Effect of Sepiolite-Loaded Fe2O3 on Flame Retardancy of Waterborne Polyurethane

In this study, a kind of inorganic composite flame retardant (Sep@Fe2O3) was prepared by combining solution deposition and calcination methods using sepiolite microfiber material as carrier. This inorganic compound flame retardant was combined with waterborne polyurethane (WPU) through layer-by-layer method to prepare WPU composites. The SEM and EDS, TEM, and XRD were used to characterize the microscopic morphology and crystal structure of WPU composites. Thermogravimetric analysis tests confirmed the good thermal stability of WPU/Sep@Fe2O3 composites; at the temperature of 600°C, the carbon residual percentage of WPU/Sep, WPU/Fe2O3, and WPU/Sep@Fe2O3 composites is 7.3%, 12.2%, and 13.4%, respectively, higher than that of WPU (1.4%). Vertical combustion tests proved better flame-retardant property of WPU/Sep@Fe2O3 composite-coated cotton than noncoated cotton. The microcalorimeter test proved that the PHRR of WPU/Sep@Fe2O3 composites decreased by 61% compared with that of WPU. In addition, after combining with Sep@Fe2O3, the breaking strength of WPU increased by 35%.

Examination of Spreading-Induced Changes in Fire Properties in Upper Layer of Compartment

In this study, a large compartment was used and opening shapes were changed to set fire-source conditions and then combustion tests were conducted to quantitatively measure temperature and heat flux near a façade wall. In addition, q was inferred from the relationship between z and q for the top of the opening under different fire-source conditions and for various opening shapes so that q could be used as a reference index.

Characterization of Strength and Quality of Cemented Mine Backfill Made up of Lead-Zinc Processing Tailings

Predicting the reactions of the backfill materials exposed to the effects of air and groundwater will eventually ensure an efficient and accurate mine fill system for sustainable mining operations. This paper reveals the effect of the mobility of sulfur ions within lead-zinc processing tailings on strength and quality of cemented mine backfills. Some laboratory tests such as X-ray diffraction, ion chromatography, scanning electron microscopy, combustion tests, chemical analysis, pH and zeta potential measurements were performed to better characterize the backfill’s mechanical and microstructural properties. Moreover, CEM II/A-P Portland pozzolan and CEM IV/A pozzolanic cements as ready-to-use cement products were used for cemented mine backfill preparation. To ensure the carrier of the lead-zinc tailings and to prevent the mobility of the sulfurous components, a binder content ranging from 3 to 7 wt% were employed in mine backfills. The experimental findings demonstrate that the used cement type and proportions were insufficient and some fractures are occurred in the samples due to the sulfur ion mobility. Accordingly, one can state clearly that the elemental analysis through the combustion test method can provide fast and reliable results in the determination of sulfur within lead-zinc processing tailings.

Passive Control of Low-Frequency Instability in Hybrid Rocket Combustion

The occurrence of low-frequency instability (LFI) appears to be related to multiple interactions among many complex physical processes, such as vortex shedding, boundary-layer oscillation, and additional combustion in the post-combustion chamber. In this study, two combustion tests were conducted to suppress LFI and to examine which physical processes its occurrence was most sensitive. In the first test, two fuel inserts were used to modify the formation of a boundary layer, vortex shedding at the end of the fuel, and vortex impingement. In the second test, the fuel insert located at the front end was replaced with swirl injection. The first test was aimed at controlling and suppressing the initiation of LFI using fuel inserts, through which a small step appeared gradually due to differences in the regression rates of the two materials, i.e., polymethyl methacrylate and high-density polyethylene. The test results confirmed that (i) there are physical connections among several processes, such as the thermoacoustic coupling between p′and q′ and the oscillations of the upstream boundary flow, and (ii) LFI suppression is possible by disrupting or eliminating the connections among these physical processes. The second test was also aimed to control LFI while minimizing the deviation in combustion performance using proper swirl injection along with a fuel insert. Even when replaced by swirl injection, LFI suppression was still possible and showed reasonable combustion performance without causing too much deviation from the baseline in terms of the oxygen-to-fuel ratio and the fuel regression rate.

ECO-DESIGN: IMPACTS OF BLEACHING CHEMICALS AND VARNISHES ON THE AMOUNT OF CARBON DIOXIDE IN THE COMBUSTION OF ORIENTAL BEECH (FAGUS ORIENTALIS LIPSKY)

This study was carried out to determine the effects of bleaching chemicals and varnishes on the amount of carbon dioxide (CO2) in the combustion of oriental beech (Fagus orientalis Lipsky). For this purpose, samples of Oriental beech prepared according to ASTM D 358 contain 18% R1 = (NaOH + H2O2), R2 = (NaOH + Ca(OH)2 + H2O2), R3 = (Na2S2O5 + H2C2O4), R4 = (NaSiO3 + H2O2), R5 = (KMnO4 + Na2S2O5 + H2O2) solution groups, after bleaching with solution groups, water based, synthetic, polyurethane and acrylic varnish were applied according to ASTM D 3023 and combustion tests were carried out in accordance with ASTM E 160-50. Gas measurements were made with the SIGMA 74172 NSU flue gas device during the combustion process. As a result, in respect to the burning types; the highest amount of CO2 (ppm) was found in the self-combustion (8.468 ppm) while the lowest was obtained from the flame combustion source (4.599 ppm). In respect to the types of bleaching; the highest in R5 (7.458 ppm) and the lowest in R3 (4.059 ppm) were found. According to the varnish types; the highest value was found in the synthetic varnish (8.261), and the lowest value was found in the acrylic varnish (4.772 ppm). According to combustion type + bleaching solution + varnish type interaction, the highest values were found for without flame combustion (II) + R3 + Sn (18.40 ppm) and lowest for flame source combustion (I) + R5 + Pu (0.600 ppm). Consequently, the highest values for combustion gases were found in samples of oriental beech wood samples treated with water-based varnish with R1 solution. According to this, in terms of human health and life safety, possibility of fire in places, R3 solution and acrylic varnish may be used in the related industries.

Local anomaly detection in hybrid rocket combustion tests

Local anomaly detection was applied to image data of hybrid rocket combustion tests for a better understanding of the complex flow phenomena. Novel techniques such as hybrid rockets that allow for cost reductions of space transport vehicles are of high importance in space flight. However, the combustion process in hybrid rocket engines is still a matter of ongoing research and not fully understood yet. Since 2013, combustion tests with different paraffin-based fuels have been performed at the German Aerospace Center (DLR) and the whole process has been recorded with a high-speed video camera. This has led to a huge amount of images for each test that needs to be automatically analyzed. In order to catch specific flow phenomena appearing during the combustion, potential anomalies have been detected by local outlier factor (LOF), an algorithm for local outlier detection. The choice of this particular algorithm is justified by a comparison with other established anomaly detection algorithms. Furthermore, a detailed investigation of different distance measures and an investigation of the hyperparameter choice in the LOF algorithm have been performed. As a result, valuable insights into the main phenomena appearing during the combustion of liquefying hybrid rocket fuels are obtained. In particular, fuel droplets entrained into the oxidizer flow and burning over the flame are clearly identified as outliers with respect to the main combustion process. Graphic abstract

Hydrogen Blending Into Ansaldo Energia AE94.3A Gas Turbine: High Pressure Tests, Field Experience and Modelling Considerations

Fuel flexibility in gas turbine development has become increasingly important and modern engines need to cope with a broad variety of fuels. The target to operate power plants with hydrogen-based fuels and low emissions will be of paramount importance in a future focusing on electric power decarbonization. Ansaldo Energia AE94.3A engine acquired broad experience with operation of various natural gas and hydrogen fuel blends, starting in 2006 in the Brindisi (Italy) power plant. Based on the exhaustive experience acquired in the field, this paper describes the latest advancements characterizing the operation of the AE94.3A burner with high pressure combustion tests adding hydrogen blends ranging from 0 to 40% in volume. The interpretation of the test results is supported by reactive and non-reactive simulations describing the effects of varying fuel reactivity on the flame structure as well as the impact of fuel / air momentum flux ratio on the fuel / air interaction and fuel distribution in the combustion chamber. As expected, increasing amounts of hydrogen in the fuel are also associated with higher amounts of NOx production, however this effect could be countered by optimization of the fuel staging strategy, based on the mentioned CFD considerations and feedback from high pressure tests.

Novel Cast Polyurethanes Obtained by Using Reactive Phosphorus-Containing Polyol: Synthesis, Thermal Analysis and Combustion Behaviors

Phosphorus-containing polyol applications in polyurethane synthesis can prevent volatilization of flame retardants and their migration on the surface of a material. In this work, novel cast polyurethanes were prepared by a one-step method with the use of different amounts of phosphorus-containing polyol, 4,4′–diphenylmethane diisocyanate and 1,4-butanediol. The chemical structure, thermal, physicochemical and mechanical properties and flame resistance of the prepared materials were investigated. The results obtained for cast flame-retarded polyurethanes were compared with cast polyurethane synthesized with commonly known polyether polyol. It has been shown that with an increasing amount of phosphorus content to polyurethane’s chemical structure, an increased flame resistance and char yield were found during combustion tests. Phosphorus polyol worked in both the condensed (reduced heat and mass exchange) and gas phase (inhibition of flame propagation during burning). The obtained materials contained phosphorus polyol, indicating higher thermal stability in an oxidative environment than an inert atmosphere.

Experimental Study on Occurrence Limit Heat Release Rate of Flashover in a Building Fire

In this study, to allow the flashover to occur, combustion tests were conducted by setting the conditions of a fire source using a large-scale compartment and changing the opening condition. As a result, the inside temperature of the compartment was measured under the fire source conditions. Moreover, according to the “Handbook on Design Calculation &#x0004d;ethods of Fire Behavior” by the Architectural Institute of Japan, the validity of the heat release rate required for the flashover to occur was verified through the correlation between <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>Q</mi><mrow><mi>F</mi><mi>O</mi></mrow></msub><mo>/</mo><msub><mi>Q</mi><mrow><mi>v</mi><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>A</mi><mi>T</mi></msub><msup><mrow><mo>(</mo><mi>k</mi><mi>p</mi><mi>c</mi><mo>)</mo></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup><mo>/</mo><msub><mi>c</mi><mrow><mi>P</mi></mrow></msub><mn>0</mn><mo>.</mo><mn>5</mn><mi>A</mi><msup><mi>H</mi><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msup></math>.

Simulation of Indoor Fire Dynamics of Residential Buildings with Full-Scale Fire Test

Along with simulated firefighting training, the development of virtual training systems and associated content has recently drawn attention as an alternative method for advanced firefighting training. In particular, to develop virtual training content, it is important to understand the combustion characteristics of indoor combustible materials and appropriately simulate their behavior. In this study, seven types of building fires were selected. From these types, indoor combustible materials of residential buildings were analyzed, and combustion tests were performed for each of three types of combustible materials. Furthermore, three types of indoor spaces, determined according to the combination of indoor combustible materials they contained, were divided into full-scale compartments, and a full-scale fire test was performed using this setup. Finally, the heat release rate and smoke production release of individual combustible materials and the room test were measured over time, and a fire dynamics simulation (FDS) was performed. As a result, it was confirmed that an effective evaluation of the occurrence and spread of fire indoors in buildings is possible through full-scale fire tests and FDS simulations. It is expected that simulation can be used as firefighting training content in the future by applying indoor combustible data and implementing complex and various fire development conditions.