porous foamed carbon layer that further coats the coal. After INI inhibition treatment, the characteristic temperature and activation energy of coal were significantly improved, and the production of carbon monoxide and carbon dioxide decreased. Hence, irrespective of physical properties, physical inhibition performance, or chemical inhibition performance, INI performed well. Research results can provide valuable references for the preparation and performance study of a coal spontaneous combustion inhibitor.

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“…Coal spontaneous combustion (CSC) affects the safe production and sustainable development of coal mines. CSC, a rather complex physical and chemical process [1][2][3], has not been clearly described at the chemical level; therefore, revealing the mechanism of CSC can provide a theoretical basis for its prevention and control. Coal has a complex molecular structure.…”

Section: Introductionmentioning

confidence: 99%

Study on the Reaction Path of -CH3 and -CHO Functional Groups during Coal Spontaneous Combustion: Quantum Chemistry and Experimental Research

Han

Jiang

et al. 2022

Energies

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Coal spontaneous combustion (CSC) is a disaster that seriously threatens safe production in coal mines. Revealing the mechanism of CSC can provide a theoretical basis for its prevention and control. Compared with experimental research is limited by the complexity of coal molecular structure, the quantum chemical calculation method can simplify the complex molecular structure and realize the exploration of the mechanism of CSC from the micro level. In this study, toluene and phenylacetaldehyde were used as model compounds, and the quantum chemical calculation method was adopted. The reaction processes of the methyl and aldehyde groups with oxygen were investigated with the aid of the Gaussian 09 software, using the B3LYP functional and the 6-311 + G(d,p) basis set and including the D3 dispersion correction. On this basis, the generation mechanisms of CO and CO2, two important indicator gases in the process of CSC, were explored. The calculation results show that the Gibbs free energy changes and enthalpy changes in the two reaction systems are both of negative values. Accordingly, it is judged that the reactions belong to spontaneous exothermic reactions. In the reaction processes, the activation energy of CO is less than that of CO2, indicating that CO is formed more easily in the above-two reaction processes. In addition, the variations in concentrations of important oxidation products (CO and CO2) and main active functional groups (such as methyl, carboxyl and carbonyl) with temperature were revealed through a low-temperature oxidation experiment. The experimental results verify the accuracy of the above quantum chemical reaction path. Moreover, it is also found that the generation mechanisms of CO and CO2 in coal samples with different metamorphic degrees are different. To be specific, for low-rank coal (HYH), CO and CO2 mainly come from the oxidation of alkyl side chains; for high-rank coal (CQ), CO is produced by the oxidation of alkyl side chains, and CO2 is attributed to the inherent oxygen-containing structure.

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Numerical simulation on response characteristics of coal ignition under the disturbance of fluctuating heat

Cited by 29 publications

References 42 publications

Effect of Structural Optimization of Scrubbing Cooling Rings on Vertical Falling Film Flow Characteristics

Effect of Structural Optimization of Scrubbing Cooling Rings on Vertical Falling Film Flow Characteristics

Characterization and Performance Testing of an Intumescent Nanoinhibitor for Inhibiting Coal Spontaneous Combustion

Study on the Reaction Path of -CH3 and -CHO Functional Groups during Coal Spontaneous Combustion: Quantum Chemistry and Experimental Research

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