Journal articles on the topic 'High temperature gas stream'
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1
Rice, I. G. "Split Stream Boilers for High-Temperature/High-Pressure Topping Steam Turbine Combined Cycles." Journal of Engineering for Gas Turbines and Power 119, no. 2 (April 1, 1997): 385–94. http://dx.doi.org/10.1115/1.2815586.
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Research and development work on high-temperature and high-pressure (up to 1500°F TIT and 4500 psia) topping steam turbines and associated steam generators for steam power plants as well as combined cycle plants is being carried forward by DOE, EPRI, and independent companies. Aeroderivative gas turbines and heavy-duty gas turbines both will require exhaust gas supplementary firing to achieve high throttle temperatures. This paper presents an analysis and examples of a split stream boiler arrangement for high-temperature and high-pressure topping steam turbine combined cycles. A portion of the gas turbine exhaust flow is run in parallel with a conventional heat recovery steam generator (HRSG). This side stream is supplementary fired opposed to the current practice of full exhaust flow firing. Chemical fuel gas recuperation can be incorporated in the side stream as an option. A significant combined cycle efficiency gain of 2 to 4 percentage points can be realized using this split stream approach. Calculations and graphs show how the DOE goal of 60 percent combined cycle efficiency burning natural gas fuel can be exceeded. The boiler concept is equally applicable to the integrated coal gas fuel combined cycle (IGCC).
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Zhang, Junming, Xiaoping Chen, and Yi Li. "Velocity–temperature correlations in high-temperature supersonic turbulent channel flows for two gas models." Modern Physics Letters B 33, no. 21 (July 30, 2019): 1950247. http://dx.doi.org/10.1142/s0217984919502476.
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Velocity–temperature correlations in a high-temperature supersonic turbulent channel flows, including thermally perfect gas (TPG) and calorically perfect gas (CPG), are investigated based on the direct numerical simulation database [Chen et al., J. Turbul. 19 (2018) 365] to study the gas model effects. The results show that in fully developed turbulent channel flow, the Reynolds analogy factor remains close to 1.2 for both gas models. The “recovery enthalpy” is better than Walz’s equation to connect the mean stream-wise velocity with mean static temperature because it is independent with gas models. The modified strong Reynolds analogy for TPG is more accurate scaling than that for CPG, and the turbulent Prandtl number is insensitive to gas models. In addition, the influence of gas model on the probability density functions of stream-wise velocity and static temperature concentrate on the corresponding right tails.
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Abraitis, R. I., and P. P. Vaitekunas. "Destruction of refractories by a high-temperature gas stream." Refractories 32, no. 1-2 (January 1991): 51–58. http://dx.doi.org/10.1007/bf01295626.
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Mebold, Ulrich. "High velocity clouds near the Magellanic Clouds." Symposium - International Astronomical Union 148 (1991): 463–68. http://dx.doi.org/10.1017/s0074180900201162.
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High velocity clouds (HVCs) of neutral atomic hydrogen close to the position of the Magellanic Clouds (MCs) and the Magellanic Stream (Stream) are reviewed. The gas observed at velocities of +70 km/s and +130 km/s in front of the LMC is probably associated with ordinary HVCs in the galactic halo. This is not the case for the gas observed between +150 and +170 km/s which is more likely associated with the MCs. The HVCs observed superimposed onto the Stream are possibly remnants of collisions between a gaseous polar ring around our Galaxy and the bridge region between the MCs. The HVCs found close to and “behind” the tip of the Stream may be regarded as shreds of the Stream precipitating toward the galactic disk. The chemical composition, the radiation field and the temperature in the Stream is discussed in the context of the first spin temperature determination by Wakker (1990), of an HVC.
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Krishnamoorthy, V., B. R. Pai, and S. P. Sukhatme. "Influence of Upstream Flow Conditions on the Heat Transfer to Nozzle Guide Vanes." Journal of Turbomachinery 110, no. 3 (July 1, 1988): 412–16. http://dx.doi.org/10.1115/1.3262212.
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The influence of a combustor located just upstream of a nozzle guide vane cascade on the heat flux distribution to the nozzle guide vane was experimentally investigated. The surface temperature distribution around the convectively cooled vane of the cascade was obtained by locating the cascade, firstly in a low-turbulence uniform hot gas stream, secondly in a high-turbulence, uniform hot gas stream, and thirdly in a high-turbulence, nonuniform hot gas stream present just downstream of the combustor exit. The results indicate that the increased blade surface temperatures observed for the cascade placed just downstream of the combustor can be accounted for by the prevailing turbulence level measured at cascade inlet in cold-flow conditions and the average gas temperature at the cascade inlet.
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Nakagawa, Tsuguhiko, Kazuaki Hara, Tomohiko Furuhata, and Norio Arai. "Non-Oxidizing Heating by High Temperature Nitrogen Gas Jet Stream." JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 32, no. 1 (1999): 110–15. http://dx.doi.org/10.1252/jcej.32.110.
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Drobyshevskii, A. S., and A. B. Gots. "Measurement of particle velocity in a high-temperature gas stream." Soviet Powder Metallurgy and Metal Ceramics 24, no. 2 (February 1985): 132–34. http://dx.doi.org/10.1007/bf00799717.
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Peterson, R. C. "A flame-heated gas-flow furnace for single-crystal X-ray diffraction." Journal of Applied Crystallography 25, no. 5 (October 1, 1992): 545–48. http://dx.doi.org/10.1107/s0021889892004023.
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A furnace using an inert-gas stream heated by an acetylene torch has been designed to conduct high temperature X-ray diffraction experiments. The design makes use of the stability of electrically heated gas-flow devices and the high-temperature capability of flame heaters. The gas flow is coaxial with the crystal mounting fibre resulting in a thermally stable environment controlled by the composition of the heated gas stream. Temperatures from 373 up to 1573 K are maintained by computer-controlled flow regulation of the acetylene flame based on the signal from a thermocouple on which the crystal is mounted. The results of a high-temperature X-ray diffraction study of Mg0.54Fe2+ 0.46Fe2O4, spinel are given as an example of the application of this furnace.
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Cämmerer, Malcolm, Thomas Mayer, Stefanie Penzel, Mathias Rudolph, and Helko Borsdorf. "Application of Low-Cost Electrochemical Sensors to Aqueous Systems to Allow Automated Determination of NH3 and H2S in Water." Sensors 20, no. 10 (May 15, 2020): 2814. http://dx.doi.org/10.3390/s20102814.
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Usage of commercially available electrochemical gas sensors is currently limited by both the working range of the sensor with respect to temperature and humidity and the spikes in sensor response caused by sudden changes in temperature or humidity. Using a thermostatically controlled chamber, the sensor response of ammonia and hydrogen sulfide sensors was studied under extreme, rapidly changing levels of humidity with the aim of analyzing nebulized water samples. To protect the sensors from damage, the gas stream was alternated between a saturated gas stream from a Flow Blurring® nebulizer and a dry air stream. When switching between high and low humidity gas streams, the expected current spike was observed and mathematically described. Using this mathematical model, the signal response due to the change in humidity could be subtracted from the measured signal and the sensor response to the target molecule recorded. As the sensor response is determined by the model while the sensor is acclimatizing to the new humid conditions, a result is calculated faster than that by systems that rely on stable humidity. The use of the proposed mathematical model thus widens the scope of electrochemical gas sensors to include saturated gas streams, for example, from nebulized water samples, and gas streams with variable humidity.
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Al-Mhanna, Najah. "Simulation of High Pressure Separator Used in Crude Oil Processing." Processes 6, no. 11 (November 5, 2018): 219. http://dx.doi.org/10.3390/pr6110219.
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The aim of this research was to simulate a high-pressure (HP) separator in order to investigate the effect of changing separator operating conditions on product properties. In this study, the results obtained using the CHEMCAD simulation software package were compared with those obtained using the UniSim software package. The simulation results were comparable with industrial data. A sensitivity study was conducted by changing the gas stream properties, such as temperature, pressure, and flow rate, in order to investigate and optimize the process. The results showed that increasing the separator inlet pressure from 30 to 80 bar decreased the outlet gas flow rate from 1202 to 871.15 kmol/h. Also, the methane mole fraction increased from 0.69 to 0.74; however, the preheater heating duty was increased from 8.71 to 11.48 GJ/h. The simulation results showed that increasing the temperature of the separator feed stream from 43 to 83 °C increased the flow rate of the outlet gas stream from 871.15 to 1142.98 kmol/h. However, this temperature change reduced the methane concentration in the gas product and decreased the heating duty of the heat exchanger. Finally, the study demonstrated that there is no effect of increasing the inlet feed flow rate on the produced methane gas concentration.
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MILLER, R. S., and J. BELLAN. "Direct numerical simulation of a confined three-dimensional gas mixing layer with one evaporating hydrocarbon-droplet-laden stream." Journal of Fluid Mechanics 384 (April 10, 1999): 293–338. http://dx.doi.org/10.1017/s0022112098004042.
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Direct numerical simulations are performed of a confined three-dimensional, temporally developing, initially isothermal gas mixing layer with one stream laden with as many as 7.3×105 evaporating hydrocarbon droplets, at moderate gas temperature and subsonic Mach number. Complete two-way phase couplings of mass, momentum and energy are incorporated which are based on a thermodynamically self-consistent specification of the vapour enthalpy, internal energy and latent heat of vaporization. Effects of the initial liquid mass loading ratio (ML), initial Stokes number (St0), initial droplet temperature and flow three-dimensionality on the mixing layer growth and development are discussed. The dominant parameter governing flow modulation is found to be the liquid mass loading ratio. Variations in the initial Stokes number over the range 0.5[les ]St0[les ]2.0 do not cause significant modulations of either first- or second-order gas phase statistics. The mixing layer growth rate and kinetic energy are increasingly attenuated for increasing liquid loadings in the range 0[les ]ML[les ]0.35. The laden stream becomes saturated before evaporation is completed for all but the smallest liquid loadings owing to: (i) latent heat effects which reduce the gas temperature, and (ii) build up of the evaporated vapour mass fraction. However, droplets continue to be entrained into the layer where they evaporate owing to contact with the relatively higher-temperature vapour-free gas stream. The droplets within the layer are observed to be centrifuged out of high-vorticity regions and to migrate towards high-strain regions of the flow. This results in the formation of concentration streaks in spanwise braid regions which are wrapped around the periphery of secondary streamwise vortices. Persistent regions of positive and negative slip velocity and slip temperature are identified. The velocity component variances in both the streamwise and spanwise directions are found to be larger for the droplets than for the gas phase on the unladen stream side of the layer; however, the cross-stream velocity and temperature variances are larger for the gas. Finally, both the mean streamwise gas velocity and droplet number density profiles are observed to coincide for all ML when the cross-stream coordinate is normalized by the instantaneous vorticity thickness; however, first-order thermodynamic profiles do not coincide.
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El-Maghraby, Rehab M., Mahmoud Ramzy, and Ahmed K. Aboul-Gheit. "High Pressure Supercritical Carbon Dioxide Separation from its Mixture with Nitrogen at Different Temperatures." Materials Science Forum 1008 (August 2020): 1–14. http://dx.doi.org/10.4028/www.scientific.net/msf.1008.1.
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Carbon dioxide (CO2) capturing from point sources is currently being proposed as a way to minimize CO2 emissions to the atmosphere. Carbon dioxide is considered one of the greenhouse gases that affects our environment. Legislations are being enforced in many countries to limit CO2 emissions to the atmosphere. Two methods are mostly used for CO2 capturing from flue gases and natural gases; the first method is absorption using amine-based solvents, while the second is membrane separation. The first method is effective for CO2 separation from gas mixtures with low CO2 concentration in the range of 10 to 20%, while the other can handle gas mixture with intermediate CO2 concentration but there is a limit on the CO2 purity. Hence, such methods cannot be used in pre-combustion and oxy fuel technologies where a more concentrated CO2 gas stream is produced. Throughout this work, a new method is introduced to separate carbon dioxide from its mixture with nitrogen (N2) at high concentrations, 90 mol.% CO2 and 10 mol.% N2 gas mixture. A customized high-pressure experimental set-up was built. Three temperature were tested: 15 °C, 25 °C and 38 °C at 150 bar. At such condition CO2 will be in the liquid and the supercritical phase respectively. The composition of the top and bottom streams where analyzed. The amount of CO2 in the top stream was the smallest at the supercritical condition. In addition, the purity of CO2 in the bottom stream was the highest at 38 °C and 150 bars, when CO2 is at the supercritical phase.
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Wu, H., M. Tan, W. Zhu, and Z. S. Ma. "The Interaction between Erosion Particle and Gas Stream in High Temperature Gas Burner Rig for Thermal Barrier Coatings." High Temperature Materials and Processes 38, no. 2019 (February 25, 2019): 125–34. http://dx.doi.org/10.1515/htmp-2017-0172.
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AbstractThermal 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.
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Abejón, Ricardo, Ana Fernández-Ríos, Antonio Domínguez-Ramos, Jara Laso, Israel Ruiz-Salmón, María Yáñez, Alfredo Ortiz, et al. "Hydrogen Recovery from Waste Gas Streams to Feed (High-Temperature PEM) Fuel Cells: Environmental Performance under a Life-Cycle Thinking Approach." Applied Sciences 10, no. 21 (October 23, 2020): 7461. http://dx.doi.org/10.3390/app10217461.
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Fossil fuels are being progressively substituted by a cleaner and more environmentally friendly form of energy, where hydrogen fuel cells stand out. However, the implementation of a competitive hydrogen economy still presents several challenges related to economic costs, required infrastructures, and environmental performance. In this context, the objective of this work is to determine the environmental performance of the recovery of hydrogen from industrial waste gas streams to feed high-temperature proton exchange membrane fuel cells for stationary applications. The life-cycle assessment (LCA) analyzed alternative scenarios with different process configurations, considering as functional unit 1 kg of hydrogen produced, 1 kWh of energy obtained, and 1 kg of inlet flow. The results make the recovery of hydrogen from waste streams environmentally preferable over alternative processes like methane reforming or coal gasification. The production of the fuel cell device resulted in high contributions in the abiotic depletion potential and acidification potential, mainly due to the presence of platinum metal in the anode and cathode. The design and operation conditions that defined a more favorable scenario are the availability of a pressurized waste gas stream, the use of photovoltaic electricity, and the implementation of an energy recovery system for the residual methane stream.
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Halim, M. H. M., F. Kadirkhan, W. N. F. W. Mustapa, W. K. Soh, and S. Y. Yeo. "Natural gas sweetening polymeric membrane: Established optimum operating condition at 70% of CO2 concentration feed gas stream." Malaysian Journal of Fundamental and Applied Sciences 16, no. 1 (February 2, 2020): 54–58. http://dx.doi.org/10.11113/mjfas.v16n1.1471.
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PETRONAS embarks on breakthrough technology for natural gas sweetening in high CO2 gas fields. Membrane technology is found to be one with high potential and a promising technology for bulk CO2 removal from natural gas. It can be suited to wide operating conditions to process varied natural gas composition, pressure and temperature. This paper focuses on the extensive development of PETRONAS in-house membrane and its evaluation for gas separation performance for high CO2 feed gas at different operating conditions; eg. feed gas flowrate, temperature, pressure, CO2 concentration in mixed gas system, and permeate pressure. For all the cases in this study, samples were tested at optimum gas flowrate of 1000 standard cm3/min (sccm) to obtain representative membrane performance. Feed gas pressure and CO2 concentration have shown significantly affect membrane permeation properties; whereas feed gas temperature and permeate pressure showed negligible impact. There is a trade-off between permeance and selectivity when CO2 concentration is increased from 40% to 70%; where the CO2 permeance increased by 12% which consequently reduces CO2/CH4 selectivity by 15%. In summary, the membrane developed in this study demonstrates high pressure durability up to 50 bar and temperature up to 55oC with satisfactory gas separation performance in the presence of high CO2 concentration in feed gas (up to 70% CO2). This work is breakthrough in establishing the operational boundary of PETRONAS Membrane for technology development and deployment in monetizing high CO2 gas field.
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Li, Junpeng, and Rui Wang. "Polyoxometalate/Ionic Liquid Desulfurization System for Hydrogen Sulfide Removal from High-Temperature Gas Stream." Molecules 27, no. 19 (October 9, 2022): 6723. http://dx.doi.org/10.3390/molecules27196723.
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The temperature of industrial gas containing harmful H2S can reach hundreds of degrees. However, few processes can be used directly for H2S removal from industrial high-temperature gas. In this work, three polyoxometalates with different central atoms ((n-Bu4N)3VMo12O40, (n-Bu4N)3PMo12O40, and (n-Bu4N)4[α-SiMo12O40]) were synthesized and dissolved in four ionic liquids (Bmim]Cl, [Bmim]HCO3, [Bmim]Mes, or [Bmim]OAc) for H2S removal from high-temperature (90–180 °C) gases. The result showed that (n-Bu4N)3VMo12O40/[Bmim]OAc exhibited the optimal desulfurization performance, maintaining more than 98.6% desulfurization efficiency within 10 h. The reacted desulfurization solution can be regenerated by blowing air. FT-IR and XPS results show that both the central atom V and the coordination atom Mo of the polyoxometalate are involved in the oxidation of H2S; after the regeneration by introducing air, V(+IV) and Mo(+IV) recovered to V(+V) and Mo(+VI), respectively. Our research shows that (n-Bu4N)3VMo12O40/[Bmim]OAc is an efficient, easy-to-regenerate, and suitable high-temperature gas desulfurization solution.
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Gudenau, H. W., H. Hoberg, A. R. Pande, M. Weinberg, and J.-E. Becker. "High-temperature fuel gas cleaning and removal of alkalis using molten slag." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 212, no. 3 (May 1, 1998): 151–58. http://dx.doi.org/10.1243/0957650981536817.
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Fuel gas cleaning is an important step in the development of coal-based combined cycle technologies. By integrating hot gas cleaning facilities in the combined cycle power plant, higher operating temperatures can be achieved. Research is being carried out at the Institute of Ferrous Metallurgy, Technical University of Aachen, to develop a process for gas cleaning at temperatures above 1300°C using a venturi scrubber with molten slags as sorbents. This process offers simultaneous removal of particulate matter and alkali vapours in the gas stream. The present paper deals with the particulate removal tests, with major emphasis on investigations carried out to study the reaction between molten slags of various compositions and alkali vapours. These investigations included thermochemical calculations as well as an experimental reaction study.
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El-Emam, Salah, and Mahmoud Awad. "A Study on Liquid Spray Evaporation into a High Temperature Gas Stream.(Dept.M)." MEJ. Mansoura Engineering Journal 13, no. 1 (May 27, 2021): 36–48. http://dx.doi.org/10.21608/bfemu.2021.172700.
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Hu, Xuechao, and Junhui Dong. "Regeneration Mechanism of Sulfur Absorption Via Samarium-doped Cerium Adsorbents in the Gas Atmosphere of O2/N2." Materials 13, no. 5 (March 9, 2020): 1225. http://dx.doi.org/10.3390/ma13051225.
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Sulfides existing in many high-temperature gas mixtures have a negative effect on various industrial applications. Ce-based adsorbents are becoming a hotspot in the high-temperature desulfurization process owing to their excellent thermal stability at high temperatures and regeneration capacity. In this study, we investigate the regeneration path of samarium-doped cerium (SDC) sorbent at high temperature. The SDC adsorbent showed a good sulfur removal ability and excellent regeneration capacity. Ce2O2S and Ce(SO4)2 are observed in the used adsorbent, and Ce2O2S is the main sulfur-containing species. The regeneration path of the Ce2O2S is the key to the regeneration mechanism of the adsorbent. There are two regeneration paths for the Ce2O2S at high temperature in O2/N2 gas mixture. In air stream, the Ce2O2S is oxidized to Ce2O2SO4 and then decomposes into CeO2 and SO2. In a 2% O2/N2 gas condition, the Ce2O2S directly generates CeO2 and elemental sulfur with O2 assistance.
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Solomon, P. R., M. A. Serio, J. E. Cosgrove, D. S. Pines, Y. Zhao, R. C. Buggeln, and S. J. Shamroth. "A Coal-Fired Heat Exchanger for an Externally Fired Gas Turbine." Journal of Engineering for Gas Turbines and Power 118, no. 1 (January 1, 1996): 22–31. http://dx.doi.org/10.1115/1.2816545.
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Significant improvements in efficiency for electricity generation from coal can be achieved by cycles that employ a high-temperature, highly recuperative gas turbine topping cycle. The principal difficulty of employing a gas turbine in a coal-fired power generation system is the possible erosion and corrosion of the high-temperature rotating gas turbine components caused by the coal’s inorganic and organically bound constituents (ash, sulfur, and alkali metals). One route to overcome this problem is the development of an externally fired gas turbine system employing a coal fired heat exchanger. The solution discussed in this paper is the design of a Radiatively Enhanced, Aerodynamically Cleaned Heat-Exchanger (REACH-Exchanger). The REACH-Exchanger is fired by radiative and convective heat transfer from a moderately clean fuel stream and radiative heat transfer from the flame of a much larger uncleaned fuel stream, which supplies most of the heat. The approach is to utilize the best ceramic technology available for high-temperature parts of the REACH-Exchanger and to shield the high-temperature surfaces from interaction with coal minerals by employing clean combustion gases that sweep the tube surface exposed to the coal flame. This paper presents a combined experimental/computational study to assess the viability of the REACH-Exchanger concept. Experimental results indicated that the REACH-Exchanger can be effectively fired using radiation from the coal flame. Both computation and experiments indicate that the ceramic heat exchanger can be aerodynamically protected by a tertiary stream with an acceptably low flow rate.
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Arroyo, Jorge, Luis Pérez, and Víctor Cuervo-Piñera. "CFD Modeling and Validation of Blast Furnace Gas/Natural Gas Mixture Combustion in an Experimental Industrial Furnace." Processes 11, no. 2 (January 19, 2023): 332. http://dx.doi.org/10.3390/pr11020332.
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The use of residual gases from steel production processes as fuel for steel treatment furnaces has attracted great interest as a method for reducing fossil fuel consumption and the steel footprint. However, these gases often have a low calorific value, and a direct substitution can lead to low temperatures or combustion instability issues. CFD simulations of the combustion of these gases can help steel producers forecast the results of the substitution before real testing and implementation. In this study, a CFD model of an industrial experimental furnace in the steel sector is developed and validated. The results are calculated using the combustion, radiation, and heat transfer models included in the software Ansys Fluent. The validation of the simulated results is performed with data acquired from experimental tests under the same simulated conditions at three air-to-fuel equivalence ratios, which vary from an excess of 0% to an excess of 5% oxygen at the outlet. The model is adjusted to the results, capturing the trends of the measured physical variables and pollutant concentrations. In the case of the combustion temperature, the differences between the simulated and measured values vary from 0.03% to 6.9. Based on the simulation results, the use of blast furnace gas as fuel produces temperatures inside the chamber between 1004 °C and 1075 °C and high stream velocities because of the high flow needed to keep the power constant. Flames exhibit straight movements since the high flows absorb the effect of the swirling flames. The addition of natural gases increases the combustion temperature up to 1211 °C and reduces the flow and length of the flames. Finally, temperatures up to 1298 °C and shorter flames are reached with natural gas enriched with a stream of oxygen, but in this case, NOx emissions need to be controlled.
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Ebuehi, Osaretin N. I., Kingsley Abhulimen, and Daniel O. Adebesin. "Modelling Production of Renewable Energy from Water Splitting High Thermal Electrolysis Processes." European Journal of Engineering and Technology Research 6, no. 3 (April 12, 2021): 14–21. http://dx.doi.org/10.24018/ejers.2021.6.3.2391.
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Recently, fuel gas from water has become the center of attention because it is a renewable source of energy and eco-friendly. In this study, the hydrogen gas simulated was obtained from the high-temperature water splitting electrolysis model, because it is more efficient than the low-temperature water splitting electrolysis process. It also releases oxygen as a byproduct. The high-temperature electrolysis model is made up of three loops: primary high-temperature helium loop, secondary helium loop, and high-temperature electrolysis loop. Hydrogen gave a temperature of 27.20C, a pressure of 49.5 bars, and a molar flow of 84.02MMSCFD. The hydrogen gas from a high-temperature electrolysis model is simulated with a CO2 gas stream to produce methane and water, also releasing unreacted carbon dioxide and hydrogen. Key parameters such as molar entropy, molar enthalpy, heat flow, and cost flow were evaluated by Aspen HYSYS V8.8. The simulation model used for this work is the Sabatier Process Model. In this model, Continuous stirred tank, Converter, Equilibrium, Gibbs, Plug flow reactors were used to generate methane. The Converter reactor gave the highest yield of methane gas with a mole fraction of 0.2390. Key benchmarks, including temperature, heat flow, cost flow, cost factor were varied to see how they can affect methane gas and other products.
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Ebuehi, Osaretin N. I., Kingsley Abhulimen, and Daniel O. Adebesin. "Modelling Production of Renewable Energy from Water Splitting High Thermal Electrolysis Processes." European Journal of Engineering and Technology Research 6, no. 3 (April 12, 2021): 79–86. http://dx.doi.org/10.24018/ejeng.2021.6.3.2391.
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Recently, fuel gas from water has become the center of attention because it is a renewable source of energy and eco-friendly. In this study, the hydrogen gas simulated was obtained from the high-temperature water splitting electrolysis model, because it is more efficient than the low-temperature water splitting electrolysis process. It also releases oxygen as a byproduct. The high-temperature electrolysis model is made up of three loops: primary high-temperature helium loop, secondary helium loop, and high-temperature electrolysis loop. Hydrogen gave a temperature of 27.20C, a pressure of 49.5 bars, and a molar flow of 84.02MMSCFD. The hydrogen gas from a high-temperature electrolysis model is simulated with a CO2 gas stream to produce methane and water, also releasing unreacted carbon dioxide and hydrogen. Key parameters such as molar entropy, molar enthalpy, heat flow, and cost flow were evaluated by Aspen HYSYS V8.8. The simulation model used for this work is the Sabatier Process Model. In this model, Continuous stirred tank, Converter, Equilibrium, Gibbs, Plug flow reactors were used to generate methane. The Converter reactor gave the highest yield of methane gas with a mole fraction of 0.2390. Key benchmarks, including temperature, heat flow, cost flow, cost factor were varied to see how they can affect methane gas and other products.
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NAKAGAWA, TSUGUHIKO, and NORIO ARAI. "Characteristics of Non-Oxidizing Heater System by High Temperature Jet Stream of Inert Gas." KAGAKU KOGAKU RONBUNSHU 25, no. 2 (1999): 282–89. http://dx.doi.org/10.1252/kakoronbunshu.25.282.
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Jangsawang, W., A. Klimanek, and Ashwani K. Gupta. "Enhanced Yield of Hydrogen From Wastes Using High Temperature Steam Gasification." Journal of Energy Resources Technology 128, no. 3 (July 22, 2005): 179–85. http://dx.doi.org/10.1115/1.2134733.
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Equilibrium calculations using the element potential method have been used to determine optimum conditions for the gasification of wood pellets and to understand the limitations and influence of preheated gasifying agent on the product gas composition. The calculations were carried out under isobaric (1 atm) and isothermal conditions using cellulose as the waste fuel. For each isothermal case results were obtained for the effect of feed gas composition. Various mixtures of steam/cellulose [mol/mol] and oxygen/steam [mol/mol] were examined to determine conditions for high yields of H2 and CO at a given temperature. The yield of hydrogen and carbon monoxide with different input feed composition and temperature of the process are therefore considered. The results showed strong effect of temperature on hydrogen and carbon monoxide yield in the gasified product stream. High temperatures resulted in high yields of hydrogen. Pure steam resulted in higher yields of hydrogen than steam-air gasifying agent. The experimental results using a fixed bed reactor showed good trends with the calculated data. These results assist in the design and development of enhanced hydrogen production from steam gasification of wastes.
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Volino, R. J., and T. W. Simon. "Boundary Layer Transition Under High Free-Stream Turbulence and Strong Acceleration Conditions: Part 1—Mean Flow Results." Journal of Heat Transfer 119, no. 3 (August 1, 1997): 420–26. http://dx.doi.org/10.1115/1.2824114.
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Measurements from heated boundary layers along a concave-curved test wall subject to high (initially 8 percent) free-stream turbulence intensity and strong (K = (ν/U∞2) dU∞/dx) as high as 9 × 10−6) acceleration are presented and discussed. Conditions for the experiments were chosen to roughly simulate those present on the downstream half of the pressure side of a gas turbine airfoil. Mean velocity and temperature profiles as well as skin friction and heat transfer coefficients are presented. The transition zone is of extended length in spite of the high free-stream turbulence level. Transitional values of skin friction coefficients and Stanton numbers drop below flat-plate, low-free-stream-turbulence, turbulent flow correlations, but remain well above laminar flow values. The mean velocity and temperature profiles exhibit clear changes in shape as the flow passes through transition. To the authors’ knowledge, this is the first detailed documentation of a high-free-stream-turbulence boundary layer flow in such a strong acceleration field.
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Camci, C., and T. Arts. "Experimental Heat Transfer Investigation Around the Film-Cooled Leading Edge of a High-Pressure Gas Turbine Rotor Blade." Journal of Engineering for Gas Turbines and Power 107, no. 4 (October 1, 1985): 1016–21. http://dx.doi.org/10.1115/1.3239805.
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This paper describes an experimental heat transfer investigation around the leading edge of a high-pressure film-cooled gas turbine rotor blade. The measurements were performed in the VKI isentropic compression tube facility using platinum thin film gauges painted on a blade made of machinable glass ceramic. Free-stream to wall temperature ratio, Reynolds, and Mach numbers were selected from actual aeroengines conditions. Heat transfer data obtained without and with film cooling in a stationary frame are presented. The effects of coolant to free-stream mass weight ratio and temperature ratio were successively investigated. Heat transfer modifications due to incidence angle variations were interpreted with the aid of inviscid flow calculation methods.
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Chung, Sung Sik, and Osamu Kawaguchi. "Evaporation Rate of Free Paraffin Hydro-carbon Droplets in a High-Temperature and High-Pressure Gas Stream." JSME International Journal Series B 38, no. 1 (1995): 121–28. http://dx.doi.org/10.1299/jsmeb.38.121.
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Inger, Marek, Bartosz Moszowski, Monika Ruszak, Jakub Rajewski, and Marcin Wilk. "Two-Stage Catalytic Abatement of N2O Emission in Nitric Acid Plants." Catalysts 10, no. 9 (September 1, 2020): 987. http://dx.doi.org/10.3390/catal10090987.
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Different variants for abatement of N2O emission from nitric acid plants with the use of catalysts developed at Łukasiewicz-INS were analyzed. Activity tests on a pilot scale confirmed the high activity of the studied catalysts. A two-stage catalytic abatement of N2O emission in nitric acid plants was proposed: by high-temperature decomposition in the nitrous gases stream (HT-deN2O) and low-temperature decomposition in the tail gas stream (LT-deN2O). The selection of the optimal variant for abatement of N2O emission depends on the individual characteristics of the nitric acid plant: ammonia oxidation parameters, construction of ammonia oxidation reactor and temperature of the tail gas upstream of the expansion turbine. It was shown that the combination of both deN2O technologies, taking into account their technological constraints (dimensions of the catalyst bed), allows for a greater abatement of N2O emission, than the use of only one technology. This solution may be economically advantageous regarding the high prices of CO2 emission allowances.
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Wadia, A. R., and D. A. Nealy. "Experimental Simulation of Turbine Airfoil Leading Edge Film Cooling." Journal of Turbomachinery 110, no. 2 (April 1, 1988): 226–32. http://dx.doi.org/10.1115/1.3262185.
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Leading edge showerhead cooling designs represent an important feature of certain classes of high-temperature turbine airfoils. This paper outlines a methodology for predicting the surface temperatures of showerhead designs with spanwise injection through an array of discrete holes. The paper describes a series of experiments and analyses on scaled cylinder models with injection through holes inclined at 20, 30, 45, and 90 deg for typical radial and circumferential spacing-to-diameter ratios of 10 and 4, respectively. The experiments were conducted in a wind tunnel on several stainless steel test specimens in which flow and heat transfer parameters were measured over the simulated airfoil leading edge surfaces. Based on the experiments, an engineering design model is proposed that treats the gas-to-surface heat transfer coefficient with film cooling in a manner suggested by a recent Purdue–NASA investigation and includes the important contribution of upstream (coolant inlet face) heat transfer. The experiments suggest that the averaged film cooling effectiveness in the showerhead region is primarily influenced by the inclination of the injection holes. The effectiveness parameter is not strongly affected by variations in coolant-to-gas stream pressure ratio, free-stream Mach number, gas-to-coolant temperature ratio, and gas stream Reynolds number. The model is employed to determine (inferentially) the average Stanton number reduction parameter for a series of pressure ratios varying from 1.004 to 1.3, Mach numbers ranging from 0.1 to 0.2, temperature ratios between 1.6 and 2.0, and Reynolds numbers ranging from 3.5×104 to 9.0×104.
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Park, Ji-Woong, and Chang Bo Oh. "Numerical Study of CO Reduction Characteristics in High-temperature Air Stream Diluted with Exhaust Gas." Journal of the Korean Society of Combustion 20, no. 3 (September 30, 2015): 8–12. http://dx.doi.org/10.15231/jksc.2015.20.3.008.
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Miller, Fletcher J., and Roland W. Koenigsdorff. "Thermal Modeling of a Small-Particle Solar Central Receiver." Journal of Solar Energy Engineering 122, no. 1 (February 1, 2000): 23–29. http://dx.doi.org/10.1115/1.556277.
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This paper presents a thermal model of a solar central receiver that volumetrically absorbs concentrated sunlight directly in a flowing gas stream seeded with submicron carbon particles. A modified six-flux radiation model is developed and used with the energy equation to calculate the three-dimensional radiant flux and temperature distributions in a cavity-type particle receiver. Results indicate that the receiver is capable of withstanding very high incident fluxes and delivering high temperatures. The receiver efficiency as a function of mass flow rate as well as the effect of particle oxidation on the temperature profiles are presented. [S0199-6231(00)00201-X]
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Dong, Zhimin, and Qinglin Du. "The Local Distribution of Temperatures and Entropy Generation Rate in an Ideal Counterflow Heat Exchanger." Coatings 11, no. 8 (August 15, 2021): 970. http://dx.doi.org/10.3390/coatings11080970.
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The process of heat exchange between two fluids of different temperatures and separated by a solid wall occurs in many engineering applications. Log mean temperature difference and effectiveness-NTU methods are widely used to assist in the design of heat exchangers. However, the two methods focus on overall analysis and cannot show the local temperature distributions. This paper obtains the mathematical solutions to the temperature profiles in an ideal counterflow heat exchanger. The aim of this research is to explain the phenomenon called the “entropy generation paradox”, which indicates a discrepancy between effectiveness and optimal entropy generation. The theoretical analysis reveals that the temperature curves are exponential functions when the heat capacity rates of the two streams are different; otherwise, the curves are linear functions. A heat exchanger is demonstrated to draw the temperature profiles under different working conditions. Local entropy generation rates are determined by the ratio of local stream temperatures in the form of a hook function. To realize a certain heat duty, there are many stream flow rate couples, and each couple results in a different entropy generation profile and obtains a corresponding total entropy generation. The helical steam generator of a high-temperature gas-cooled reactor is analyzed in this article and the principle of equipartition of entropy generation is confirmed. This principle indicates that, among the many working conditions to achieve a certain heat duty, a heat exchanger characterized by a nearly constant entropy production gives the best second law efficiency possible in order to achieve the best energy conversion.
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Emmerton, C. A., V. L. St. Louis, I. Lehnherr, E. R. Humphreys, E. Rydz, and H. R. Kosolofski. "The net exchange of methane with high Arctic landscapes during the summer growing season." Biogeosciences Discussions 11, no. 1 (January 28, 2014): 1673–706. http://dx.doi.org/10.5194/bgd-11-1673-2014.
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Abstract. High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and desert and wetland landscapes on northern Ellesmere Island, Canada, we made static chamber measurements at both locations over five growing seasons and eddy covariance (EC) measurements at the wetland in 2012. Chamber measurements revealed that desert soils consumed CH4 (−1.37 ± 0.10 mg-CH4 m−2 d−1) whereas the wetland emitted CH4 (+0.22 ± 0.19 mg-CH4 m−2 d−1). Desert CH4 consumption rates were positively correlated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27± 0.18 mg-CH4 m−2 d−1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC incorporated a arger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenisis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.
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Chung, Sung Sik, and O. Kawaguchi. "An experimental study on the evaporation of freely falling droplet under high temperature and high pressure gas stream." KSME Journal 4, no. 2 (September 1990): 172–77. http://dx.doi.org/10.1007/bf02954040.
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Musavuli, Kyatsinge Cedric, Nicolaas Engelbrecht, Raymond Cecil Everson, Gerrit Lodewicus Grobler, and Dmitri Bessarabov. "CO Preferential Oxidation in a Microchannel Reactor Using a Ru-Cs/Al2O3 Catalyst: Experimentation and CFD Modelling." Processes 9, no. 5 (May 14, 2021): 867. http://dx.doi.org/10.3390/pr9050867.
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This work presents an experimental and modelling evaluation of the preferential oxidation of CO (CO PROX) from a H2-rich gas stream typically produced from fossil fuels and ultimately intended for hydrogen fuel cell applications. A microchannel reactor containing a washcoated 8.5 wt.% Ru/Al2O3 catalyst was used to preferentially oxidise CO to form CO2 in a gas stream containing (by vol.%): 1.4% CO, 10% CO2, 18% N2, 68.6% H2, and 2% added O2. CO concentrations in the product gas were as low as 42 ppm (99.7% CO conversion) at reaction temperatures in the range 120–140 °C and space velocities in the range 65.2–97.8 NL gcat−1 h−1. For these conditions, less than 4% of the H2 feed was consumed via its oxidation and reverse water-gas shift. Furthermore, a computational fluid dynamic (CFD) model describing the microchannel reactor for CO PROX was developed. With kinetic parameter estimation and goodness of fit calculations, it was determined that the model described the reactor with a confidence interval far greater than 95%. In the temperature range 100–200 °C, the model yielded CO PROX reaction rate profiles, with associated mass transport properties, within the axial dimension of the microchannels––not quantifiable during the experimental investigation. This work demonstrates that microchannel reactor technology, supporting an active catalyst for CO PROX, is well suited for CO abatement in a H2-rich gas stream at moderate reaction temperatures and high space velocities.
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Li, Dian Xun, and Shu Sheng Zhang. "Numerical Simulation of Accident Spray Cooling System in FGD System Inlet." Applied Mechanics and Materials 703 (December 2014): 237–40. http://dx.doi.org/10.4028/www.scientific.net/amm.703.237.
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By accident of a power plant desulfurization CFD Research sprinkler system model to simulate the process of considering the two-way coupling between the droplet atomization, evaporation, with the main flue gas stream. The results showed that x = 3300 sectional arrangement 40 nozzles, high temperature flue gas through a water spray after 10.8m reach x = 14100 section of the temperature has dropped to 358K, before entering the GGH down to 345K, meet an accident situation spray cooling requirements.
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Coat, C. A., and G. D. Lock. "Flow visualisation experiments for turbine film cooling." Aeronautical Journal 108, no. 1086 (August 2004): 403–9. http://dx.doi.org/10.1017/s000192400000021x.
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Abstract Flow visualisation experiments related to turbine film cooling have been conducted. These investigated the fluid mechanics of coolant ejection using a large-scale, flat-plate model at engine-representative Reynolds numbers in a low-speed tunnel with ambient-temperature mainstream flow. The coolant trajectories were captured using a fine nylon mesh covered with thermochromic liquid crystals, allowing measurement of gas temperature contours in planes perpendicular to the flow. Three injection geometries were assessed: cylindrical holes with stream-wise injection, cylindrical holes with cross-stream injection, and fan-shaped holes. The data demonstrated that the cylindrical holes produced discrete jets, which lifted off the surface at high coolant-to-mainstream momentum flux ratios; these jets were characterised by the kidney-shaped stream-tubes expected for injection into cross-flow. The jets injected with cross-stream momentum exhibited a more obvious kidney-shaped cross-section, which rotated with distance downstream of injection. The jets from the fan-shaped holes were attached to the surface even at high momentum flux ratios, were more diffuse, and exhibited two cores of high temperature. The trajectory visualisation data were used to interpret the adiabatic cooling effectiveness measured at the surface.
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Emmerton, C. A., V. L. St. Louis, I. Lehnherr, E. R. Humphreys, E. Rydz, and H. R. Kosolofski. "The net exchange of methane with high Arctic landscapes during the summer growing season." Biogeosciences 11, no. 12 (June 16, 2014): 3095–106. http://dx.doi.org/10.5194/bg-11-3095-2014.
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Abstract. High Arctic landscapes are essentially vast cold deserts interspersed with streams, ponds and wetlands. These landscapes may be important consumers and sources of the greenhouse gas methane (CH4), though few measurements exist from this region. To quantify the flux of CH4 (FCH4) between the atmosphere and high Arctic landscapes on northern Ellesmere Island, Canada, we made static chamber measurements over five and three growing seasons at a desert and wetland, respectively, and eddy covariance (EC) measurements at a wetland in 2012. Chamber measurements revealed that, during the growing season, desert soils consumed CH4 (−1.37 ± 0.06 mg-CH4 m−2 d−1), whereas the wetland margin emitted CH4 (+0.22 ± 0.14 mg-CH4 m−2 d−1). Desert CH4 consumption rates were positively associated with soil temperature among years, and were similar to temperate locations, likely because of suitable landscape conditions for soil gas diffusion. Wetland FCH4 varied closely with stream discharge entering the wetland and hence extent of soil saturation. Landscape-scale FCH4 measured by EC was +1.27 ± 0.18 mg-CH4 m−2 d−1 and varied with soil temperature and carbon dioxide flux. FCH4 measured using EC was higher than using chambers because EC measurements incorporated a larger, more saturated footprint of the wetland. Using EC FCH4 and quantifying the mass of CH4 entering and exiting the wetland in stream water, we determined that methanogenesis within wetland soils was the dominant source of FCH4. Low FCH4 at the wetland was likely due to a shallow organic soil layer, and thus limited carbon resources for methanogens. Considering the prevalence of dry soils in the high Arctic, our results suggest that these landscapes cannot be overlooked as important consumers of atmospheric CH4.
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Poletaev, N. L. "The heating of a stream of particles by thermal counter radiation." Pozharovzryvobezopasnost/Fire and Explosion Safety 30, no. 2 (May 15, 2021): 15–22. http://dx.doi.org/10.22227/pvb.2021.30.02.15-22.
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Introduction. It is accepted that the depth of heating of the dust/gas/air mixture by the radiation of combustion products SR is equal to the length LR of the free path of radiation in the mixture. Numerical simulation of combustion of a gas-air mixture that has inert particles, taking into account the re-radiation of heat by heated particles of the fresh mixture, led to ratio SR >> LR. In this work, the analytical assessment of ratio χS = SR/LR is performed.One-dimensional problem model. The co-authors determined stationary temperature distribution over the flow of initially cold monodisperse particles suspended in vacuum. Particle velocity V is directed toward a heat-radiating, absolutely black surface that is permeable by particles. Simplifying assumptions are used: radiation consists of two oppositely-directed flows of electromagnetic energy; interaction between particles and radiation is described in the approximation of geometric optics; the temperature inside the particle is the same. Problem solving. It is shown that χS is determined by V=Vcp / (εT 0,5, σTb)3 , where cp, εT, σ, Tb are, respectively, heat capacity per unit volume of the suspended matter, integral emissivity of the particle material, the Stefan-Boltzmann constant, and the surface temperature. For ≤ 2.8, re-emission can be neglected: χS ≈ 1. At ≤ 1.2, temperature distribution regulates re-emission: χS ≈ 5 –1/(2 – εT) >> 1.Solution discussion. The analytical solution satisfactorily describes the available numerical solutions and experimental data for the case of combustion of a dust/gas/air mixture after specifying the parameters of a simplified model: the radiating surface should be understood as the flame front, Tb is the combustion temperature, and cp is the overall heat capacity of the mixture. The estimate ≤ 1.2 indicates the final high temperature of the gas suspension, the possibility of its autoignition far from the flame, and the need to change initial assumptions when simulating re-emission.Conclusions. Analytical evaluations make it possible to employ ratios SR >> LR and SR ≈ LR for the suspension over a thermal radiation source in vacuum. Conditions for the application of the results of simplified simulation of re-emission to the combustion of a dust/gas/air mixture are formulated.
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Konstanciak, Anna. "High-Temperature Testing of the Properties of Blast Furnace Coke." Materials Science Forum 638-642 (January 2010): 2616–21. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.2616.
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The article describes the behaviour of coke in the blast furnace. Factors, which cause weakening and degradation of coke lumps at temperatures above 1300°C have been analyzed. On the basis of preliminary testing of samples taken from a blast furnace at different distances from the tuyère outlet and tests for thermo-abrasion ξ, the advisability of using the pre-tuyère chamber for the assessment of coke quality at high temperatures has been indicated. Thermodynamic calculations for the determination of the chemical composition of the products of reaction of coke ash mineral substances with elementary carbon and air, as well as the behaviour of coke at high temperatures under inert gas conditions are presented. The number of compounds forming from coke ash components during heating in a stream of gases of highly differential reductiveness reflects the complexity of the physicochemical phenomena.
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Zhou, Jinming, Zhe Chen, Henrik Persson, Ru Lin Peng, Rachid M’Saoubi, and David Gustasson. "Comparative Assessment of the Surface Integrity of AD730® and IN718 Superalloys in High-Speed Turning with a CBN Tool." Journal of Manufacturing and Materials Processing 3, no. 3 (August 19, 2019): 73. http://dx.doi.org/10.3390/jmmp3030073.
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Nickel-based superalloys are typical materials used in components of aeroengines and gas turbine machinery. The strength properties of these alloys at high temperatures are crucial not only to the performance (e.g., power generation efficiency, energy consumption, and greenhouse gas emissions) of aeroengines and industrial gas turbines, but also to machinability during component manufacturing. This study comparatively evaluated the surface integrity of two superalloys, AD730® and Inconel 718 (IN718), during high-speed finishing turning using cubic boron nitride (CBN) tools. IN718 is a conventional superalloy used for the hot section components of aeroengines and industrial gas turbines, while AD730® is a novel superalloy with enhanced high-temperature mechanical properties and good potential as a next-generation superalloy for these components. High-speed turning tests of two superalloys were conducted using a CBN cutting tool and jet stream cooling. The achieved surface integrity of the AD730® and IN718 superalloys was characterized and analyzed to assess the comparability of these alloys.
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Lunev, V. V. "Three-dimensional theory of the equation of ablation of bodies in a high-temperature gas stream." Fluid Dynamics 22, no. 1 (1987): 121–29. http://dx.doi.org/10.1007/bf01050862.
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Bartnik, Andrzej, Karol Jach, Robert Świerczyński, Mateusz Majszyk, Tomasz Fok, Łukasz Węgrzyński, Przemysław Wachulak, and Henryk Fiedorowicz. "Dynamics of plasmas produced by a laser pulse, inside a dense gaseous target, formed in an ambient gas." Physics of Plasmas 29, no. 9 (September 2022): 093302. http://dx.doi.org/10.1063/5.0099683.
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In this work, the time development of plasmas produced by interaction of laser pulses, with a nitrogen gas, was investigated. The interaction took place inside a small portion of dense nitrogen gas injected temporarily into a chamber filled with the gas under low pressure. High-temperature plasmas produced directly by the laser pulse were a source of soft x rays and charged particles, ionizing and exciting the surrounding gas. In this way, low-temperature plasmas were produced. The formation of high-temperature plasmas was studied using soft x-ray spectroscopy and x-ray streak imaging. Low-temperature plasmas formed at various distances from the laser focus were investigated using an optical streak camera. Interpretation of the experimental data was supported by numerical modeling of the laser-produced plasma hydrodynamics. It was concluded that depending on the distance from the focal spot, the formation of the low-temperature plasmas was dominated by ion streams or by soft x-ray radiation.
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Mersinligil, M., J. Desset, and J. F. Brouckaert. "High-temperature high-frequency turbine exit flow field measurements in a military engine with a cooled unsteady total pressure probe." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 225, no. 7 (September 29, 2011): 954–63. http://dx.doi.org/10.1177/0957650911413697.
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The measurement of unsteady pressures within the hot components of gas turbine engines still remains a true challenge for test engineers. Several high-temperature pressure sensors have been developed, but so far, their applications are restricted to unsteady wall static pressure measurements. Because of the severe flow conditions such as turbine inlet temperatures of 1700 °C and pressures of 50 bar or more in the most advanced aero-engine designs, few (if any) experimental techniques exist to measure the time-resolved flow total pressure inside the gas path. This article describes the measurements performed at the turbine exit of a military engine with a cooled fast response total pressure probe. The probe concept is based on the use of a conventional miniature piezo-resistive pressure sensor, located in the probe tip to achieve a bandwidth of at least 40 kHz. Due to the extremely harsh conditions, the probe and sensor are heavily water cooled. The probe was designed to be continuously immersed into the hot gas stream to obtain time series of pressure with a high bandwidth and therefore statistically representative average fluctuations at the blade passing frequency (BPV). The experimental results obtained with a second-generation prototype are presented. The probe was immersed into the engine through the bypass duct between turbine exit and flame-holders of the afterburner of a Volvo RM12 engine, at exhaust temperatures above 900 °C. The probe was able to resolve the BPV (∼17 kHz) and several harmonics up to 100 kHz.
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PUZDROWSKA, Patrycja. "Identification of damages in the inlet air duct of a diesel engine based on exhaust gas temperature measurements." Combustion Engines 177, no. 2 (May 1, 2019): 108–14. http://dx.doi.org/10.19206/ce-2019-219.
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The temperature of the exhaust gas of a diesel piston engine, measured in the characteristic control sections of its thermo-flow system, can be a valuable source of diagnostic information about the technical condition of the elements limiting the working spaces thus separated, including the turbocharging system, but also its fuel supply system and replacement of the medium. In standard marine engine measurement systems equipped with an impulse turbocharging system, the exhaust gas temperature is measured at the outlet of individual cylinders and before and after the turbocharger turbine, using traditional thermocouples with high measurement inertia (time constant of tenths of a second and more). This means that for further diagnostic analyses, the average value of the periodically changing temperature of the exhaust stream leaving individual engine cylinders, the exhaust stream in the collective duct feeding the turbine and the exhaust stream in the exhaust duct of the turbine is used. This article proposes a new approach to the issue of diagnostic informationiveness of the exhaust gas temperature of a diesel engine, extending its observations with the dynamics of changes in the duration of one working cycle. The aim of the tests carried out on the laboratory stand of Farymann Diesel engine type D10 was to determine the diagnostic relations between the loss of permeability of the inlet air channel filter baffle and selected standards of the quick-changing signal of the exhaust gas temperature. On the basis of the calculations carried out, the following dynamic features of the recorded signal were determined: maximum amplitude of instantaneous exhaust gas temperature values (peak-to-peak value), its rate of increase and decrease, and the specific enthalpy of exhaust gases within one engine work cycle. Comparative analysis of numerical data characterizing the recorded quick-changing exhaust gas temperature courses clearly indicates obvious thermodynamic and energy consequences of partial loss of flow capacity of the air channel supplying the combustion chamber of the test engine. A further development of the experimental test programme is foreseen in order to determine a diagnostic matrix to support the diagnostic inference about the technical condition of the diesel engine on the basis of measurements and analysis of the quick-changing exhaust gas temperature.
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Balasundram, V., N. Ibrahim, and R. Isha. "The Effect of Temperature on Catalytic Pyrolysis of HDPE Over Ni/Ce/Al2O3." Journal of Advanced Research in Materials Science 77, no. 1 (February 28, 2021): 26–35. http://dx.doi.org/10.37934/arms.77.1.2635.
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The main objective of the current work is to investigate the influence of reaction temperature on catalytic pyrolysis of High-Density Polyurethane (HDPE) over Ni/Ce/Al2O3 into enriched hydrocarbons of pyrolytic oil and gas The experiments were performed at four different pyrolysis reaction temperatures (500, 600, 700, and 800 °C) via in-situ fixed bed reactor. The Al2O3 (75 wt.%) was used as a support, while nickel (20 wt.%) and cerium (5 wt.%) were impregnated as promoters via incipient wetness impregnation method. The catalyst to plastic mass ratio was kept constant at 1:1 for all investigated samples. The results revealed that the Ni/Ce/Al2O3 catalyst has synergistic effects on the catalytic pyrolysis of HDPE into a high yield of hydrocarbon compounds (C5 – C20) in pyrolytic oil and hydrogen gas composition in pyrolytic gas. The highest yield of pyrolytic oil was achieved at 700 °C (53.23 %), while the highest yield of pyrolytic gas was achieved at 800 °C (67.85 %). The small molecular hydrocarbons in pyrolytic oil (C5 - C9) decreases with increasing temperature from 500 to 800 °C. The highest hydrogen gas yield of 77.59 %. was achieved at 700 °C. Thus, this research has economic feasibility in producing alternative valuable energy from the plastic waste stream.
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Damma, Devaiah, and Panagiotis G. Smirniotis. "FeCeOx Supported Ni, Sn Catalysts for the High-Temperature Water–Gas Shift Reaction." Catalysts 10, no. 6 (June 8, 2020): 639. http://dx.doi.org/10.3390/catal10060639.
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In this work, the effect of monometallic Ni or Sn and bimetallic NiSn deposition on the activity of FeCeOx catalysts in high-temperature water–gas (HT-WGS) reactions was investigated. It was found that the HT-WGS performance of FeCeOx has significantly improved after the deposition of Sn together with Ni on it. Furthermore, the bimetallic NiSn/FeCeOx catalyst showed higher activity compared to the monometallic Ni/FeCeOx and Sn/FeCeOx catalysts within the tested temperature range (450–600 °C). Although the Ni/FeCeOx catalyst showed methanation activity at a temperature below 550 °C, the NiSn/FeCeOx catalyst suppressed the methane formation to zero in the WGS. Besides, the NiSn/FeCeOx catalyst exhibited an excellent time-on-stream stability without methanation reaction, even at a steam-to-CO ratio as low as 0.8. The combination of Ni and Sn supported on FeCeOx led to a large lattice strain, the formation of NiSn alloy, and a strong synergistic effect between the bimetallic NiSn and FeCeOx mixed oxide support interface. All these features are very important in achieving the best activity and stability of NiSn/FeCeOx in the HT-WGS reaction.
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Radomsky, R. W., and K. A. Thole. "High Free-Steam Turbulence Effects on Endwall Heat Transfer for a Gas Turbine Stator Vane." Journal of Turbomachinery 122, no. 4 (February 1, 2000): 699–708. http://dx.doi.org/10.1115/1.1312807.
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High free-stream turbulence along a gas turbine airfoil and strong secondary flows along the endwall have both been reported to increase convective heat transfer significantly. This study superimposes high free-stream turbulence on the naturally occurring secondary flow vortices to determine the effects on the flowfield and the endwall convective heat transfer. Measured flowfield and heat transfer data were compared between low free-stream turbulence levels (0.6 percent) and combustor simulated turbulence levels (19.5 percent) that were generated using an active grid. These experiments were conducted using a scaled-up, first-stage stator vane geometry. Infrared thermography was used to measure surface temperatures on a constant heat flux plate placed on the endwall surface. Laser-Doppler Velocimetry (LDV) measurements were performed of all three components of the mean and fluctuating velocities of the leading edge horseshoe vortex. The results indicate that the mean flowfields for the leading edge horseshoe vortex were similar between the low and high free-stream turbulence cases. High turbulence levels in the leading edge–endwall juncture were attributed to a vortex unsteadiness for both the low and high free-stream turbulence cases. While, in general, the high free-stream turbulence increased the endwall heat transfer, low augmentations were found to coincide with the regions having the most intense vortex motions. [S0889-504X(00)00704-2]
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Maciejewski, P. K., and R. J. Moffat. "Heat Transfer With Very High Free-Stream Turbulence: Part I—Experimental Data." Journal of Heat Transfer 114, no. 4 (November 1, 1992): 827–33. http://dx.doi.org/10.1115/1.2911889.
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The present research investigates boundary layer heat transfer with very high freestream turbulence, a problem of primary interest in the gas turbine industry where existing boundary layer correlations and codes underpredict local heat transfer rates on first-stage turbine blades and vanes by as much as a factor of three for some engine designs. The problem was studied experimentally by placing a constant-temperature heat transfer surface at various locations in the margin of a turbulent free jet and measuring both the surface heat transfer rate and the turbulence in the free stream. In this experiment, free-stream turbulent fluctuations 20 to 60 percent relative to the mean velocity augment heat transfer 1.8 to 4 times that which would be predicted locally using accepted correlations for turbulent boundary layers at the same Reynolds number.