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Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures

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A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Environmental and Green Processes".

Deadline for manuscript submissions: closed (5 August 2022) | Viewed by 16419

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Special Issue Editor

Dr. Maria Mitu

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Guest Editor

Institute of Physical Chemistry, Romanian Academy, 202 Spl. Independentei, 060021 Bucharest, Romania
Interests: combustion of liquid and gaseous fuels; explosion risk; explosion protection; safety; explosion parameters; flame propagation; chemical kinetics; ignition
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

You are invited to contribute to a Special Issue of Processes on “Experimental and Numerical Study of Flame propagation of Biofuels/Oxidizers/Inert Mixtures”. Biofuels have recently attracted more attention for applications in energy generation and transportation. The flame propagation of fuels/oxidizers/inert mixtures is studied in order to estimate their normal burning velocity, which is considered to be a fundamental property of a fuels/oxidizers/inert mixtures, depending on the fuel type, oxidizer type, equivalence ratio, pressure, temperature and mass fraction of any gases, with a significant impact on many aspects of combustion. The normal burning velocities are used also for predicting the emissions and performance of internal and external combustion systems. In basic research, the laminar burning velocity is a key parameter for validating models of combustion wave propagation, which take into account a detailed chemical kinetics.

This Special Issue aims to present high-quality research studies addressing challenges in the broad area of flame propagation of biofuels/oxidizers/inert mixtures. Recent research involving experimental and numerical studies of burning velocities of biofuels/oxidizers/inert mixtures are highly encouraged but are not limited to this.

Dr. Maria Mitu
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

biofuels
bioalcohols
biogas
syngas
biodiesel
biogasoline
explosion
deflagration
burning velocity
inert additive

Published Papers (7 papers)

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Research

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12 pages, 1958 KiB

Open AccessArticle

Study of Gases and Thermal Behavior of Oxidized Coal during Spontaneous Combustion Process

by Yan Tang, Wei-Chun Chen, Hai-Lin Zhou, Jing-Yu Zhao, Chi-Min Shu and An-Chi Huang

Processes 2022, 10(9), 1849; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10091849 - 14 Sep 2022

Cited by 3 | Viewed by 1340

Abstract

Coal spontaneous combustion is one of the most severe and constant hazards in the coal industry. Understanding the mechanisms is the basis for effective hazard control in the coal-producing process. This paper investigated two types of oxidized coal samples from the re-mining faces of an underground coal mine. Proximate analysis, elemental analysis, surface analysis, temperature-programmed experiments, and differential scanning calorimetry analysis were conducted to study the spontaneous combustion characteristics. Various reaction mechanism functions were adopted to calculate the kinetic parameters, and multiple linear regression was performed to simulate the reaction behavior. The results show that the thermal decomposition of the oxidized coal followed a two-stage reaction model. The first stage reaction occupied smaller apparent activation energy and promoted the second stage reaction, dominating the heat production. Therefore, significant prevention measures for coal spontaneous combustion should be conducted and emphasized appropriately in the first stage to break the continuous reaction. The findings of this study can serve as a reference for predicting and preventing spontaneous combustion of oxidated coal. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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13 pages, 6438 KiB

Open AccessArticle

Influence of Water Mist Temperature Approach on Fire Extinguishing Effect of Different Pool Fires

by Tao Liu, Xiao-Yu Yin, Ye-Cheng Liu, Yan Tang, An-Chi Huang, Xi-Lin Dong and Yuan-Jun Liu

Processes 2022, 10(8), 1549; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10081549 - 07 Aug 2022

Cited by 7 | Viewed by 1641

Abstract

The aim of this paper was to study the suppression influence of water mist on oil pool fires, taking diesel fires and n-heptane fires as experimental objects. The effects of spray pressure and temperature on water mist suppression were examined, and an experimental platform for the suppression of water mist in a small space was set up. Their fire prevention performance and fire extinguishing mechanisms were analyzed by comparing the flame temperature and extinguishing time of diesel and n-heptane pool fire. Three types of spray pressure were set. Water mist was designed at different temperatures and design experiments were carried out for this purpose. The change process of smoke concentration, thermocouple temperature, and flame combustion under different working conditions were analyzed, and the factors affecting the fire extinguishing effect of water mist on oil pool fire were discussed. The results show that 20 °C water mist is more effective at medium and high pressure than at low pressure. Moreover, 80 °C water mist at 9 MPa is more effective in extinguishing n-heptane fire. The flame extinction time is about 10 s, which is more than 40 s higher than that of cold water. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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12 pages, 5236 KiB

Open AccessArticle

Feasibility Study of Fine Water Mist Applied to Cold Storage Fire Protection

by Xiao-Yu Yin, Tao Liu, Ye-Cheng Liu, Yan Tang, An-Chi Huang, Xi-Lin Dong and Yuan-Jun Liu

Processes 2022, 10(8), 1533; https://0-doi-org.brum.beds.ac.uk/10.3390/pr10081533 - 05 Aug 2022

Cited by 6 | Viewed by 1495

Abstract

The self-built fine water mist fire extinguishing platform studied the fire extinguishing effect of ultra-fine water mist in cold storage fires. The combustible material selected for our experiments is the cold storage insulation material—polystyrene insulation foam board. The combustion characteristics of the insulation board were studied by pyrolysis analysis. We analyzed the temperature, smoke, and other characteristics of the fire scene when a fire occurs in the cold storage and then manipulated the water mist to carry out the fire extinguishing experiment. Experiments aim to change the particle size and pressure of water mist and study the fire extinguishing efficiency of water mist under different conditions. A thorough analysis was used to determine the particle size range of fine water mist most suited for extinguishing fires in cold storage to offer a theoretical foundation for fire protection design. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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19 pages, 2318 KiB

Open AccessArticle

The Effect of Variable Air–Fuel Ratio on Thermal NOx Emissions and Numerical Flow Stability in Rotary Kilns Using Non-Premixed Combustion

by Mohamed el Abbassi, Domenico Lahaye and Cornelis Vuik

Processes 2021, 9(10), 1723; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9101723 - 26 Sep 2021

Cited by 3 | Viewed by 3031

Abstract

One of the quickest ways to influence both the wall temperature and thermal NOx emissions in rotary kilns is to change the air–fuel ratio (AFR). The normalized counterpart of the AFR, the equivalence ratio, is usually associated with premixed flames and studies of its influence on diffusion flames are inconsistent, depending on the application. In this paper, the influence of the AFR is investigated numerically for rotary kilns by conducting steady-state simulations. We first conduct three-dimensional simulations where we encounter statistically unstable flow at high inflow conditions, which may be caused by vortex stretching. As vortex stretching vanishes in two-dimensional flow, the 2D simulations no longer encounter convergence problems. The impact of this simplification is shown to be acceptable for the thermal behaviour. It is shown that both the wall temperature and thermal NOx emissions peak at the fuel-rich and fuel-lean side of the stoichiometric AFR, respectively. If the AFR continues to increase, the wall temperature decreases significantly and thermal NOx emissions drop dramatically. The NOx validation, however, shows different results and indicates that the simulation model is simplified too much, as the measured NOx formation peaks at significantly fuel-lean conditions. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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16 pages, 3304 KiB

Open AccessArticle

Combustion Instability of Swirl Premixed Flame with Dielectric Barrier Discharge Plasma

by Kai Deng, Shenglang Zhao, Chenyang Xue, Jinlin Hu, Yi Zhong and Yingjie Zhong

Processes 2021, 9(8), 1405; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9081405 - 14 Aug 2021

Cited by 6 | Viewed by 1644

Abstract

The effects of plasma on the combustion instability of a methane swirling premixed flame under acoustic excitation were investigated. The flame image of OH planar laser-induced fluorescence and the fluctuation of flame transfer function showed the mechanism of plasma in combustion instability. The results show that when the acoustic frequency is less than 100 Hz, the gain in flame transfer function gradually increases with the frequency; when the acoustic frequency is 100~220 Hz, the flame transfer function shows a trend of first decreasing and then increasing with acoustic frequency. When the acoustic frequency is greater than 220 Hz, the flame transfer function gradually decreases with acoustic frequency. When the voltage exceeds the critical discharge value of 5.3 kV, the premixed gas is ionized and the heat release rate increases significantly, thereby reducing the gain in flame transfer function and enhancing flame stability. Plasma causes changes in the internal recirculation zone, compression, and curling degree of the flame, and thereby accelerates the rate of chemical reaction and leads to an increase in flame heat release rate. Eventually, the concentration of OH radicals changes, and the heat release rate changes accordingly, which ultimately changes the combustion instability of the swirling flame. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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15 pages, 2524 KiB

Open AccessFeature PaperArticle

Experimental and Numerical Study of Ignition and Flame Propagation for Methane–Air Mixtures in Small Vessels

by Maria Prodan, Emilian Ghicioi, Robert Laszlo, Irina Nalboc, Sonia Suvar and Aurelian Nicola

Processes 2021, 9(6), 998; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9060998 - 04 Jun 2021

Cited by 5 | Viewed by 2054

Abstract

Methane is one of the most common gaseous fuels that also exist in nature as the main part of the natural gas, the flammable part of biogas or as part of the reaction products from biomass pyrolysis. In this respect, the biogas and biomass installations are always subjected to explosion hazards due to methane. Simple methods for evaluating the explosion hazards are of great importance, at least in the preliminary stage. The paper describes such a method based on an elementary analysis of the cubic law of pressure rise during the early stages of flame propagation in a symmetrical cylindrical vessel of small volume (0.17 L). The pressure–time curves for lean, stoichiometric and rich methane–air mixtures were recorded and analyzed. From the early stages of pressure–time history, when the pressure increase is equal to or less than the initial pressure, normal burning velocities were evaluated and discussed. Qualitative experiments were performed in the presence of a radioactive source of ⁶⁰Co in order to highlight its influence over the explosivity parameters, such as minimum ignition energy, maximum rate of pressure rise, maximum explosion pressure and normal burning velocity. The results are in agreement with the literature data. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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Review

Jump to: Research

32 pages, 3904 KiB

Open AccessFeature PaperReview

Laminar Burning Velocity of Biogas-Containing Mixtures. A Literature Review

by Venera Giurcan, Codina Movileanu, Adina Magdalena Musuc and Maria Mitu

Processes 2021, 9(6), 996; https://0-doi-org.brum.beds.ac.uk/10.3390/pr9060996 - 04 Jun 2021

Cited by 9 | Viewed by 3066

Abstract

Currently, the use of fossil fuels is very high and existing nature reserves are rapidly depleted. Therefore, researchers are turning their attention to find renewable fuels that have a low impact on the environment, to replace these fossil fuels. Biogas is a low-cost alternative, sustainable, renewable fuel existing worldwide. It can be produced by decomposition of vegetation or waste products of human and animal biological activity. This process is performed by microorganisms (such as methanogens and sulfate-reducing bacteria) by anaerobic digestion. Biogas can serve as a basis for heat and electricity production used for domestic heating and cooking. It can be also used to feed internal combustion engines, gas turbines, fuel cells, or cogeneration systems. In this paper, a comprehensive literature study regarding the laminar burning velocity of biogas-containing mixtures is presented. This study aims to characterize the use of biogas as IC (internal combustion) engine fuel, and to develop efficient safety recommendations and to predict and reduce the risk of fires and accidental explosions caused by biogas. Full article

(This article belongs to the Special Issue Experimental and Numerical Study of Flame Propagation of Biofuels/Oxidizers/Inert Mixtures)

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