Temperature Of Combustion Products Research Articles

Synergistic effects of a swirl generator and MXene/water nanofluids used in a heat exchanger pipe of a negative CO2 emission gas power plant

The focus on optimizing heat exchangers contributes to improved temperature control mechanisms, ensuring the sustainable operation of innovative power plants working toward negative CO2 emissions. In the realm of oxy-combustion within Negative CO2 Emission Power Plants (nCO2PP), the temperature of combustion products surpasses 3000 ( K ) . Addressing this challenge, the imperative arises to reduce these elevated temperatures to a manageable 1100 ( ° C ) . This critical cooling process is achieved through the injection of water, facilitated by the implementation of heat exchangers. The study delves into the optimization of heat transfer within the heat exchanger pipe, specifically tailored for the context of a nCO2PP. Employing a numerical simulation, the investigation explores the impact of vortex generator geometry, vane angles, single and dual propeller-type swirl generators, and the integration of a novel class of fluid, MXene/water nanofluid. Initially, the study scrutinizes propeller-type geometry at vane angles spanning from 15° to 60°. The enhanced swirl flow associated with lower vane angles leads to improved fluid mixing, fostering more effective heat transfer. Results showed that the 15-degree vane angle, with a wider circumferential coverage, may result in increased wall contact, influencing heat transfer efficiency. Subsequently, at Re = 6000, incremental rates of the Nusselt number ( Nu n − Nu s Nu s %), for θ = 15°, 30°, 45°, and 60° are 175.1, 108.8, 90.7, and 40.3%, respectively. Also, the increment rates of Friction Factor ( f n f s ) for aforementioned vane angle are 38.48, 9.26, 4.08, and 2.42%, respectively. In addition, for ∅ MXene = 0.5 % , the Nusselt number experiences considerable increments of 22.94, 24.17, 24.70, and 24.707% at Reynolds numbers of 6000, 12,000, 18,000, and 24,000, respectively, compared to pure water, emphasizing the potential of MXene to enhance heat transfer efficiency.

Effect of humidification of combustion products in the boiler economizer with spiral geometry

In light of rising fuel prices and climate change in recent decades, improving the performance of heat recovery equipment such as boiler economizers is critical. Currently, numerical work is being done to improve the performance of the economizer with spiral geometry by humidifying combustion products. Simulations are performed using the finite volume method (FVM) and, in three cases, in a two-dimensional, steady, single-phase, and turbulent condition. In the first case, water vapor condensation and liquid water spray are not considered. In the second case, the impact of water vapor condensation is considered, and the effect of liquid water spray is not considered. In the third case, the water vapor condensation and the liquid water spray are simultaneously considered. Experimental correlation relations are used to predict the condensation rate in the second and third cases. The results are presented and discussed in the form of Nusselt number, convection heat transfer coefficient (h), outlet temperature, and heat transfer rate for different inlet temperatures of combustion products. Moreover, velocity, pressure, temperature contours, and velocity vectors are obtained and analyzed. The results showed that the cold-water outlet temperature in the third case was 2.85% higher than in the first case. In addition, a maximum improvement of 1.39% in the third case is obtained compared to the second case. Also, the heat transfer rate in the third case is improved by 8.2% compared to the first case and by 3.9% compared to the second case. The proposed method in the present work can be used to predict the effect of liquid water spray on the performance of boiler economizers.

Методика определения температуры точки росы продуктов сгорания природного газа

Currently, there are various methods to determine the dew point temperature of humid air and combustion products of distinct types of fuels. It is especially important when designing deep flue gas cooling systems in boiler plants that do not consider the composition of a particular type of fuel. In this regard, the urgent issue is the development of a simple method to calculate this value when using natural gas as fuel. The authors have used the methods of thermodynamic analysis of processes in humid air and fuel combustion products, and the results of thermal calculations of fuel combustion processes. The authors have conducted the analysis of existing methods to determine the dew point temperature for natural gas combustion products, since it is necessary to prevent condensation of water vapor in chimneys and chimney flue to ensure their operation conditions, especially during deep cooling. A simple method to calculate this value is proposed, and an example of its use is presented. The authors have analyzed the influence of such factors as the moisture content of air and natural gas, the absolute pressure of combustion products and the air flow coefficient per the dew point temperature. It is shown that the final refinement of the given value can be quite significant, and therefore the use of the method that allows considering these patterns is advisable when designing deep flue gas cooling systems. It is established that the proposed method is quite universal and can be used during combustion of natural gas of various compositions and various values of factors characterizing fuel combustion.

Theoretical analysis on applying steam reforming to the primary combustion of the boron-based fuel-rich propellant

The primary combustion products of boron-based fuel-rich propellant contain a significant amount of condensed boron, which poses challenges for complete burnout of the primary combustion products during the secondary combustion process. To enhance the ignition and combustion characteristics of these primary combustion products, a pioneering theoretical analysis on applying steam reforming to the primary combustion of the boron-based fuel-rich propellant was conducted. The results demonstrate that steam reforming improves the ignition and combustion characteristics of the primary combustion products through three main aspects: optimizing the composition of combustion products, improving energy distribution between the primary combustion and secondary combustion process, and elevating combustion temperature, respectively. It theoretically confirms the feasibility of this innovative combustion organization method for solid rocket scramjet. Furthermore, it has been found that there is an optimal steam-fuel ratio (the value is 1.0 for B35), which facilitates the conversion of combustible components in the primary combustion products from a gas–solid state to a pure gaseous phase. Simultaneously, the temperature of combustion products after steam reforming reaches the highest. Therefore, theoretically speaking, the steam-fuel ratio of solid rocket scramjet with steam reforming should not exceed the optimal steam-fuel ratio to ensure better ignition and combustion characteristics of the combustion products after steam reforming. This analysis provides valuable theoretical support for the design of solid rocket scramjets with steam reforming.

Evaporation rates of water droplets with soluble and insoluble additives

The relevance. Caused by a wide practical use of water with typical soluble and insoluble additives in the following technologies. They are: thermal and fire purification of liquids, polydisperse fire extinguishing, combustion of waste-derived slurry fuels, cleaning of heat-loaded surfaces, creation of heat agents based on combustion products. Any change in liquid component composition leads to a change in its thermophysical properties, heating rates and phase transformations. So far, there is not enough experimental data on evaporation rates of water droplets with typical soluble and insoluble additives. The aim. Experimental determination of evaporation rate of water droplets with typical additives under various heating methods. The methods. To register sizes of moving droplets, optical registration methods based on a high-speed video camera were used. To register the temperature of combustion products, a measuring complex, consisting of an NI 9219 board and four chromel-alumel fast-response thermocouples, was used. The authors used four methods of droplet heating: in the flow of combustion products with the dominance of convective heat transfer, in a tubular muffle furnace with the dominance of radiative heat transfer, on a solid surface with the dominance of conductive heat transfer, and in a flame with the dominance of mixed (convective and radiative) heat transfer. The results. The authors have determined the ranges of change in evaporation rates of water droplets with typical (soluble and insoluble) additives for various heating methods with the dominance of convective, radiative, and conductive heat transfer. The effect of an additive type and concentration, heating method and heating medium temperature on of droplet evaporation characteristics was established.

Effect of the swirl angle on calcium carbide gas combustion characteristics of lower burner under annular shaft kiln

In order to solve the problem of high CO concentration in the emitted flue gas after adopting the flue gas recirculation technology in the annular shaft kiln, in this paper, the combustion characteristics of calcium carbide gas in swirl burners under the annular shaft kilns were studied by numerical simulation, the influence of fuel and primary air swirl intensity on combustion characteristics were studied, and the gas temperature distribution, pressure distribution and combustion products including CO, CO2 and NO was analyzed. The results show that the fuel gas swirl intensity has a great influence on the improvement of fuel burn-out ratio. The angle of the fuel gas blade increases, the maximum temperature of the combustion flame and the fuel combustion rate increase, and the CO content at the outlet of the burner decreases. When the angle of the fuel gas blade increased from 30o to 55o, swirl number increased from 0.41 to 1.02, the CO content at the inner sleeve position decreased from 8929 mg/m3 to 2467 mg/m3. The results also show that the effect of the primary air swirl intensity on reduce CO emissions and NOx formation was not obvious.

Fire protection of wooden building structures

The paper covers the issues of fire protection of cellulose-containing materials, in particular wood. It is shown that despite a number of valuable properties that wood possesses, it is a rather flammable material by its composition. It is known from the literature that one of the most important steps in protecting wood from fire is fire protection treatment. It is carried out in two main ways: surface treatment (applying special compounds to the wood surface to form a fireproof layer) and deep impregnation of wood with flame retardants. For the fire protection of OSB samples, a water-based intumescent paint consisting of a system of flame retardants in combination with fillers, pigment, and functional additives was developed. The research was conducted using analytical and experimental methods, which consist of analyzing and studying the provisions of national standards that describe the method for determining the flammability group of substances and materials and the method for determining the fire protection efficiency of fire retardants. The experimental part of the study involved the manufacture of test samples, application of fire retardants to them, recording the temperature of gaseous combustion products, the maximum temperature increase, the time interval for reaching the maximum temperature, the weight of the samples, and the weight loss of the samples. The research methodology states that the wood samples were tested in accordance with DSTU 8829 at the OTM installation. It also provides means for measuring the flue gas temperature, test time, and determining the mass loss of samples before and after testing. The test results showed that the developed fire retardant based on intumescent paint provides a group of refractory materials in accordance with DSTU 8829, i.e., the wood protected by this method belongs to refractory materials, namely: the flue gas temperature does not exceed 260˚C, the mass loss of samples after testing is not more than 60%.

Improvement of Heat Release Rate Measurement from Woods Based on Their Combustion Products Temperature Rise

Heat release rate (HRR) is the principal fire characteristic of materials. There are three known methods for the measurement of HRR (based on oxygen consumption, mass loss rate, and combustion products temperature rise). The method based on oxygen consumption is considered to be the reference. However, this method is expensive and for a large part of laboratories and universities unavailable. The simplest method is based on combustion products’ temperature rise. However, this method has a fundamental problem with the temperature dependence of the heat capacity of combustion products and the thermal inertia of the measurement system. This problem has been solved by training neural networks to predict molar heat capacity and the amount of substance (chemical amount) flow rate of combustion products in the cone calorimeter exhaust duct. Data were obtained for six different wood species: birch (Betula verrucosa Ehrh.), oak (Quercus robur L.) spruce (Picea abies (L.) H. Karst.), locust (Robinia pseudoacacia L.), poplar (Populus nigra × P. maximowiczii L.), and willow (Salix alba L.) woods at heat fluxes from 25 to 50 kW m−2 have been used for neural network training. Data from three other wood species iroko (Milicia excelsa (Welw.) C.C. Berg), pine (Pinus sylvestris L.), and paulownia (Paulownia tomentosa (Thunb.) Steud.) woods have been used for testing of trained neural network. The average percentage ratio of the predicted to the true value of HRR (during the test) has been 103.8%. In addition to that, some key average fire characteristics of wood have been determined: critical heat flux 20.7 kW m−2, effective heat of combustion 14.01 MJ kg−1, and the average value of molar heat capacity of combustion products 0.045 kJ mol−1 K−1.

Динамічні процеси у твердопаливних ракетних двигунах та їх взаємодія з вібраціями конструкції ракети: стан питання та актуальні проблеми

The most critical operating conditions of solid rocket motors (SRMs) are often due to the development of dynamic processes characterized by excess values of operating parameters. Pressure surges and a sharp increase in the combustion product temperature may impair the strength of the combustion chamber structure, cause its failure, and lead to critical conditions of the motor operation, up to extinguishing the propellant combustion in the motor. It is shown that both in steady and in unsteady operating conditions of an SRM, dynamic processes in its combustion chamber feature a complex interrelation of a large number of processes in the gas-dynamic space of the combustion chamber: physical, chemical, and thermodynamic (heat and mass exchange) processes. It is found that current studies of SRM operation instability are aimed at identifying mechanisms of combustion chamber pressure oscillations, which are usually due to combustion product vortex formation in the chamber space and acoustic feedback resulting from collisions of vortices with the SRM’s combustion chamber components or nozzle. Other lines of investigation are the analysis of SRM resonant damping and the establishment of a relationship between aluminum droplet combustion and SRM internal instability. It is noted that accelerations and vibrations of mixed-propellant combustion surfaces may greatly affect the combustion rate and the agglomeration, on-surface confinement, and burn-up of metal additives, which, in its turn, governs the combustion chamber acoustics. It is pointed out that the interaction of SRM combustion chamber pressure oscillations and the response of the SRM structure observed in flight tests of some rockets should be taken into account in predicting the stability of SRM dynamic processes. This interaction may call into question the sufficiency of SRM static tests and subsequent conclusions on the magnitude of its dynamic effect on the rocket structure.

Experimental Study of Stretched Premixed Flame Stabilized in a Flat Channel near a Heated Wall

In this work, the behavior of a lean premixed stretched flame stabilized in a flat channel near a heated wall was studied. Dependences of the flame front position on the stretch rate parameter at temperatures of the heated wall of 1000 and 1200 K and the combustible mixture composition (ϕ = 0.7 and 0.6) were obtained experimentally. The reduced thermal diffusive model was used in numerical simulation for an explanation of obtained experimental results. Theoretical estimates are in qualitative agreement with the experiment. The performed qualitative analysis may be useful in estimation of the combustion product temperature and the residence time of the nanoparticles forming in combustion products before their impact with the hot wall.

Radiative properties of micron-sized Al/air premixed flames described by an effective medium core-shell formulation

The goal of this article is to contribute to the knowledge of the phenomenology of the poorly understood micron-sized Al/air flames, with the intention of assessing the viability of an energy carrier based on aluminum powders. To this end, the combustion efficiency, temperature, radiative profile, and solid combustion products of a flame prototype have been studied in depth. These fundamental parameters are required to explore the possibilities of recovering the energy released by these flames. In addition, a theoretical model has been established to analyze the radiative properties of the flame, derived for an optically thin collection of independent burning Al particles, each modeled by a core-shell geometry. The structure of the shell, made up of a cloud of alumina nanoparticles, has been modeled with an effective medium following the Maxwell-Garnett relation. This approach can reproduce the experimental results and is thus suggested as a starting point for modeling experiments characterized by strong emission by the nanoparticle cloud.

Проветривание частично открытых автостоянок

Purpose. The article evaluates the effectiveness of the natural ventilation system of partially open car parks using numerical simulation in the Fire Dynamics Simulator software package. In large shopping centers, along with open and closed car parks, there are car parks, whose open doorways areas are comparable to the areas of enclosing structures. The study is due to the lack of requirements for smoke protection of partially open car parks in the current regulatory documents. Methods. The authors have carried out numerical simulation in the Fire Dynamics Simulator software package, which implements a field model of a fire in the room. Findings. The study has showed that the efficiency of the system with natural draft induction (with natural ventilation) and with mechanical draft induction (exhaust smoke ventilation systems) is almost the same. The combustion temperature of a car reaches 816 °С, the temperature of the combustion products drops to the level of the average value of a car park area (24 °С) at a distance of no more than 2 m. Research application field. The results of the study can be used in the development of regulatory requirements for smoke protection of partially open car parks. Conclusions. The conducted research allowed the authors to draw a number of conclusions. 1. For a partially open car park in “Mega-Khimki” shopping mall the use of natural ventilation is effective: the temperature of combustion products and the visibility distance inside the car park practically do not differ from the corresponding values outside the building. The distance from the burning car to the point where the temperature of combustion products drops to about 20 °С is no more than 9 m. 2. The distance from the burning car to the point where the temperature of the combustion products drops to about 20 °С is no more than 9 m. 3. Taking into consideration the possible variety of planning solutions and sizes of partially open car parks, it is advisable to support the requirements of current regulatory documents with calculations using a field mathematical model.

Heat Exchange and Aerodynamics of the Vertical Conical Funnel at the Thermal Power Plant Site

The funnel is the most important element of the thermal power station. An appropriate arrangement of the system for the removal of the gaseous products of fuel combustion inside the funnel results in no moisture condensation and proper maintenance of the operation conditions of the funnel. To measure the temperature of combustion products along the funnel height we need to define the boundary conditions of the third kind for the external surface of the funnel. The studies showed that in the case of the uniform velocity profile, the heat exchange and aerodynamics on the surface of the single vertically arranged funnel have specific features conditioned by the funnel configuration and the contact of its base with the ground surface. In particular, the rear part of the funnel is characterized by a periodic change in the static pressure, velocity and the height heat loss coefficient. The purpose of this research was to define the average heat loss along the height of the conical funnel situated at the industrial site of the thermal power station for different wind vectors and velocities. To simulate the heat exchange and aerodynamics near the funnel situated at the thermal power plant site we used the infrastructure that includes the following elements: mechanical compartment, substation, administrative building, warehouse and two cooling towers. The network model of the hydropower plant includes 1137782 units and 4741859 elements. A minimum orthogonal quality is 0.1 and a maximum biasing is 0.89. The ĝ RNG k- turbulence model, the Enhanced Wall Function and the Simplex algorithm were used for the velocity-pressure interrelation problem in steady flows. The air density is independent of the temperature at the computational volume inlet (the gravitation is neglected). The funnel surface temperature was specified as constant and equal to 100 C. The heat exchange near the funnel was studied at different wind directions in the wind velocity range of 5 to 25 m/s. Hence, the wind direction, the environmental infrastructure and the industrial thermal power plant site have an essential effect on the funnel height heat exchange distribution pattern. Evidently, it is defined to a great extent by the funnel aerodynamics. A maximum heat loss level is observed when the flow is rushed to the backside of the building at the south- to-north wind direction and a minimum heat loss level is observed for the east- to -west and west -to -east wind directions for the parallel flow. А minimum heat loss is observed at a longitudinal wind motion along the mechanical compartment building in west-to-east and east-to- west directions. These specific features should be taken into account when designing tall funnels with an optimal change in the combustion product temperature along the funnel height. We can draw a conclusion that the specific features of the heat exchange in question should be obligatory taken into account when designing tall funnels. Keywords: heat exchange, funnel, thermal power plant infrastructure, mechanical compartment, wind direction and 3D model.

On the effects of NH3 addition to a reacting mixture of H2/CH4 under MILD combustion regime: Numerical modeling with a modified EDC combustion model

This paper examines the behavior of reacting NH3/H2/CH4 mixtures in moderate or intense low oxygen dilution (MILD) condition. A series of axisymmetric, turbulent reacting flow simulations are carried out incorporating a modified version of eddy dissipation concept and a few reaction mechanisms. The effects of adding a progressively increasing amount of NH3 to a reacting H2/CH4 mixture in moderate condition are investigated. It is observed that addition of NH3 to MILD combustion leads to markedly different behaviors compared to that in conventional combustion. Most notably, the inherently strong preheating of reactants in MILD combustion causes thermal cracking of NH3 prior to ignition. The resultant production of H2 profoundly affects the reacting flow as such increasing the NH3 mass fraction in the fuel blend decreases the flame lift-off. Further, unlike that in conventional combustion, adding NH3 to MILD combustion increases the process reactivity. In addition, the usual flame thickening typically seen in NH3 flames is not observed here, while in keeping with the thermodynamic predictions, NH3 addition lowers the temperature of combustion products. The results also show that in sharp contrast to that reported for conventional combustion, addition of NH3 in MILD condition does not increase the emission of NO, while the mass fraction of NO2 drops slightly. Overall, it is concluded that MILD combustion could be a promising route to NH3 combustion.

A zero carbon route to the supply of high-temperature heat through the integration of solid oxide electrolysis cells and H2–O2 combustion

Previously suggested options to achieve carbon neutrality involve the use of fossil fuels with carbon capture or exploiting biomass as sources of energy. Industrial high-temperature heating could possibly exploit electrical heating or combustion using hydrogen. However, it is difficult to replace all the current coal or natural gas furnaces with these options for chemical industry. In this work, a method that integrates solid oxide electrolysis cells (SOEC) and H2–O2 combustion is proposed, and the related parameters are modelled to analyze their impacts. There is no waste heat and waste emissions in the proposed option, and all substances are recycled. Unlike previous research, the heat required for SOEC operation is generated from H2 combustion. The best working condition is under thermoneutral voltage, and the highest electricity-to-thermal efficiency that can be achieved is 86.88% under a current density of 12000 A/m2 and operating temperature of 750 °C. Ohmic overpotential has the greatest effect on electricity consumption, and the anode activation overpotential is the second most important option. Increasing combustion product temperature cannot significantly improve thermal efficiency, but can raise the available maximum thermal energy.

Investigation of the Regularities of the Influence of Technological Factors and External Conditions on the Temperature and Content of Condensed Products Oxide-Containing Mixtures

The results of thermodynamic calculations of temperature dependences of combustion products of pyrotechnic mixtures based on magnesium, aluminum and metal oxides and their content of high-temperature condensate on the relevant technological parameters and relevant external conditions are presented. The ratio of the components of the mixture, the type of metal fuel, the type of oxidant are considered as technological parameters of pyrotechnic mixtures. The influence of temperature and external pressure is determined as external conditions. It is determined that high values of combustion products and high content of condensed combustion products of pyrotechnic oxide-containing mixtures pose a fire hazard to the surrounding objects when the products are forced to operate under external thermal conditions. As a result of the calculations, it was found that the value of the combustion temperature of oxide-containing mixtures has a maximum value of 3870 K at a maximum value of the relative fuel content of 0.35 and the corresponding external pressures of 105...3107 Pa. It is determined that with increasing external pressure in the ranges from 105 tо 3107 Pa there is a significant increase in the temperature of combustion products: for oxide-containing mixtures based on metallic fuel magnesium - up to 3650 K; for oxide-containing mixtures based on metallic aluminum fuel - up to 3870 K. It is determined that in oxide-containing mixtures with metallic fuel content from 0.06 to 0.49, regardless of the type of metallic fuel and oxidant with increasing external pressure increases the temperature to 1.8 times.

Thermal and aerodynamic parameters radiation chambers of the hydrocarbon pyrolysis furnace

THE PURPOSE. To carry out mathematical modeling of interrelated physicochemical processes in radiation chambers of tubular furnaces of pyrolysis of hydrocarbons. Perform numerical calculations of heat and mass transfer in the furnace furnace chamber with a multi-tiered arrangement of wall burners on the side lined walls.METHODS. Using our own package of applied programs based on the numerical solution of a system of differential equations of energy conservation and equations of radiation gas dynamics, the fields of velocities and temperatures of natural gas combustion products in the radiation chamber of a hydrocarbon pyrolysis tubular furnace are calculated. Interrelated processes of natural gas combustion, radiant-convective heat transfer, and turbulent flow of flue gases take place in the radiation chamber. These processes are modeled by two-dimensional equations of the combustion model, energy transfer by radiation, and equations of motion. In the side walls of the radiation chamber on both sides in eight horizontal tiers there are wall burners in the amount of 128 pieces. Combustion products emerging from the nozzles of these burners create complex velocity and temperature fields in the chamber volume. Due to the radiation of flue gases, the smallest soot particles and hot lined walls of the radiation chamber, heat flows are formed to the tubular screen, where hydrocarbons are pyrolyzed to produce ethylene.RESULTS. As a result of calculations, the velocity fields, the temperature in the volume of the radiation chamber and the concentration of the main components of the combustion products were obtained. Local values of surface densities of radiant heat fluxes to reaction pipes for methane and propane pyrolysis furnaces are calculated. Comparisons of some of the results obtained with the readings of the devices of existing technological installations are carried out.CONCLUSION. Calculations show that the developed software package makes it possible to obtain realistic values of local velocities and temperatures in the radiation chambers of tube furnaces, surface densities of convective and radiant heat fluxes to boundary surfaces, and other thermal and gas-dynamic parameters in the furnace volume. With a multi-row arrangement of a large number of wall burners of low thermal power, a complex field of temperature and velocities of combustion products in the furnace volume is formed on the side walls of the radiation chamber of the furnace. At the same time, this arrangement of the burners ensures a fairly uniform distribution of heat flows over the surface of the tubular screen of the hydrocarbon pyrolysis furnace.

Thermal radiative properties of zirconium oxide films in the near‐infrared wavelengths

AbstractThermal barrier coatings (TBCs) using yttria‐stabilized zirconium dioxide (YSZ) are widely used in gas turbines to protect metal components against the high combustion product temperature. Increasing combustion temperature and pressure, radiative heat transfer becomes an essential portion of the overall heat transfer in TBCs. This necessitates a greater understanding of the thermal radiative properties of YSZ films, especially in the near‐infrared wavelength range. The commonly used Kubelka–Munk (KM) method in the radiative property reduction from the measured transmittance and reflectance spectra of YSZ films can incur inaccurate results when the coating optical thickness is not sufficiently large. The discrete ordinates method with the asymmetric spherical ring angular quadrature can solve the radiative transfer equation with good accuracy in optically thin media. Considering the solution accuracy and computational efficiency, a hybrid approach of combining the KM and discrete ordinate methods is used to invert radiative properties. The absorption and scattering coefficients of air plasma sprayed YSZ films are determined over the wavelength range from 1 to 2.6 μm at room temperature. Over this near‐infrared wavelength range, the scattering coefficient decreases with the increasing wavelength, and the absorption coefficient is very small overall.

Research of Mechanism of Fire Protection with Wood Lacquer

The results of researches of wood burning parameters and influence of fire-retardant substances on them are given. Studies have shown that the process of heat insulation of a wooden structure is the formation of soot-like products on the surface of natural combustible material. Under the action of the burner flame on the protected sample treated with impregnating solutions based on a mixture of ammonium phosphate with antiseptic, the temperature of gaseous combustion products was 230 oC, and weight loss did not exceed 9%, while wood treated with a composition of urea and phosphoric acids and starch showed temperature of 160 oС with a weight loss of 3.6%. It is established that fire protection by coatings provides a low rate of burnout of wood samples and with increasing temperature exposure and translates into a non-flammable material that does not spread the flame on the surface.

Elaboration, thermogravimetric analysis, and fire testing of a new type of wood‐sawdust composite materials based on epoxy–amine polymers modified with copper(II) hexafluorosilicate

SUMMARYThe study reports the development of a new type of wood‐sawdust (WS) composite based on CuSiF6‐modified epoxy–amine polymers (EAPs) with reduced combustibility. The thermo‐oxidative behavior of the obtained WS/EAP–CuSiF6 and WS/EAP specimens was studied using the complex thermal analysis. Thermal analysis data show that incorporating CuSiF6 (flame retardant) into WS/EAP increases the thermal oxidation resistance of WS/EAP–CuSiF6. It is shown that for WS/EAP–CuSiF6 and WS/EAP, thermo‐oxidative destruction ends at 571°C and 625°C, and the maximum temperature of this exothermic process is 435°C and 499°C, respectively. The combustibility of WS/EAP–CuSiF6 and WS/EAP was studied by the “ceramic tube” (CT) method. The CT results obtained demonstrate impressive differences in the combustibility of these two composites; the maximum temperature of gaseous combustion products for WS/EAP–CuSiF6 is 265°C, and for WS/EAP, it is 910°C. Flammability tests for WS/EAP–CuSiF6 and WS/EAP were carried out in accordance with ASTM D635‐18 and ASTM D3801‐19a. According to the results of vertical burning tests, the WS/EAP–CuSiF6 composite material was classified as V‐0.