Smoke Emission Characteristics Research Articles

Smoke Emission and Distribution Characteristics of Overloaded Wire Insulations under Microgravity

With the development of manned space technology, spacecraft safety and fire prevention have attracted more and more attention. Due to the disappearance of buoyancy in microgravity, the fire early monitoring, detection and alarm technologies designed based on the ground experimental results are not suitable for spacecraft. It is necessary to develop fire early monitoring technology in microgravity. Smoke is an important early monitoring signal for fire prevention both in normal gravity and microgravity. Under microgravity, fire is mostly caused by overload or aging of wire insulations. In order to study the smoke emission characteristics of wire insulations under microgravity, we carried out the overload experiments of wire insulations on board the SJ-10 Chinese recoverable satellite. The smoke generation characteristics captured by laser extinction methods, and a large number of experimental data in the real microgravity environment were obtained for the first time. In this paper, the smoke volume fraction in the early and axisymmetric stages of smoke emission from the wire insulating layer are obtained by using the method of Abel transform and convolution, and the MATLAB algorithm program is compiled. In the later stage of smoke emission, it does not show axisymmetric distribution, but the laser extinction results can be used for obtaining the smoke emission trajectory. According to the results, edge jet smoke emission modes in the early stage of ignition of wire insulation in microgravity are quantitatively analyzed. The effects of insulation thickness, overload current and insulation material on smoke emission are discussed.

Experimental investigation on performance, combustion, and emission characteristics of diesel doped with green synthesized nano cerium oxide

AbstractThis study reports the potential of Cerium oxide (CeO2) nanoparticles synthesized from Jatropha curcus leaves and Insulin plant extracts to use as a doping constituent with diesel fuel. Investigations were carried out to analyze the effect of cerium oxide nanoparticles on engine performance and smoke emission characteristics. X‐ray diffraction study witness the presence of Cerium oxide in the plant extracts and the average crystal size of CeO2 nanoparticles synthesized from J. curcus leaves and insulin plant extracts was 5 and 25 nm, respectively. Experimental runs were carried out on a 4 stroke direct injection VCR diesel engines at two different compression ratios. The result showed that the brake thermal efficiency is increased by a maximum of 5.5% for 25 ppm CeO2 extract blend from insulin plant with diesel fuel. CO and HC emissions of CeO2 doped diesel blends are lowered by up to 38 and 40% at full load conditions in line with neat diesel and also presents significant results in emission characteristics. Finally, it is worth stating that doping of 25 ppm CeO2 nanoparticles from insulin extracts with diesel at compression ratio of 16 can establish better results than diesel.

Study on NOx and smoke emission reduction techniques in biodiesel fuelled research engine

This work presents the practicability of using carbamide as an additive on biodiesel fuel to evaluate the NOX and smoke emission characteristics. Four blends of fuels namely, neat diesel, biodiesel (MME100), a blend of biodiesel – carbamide (10 and 20%) is prepared and tested in a diesel engine. The experimental results were revealed that the adding of carbamide (MME90C10 and MME80C20) to biodiesel has shown a significant reduction of Smoke and NOx emissions.

Functionalized multiwalled carbon nanotubes with monocomponent intumescent flame retardant for reducing the flammability and smoke emission characteristics of epoxy resins

A novel monocomponent intumescent flame retardant named pentaerythritol phosphate melamine salt (PPMS)‐functionalized multiwalled carbon nanotubes (PPMS‐CNT) was synthesized via grafting PPMS on the surface of multiwalled carbon nanotubes, and thoroughly characterized by Fourier transformed infrared (FTIR) spectrometry,1H nuclear magnetic resonance (1H NMR) spectrometry, scanning electron microscope (SEM)‐energy‐dispersive spectroscopy (EDS), and thermogravimetric (TG) analyses. Then, PPMS‐CNT was incorporated into epoxy resins (EPs) to investigate flame‐retardant and smoke suppression properties. The results show that the addition of PPMS‐CNT increases the limited oxygen index (LOI) and UL94 rating of EP composites, and the LOI value of EP‐3 containing 15 wt% PPMS‐CNT is increased to 24.5%. Cone calorimeter test indicates that the heat release and smoke production of EP composites are gradually decreased with increasing PPMS‐CNT content concomitant with the increase in the intumescent factor and residual weight. Thermogravimetric analysis shows that the thermal stability and char‐forming ability of the EP composites are increasingly improved with increasing PPMS‐CNT content. Char residue analysis reveals that the same addition of PPMS‐CNT tends to form a more continuous and compact char than that of PPMS because of more phosphorus‐rich cross‐linking char and aromatic char remained in the condensed phase, thus exhibiting higher flame‐retardant and smoke suppression efficiencies in EP matrix. Overall, PPMS‐CNT can serve as a promising monocomponent intumescent flame retardant for reducing the flammability and smoke emission characteristics of EP materials.

Enhancing the flame-retardant and smoke suppression properties of transparent intumescent fire-retardant coatings by introducing boric acid as synergistic agent

A series of novel phosphorus-boron flame retardants (BPEAs) were successfully synthesized by introducing boric acid (BA) into cyclic phosphate ester acid (PEA) via the esterification and thoroughly characterized by 1H nuclear magnetic resonance spectroscopy and Fourier transform infrared (FTIR) spectroscopy. Five kinds of transparent fire-retardant coatings applied to wood substrates were produced by thoroughly mixing amino resin with PEA and BPEAs. The effects of BA on the optical transparency, thermal stability, fire performance and smoke emission characteristics of the coatings were investigated by various analytical instruments. The transparency analysis reveals that the transparency value of the coatings gradually decreases with increasing BA loading, and MPEA4 with the highest BA content still exhibits a high degree of transparency. The results from fire protection, cone calorimeter and smoke density tests show that the introduction of BA greatly decreases the flame spread rating, mass loss, char index, heat release rate, smoke production rate, total heat release, total smoke release and specific optical density of the coatings concomitant with the increase in the residual mass and intumescent factor, which is ascribed to the formation of a more dense and continuous intumescent char judging by digital photographs and scanning electron microscope images. Thermo-gravimetric analysis indicates that the onset decomposition temperature, high-temperature stability and residual mass of the coatings greatly improve with increasing BA content. FTIR analysis shows that the introduction of BA into the coatings contributes to generate more phosphorus-rich cross-linked structures and aromatic structures and then create a compact and intumescent char layer, thereby effectively enhancing the flame retardancy and smoke suppression properties of the coatings.

Effects of carbon fibers on the flammability and smoke emission characteristics of halogen-free thermoplastic polyurethane/ammonium polyphosphate

In the present study, the effects of carbon fibers (CFs) on flame retardancy, smoke emission, thermal and mechanical properties of thermoplastic polyurethane (TPU)/ammonium polyphosphate (APP) are investigated. The cone calorimeter results show that the combination of 15.00 wt% APP + 5.00 wt% CF greatly lowered peak heat release rate, total heat release, and total smoke release, as well as increased char residue, which is due to a compact char layer formed on the ablating surface of TPU-4 composites, as shown by the SEM results. Smoke suppression properties investigated by smoke density test demonstrate that CF combined with APP greatly reduced the smoke emission. The TPU composite containing 5.00 wt% CF has the highest LOI value of all the intumescing composites studied. Meanwhile, the addition of CF also caused enhanced mechanical properties of TPU composites to a certain degree. Thermogravimetric (TG) analysis indicates that CF combined with APP enhanced the high-temperature thermal stability of TPU composites compared with the pristine TPU, due to the increase of the char residue. Thermogravimetric analysis/infrared spectrometry (TG–IR) results demonstrate that CF could catalyze the further decomposition of TPU composites and remarkably reduce the production of aromatic compounds as a smoke precursor, which are the major parts of smoke.

시뮬레이션 분석을 통한 EPS실 화재위험성 평가에 관한 연구

This study was conducted by utilizing simulation (FDS6) the fire characteristics of the flammable substances such as cable compartment of a small space in the EPS room type. In the partitioned space of a room EPS supply of oxygen does not facilitate the combustion of the upward-sloping curve, as in a standard fire curve is not observed. Simulation results in a situation where ventilation is limited to the heat release rate and smoke emission characteristics of the fire showed a complex and unstable form a repeating rise and fall. Fire time was longer than the fire load. Change in the smoke emission than the heat release rate is slow, but changes of the overall surface was found to exhibit affinity.

Detailed modelling of soot oxidation by O2 and OH in laminar diffusion flames

A detailed knowledge of soot formation and oxidation processes is desired to reduce the soot emissions in combustion devices. Soot oxidation is one of the most complex processes in the numerical modeling of soot. In this work, the oxidation of soot has been numerically studied in laminar ethylene/air coflow diffusion flames. There has been disagreement in the literature over the rates of soot oxidation by O2 molecules and OH radicals. A sensitivity analysis has been performed on the roles of O2 and OH in various parts of the diffusion flame, isolating the effects these species have on soot oxidation. A new oxidation model is developed based on the observation that soot ageing reduces surface reactivity and is primarily based on temperature and residence time. A function for surface reactivity of soot, based on the temperature history a soot particle experiences, has been proposed to model soot oxidation. Using this new model, it is now possible to capture the correct behavior of both smoking and non-smoking flames in various flame configurations. Along with a detailed sectional soot model, the new oxidation model predicts the correct soot volume fractions, smoke emission characteristics, and primary particle diameters for different flames without any variation in model parameters between cases.

A study on performance and smoke emission characteristics by blending low purity methanol in a DI diesel engine with the EGR rates of 0, 12.8 and 16.5%

The purpose of this study is to investigate experimentally the effect of low purity methanol (LPM) on performance and smoke emission characteristics by using a four-cycle, four-cylinder, water-cooled, direct injection diesel engine with EGR system. The experiments are performed by the change of engine load in the engine load ranges of 25 to 100% with an interval of 25% under the constant engine speed of 2000 rpm. The LPM in the fuel blends contained 24.88% water by volume. The blended fuel ratios of diesel oil to LPM are maintained at 100/0, 95/5, 90/10 and 85/15% on the volume basis. In this paper, EGR rates are varied in three conditions of 0, 12.8 and 16.5%. The result shows that the brake power of a blended fuel with 15% LPM is reduced more 11.1% than that of the neat diesel oil at the full load with the EGR rate of 16.5%. At this condition, also, the brake specific fuel consumption (BSFC) is increased by 3.2%, the exhaust gas temperature is decreased by 10.7%, the smoke opacity is decreased by 18.7% and the brake thermal efficiency is increased by 7.3%. The sharp reduction of smoke opacity for a blended fuel with the LPM content of 15% at the full load without EGR system is observed by 68.4% compared with that of the neat diesel oil due to the high oxygen content of LPM.

Improved NOx and Smoke Emission Characteristics of a Biodiesel-Fueled Engine with the Port Fuel Injection of Various Premixed Fuels

This work investigated the regulated emission characteristics of a biodiesel-fueled direct-injection (DI) engine with the addition of n-heptane, dimethoxymethane (DMM), and ethanol from the intake port on a single-cylinder engine. The effects of physical and chemical properties of the premixed fuel, partial equivalence ratio of biodiesel, and premixed ratio on emissions were evaluated. The experimental results revealed that the overall heat release curve exhibited a three-stage combustion with the addition of n-heptane but only one-stage with the addition of other two compounds. A simultaneous reduction of NOx and smoke opacity was obtained with the premixed fuels, and ethanol premixing showed the most significant effects on the reduction of NOx and smoke opacity. For a fixed partial equivalence ratio of each premixed fuel, premixing n-heptane showed a larger NOx increase slope and premixing DMM showed a larger smoke opacity increase slope with the increase of the partial equivalence ratio of biodiesel. HC emission was mainly influenced by the premixed fuel properties but not the equivalence ratio, and ethanol premixing had larger HC levels than n-heptane and DMM premixed fuels. When the overall equivalence ratio was kept constant, both HC and CO emissions increased but NOx emissions decreased at first up to a critical premixed ratio. As the premixed ratio exceeded the critical value, NOx emissions started to increase gradually, CO emissions began to decrease, but HC emissions almost remained constant. Under the above conditions, smoke opacity always improved with the increase of the premixed ratio.

Fire resistance of inorganic sawdust biocomposite

The objective of this study was to manufacture fire-resistant biocomposite sandwich plates using waste sawdust as filler and an inorganic potassium aluminosilicate binder. Using binder contents of 29% and 34%, twelve biocomposite plates were fabricated without using any specialized equipment, heat, or pressure, thus producing an environmentally conscious biocomposite material. Several of the plates were strengthened with carbon and glass fiber reinforcements to create a more durable sandwich structure. The influence of binder content and reinforcement type on the heat release rate and smoke emission characteristics were investigated using the OSU heat calorimeter and the NBS smoke chamber, respectively. All specimens passed the Federal Aviation Administration requirements for heat release and smoke emission, the criteria used for evaluation of the test results in this study. Relative to 15 other wood plastic composites that utilize organic polymers, the inorganic biocomposite showed superior heat release rates during 5 min of fire exposure.

Effects of tin additives on the flammability and smoke emission characteristics of halogen-free ethylene-vinyl acetate copolymer

Zinc hydroxystannate (ZHS) is found to be an effective partial replacement for the conventional hydrated fire-retardant fillers alumina trihydrate (ATH) and magnesium hydroxide (MH) when incorporated into a halogen-free EVA cable compound. In contrast to earlier findings for halogen-containing polymers, ZHS-coated versions of the fillers are somewhat less effective than equivalent composition mixtures of ZHS+filler. Incorporation of ZHS also greatly enhances the performance of an ATH/nano-clay synergistic fire-retardant system in the EVA formulation and allows marked reductions to be made in overall filler level with no or little compromise in terms of flame-retardant and smoke-suppressant properties.

00/02431 Catalytic steam gasification of pine sawdust. Effect of catalyst weight/biomass flow rate and steam/biomass ratios on gas production and composition

The objective of this study was to manufacture fire-resistant biocomposite sandwich plates using waste sawdust as filler and an inorganic potassium aluminosilicate binder. Using binder contents of 29% and 34%, twelve biocomposite plates were fabricated without using any specialized equipment, heat, or pressure, thus producing an environmentally conscious biocomposite material. Several of the plates were strengthened with carbon and glass fiber reinforcements to create a more durable sandwich structure. The influence of binder content and reinforcement type on the heat release rate and smoke emission characteristics were investigated using the OSU heat calorimeter and the NBS smoke chamber, respectively. All specimens passed the Federal Aviation Administration requirements for heat release and smoke emission, the criteria used for evaluation of the test results in this study. Relative to 15 other wood plastic composites that utilize organic polymers, the inorganic biocomposite showed superior heat release rates during 5 min of fire exposure.

Vitreous fillers in intumescent coatings

The introduction of vitreous fillers in some intumescent coatings compositions proved to be useful both in improvement of thermal insulation and durability of char under fire and in smoke emission characteristics. In this paper a comprehensive experimental study is presented showing results for solvent-borne, 2K epoxy and water-borne intumescent paints. Blends of vitreous fillers with different melting temperatures, between 350°C and 850°C, have been tested together with refractory fillers (with melting temperatures between 1100°C and 1350°C). Lead free vitreous fillers with very low melting temperatures (from 350°C to 550°C) and with low water solubility were developed. Different types of paints have been prepared by adding different amounts of vitreous fillers. These compositions were then fire tested after application on steel plates. The effect of vitreous fillers on fire performance and stabilization of char (by means of encapsulation, with or without self-extinguishing additives) has been studied. The fillers’ effect on smoke emission under fire was also examined both in terms of optical density and toxicity index. A special attention was focused on water-borne intumescent paints modified with vitreous fillers of different solubility and melting temperature. Residual solubility of the vitreous fillers, which appeared as a very important parameter for paint stability, has been assessed. Vitreous fillers releasing alkaline ions in such an amount to give a conductivity higher than 500 μS cm, make the intumescent paint composition unstable.

Aspectos do comportamento de polímeros em condições de incêndio

RESUMO: No presente trabalho apresentaremos uma revisão do comportamento dos polímeros quando queimados, procurando enfocar o antagonismo comumente observado entre os aspectos de retardância de chama e emissão de fumaça dos compostos desenvolvidos com vistas à prevenção de incêndio. Apresentaremos também uma breve descrição de alguns testes comumente empregados e uma lista das principais normas internacionais, relevantes para a caracterização dos materiais em relação ao fogo.

Synthesis and characterization of epoxidized phenolic novolacs modified by furfuryl alcohol

AbstractThe possibility of reacting furfuryl alcohol with the p‐position of phenolic rings, under acid conditions, was proved using different experimental techniques: size exclusion chromatography, Fourier transform infrared spectroscopy and 13C NMR. This reaction was then used in the modification of phenolic novolacs with furfuryl alcohol. After reaction with epichlorohydrin, epoxidized phenolic novolacs (EPN) modified with furan rings were obtained. They could be cured with aromatic diamines in a similar way to conventional EPNs. The presence of furan rings should improve burning resistance and smoke emission characteristics of the resulting networks.

Smoke Emission Characteristics of an Air Cell DI Diesel Engine

排気煙低減を目的に、直噴式ディーゼル機関の燃焼室上部に空気室を設けた空気室付き直噴式機関を提案し、その排気・出力・燃費特性を調べた。本機関は、圧縮行程中に空気室に蓄えた空気を、噴射終了後火炎が高温に保たれている期間に燃焼室に噴出して、火炎中に生成されたすすの酸化を促進して排気煙濃度を低減しようとするもので、この意図が空気室機関において広い運動条件の範囲で達せられることを実験的に明らかにした。

Barium Additives As Diesel Smoke Suppressants

The body of information presented in this paper is directed to those individuals concerned with the emission of smoke from diesel engines. A series of tests was performed on a Petter Type AA1 diesel engine using barium smoke suppressant additives. An Andersen cascade type sampler was used to collect samples and thus study the effect of the additive upon the total smoke emission, smoke size distribution and smoke composition. For a portion of the tests radioactive barium (133Ba) and scintillation counting techniques were used. Type 1-D fuel was used for all tests. Baseline tests were performed to determine the smoke emission characteristics using nontreated fuel, 0.5% by volume of Bryton additive, and 0.75% by volume of Lubrizol additive. For the radioactive additive, tests were conducted using dosages of 0.13%, 0.26%, 0.41%, and 0.82% by volume. The results of these tests revealed that the additive does not alter the particle size distribution, but the total mass emission from the engine is reduced by approximately 50% at the dosages tested. The dosage level of the additive does not influence the distribution of barium within the exhaust particles. Also it seems that the soluble percentage (in 0.1 N HCI) is influenced by the dosage level. The results of the solubility tests at low dosage levels seem to imply that the smoke inhibition mechanism occurs within the fuel droplet.