Flame Research Articles

Experimental study on characteristics of flame propagation and pressure development evolution during methane-air explosion in different pipeline structures

A gas explosion experimental system based on a piece of 15 m-long and φ180 semi-closed wide open steel pipe was constructed. An explosion experimental study on straight pipelines and pipeline structures with different angles (45°, 90°, and 135°) was conducted. Research results demonstrated that before the turn, flame propagation speed and flame sustaining time in different pipeline structures were consistent. With the increase of the distance away from the ignition source, the flame propagation velocity increases and the flame sustaining time decreases; at the turning point, the flame velocity suddenly decreases and the flame duration increases obviously. Meanwhile, the peak value of overpressure on the lateral wall of the turning corner is greater than that on the inner wall. Among the three different angles, the peak value of overpressure on the lateral wall of 135° bend is the highest. Different pipeline structures have great influence on gas explosion overpressure and flame propagation speed. These research conclusions provide theoretical references for gas explosion resistance in coal mines.

Effect of ignition distance on deflagration characteristics of non-uniform oil mist in closed cabins

The deflagration of non-uniform oil mist in closed cabins can easily cause damage to ship equipment and casualties. In this work, the influence of ignition distances on the oil mist deflagration hazard is experimentally investigated, focusing on analyzing the oil mist deflagration propagation process, flame propagation speed, deflagration overpressure, and gas temperature, and exploring its influence mechanism. The results show that as the ignition distance decreases, the oil mist deflagration intensifies, flame propagation speed increases, deflagration overpressure improves, and gas temperature increases. Oil mist deflagration is divided into deflagration stage, turbulent combustion stage, and self-extinguishing stage. In deflagration stage, the center of the flame volume grows, and then gradually shrinks, moving in the direction of the nozzle. Flame propagation speed increases firstly and then decrease, accompanied by oscillatory changes in the process. The deflagration peak overpressure gradually decreases from the nozzle position to the right side of the cabin. With a nozzle diameter of 0.1 mm, the peak oil mist deflagration overpressure is around 0.25 MPa when the ignition distance is 10 cm away from the nozzle. However, when the ignition distance is 30 cm away from the nozzle, the oil mist deflagration peak overpressure is around 0.21 MPa. The high-temperature range of oil mist deflagration is mainly concentrated in the deflagration center area.

On the stabilization mechanisms of a diffusion edge flame in a cross-flow configuration

This work focuses on the stabilization and combustion efficiency of a gaseous diffusion flame at the lip of a hole where pure methane is injected into a crossflow of air. This configuration mimics the flame base of many flares, used to burn excess gas in the oil and gas industry. In a flare, the flame base, near the lips of the fuel jet duct, is a critical zone where the flame attaches or not. When the cross flow air speed is too high or the torch lips too cold, the flame cannot attach to the lips so that methane can leak below the lifted flame front near the injector lip and avoid combustion totally. This cannot be accepted for climate change since unburnt fuel like methane has a radiation forcing larger than 20 times the value reached for CO2. Combustion efficiencies close to unity are expected for the flares of the future. Two main parameters control the anchoring of the diffusion flame on a thin lip: the air cross-flow velocity uair and the temperature of the lip or equivalently its cooling, measured here by a thermal resistance Rth. Dimensional analysis is used to construct two reduced parameters controlling stabilization and simulations are performed to populate this diagram. The resulting diagram shows how uair and Rth control flame anchoring. Large values of Rth (adiabatic lips) lead to high lips temperatures and to flames which can resist high air cross-flow velocities. For low values of Rth (cold lips), the flame lifts off for smaller values of uair. The simulations also reveal that triple flames are the flame elements controlling the flame anchoring and how these triple flames interact with the lips forming a flame topology called RS (Rim Stabilized) edge flame.

Оценка опасности теплового излучения водородного пламени

Today, due to the rapid development of the hydrogen power industry, fire safety of hydrogen-containing facilities becomes a matter of great importance. Risk assessment for the hydrogen power facilities is one of the key objectives of the development. To find the solution, the information on the intensity of hydrogen flare radiation must be obtained. At the same time, such information published in literary sources is often incomplete and sometimes even contradictory. Therefore, the study aims to review the literary sources published in Russian and international journals. The basic value required to assess fire hazard is the intensity of the surface radiation of hydrogen flame. The study considered four types of the flame; i.e., the gaseous jet flame, the jet flame of liquid hydrogen, the flame in the liquid hydrogen pool, and the fireball. Remarkably, the intensity of the surface thermal radiation of hydrogen flame is significantly lower when compared with the hydrocarbon flame. For fire hazard calculations, the intensity of the surface thermal radiation of jet flame of gaseous hydrogen can be adopted as equal to 33 kW/m2. The surface thermal radiation intensity value for the hydrogen fireball can be adopted as equal to 330 kW/m2. The intensity of the surface thermal radiation at liquid hydrogen combustion (for both jet flame and pool fire) can be adopted as equal to 80 kW/m2.

Experimental study on gas and coal dust explosive overpressure and flame dynamic characteristics in an engineering-level test roadway

The continuous development of coal science and technology has made gas and coal dust explosion disasters an important factor that restricts efficient and intelligent coal mining, which seriously threatens the safe production process of coal mines. To explore the gas and coal dust explosive overpressure and flame propagation characteristics in an actual roadway, the dynamic characteristics of gas and coal dust mixed explosion propagation and evolution laws of explosion flames were investigated using an integrated explosion test system and a high-speed image acquisition system in an engineering-level test roadway with a length of about 700 m and a cross-sectional area of 7.2 m2. Experimental results showed that the peak overpressure measured at each measuring point during the propagation process of explosion shock wave in the roadway did not rise or fall monotonously but fluctuated. The power of explosion shock wave was significantly strengthened by adding coal dust, while the flame propagation speed sharply increased in a certain zone, which generally showed a first increasing and then declining trend. In addition, the flame was blue white after the gas in the roadway was ignited, developed in an irregular shape, and ignited the surrounding combustible gas soon, which further ignited the coal dust under the combined action of pressure wave and flame front. In this case, the flame was deep yellow on the whole. The gas and coal dust explosion flame propagated along the longitudinal section above the roadway, and the flame propagated at an accelerated speed on the transverse section due to the disturbance of obstacles. The study results will provide an important theoretical basis for the R&D of technical active explosion suppression equipment in coal mines and the improvement in their installation technologies.

Pengaruh Starter Ragi, EM4 Dan Variasi Rasio C/N Terhadap Hasil Biogas Kulit Kakao

Cocoa is an essential ingredient for making chocolate. Still, the only part of the cocoa used to produce chocolate is the cocoa beans, while around 90% of the total weight of the cocoa is immediately discarded in the form of cocoa shells. This causes cocoa shells to become plentiful, whereas many are processed into animal feed and compost. In compost processing, a decomposition process occurs, which potentially produces biogas. Biogas production from cocoa shells can use fermentation tools such as digesters. This research method is carried out through several stages. First, cocoa shells are collected from cocoa production originating from the Lima Puluh Kota district of West Sumatra. Then, the cocoa shells are prepared and processed into raw materials for biogas production. The fermentation process is carried out using yeast starter and EM4 for 21 days of observation, which is a mixture of microorganisms. The research variation consisted of adding 150 g of yeast and increasing the volume of EM4 in each digester except the control digester. The addition of EM4 for the C/N ratio test digesters 25, 27, 29 is 0.124, 0.099, 0.083 liters. The total gas production obtained from each digester is 9.054 liters (DU29), 2.590 liters (DU27), 2.562 liters (DU25), and 1.307 liters (DK). Meanwhile, the levels of methane gas produced in each test sample are 8.77% (DK), 10.47% (DU25), 18.02% (DU27), and 21.43% (DU29). The color of the gas flame produced by the DU29 and DU27 is blue, the DU25 is red, and the DK is reddish yellow.

Identification and Quantification of Lithium Ion Battery Electrolyte Residues in Blackmass Via Headspace-GC-MS/FID

Due to the increasing demand for lithium-ion batteries (LIBs) in recent years, the demand for resources has also risen. As a result, the amount of LIBs that have reached the end of their life is increasing, leading to stricter guidelines that require certain proportions of recycled materials in the production of new LIBs. Typical recycling strategies start by deactivating, dismantling and shredding LIBs, thereby generating blackmass consisting of active and inactive materials (e.g. Li, Mn, Ni, Co, Cu and organic carbonates). However, black mass is a non-standardized resource, and its composition and purity vary depending on the respective process. 1,2 Therefore, it is essential to characterize and quantify its composition in order to make use of this highly variable resource stream while maintaining quality and safety.This work aims to identify and quantify organic electrolyte residues in black mass without further sample preparation. To achieve this, the samples were agitated using a headspace sampler and then analyzed by gas chromatography-mass spectrometry (GC-MS) and flame ionization detector (FID). Linear and cyclic carbonates such as dimethyl carbonate, ethyl methyl carbonate, and ethylene carbonate, as well as aging products such as 2,5-dioxahexanedioic acid dimethyl ester (DMDOHC), were detected. The identification results were compared to those achieved by thermodesorption and solid-phase microextraction.Overall, this study demonstrates a method for identifying and quantifying organic electrolyte residues in black mass, which can aid in the development of more efficient and sustainable recycling processes for LIBs.References(1) Peschel, C.; van Wickeren, S.; Preibisch, Y.; Naber, V.; Werner, D.; Frankenstein, L.; Horsthemke, F.; Peuker, U.; Winter, M.; Nowak, S. Comprehensive Characterization of Shredded Lithium-Ion Battery Recycling Material. Chemistry (Weinheim an der Bergstrasse, Germany) 2022, 28, e202200485.(2) Neumann, J.; Petranikova, M.; Meeus, M.; Gamarra, J. D.; Younesi, R.; Winter, M.; Nowak, S. Recycling of Lithium‐Ion Batteries—Current State of the Art, Circular Economy, and Next Generation Recycling. Advanced Energy Materials 2022, 761, 2102917.

Optimization and validation for identification of volatile organic com-pounds released from Trogoderma variabile Ballion using headspace solid-phase microextraction and GC-FID/MS

Volatile organic compounds (VOC) emitted by Trogoderma variabile at different life stages (larvae, female and male) can help us to understand the chemical signals that are released by the beetle which can serve as biomarkers for diagnostic purpose. There are several factors that effect on the optimization of VOC extraction including, temperature, jar size, number of insects, duration of extraction, and gas chromatography (GC) conditions. This study used headspace solid phase microextraction (HS-SPME) fibre coupled with flame ionization detection (FID) and gas chromatography with mass spectrometry (GC-MS) to determine the optimal method for accurate, rapid and cost-effective extraction and identification of VOC from different life stages of T. variabile. The HS-SPME technique and the analytical conditions with GC and GCMS were optimized and validated for the determination of VOCs released from T. variabile. Selection of the number of insects was based on the height and the number of peaks. Results showed that 15 and 20 larvae and adults respectively gave the best number of peaks. Sixteen hours were optimized as the best extraction time for larvae and adults to get maximum number of emitted VOCs. The number of compound released from T.variabile different stages was 7, 9 and 11 for male, female and larvae respectively. Furthermore, some compounds were identified in all stages such as oxime-, methoxy-phenyl, 2(3H)-furanone, 5-ethyldihydro- and nonanal. Also, most of the compounds were significantly different in peak area between different life stages.

Perancangan Alat Sensor Pendeteksi Kebocoran Gas LPG dan Api dengan Menggunakan MQ-2 Dan Flame Sensor

LPG gas leaks can become a serious threat to human safety and health, especially if they are not detected quickly and accurately in the main control system for this LPG gas leak detection system and even if the worst possibilities occur, such as a spark which could result in a light fire. This research uses the Prototype method. Another goal is to minimize the risk of accidents when using LPG gas stoves, and reduce the risk of damage and material losses arising from gas leaks and fires caused by LPG gas stoves. Design and manufacture of hardware and software by developing the MQ-2 sensor detection algorithm which is used to detect gas leaks and Flame sensors for fire detection. Testing is carried out by simulating various test scenarios from the use of gas sensors and fire sensors. The test results show that this system is capable of detecting detected gas and fire. Tests are carried out alternately between gas sensors and fire sensors. The output on the system is in the form of SMS notifications, Bazzer and LED lights. SMS notification using SIM800L. When a fire is detected there will be an SMS notification "API DETECTED!!!", the bazzer will sound and the red LED will light up. When gas is detected there will be an SMS notification "GAS DETECTED!!!!" and the yellow LED will light up, the maximum limit if gas is detected is 10cm and the maximum limit if fire is detected is 30 cm. In conclusion, the tool is made using the Arduino Nano microcontroller, by making a cable design on the PCB board, after which the soldering process or connecting the modules is carried out.

The effect of mixture inhomogeneity and turbulence on the flame front curvature and flame surface density of turbulent planar flames of natural gas

The present study is an extension of our earlier mixing field investigation in partially premixed flames. In the current work, the link between the mixing field and flame structure, and hence flame curvature and surface density are experimentally studied. The flame structure is captured using a high-speed OH-PLIF technique, whereas the crosswise mixing fields were previously presented in our earlier study. A concentric flow slot burner is employed for producing turbulent planar partially premixed natural gas flames at different levels of mixture inhomogeneity. The effects of the level mixture inhomogeneity, the equivalence ratio, the air to fuel stream velocity ratio, and Reynolds number “Re” on the flame characteristics are investigated. The link between the previously reported data on the mixing field and the flame structure are examined. The correlations between the mixing field and the flame structure were clearly observed in the current study. That is, as the mixture becomes highly inhomogeneous, in rich input jet conditions cases, altering Reynolds number and the mixing length led to a pronounced change in both flame structure and flame curvature while altering L/D influences the flame structure. On the other hand, the effects of the mixing length and Reynolds number on the flame structure and curvature in a more homogeneous mixture were not significant. The data showed that the flame surface density was inversely proportional to the level of the mixture inhomogeneity and directly proportional to the Reynolds number. The significant effect of the jet equivalence ratio on the level of mixture inhomogeneity leads to a significant change in the flame structure and flame curvature. In addition, if the mixture inhomogeneity is less pronounced the variation s of the mixing length and Reynolds number lead to minimal effects on the flame structure and flame curvature.

Combustion characteristics of charcoal, semicoke, and pulverized coal in blast furnace and their impacts on reactor performance

Injecting new fuels like charcoal and semicoke into ironmaking blast furnaces (BF) helps reduce pulverized coal and coke consumption, leading to significant environmental and economic benefits. This paper comprehensively assesses the performance of blast furnace with the injection of charcoal, semicoke, or pulverized coal. For this purpose, a recently integrated BF model that simulates the whole BF below the burden surface in terms of the gas-solid-liquid-powder multiphase reacting flows is extended to simulate the application of charcoal and semicoke injection. The combustion characteristics of charcoal, semicoke, and pulverized coal in raceways are first revealed. Then, the effects of the combustion on the in-furnace states and overall BF performances are compared in detail. The results show that the overall BF performance in terms of gas flame temperature, coke rate, and hot metal temperature is susceptible to specific components in the injected fuels, including moisture content and fixed carbon ratio. A lower moisture and a higher fixed carbon ratio result in a higher gas flame temperature and fuel-coal replacement ratio and thus a lower coke rate. Overall, the charcoal and semicoke injection is feasible, however, subject to approximate pre-treatment. This integrated BF model can offer a cost-effective way to explore the injection of new fuels of various types to reduce carbon dioxide emissions.

Thermoacoustic Characterization of a Premixed Multi Jet Burner for Hydrogen and Natural Gas Combustion

Abstract In this study, the acoustics and flame dynamics of a prototype multi jet burner with 19 individual mixing tubes for operation with pure hydrogen and pure natural gas are experimentally investigated. The burner transfer matrix (BTM) of the jet burner is determined from experimental data and acoustic network modeling, showing very good agreement. The burner plate and attached mixing tubes are shown to be well approximated with an acoustic model of a perforated plate with bias flow. Accordingly, the burner is found to feature a high level of acoustic damping. A comparison of the flame dynamics of the two fuels considering mass flow and equivalence ratio variation reveals that the flame transfer functions (FTFs) are dominated by a convective mechanism originating from the upstream end of the mixing tubes where the fuel is injected. Consequently, these are most likely fluctuations in the equivalence ratio that feature two characteristic time scales: the convection time in the mixing tubes and along the flame. The overall qualitative shape of the FTFs for hydrogen and natural gas at equal thermal power is found to be similar, with the dynamics of the natural gas flames being more responsive to acoustic excitation, as evident in generally higher gain values. Distinctly less pronounced phase decays are observed for hydrogen compared to natural gas operation. Moreover, the FTFs for H2 are found to change only slightly across the considered range of equivalence ratios. At the same time, we observe only small changes in the corresponding static flame shapes. These observations are consistent with the hypothesis of a dominant convective mechanism. In conclusion, the study provides valuable information on the acoustics and flame dynamics of multi jet burners for flexible fuel operation.

Intrinsic transition mechanism to detonation of gaseous laminar flames in tubes

Intrinsic transition mechanism to detonation of gaseous laminar flames in tubes

Tribotechnical Characteristics of Nickel-Based Composite Coatings Obtained by Hybrid Technologies

As an object of this study, the coatings were used, which are composed of self-fluxing nickel-based alloys or compositions containing them, formed in a hybrid technological process with two main stages: spraying by the plasma method and subsequent remelting – by the gas-flame method or laser heating. An experimental measurement of their resistance to abrasive wear under conditions of boundary friction with the introduction of lubricants has been carried out for the coatings obtained in this process. At the same time, the influence of the coating composition and the remelting method on the wear value measured by the artificial base method has been investigated. To evaluate the dynamics of structure formation in the surface layer subjected to mechanical loads during the friction, X-ray diffraction analysis, metallographic method, and scanning electron microscopy in the electron diffraction mode have been used. After the laser remelting stage, it is possible to obtain coatings with wear resistance that is twice or more superior to the level for sprayed coatings of the same composition processed by the gas flame method. Wear of the coating surface has been found to occur through the mechanism of fatigue failure of the least hard component of the coating, i. e., the nickel-containing intermetallic phase, with the formation of an island-type film of hard crystallites of the carbide-boron phase weakly bound to the coating base, which ultimately leads to cracking of particles of this phase and their crumbling from the surface. The durability of layers obtained after the laser remelting stage can be increased, according to experimental data, by reducing the grain size of the phases in the coating and its texturing, as well as increasing the concentration of alloying elements in the composition of the metal-containing binder phase of the coating. The use of alloying additives leads to an additional increase in wear resistance by 2–4 times. This is due, depending on the type of additives, with an increase in the amount of the hardening phase while maintaining the plasticity of the matrix (coatings with chromium carbide additives), the degree of alloying of the nickel matrix (by the tungsten carbide and boron carbide additives), as well as the presence of a finely dispersed carbide-boride component, which reduces the processes of deformation and scratching.

Role of Oxides of Iron on the Combustion of Composite Solid Propellants: A Review

The effects of iron oxides (α-Fe2O3, γ-Fe2O3, Fe3O4 in the different size ranges from micron to nano) on the combustion of composite solid propellants, also known as hydroxyl terminated polybutadiene/aluminium/ammonium perchlorate (HTPB/Al/AP) systems, are thoroughly reviewed in this work. The effect of the oxides of iron in (i) condensed phase; (ii) sub-surface and surface; (iii) premix flame (gas phase); and (iv) final flame (gas phase) in deflagration zone are also critically reviewed. The effect of catalyst on the lower pressure limit (LPL), upper pressure limit (UPL) and ignition delay is also studied as a part of the combustion phases. It is understood that unlike during the combustion of pure ammonium perchlorate, the role of iron oxides starts its influence on binder system degradation, binder-ammonium perchlorate reactions at surface and HClO4 decomposition in gas phase. The role of aluminium is to contribute for larger energies in both primary and diffusion flame zone, the heat generated accelerates the surface reactions further. Another interesting topic is nano-oxides of iron, since nanosize contribute for definite increase in burn rate, but the disadvantage of agglomerations both at mixing level and combustion level needs to be addressed. Several strategies are suggested, with the most significant ones being co-precipitation with ammonium perchlorate and the utilization of dispersion agents.

The interactive impact of sex and APOE genotype on post‐mortem brain fatty acids profile in Alzheimer’s Disease, Results from the UK BrainBank.

AbstractBackgroundTwo‐thirds of Alzheimer’s Disease (AD) patients are women, with the risk becoming higher if carrying the APOE4 genotype. Omega‐3 fatty acids status is associated with reduced risk of AD. Little is known about the interactive impact of sex and APOE genotype on brain fatty acids status. In this study, fatty acids were measured in post‐mortem brain tissue of AD patients and stratified according to sex and APOE genotype.MethodFatty acids were extracted from the hippocampus and frontal cortex of AD cases (n = 25, 11 are women) and controls (n = 25, 12 are women) using Folch method (from total lipids). Fatty acids were analysed using gas chromatography and flame ionization detection (GC‐FID). Samples were requested and granted from the UK Brain Bank. Adjustment for age and post‐mortem delay was done.ResultArachidonic acid (ARA) and n‐6DPA were higher in APOE4 women with AD compared to control (P‐Disease*sex*APOE = 0.01 and <0.001 respectively).These results were more evident in the hippocampus than the frontal cortex. n‐3DPA/ARA ratio (indicator of inflammatory status) was significantly higher in APOE4 women control compared to AD in both the hippocampus and frontal cortex (P‐disease*sex*APOE = 0.028 and <0.001 respectively). Similar trends were observed for EPA/ARA ratio. There was no impact of sex or APOE on BRAAK stage.ConclusionAPOE4 women with AD show a pro‐inflammatory brain fatty acid profile compared to controls, with increased n‐6 PUFAs (ARA and DPA) and reduced n‐3DPA/ARA ratios. Further extraction and analysis of fatty acids‐derived oxylipins and SPMs will be carried out.

Arduino-Based Safety System for Gas Flame Monitoring, Leakage Detection, and Utensil Presence Using Sensor Integration and SMS Alerts

Abstract: In this research project, we present an innovative Arduino-based safety system designed to enhance household gas safety by monitoring gas flame, detecting gas leakage, and ensuring the presence of utensils in the cooking area. By integrating various sensors such as a flame sensor, gas leakage sensor, and ultrasonic sensor, coupled with servo motor control and GSM technology, our system provides real-time monitoring and proactive response to potential hazards. This project showcases the integration of hardware components and intelligent control algorithms, enabling an efficient and reliable safety system. The use of Arduino as the central control unit provides a flexible and cost-effective solution for gas safety applications. Experimental results demonstrate the effectiveness of our system in detecting potential hazards, triggering appropriate actions, and notifying users via SMS alerts.

Colourless distributed combustion effects on a pre‐mixed coke oven gas flame

AbstractFuels consisting of high hydrogen concentration can be consumed under colourless distributed combustion (CDC) to suppress flashback tendency in premixed conditions. Higher NOX challenges can also be overcome through CDC. For those purposes, coke oven gas was consumed under CDC within the scope of this study. To achieve CDC, or diluents were introduced into the oxidizer so that oxygen concentration in the oxidizer would be decreased from 21% O2 to its lean blow‐off limits. Excess air ratios were determined as λ = 1.2 and λ = 1.5 along with a thermal power of 10 kW under premixed conditions. A commercial computational fluid dynamics code was used to predict temperature distribution and , CO, and emissions. 162‐step reactions created with GRI‐Mech 3.0 chemical kinetics was integrated to the eddy dissipation concept combustion model. The temperature and profiles predicted were compared with the experimental results. Consistency was achieved at ~95% for temperature profiles, and almost 100% for profiles between the measured and the predicted ones. According to the results, it is concluded that a more homogeneous temperature distribution with the ~21% decrease in the maximum temperature was observed, and there was about 96% decrease in level. It was also demonstrated that using as a diluent is more effective in terms of temperature distribution over the combustor and reduction, while dilution with is more effective in terms about 70% in decrease on CO.

A comparative study of combustion models for simulating partially premixed swirling natural gas flames

Combustion models are important for simulating chemical reaction properties and the turbulence-chemistry interaction (TCI) in combustion. However, little attention has been paid to the temperature/species distributions/velocity flow fields predicted by different combustion models and their requirements for mesh resolution. In the present work, a partially premixed swirling natural gas flame was separately simulated by two commonly-used combustion models in Reynolds-Averaged-Numerical-Simulation (RANS) simulations: the flamelet generated manifold (FGM) model and the eddy dissipation concept (EDC) model. It is found that the EDC model requires a higher quality of mesh than the FGM model from the temperature and species distributions perspective. It is possible for the EDC model to overpredict temperature, however, such a problem can be solved by improving the mesh quality. The combustion models do not differ obviously for the mesh refinement for flow fields. The further analysis find that the EDC model brings forward the reaction location (11 mm upstream than the FGM model). The weakened turbulence mixing and early chemical reactions make the EDC model derive discrepancies with measured values, resulting from the variations between its modelling principles and actual applications in the software ANSYS Fluent. The low turbulence viscosity makes the EDC model flame thicker. Overall, the FGM model showed better suitability and accuracy for such a partially-premixed swirling natural gas flame. This work connects the two common combustion models and partially premixed swirling flame characteristics in the RANS simulations, and highlights the effects on the temperature/species concentration/turbulence flow fields, in concerns of mesh resolution and reaction properties rather than sole applications, which can provide foundation for subsequent researchers.

One-pot synthesis of aluminum hypophosphite encapsulation in expanded halloysite lumen for reducing fire hazard and environmental pollution

Halloysite nanotubes (HNTs) have been studied and applied in the field of flame retardant. It is still a challenge to realize a facial method to accommodate more flame retardants while expanding the inner lumen of HNTs simultaneously. In this work, the inner cavity expansion and the encapsulation of aluminum hypophosphite of HNTs is obtained (AHP@HNTs) by a simple one-pot synthesis. The prepared AHP@HNTs were applied to the flame retarded Epoxy resin (EP) and the results show that AHP@HNTs can achieve better flame retardant effect at a lower addition (3 %) than individual additions of AHP or HNTs at higher addition (5 %) manifested by the reduction of the heat and smoke release. The decrease of effective heat combustion (EHC) reveals a gaseous phase flame retardant mechanism. Moreover, the environmental pollution after combustion was evaluated by an innovative method based on the particulate collection from smoke. The reduction of particulate formation and the improvement of char residue confirms the condensed flame retardant mechanism of AHP@HNTs on EP.