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In this paper, we revisit a turbulent mixing of gas and air in a gas burner with computational fluid dynamics (CFD) models. The quality of such a turbulent mixture is based on temperature, pressure, and velocity distributions as well as the distributions of different molecules, turbulent kinetic energy, and turbulent dissipation rate. In order to identify a precise combination of a gas and air mixture in a gas burner, which directly influences the quality of the combustion flame and reduces the amount of carbon monoxide (CO) emission in flue gases, thermodynamic principles are utilized based on the balancing ratio of molecular weights and the balancing ratio of mass flows between gas and air. Moreover, input parameters, such as volume flow rates, pressure, mass ratio, temperature, turbulent kinetic energy, and turbulent dissipation rate, are judiciously chosen with proper boundary conditions for both axisymmetric two-dimensional and three-dimensional models. It is confirmed that the effectiveness of gas and air mixture and combustion depends on the gas burner model, more specifically, on the sizes and locations of gas and air inlets and outlets as well as operation conditions.

Natural gas quality assessment is a relevant issue. A critical analysis of calorimeter designs for measuring the calorific value of natural gas was carried out. The most common methods for determining the calorific value of natural gas are as follows: direct by gas calorimeters; indirect by gas chromatographs; indirect, based on correlations. The advantages of isoperibolic calorimeters of measuring calorific value of natural gas directly in the consumer’s conditions are substantiated. The design of a portable calorimeter containing a thermostated shell, calorimetric tank, Peltier element with tank, circulating pump, gas burner, thermostat systems, metered supply of natural gas and air, fuel ignition, sensors, combustion analyzer and control and measurement unit, was developed. The geometric dimensions of the calorimetric tank are optimized, materials and technologies of manufacturing parts are specified. The metrological analysis of the developed portable calorimeter was carried out. A method for measuring the calorific value of natural gas directly in the conditions of household consumers and transport enterprises was developed. The results of testing the prototype calorimeter in the laboratory confirmed its high performance and metrological characteristics, and the deviation of the measurement of the calorific value of natural gas from that determined using a gas chromatograph was 0.6%.

The utilization of low calorific gas contributes to the energy conservation and environment protection. In order to improve the utilization efficiency, a porous media burner combining the alumina pellets and ceramic foam was established. The effects of the pellets diameter and pore density of ceramic foam on the combustion characteristics were studied, and the burner starting was also investigated to optimize the porous structure. The results showed that the maximum temperature increased first and then decreased with the increasing of pore density, but it decreased with the increasing of pellets diameter with certain conditions. The smaller pore density of the ceramic foam and the larger diameter of the pellets were conducive to the rapid start-up of the burner. Through the combination of ceramic foam and pellets from the radical direction, the flame can propagate quickly to the inside of the burner. As the inlet velocity increased, the flame location moved to the downstream layer. However, the flame location moved to the upstream layer with a higher equivalence ratio.

Experimental investigations of a new burner for gas ranges have been conducted. We present a modified construction diagram of a burner with a new heat-transfer intensifier in the form of tapered-screw fins on the surface of a metal rod that has shown its efficiency and made it possible to raise the cost effectiveness of natural gas combustion compared to a base burner.

Burning experiments are analyzed for 59 successfully ignited tests using a gas burner (BRE) to emulate the steady burning of 25 mm diameter flat surface materials. More than half of the tests resulted in long burns of at least 2 and as long as 5 min. Mixtures of ethylene and nitrogen allow for 23.6 and 47.2 kJ/g heats of combustion (LHV). Nominal ambient conditions range from 40% to 21% oxygen and pressures of 1 to about 0.56 bar. NASA human habitat atmospheres have been used. Generally, it has been found that nominal oxygen mole fractions of 26% and above can allow steady flames. The flames are thin blue in color and grow slowly over time for minutes. Some self-extinguish, some had periodic oscillations, and others appear to have become steady and were shut down. Theoretical analyses show the shutdown flames were steady in growth, and all of the test endpoints were more than 94% of steady state in flame heat flux. Flame heat flux for set mass flux allowed the estimation of heats of gasification to relate to steady solid materials that might burn in microgravity. Radiometers allowed the computation of flame radiative fraction that appeared to correlate well with the measured flame height. Results are shown for heat flux, flame height and base radius, radiative fraction as a function of fuel mixture mass flux, and various oxygen and pressure atmospheres.

Cooking is an important domestic activity requiring energy. Traditionally, solid fuels, like firewood and charcoal, are used as the resources for supplying energy for cooking. However, burning of solid fuels inside the households causes indoor pollution and adversely affects the health of the users and other occupants. Various governmental and world bodies, like the UN, encourage people to shift from the traditional fuels to clean and sustainable options, of which gaseous fuel is an important one. Natural gas and liquefied petroleum gas (LPG), which are used for domestic cooking, are fired in gas burners designed for the cookstoves. Though the use of gaseous fuels lowers the household air pollution, early domestic gas burners were low in thermal performance with efficiency value of around 40%. Continuous research and development in the design and analysis of the stoves have led to a significant improvement in the thermal performance of commercial gas burners yielding efficiency exceeding 65%. Efforts are still on to improve the thermal and emission performance of the burners further without sacrificing user comfort and flexibility through innovative designs. This article presents a review on the design, development, and technological advancements in the gas burner technology for domestic stoves, and analyzes the effects of various parameters on their thermal and emission performance.

The present study investigates experimentally flame lengths in the two directions underneath a horizontal ceiling (x-direction: parallel to the longer side of the burner; y-direction: perpendicular to the longer side of the burner) produced by line-source fire. It is noted that the previous classical equations are limited for axi-symmetrical sources where only one-dimensional radial flame length is considered. They are non-applicable for the two-dimensional impinged ceiling flow induced by non-axi-symmetrical line-source in despite that it is also a basic source condition in fire science essentially and practically. Experiments are conducted employing a line-source gas burner using propane as fuel. The flame lengths due to impingement upon the ceiling in the two directions are measured, and their difference are quantified, at various heat release rates and ceiling heights. Experimental results show that the flame length in x-direction is shorter than that in y-direction. Their difference decreases with increasing of ceiling height, meanwhile increases with increasing of heat release rate. A new global formula is derived to describe the flame lengths underneath the ceiling based on the analysis of un-symmetrically distributed un-burnt fuel mass flows after impingement in the two directions reflected by their characteristic lengths, which are proposed to be the fire plume impinging zone characteristic dimensions in the two directions determined by the initial source dimensions, ceiling height and air entrainment. The proposed new function well represents the flame lengths globally in both directions. It provides for the first time a general model for describing the flame lengths underneath a ceiling of line-source fire plume impingement.

Ignition within gas burner ejectors can lead to off design conditions and has significant influence on the burner behavior. Thus ignition in the ejector should be prevented. In the present study the influence of combustion reactions on the performance of gas burner injectors is investigated. To investigate if ignition is possible, simulated ignition delay times, using a detailed reaction mechanism, are compared to predicted mean residence times of the gas in the ejector. Gas burner ejectors are designed using one dimensional analytic equations, based on energy and momentum conservation equations and conventional isentropic equations. 1D results are compared to 2D computational fluid dynamics (CFD) simulations, to take into account non-ideal mixing effects along the ejector. Results are validated with experiments with air at room temperature. 1D results show very good agreement not only with CFD simulations for the case of non-reactive flows, but also with performed experiments. It is shown that the assumption of ideal mixing along the ejector and thus the comparison of the ignition delay time to the gas mean residence time, to predict ignition in the ejector, is not valid. Ignition in the ejector is possible, even if the ignition delay time is more than thirty times higher than the mean residence time. In addition to that, it is shown, that ignition and the choice of reaction mechanism have significant influence on the predicted gas burner ejector performance. Thus, the accurate prediction of ignition delay time and the use of a detailed reaction kinetic are mandatory to correctly predict the burner ejector behavior.

The paper presents results of theoretical numerical research dealing with CO and NOx emission performed in the process of optimization of the performance of low-power atmospheric burners. The theoretical part of this paper, whose main goals were better understanding of the complex issues of methodology and establishment of performance prediction and optimization of low-power atmospheric gas burner included numerical variation of independent parameters, such as burner geometry, the coefficients of primary and secondary air and different gaseous fuels including biogas. The findings of theoretically obtained performance prediction and optimization of atmospheric burners were experimentally investigated in purpose built test rigs for a number of variable parameters. The obtained results fully justified the proposed models of performance prediction and burner optimization.

Thermocouples were used to measure gas temperatures as a function of distance to the edge of a rectangular burner. Experiments varied the energy release rate, burner aspect ratio, wind speed, and s...

The article discusses the design and operation features of two-wire gas burners developed at the Gas Institute of the National Academy of Sciences of Ukraine. These are jet-diffusion type burners and jet burners, the creation of which is based on the concept of burning gaseous fuels using a highly efficient unified tubular technology developed in conjunction with specialists from the National Technical University of Ukraine «Igor Sikorsky Kyiv Polytechnic Institute». A description of burners and burner devices of the jet diffusion type of the SG and SGL series is provided. The design of the SGL series burners provides for the possibility of interconnecting individual modules, which ensures the creation of heat generators of almost unlimited power. It is shown that such heat generators can operate in a wide range of excess air, this allows to get a coolant of any required temperature. Heat generators of this type operate in many industries. In jet burners created by tubular technology, as a result of the interaction of gas jets and air jets, diffuse gas flames are formed, which provide high reliability of the burners with possible fluctuations in the gas-air ratio. Also shown are the designs of burners created as a combination of these combustion technologies. The design of turbulent vortex burners, which provides a high degree of stabilization of the flame through the use of a central jet diffusion burner, is described. These burners are equipped with steam and hot water boilers, as well as melting furnaces. When operating these burners, it is possible to achieve 10 % of the natural gas consumption of the nominal load, which allows the operation of heating furnaces in the hot reserve with short-term shutdowns of technological equipment. Библ. 15, рис. 12.

Introduction. Currently, the industry produces a wide range of foam generators to produce fire-extinguishing foams, and the foams they produce differ significantly in their expansion ratio and, consequently, fire resistance. Since heat fluxes have the main destructive effect on the foam, the purpose of this paper is to establish the patterns of destruction of foam of different expansion ratio when heated.Methods of research. The foam with expansion ratio from 7.5 to 80 was used for the tests. It was obtained by mechanical beating of 6 % solution of foaming agent PO-6RZ. The thermal stability of the foam was studied when the heat flow from the gas burner flame affects the foam layer. During the experiment, the change in the height of the foam column in time was recorded.Results and Discussion. The results of measurements, presented in the form of dependence of foam layer destruction rate on time, quantity of released liquid phase on 1 m2·s, dependence of foam layer destruction rate on its density allowed revealing a number of patterns. The destruction rate of foam with an expansion ratio of up to 30 remains constant throughout the entire duration of thermal exposure. As the foam expansion ratio increases, the rate of destruction at the initial stage of heat flux exposure increases. With a foam expansion ratio of more than 50, there is initially a sharp increase in the rate of destruction, which subsequently decreases as the foam column decreases. In the conditions of the experiment, the best characteristics were shown by the foam with an expansion ratio of 50, because in the foam with a smaller expansion ratio the syneresis makes a significant contribution to its destruction, and the foams with a larger expansion ratio are destroyed by the mechanical effect of convective flame flows.Conclusion. The study of the foam destruction patterns under thermal impact allowed establishing the fact that its destruction is limited by the rate of impoverishment of the upper layers with liquid.

Evaporation of a water–methanol solution droplet is experimentally studied. This process is mathematically modeled. Based on the results of a comparative analysis of the results of physical and numerical studies, the parameters of the evaporation of a water–methanol solution droplet are determined for the purpose of using its combustion in mathematical modeling. The results of numerical studies of the combustion of a gas flame with the injection of the water–methanol solution droplets into it in an industrial plant are presented. These results satisfactorily correlate with experimental data.

Studies have been carried out on the purification of biogas from sulfur compounds, carbon dioxide and water vapor for subsequent use in micronizer burners. The possibility of bringing it to the parameters of natural gas of the following composition: methane (CH4) – 85 % vol., carbon dioxide СО2 – 11 % vol., water vapor – 9 mg/m3, hydrogen sulfide H2S - 20 mg/m3 with minimal energy costs for its preparation is demonstrated. The basic relationships are obtained for assessing the design and technological parameters of the infrared radiation burners operation. Experimental studies of the flame stability limits on perforated ceramic nozzles have shown that flashback through them is possible when the thermal power is increased to a certain critical value. In this case, the thermal power depends on the type of gas and the air content in the combustible mixture. The heat balance equations have been derived to optimize the designs and operation modes of infrared radiation burners. The design of 40 gas burners was improved by changing the geometric dimensions and shape for a uniform distribution of biogas supplied and sustainable combustion over the entire area of the burner. It was established that the temperature of the heating surface of the GIK-8 burner on gas mixtures with a CO2 content of 18-34 % is 900-950 ° C, which does not differ from the nominal temperature when operating on natural gas. The infrared heating system was modernized, adapted for burning purified biogas with methane content up to 98 %, in particular, the biomethane feed and control system, the additional biogas input system, and the automatic burner control system were improved.

A plasma electrical installation for gasification of various organic wastes has been developed. Its constituent parts are a hydraulic supply of packaged waste to the reaction zone, a gas burner with thermal power of 42 kW, an electric arc plasma torch with power of 50 kW, and a bottom melting ash chamber. In the test mode of electric furnace operation it has been shown that plasma gasification of organic materials produces a synthesis gas suitable for application in heat and electric power engineering. The results of thermodynamic calculations are in satisfactory agreement with the obtained experimental data.

The fire modeling community currently lacks full-scale data from tests conducted in realistic residential-style structures. Controlled gas burner tests were conducted in purpose-built single- and two-story structures instrumented throughout with thermocou- ples, pressure transducers, and bi-directional probes. Experi- ments consisted of sequences of ventilation events. The data collected in these tests was intended to provide several new val- idation cases for the fire modeling community.

The results of an experimental study of a new gas burner that can be effectively used in domestic gas stoves are presented. The presented modified design of a burner with new heat-transfer enhancers made it possible to reduce heat loss to the environment and increase the efficiency of burning natural gas.

The improvement of thermodynamic and environmental indicators of energy facilities is a vital and topical problem. Numerical simulation methods are used to investigate the processes of combustion and formation of hazardous substances by computation, and to work out recommendations on increasing the effectiveness of fuel combustion. The paper examines the impact of atmospheric air humidity on the process of combustion of a stoichiometric methane-air mixture in a burner. The combustion process is simulated in the 3D unsteady statement in Cartesian coordinates. In the investigation, the combustion of the methane-air mixture is considered in one stage. Air humidity is considered in the 0 to 100% range. The monoxide nitrogen formation process is described using the extended Zeldovich-Fenimore mechanism. A comparative study has found that increasing air humidity up to 100% reduces the mass emission of monoxide nitrogen by a factor of 1.27, as compared to dry air. The study results can be used for designing equipment that uses methane as fuel.

On the basis of gas-burning devices of the GS series, new devices have been developed, in which gas channels are installed for operation in the mode of maximum or minimum flame length. This allows to increase the stability of the flame at low temperatures of the working space (below the natural gas ignition temperature), which in turn provides an increase in the economic performance of the tunnel kiln firing ceramic bricks. Bibl. 5, Fig. 2.

Gas burner has been widely utilized to many industrial fields and personal outdoor activities and so on. Portable small-sized gas burner is, especially, useful in personal outdoor activities. The performance and safety of portable small-sized gas burner is important because it uses gas as fuel. The purpose of this study was to investigate the possibilities of performance improvement of portable small-sized gas burner through flow and structural analysis, respectively. As the results, it showed that mass fraction of butane gas in all cases(Type 1, Type 2, Type 3) was about 12~18% and further safety load of 3 stand leg was below 10 kgf.

The domestic cooking-gas burner consumed the highest amount of Liquefied Petroleum Gas (LPG) not over 5.78 kW ( 280 mmH2O) based on Thailand Industrial Standard (TIS 2312-2549) is modified by using the open-cellular porous media. The Nickel-Chrome (Ni-Cr) with pores per inch (PPI) of 8.5 and porosity (ε) of 0.92 is selected as porous media. To investigate the performance of a new cooking-gas porous burner, three outlet diameters of mixing tube (Dout) between primary air and LPG, i.e., 27, 35 and 43 mm., are examined. The temperatures at bottom vessel (TV) and water (TW) are monitored. The exhaust gas (CO and NOX) is also observed. Thermal efficiency (η) of three modified burners are estimated in accordance with TIS 2312-2549. From the experiment, the TVis increased with Doutleading to the boiling time (t) of TWfor reaching to about 99°C (depend on TIS 2312-2549) in the case of Dout= 43 mm gives the fastest. The CO and NOXof all burners are not difference and are in relative low level: CO is in the range of 140 to 180 ppm and NOXis not over 70 ppm. The ηthis raised with increasing Doutin which yield as 47.53, 52.86 and 54.77% for Doutof 27, 35 and 43 mm., respectively.

This study proposes a novel design of an atmospheric gas burner that introduces the concept of heat recirculation combustion by means of porous media combustion technology. A combustor and heat recirculation unit, used for preheating the combustion air, are part of the assembly of the porous material. The combustor is a self-aspirating annular porous medium burner (APMB) formed by a packed bed of alumina spheres with a diameter of 10 mm. A porous radiant recirculation heater was integrated into the APMB to obtain an elevated air temperature. To stabilize flames at the middle of the porous media packed bed, the flow velocity of the mixture has to be equal to the flame propagation velocity, making this a critical criterion for the design of the burner. A critical variable required to determine the flame velocity is the primary equivalence ratio. It was predicted using the empirical formula derived from the experimental data, and considers the momentum equation and pressure drop in the porous medium burner. Operation of the burner with firing rates from 21 to 44 kW resulted in evaluated air temperatures of 136–252 °C, yielding maximal temperatures greater than the adiabatic flame temperature. The NOx emissions were low because of the combustion within a porous medium. The CO emissions were high compared with the conventional burner but still conformed to the requirements of the national standard.

Fire risk analysis for cables in a vertical cable tray is important for fire protection design in nuclear power plants. One important characteristic of vertical cable tray fires is the upward spreading of the cable flame along the cable tray, which should be considered as a time-varying fire source. Experiments involving vertical cable tray fires with a spacing of 0 and 8 mm between cable lines were conducted in confined compartments with dimensions of 3 m × 3 m × 3 m (length × width × height). The cable in a 0.3 m wide × 2 m long vertical cable tray was ignited using a line-source gas burner of a 20-kW premixed flame system. The experiments indicate that a room with a vertical cable tray fire could be divided into three zones with respect to thermal characteristics. Notably, a middle zone having reduced temperature was observed, even though the intensity of burning did not decrease. By considering the effect of a time-varying fire source, an expression for predicting the ceiling jet temperature was proposed. For the prediction of the maximum ceiling jet temperature, the relative errors were less than 18.8%; for the entire cable fire process, the normalized Euclidean distances were less than 20.4%. The available literature data concerning a vertical cable tray fire in a confined room were used to validate this expression. It is further confirmed that the proposed expression predicts well the literature data for vertical cable tray fires in a confined space. This new expression can be used for estimating the hazards from a vertically spreading fire in a compartment in nuclear power plants.

A gas burner is often used in science experiments in Japanese lower secondary school education, and its correct operating procedures are included in the study content. However, students are given only inadequate learning opportunities for the operating procedures with the actual gas burner, due to time and instrumentation constraints. Therefore, this article proposes an operation learning system of a gas burner using virtual reality technology with high realistic sense to supplement the learning with the real one. The proposed system provides interactivity through a dial controller and a pair of hand controllers as an input device, and a stereoscopic HMD as an output device. The dial controller imitates an adjusting screw, so that a learner can easily get a realistic sense of turning screws for air and gas. Also judging whether the user’s operation is correct or not, the system displays necessary information on the virtual scene of the gas burner for learning to promote the learner’s understanding.

Nowadays, people are having a hectic schedule and hence sometimes unconsciously forget to turn off their gas burner in the kitchen. A significant amount of gas is being wasted. This system's fundamental goal is to develop a device for kitchen safety and reduce gas wastage, which concentrates on additional protection. This paper proposes an approach to automatically prevent any threat from the usage of the gas stove. This system is an ATmega328p microcontroller-based that deals with turning off the kitchen gas valve mechanism in various situations. It turns off the gas supply when it is not used for cooking purposes utilizing a solenoid valve. The gas burner will turn on when there must have a flame in the gas burner and a cooking pot on the gas burner. When smoke is detected, the temperature is high from its range, and there is any kind of unnecessary gas amount in the kitchen, then the exhaust fan will turn on automatically. Like a micro oven, there is also a timer system for cooking purposes at a particular time. Here also include a Bluetooth system for controlling the burner by voice. If there any gas leakage is detected, the system will make an alarm and inform the house owner by calling and sending a text. Also, there are various modes involved in this system. It highlights the provision for kitchen safety. It greatly assists in securing safety and making use of gas stove more convenient and easy.

The article is devoted to decision of actual task of energy saving. As a fact, a large-scale energy saving policy is being implemented in Ukraine, and energy efficiency objectives are comprehensive and cover both the legislative framework and technical innovations. It is consumed in the boiler rooms too much amount of gas. One of the effective ways to reduce energy consumption for boiler gas supply is to carry out the thermal modernization of the boiler rooms. This article describes the economic indicators of thermal renovation measures during the reconstruction of the boiler rooms. During the reconstruction of boiler rooms the following thermal modernization measures were taken for comparison: equipping the existing boiler with a modern domestic gas burner, economizer or condensing economizer; replacement of the existing boiler with a modern Ukrainian-made boiler with a modern domestic burner with the possibility of its additional equipping with economizer or condensing economizer; replacement of the existing boiler by Viessmann boiler. Conducted energy audit of the boiler room during its reconstruction has showed that the profit from the introduction of energy-saving technologies during their operation is the maximum, if it is provided the modernization of the existing boiler by its equipment at the same time modern burner domestic production and condensing economizer.

In this study, a series of experiments were performed to investigate the flame height of double rectangular pool fires with different aspect ratios and distances in open space. Two identical rectangular gas burners with the same heat release rate were used as the fire sources. Four gas burners with the same surface area but with different aspect ratios were used. Different distances between two gas burners were considered. The experimental results indicated that the flame height decreased sharply with the increase of distance and subsequently exhibited a slight change with further increase of distance. The buoyancy force in the region between these two pools is the main factor to influence the flame height. A characteristic length D , which depends on the gas burner geometrical shape and distance, were proposed, and the experimental data indicate that the value of coefficient C decreases with the increase of D . A correlation has been achieved which can estimate the flame height of the rectangular pool fires with different aspect ratios in open space.

The performance of thermodynamic cycle strongly depends on the properties of working fluids. A gas-fuelled hot water system based on coupling of an organic Rankine cycle and an air source heat pump cycle (ORC-ASHP) was investigated in this paper. This system is integrated with a gas burner to provide heat for ORC. The power generated in ORC is used to drive the air source heat pump cycle. Comparisons on the system performance are presented for seven different organic working fluids, with emphasis on the effect of thermodynamic properties of the working fluids. In terms of fuel-to-heat efficiency, benzene, toluene and cyclohexane have better performance for the high temperature heat source. The results indicate that working fluids presenting higher decomposition temperatures shows a higher fuel-to-heat-efficiency. When benzene is used as working fluids, the fuel-to-heat efficiency reaches 161.7% and 139.47% to provide 50 °C and 65 °C hot water respectively.

In climate regions with large seasonal variations in solar radiation, such as the Pacific Northwest of the United States, a solar thermal energy collector might not economically satisfy year-round domestic water heating demands, requiring an auxiliary unit, such as a natural gas-fired water heater. Previous studies have shown that the burner efficiency of a gas-fired water heater varies depending on the log-mean temperature difference between the cold fluid (water) and the hot fluid (combustion gases). In a solar/gas hybrid water heating system, where solar collectors are used in conjunction with a gas-fired heater, the partial heating of water provided by solar input reduces the log-mean temperature difference value for the gas heater, reducing the efficiency of the gas burner. Since this efficiency reduction varies depending on the amount of pre-heating provided by solar energy input, it is difficult to accurately predict the actual cost and energy savings offered by solar/gas hybrid water heaters in different climates and operation scenarios. Hence, to predict the actual energy and cost savings under various design conditions, the performance of solar/gas hybrid systems must be better understood. The objective of this work is to experimentally determine the thermal performance of a solar/gas water hybrid water heating system with a 6.44 m2 flat plate solar collector array and a 22.3 kW natural gas burner in Corvallis, Oregon, USA. Under different temperature lifts and solar insolation values, the system was operated at three different modes of heating: solar, gas, and combined solar/gas mode. The overall system thermal efficiency value for each mode is calculated. The efficiency of the solar collector heating system was found to be 41.97%, 39.82%, and 35.05% at initial water temperature of 20, 30, and 51.5 °C, respectively. For initial water temperatures of 20, 30, and 51.5 °C, the efficiency of the gas burner was found to be 69.2%, 66.4%, and 65.5% at the HHV, and 76.7%, 73.6%, and 72.6% at the LHV of natural gas, respectively. In the combined solar/gas heating mode, the efficiency of the gas burner decreased with increasing solar fraction. For solar fractions of 4.93%, 9.40%, 11.39%, and 14.27%, the efficiency of the gas burner in terms of the HHV of natural gas was found to be of 69.08%, 66.80%, 66.17%, and 65.18%, respectively. Based on the experimental results, a configuration that would provide higher overall system efficiency for combined solar/gas heating is suggested.

A method for measuring local flame temperatures using a spectral-ratio pyrometer and a tomographic system based on this method are described. The theoretical substantiation of the proposed measurement method is given. A block diagram of the system containing four measuring mirrors and one multiplexing mirror is shown. The results of the computer simulation are presented, with which it is possible to estimate the error of the system depending on the number of mirrors used in it. The software developed for carrying out measurements with the maximum degree of automation under the test-bench conditions is described. The results of an experimental study using the tomographic system for measuring the field of local flame temperatures of a gas burner (in the range of 1500–2300 K) are presented. The results demonstrate the operability of the developed system.

Boilers have contributed significantly to the production of energy and other processes in industry. Understanding the combustion characteristics inside a boiler is essential to increase the efficiency and reduce environmental-related concerns. The novelty of this work is associated with a detailed analysis of the effectiveness of a developed co-firing coal-natural gas burner and the arrangements of the burners in the boiler for efficient combustion. Comparisons were made between the front-wall, the opposite-wall, and the tangential firing types. The characteristics of the flow, the coal particle motion, the temperature distribution, the concentrations of species, and NOx emission levels are examined. The results showed that each burner in the front-wall-fired type creates independent long flame zones. In an opposite-wall fired type, the flames of burners impinge upon the center of the furnace to create turbulence. Results show that front-wall and opposite-wall firing configurations exhibit hot peak zones and temperature imbalances near the furnace sidewall. This emphasizes the need for heavily swirling vanes in the main burner to shorten the flame length and mix the fuel and oxidant well for efficient combustion. The state-of-the-art tangentially fired configuration produced a fireball, ensuring thorough mixing in the furnace and allowing for the complete combustion and uniform distribution of the temperature such that NOx reduction occurs preferentially. Additionally, these results confirm the advantage of combusting coal with natural gas in the main burner, as doing so reduces NOx emissions up to 19%. The technological options identified offer potential for interested manufacturers, researchers, and others in related industries to improve the performance and reduce the emissions of industrial dual-fuel-fired combustion utilities.

Gas burner is the key component of coal-water slurry gasifier system. However, due to the sulfidation at high temperature, gas burner often fails in advance, which affects the stable operation of the system. In this work, Al-Mo coatings were deposited by plasma spraying with a Mo bonding layer. The sulfidation and oxidation behavior of the Al-Mo coatings was studied and compared with those of Mo coatings and Inconel 600 alloy at 973, 1073 and 1173 K. Results show that both the high-temperature sulfidation resistance and the high-temperature oxidation resistance of Al-Mo coatings are superior to those of Mo coatings. The high temperature sulfidation resistance of coatings is better than that of Inconel 600 alloy. Plasma-sprayed Al-Mo coatings with a Mo bonding layer are promising candidates for the corrosion protection of steels in a sulfur/oxide-rich atmosphere.

Gas cooling is a technique used by firefighters to reduce the dangers posed by the hot smoke in enclosure fires and, to thereby approach a fire while keeping their escape route safe. The technique includes bursts of water from a fog nozzle producing small droplets into the hot gases. The purpose of this work was to experimentally investigate the effects of gas cooling. A total of 44 tests were conducted in an 1800 × 1200 × 1200 mm room with an added fire room sizing 1200 × 760 × 1200 mm. A gas burner with a RHR of approximately 90 kW was used as a heat source. Four different nozzles were used, differing in droplet size, flow, and spray pattern. Also, reach, number of bursts and open time of the nozzles varied between tests. In this paper, six of the test with the most important and pronounced results were used for comparison. Conclusions from the tests included that nozzles producing droplets with a median diameter of approximately 500 µm delivered in multiple short burst with time in between bursts kept as short as possible were most effective for gas cooling. However, overall in this experimental setup taking all droplets sizes into consideration, a single longer burst performed slightly better than several short bursts as a similar temperature reduction is achieved in 1/3rd of the time of 5 short bursts and gases are cooled over a larger part of the room. The volume of the smoke was not observed to change significantly due to gas cooling.

Thermally efficient gas burners can be designed by optimising the parameters associated with combustion and heat transfer mechanisms. The current study presents the thermal analysis of the premixed methane-air flame jets of circular tube gas burner impinging on a target surface. The effect of flame jet parameters such as mixture Reynolds number, equivalence ratio and burner to target surface spacing on heat transfer characteristics is investigated. The thermal performance is quantified in terms of thermal efficiency. The lean and stoichiometric mixtures release maximum amount of thermal energy. However, in lean flames, a part of the energy released is used for rising the temperature of excess air. Though the combustion is incomplete for fuel rich flames, higher heat transfer is achieved because of higher flame height. The optimal thermal performance is observed when the mixture is near stoichiometric and the burner is spaced from the target surface such that the premixed cone tip just touches the surface.

A method for automatic determination of combustion regimes using flame images on the basis of a convolutional neural network on labeled data is under consideration. It is shown that the accuracy of regime classification reaches 98% on the flame images of a gas burner. The results of the operation of the convolutional neural network and classification using different linear models are compared.

Thermal barrier coatings (TBCs) as a kind of temperature-resistance materials have been widely applied in super high temperature components in aircraft engines. However, TBCs are subjected to harsh service environment such as high temperature oxidation and erosion, which lead to the coating failure. It is important to investigate the effect of fire temperature, angle and velocity of particle on erosion to understand the failure mechanism. In this paper, the temperature and velocity distributions of erosion particles in high temperature gas burner rig are investigated by using the fluid–solid coupling method with the discrete random walk model. The results show that a non-uniform distribution of temperature appears in different positions of the central axis, and the temperature of particle is affected obviously by the gas stream and particle size. The trajectory of particles and velocity diagrams under different particle size are determined by coupling the continuous phase with the erosion particles.

This paper concerns the flame extinguishing with the use of acoustic waves. A small laboratory stand allowing to generate acoustic waves in the horizontal direction was used for that purpose. The speaker extinction power and the acoustic extinction pressure were selected to quantify the process. Varying frequencies (30–50 Hz) burner powers (3.45-11.72 kW) and distances between the acoustic source and the flame (0.02–0.06 m) were investigated. It was shown that the lower the frequency is it is easier to extinguish the flame. It was also found that the fuel load has a minor impact on the extinction pressure. The results are supplemented with the visualisation of the flame behaviour under the influence of acoustic waves performed with the use of Schlieren apparatus. It was shown that the extinction is a result of cumulative effect of acoustic mean flow and oscillatory perturbations.

The thermal radiation impact of organic peroxide fireballs is experimentally assessed using an infrared camera. Fireballs are generated while liquid peroxide filled steel drums are subjected to gas burner fire at different heating rates. Three large burning clouds are observed with varying flame characteristics. Thermal radiation properties are assessed by infrared images with the presented methods. Despite of the two-dimensional temperature fields, the flames are treated and characterized as three-dimensional objects. Fireball diameters and heights are calculated based on a representing radiating sphere with the same cloud volume. By the use of the solid flame model and assumptions for emissivity and transmissivity, heat fluxes and thermal radiation doses against distance are predicted. Thermal safety distances are presented based on the maximum irradiance and the allowed exposure time. The validation of the maximum and time-dependent radiation fields is achieved through heat flux sensors in varying distances to the fireball. The results prove the use of an infrared camera and a volume based size calculation to fully assess the thermal radiation hazards of fireballs.

The drying kinetics of cassava chips in a newly developed multipurpose convective-type tray dryer heated by a gas burner (consisting of four drying compartments) was studied. The temperature of the drying air was 50 °C, and drying loads were 8 kg and 12 kg. Drying of cassava chips occurred in both heating and falling periods. It was found that cassava chips dried faster in the drying compartments that were closer to the heat source, that is, the first to the fourth drying compartments, consecutively. Twelve thin layer drying models were placed to the experimental moisture ratio data. The models were compared based on their coefficient of determination (R2), reduced mean square of deviation (χ2), and root means square error (RMSE) between experimental and predicted moisture ratios. From all the mathematical models investigated, the Page and Midilli et al. models satisfactorily described the drying behavior of cassava chips in all drying compartments with drying loads of 8 kg and 12 kg, respectively.

A modular framework to model the steady off-design behavior of micro-CHP natural gas boilers based on Rankine technology is presented. The system charge integration into the model eliminates the use of any assumptions (i.e. subcooling, superheating, condensing pressure, etc.) which makes the presented model completely predictive. It is illustrated in the modelling a micro-CHP that satisfies the hot waters and central heating domestic needs (35 kWt) and produces electricity (≤1.5 kWe). A library of sub models of components with empirical (rotary vane pump and vapor scroll expander), semi-empirical (compact plates condenser) and spatially detailed physical (gas burner and evaporator) models is used to construct a model, using R245fa as thermal fluid. The model is calibrated and validated in tests in which 0.1 kg/s of water was heated from 20 °C to 30–36 °C, and 80–500 W mechanical power was delivered at the expander shaft, sweeping restrict ranges of three control variables: burner thermal power of combustion (10–14.5 kWt), pump (500–740 rpm) and expander (2500–2750 rpm) rotation speeds. The model predicts most output variables with acceptable errors, e.g., less than ±10% for the expander outlet pressure (190–220 kPa, abs) or the temperatures at the outlet of the evaporator (80–150 °C) or the expander (60–120 °C).

Biomass as carbon-neutral fuel is a promising alternative to mitigate global warming problems. Biomass conversion into producer gas (PG) through air gasification allows the co-firing of PG burners with fossil fuel burners in boilers for large scale power generation. However, PG is highly diluted with nitrogen which reduces the heating value resulting in significantly higher PG flow, eliminating the possibility of using conventional compact gas burner designs. To burn the low-grade PG, special design for the combustor is required. Novel combustor design which combined three theories of swirl vane, cyclonic and staged combustion to facilitate PG combustion in compact geometry was elaborately investigated. Flow hydrodynamics and combustion characteristics of low-grade PG were studied using ANSYS-FLUENT simulation software. Design of Experiments (DOE) method was applied to optimize the design of the combustor geometry. The arrangement of simulations was designed based on the instruction of DOE. The optimum geometry design of combustor was 500 mm combustor length, 150 mm combustor diameter, 60° swirl vane angle and 0.4 secondary inlets position to total combustor length ratio. The combustor achieved optimum performance of 1965 K outlet temperature, 18 ppm CO emissions and 33 ppm NOx emissions at slight lean condition with equivalence ratio of 0.9.

Multiple fire interaction is a fundamental combustion phenomenon which often occurs in forest fires and urban fires. This paper presents a systematical study of two identical buoyant fires on a slope in a facility consisting of a slope apparatus and a couple of gas burner systems. The test repeatability is justified for the proposed facility. The effects of fire spacing, fire power, slope angle and burner layout are intensively investigated on the flame merging probability and flame geometry of two interactive fires. The flame merging probability is found to well correlate the spacing normalized by the flame height of no spacing, and the variation of flame merging behavior with spacing can be divided into the consistent, intermittent, and independent regimes. However, the burner layout affects the critical dimensionless spacing that distinguishes the three regimes, due to the difference of air flow field between the side by side and tandem layouts. Data analysis clarifies the effect of slope and spacing on the flame length, flame tilt angle and flame attachment length, and a semi-empirical correlation is developed for the flame height of no spacing.

Controlled gas burner experiments were conducted in single- and two-story residential style structures instrumented with pressure transducers, thermocouples, and bi-directional probes throughout the structures. Exterior doors and window openings were vented in a controlled sequence to investigate the effect of the resulting flow paths on fire-induced flow dynamics and thermal conditions in the structures. The data collected in these experiments provides validation cases for the fire modeling community which currently lacks full-scale data from experiments in realistic residential style structures. The Fire Dynamics Simulator was used to model each scenario in a validation exercise that also investigated the sensitivity of the pressure predictions to the model parameters. The model was capable of predicting the qualitative changes in pressure measurements due to ventilation events as well as the apparent elevation of the neutral plane. Peak pressures were predicted to within 6% on average and quasi-steady static pressures were predicted to within 24% on average. The mean instantaneous error between the experimental pressures and those predicted with the “Localized Leakage” method was approximately 53% compared to 67% with the “Pressure Zone Leakage” method prior to the first ventilation event.

A series of 1:20 small-scale tunnel experiments have been carried out as a scaled down representation of a previously undertaken large-scale heavy goods vehicle (HGV) cargo load tunnel fire experiment. The small-scale tunnel has dimensions of 0.365 m (W) × 0.260 m (H) × 11.9 m (L) and a maximum forced ventilation velocity of 0.68 m/s is adopted corresponding to the velocity of 3 m/s used at large-scale. A gas burner and cribs constructed of medium density fireboard (MDF) have been used as the fuel sources with temperatures, heat release rate (HRR) and velocity data recorded in the small-scale tunnel experiments. A scaled down HRR curve derived from the large-scale experiment was reproduced by the gas burner. Temperatures in the small-scale gas burner experiment can effectively represent those at large-scale during the fire growth and decay stages although measurements at the fully developed stage are lower than the results from the large-scale tunnel experiment. In the small-scale tunnel experiments using the cribs time delays are applied to correct the recorded data in order to obtain the instantaneous HRR. Temperature profile comparisons between the small-scale crib and large-scale HGV cargo load experiments are not applicable since the HRR curves from the crib experiments only approximately reproduce the large-scale HRR profile.

In this paper, a series of experiments was conducted by using a gas burner to characterize the flame geometry under the inclined surface condition and trench configuration. The inclination angle was systematically varied from 0° to 26°. The centerline temperature distribution of the inclined surface was measured and the flame geometry parameters were obtained by the post-processing of the side-view images. Results show that the flame tilt angle appears a linear decrease with the increase of the inclination angle for both the inclined surface and trench configuration experiments, and decreases faster for the trench configuration. The flame length shows a non-monotonic variation with the inclination angle and a transformation process of flame from the plume-type to attachment type is observed. There is no significant effect of the aspect ratio on the flame geometry parameters. The flame attachment length fluctuated with time was obtained. A variable-interval time-average (VITA) method was used to determine the level-crossing rate and the peak frequency location. The peak frequency location has a linear relationship with the horizontal flame length. The flame attachment length and the centerline temperature increase sharply from 15° to 20° under the inclined surface condition, indicating the occurrence of flame attachment.