Journal articles: 'Slag heat exchange'

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Kolczyk, E., Z. Miczkowski, and J. Czernecki. "Numerical investigation of heat exchange in rotary furnace." Archives of Metallurgy and Materials 62, no. 1 (March 1, 2017): 149–53. http://dx.doi.org/10.1515/amm-2017-0020.

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Abstract Process of heat exchange in a rotary furnace during converter slag reduction was modelled.Temperature distribution in the furnace and temperature of the charge (slag) only were examined. Influence of modification of the process gas supply method by changing the number of nozzles on the course of the reduction process was analyzed. It has been found out that application of a nozzle as a submerged flame burner provides possibilities to reach higher charge temperature. Application of more nozzles in the process of converter slag reduction can increase temperature of reduced slag and provide better uniformity of charge heating.

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Chaulet, Jérémy, Abdellah Kharicha, Sylvain Charmond, Bernard Dussoubs, Stéphane Hans, Menghuai Wu, Andreas Ludwig, and Alain Jardy. "A 2D Multiphase Model of Drop Behavior during Electroslag Remelting." Metals 10, no. 4 (April 8, 2020): 490. http://dx.doi.org/10.3390/met10040490.

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Electroslag remelting is a process extensively used to produce metallic ingots with high quality standards. During the remelting operation, liquid metal droplets fall from the electrode through the liquid slag before entering the liquid pool of the secondary ingot. To better understand the process and help to optimize the operating condition choice, a 2D axisymmetric multiphase model of the slag domain has been developed using a two fluid Eulerian approach. During their fall, droplets hydrodynamic interactions are calculated thanks to an appropriate drag law. Influence of droplets on the electromagnetic field and on the slag hydrodynamics is discussed, as well as their heat exchange with the slag. Even with a small volume fraction, the droplets influence is noticeable. The present investigation shows that small droplets have a large influence on the slag hydrodynamics, due to a great momentum exchange. However heat transfer is more influenced by large drops, which are found to be relatively far from the thermal equilibrium with the slag phase.

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Kolczyk, Ewa, Zdzisław Miczkowski, and Józef Czernecki. "Influence of selected parameters on phenomena of two-phase flow and heat exchange in TSL furnace – numerical investigation." International Journal of Numerical Methods for Heat & Fluid Flow 27, no. 12 (December 4, 2017): 2799–815. http://dx.doi.org/10.1108/hff-02-2017-0053.

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Purpose The purpose of this study is application of a numerical simulation for determination of the influence of geometric parameters of a furnace and hydrodynamics of the gas introduced by a vertical submerged lance on the process of feed mixing and temperature distribution. Design/methodology/approach A numerical simulation with Phoenics software was applied for modeling of liquid phase movement and heat exchange between the gas supplied through a lance and the slag feed in a top submerged lance (TSL) furnace. The simulation of a two-phase flow of a slag–gas mixture based on the inter phase slip algorithm module was conducted. The influence of selected parameters, such as depth of lance submergence, gas flow rate and change of furnace geometry, on the phenomena of movement was studied. Findings Growth of dynamics of mixing with the depth of lance submergence and with increase of gas velocity in the lance was observed. Formation of a recirculation zone in the liquid slag was registered. Movement of the slag caused by the gas flow brought homogenization of the temperature field. Originality/value The study applied the simulation of a two-phase flow in the liquid slag–gas system in steady state, taking into account heat transfer between phases. It provides possibilities for optimization and selection of process parameters within the scope of the developed new technology using a TSL furnace.

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Синицын, Н. Н., Н. В. Запатрина, and Ю. В. Донцова. "MATHEMATICAL MODEL FOR PREDICTING HEAT EXCHANGE OF A SINGLE BLAST OF FURNACE SLAG DROPLET IN UNSTEADY MOTION IN A COUNTER GAS FLOW." ВЕСТНИК ВОРОНЕЖСКОГО ГОСУДАРСТВЕННОГО ТЕХНИЧЕСКОГО УНИВЕРСИТЕТА, no. 3(-) (August 15, 2022): 30–38. http://dx.doi.org/10.36622/vstu.2022.18.3.003.

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Cухая грануляция доменного шлака, в отличие от мокрой грануляции, позволяет утилизировать физическую теплоту жидкого доменного шлака, выход которого составляет 0.3 … 0.35 т на т чугуна, а также исключить образование вредных газообразных сернистых соединений. При проектировании опытно-промышленных установoк сухой грануляции доменного шлака необходимы инженерные методики, позволяющие рассчитывать характерные размеры грануляционной камеры, а именно: диаметр и высоту, позволяющие исключить налипание капель жидкого доменного шлака на стенки камеры. До столкновения со стенкой капли доменного шлака должны затвердеть. Pазработана математическая модель охлаждения одиночной капли жидкого доменного шлака при неустановившемся движении вo встречном потоке газа с учетом фазового перехода доменного шлака. Решение дифференциального уравнения теплопроводности осуществлено методом конечных разностей по явной схеме аппроксимации производных. Фазовый переход учитывается с помощью эффективной теплоемкости. При этом температура фазового перехода размазывается в некотором интервале температур. Граница перехода шлака из жидкого состояния в твердое определяeтся по температуре фазового перехода доменного шлака. При тестировании алгоритма определяются настроечные параметры модели: число узлов расчетной сетки и температурный интервал фазового перехода доменного шлака. Скорость движения капли доменного шлака во встречном потоке газа описывается системой обыкновенных дифференциальных уравнений, решение которых осуществлялось численным методом Рунге-Кутта, с последующим определением относительной скорости капли и коэффициента теплоотдачи в каждый момент времени. Представлены траектории движения капли доменного шлака до момента полной остановки в горизонтальном направлении и температурные поля по сечению капли в момент остановки. Разработан алгоритм расчета теплообмена капли при ее движении во встречном газовом потоке. Математическая модель теплообмена капли доменного шлака при ее движении во встречном охлаждающем газовом потоке позволяет прогнозировать поведение капель в грануляционной камере и спрогнозировать характерные ее размеры Dry granulation of blast furnace slag, unlike wet granulation, makes it possible to utilize the physical heat of liquid blast furnace slag, the yield of which is 0.3 ... 0.35 t per t of iron, as well as to exclude the formation of harmful gaseous sulfur compounds. When designing pilot plants for dry granulation of blast-furnace slag, engineering methods are needed to calculate the characteristic dimensions of the granulation chamber, namely the diameter and height to exclude the adhesion of liquid blast-furnace slag droplets to the chamber walls. Before colliding with the wall, the blast furnace slag droplets must solidify. In this paper, we developed a mathematical model for cooling a single drop of liquid blast furnace slag in unsteady motion in a counter gas flow with consideration of the phase transition of blast furnace slag. The differential equation of heat conduction is solved by the finite difference method, according to the explicit derivative approximation scheme. The phase transition is taken into account by means of effective heat capacity. In this case, the phase transition temperature is smeared out in some temperature interval. The slag transition boundary from liquid to solid state is determined by the blast furnace slag phase transition temperature. When testing the algorithm, we determined the model settings: the number of calculation grid nodes and the blast furnace slag phase transition temperature interval. The velocity of blast-furnace slag droplet in the counter gas flow is described by the system of ordinary differential equations, solved by numerical Runge-Kutta method, followed by determination of the droplet relative velocity and heat transfer coefficient at each moment of time. We presented the trajectories of blast furnace slag droplet motion up to the moment of complete stop in the horizontal direction and temperature fields along the droplet cross section at the moment of stop. We developed an algorithm for calculating the heat exchange of the droplet as it moves in the counter gas flow. Mathematical model of heat exchange of blast furnace slag droplet during its movement in the counter cooling gas flow makes it possible to predict the droplet behavior in the pelletizing chamber and to predict its characteristic sizes

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Lukin, S. V., N. I. Shestakov, and E. M. Il’icheva. "Heat Exchange in the Granulation Chamber of an Installation for Slag Dry Granulation." Metallurgist 63, no. 7-8 (November 2019): 804–12. http://dx.doi.org/10.1007/s11015-019-00892-x.

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Bruckner, Adam P. "Continuous duty solar coal gasification system using molten slag and direct-contact heat exchange." Solar Energy 34, no. 3 (1985): 239–47. http://dx.doi.org/10.1016/0038-092x(85)90061-1.

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Spirin, N. A., O. P. Onorin, A. S. Istomin, and I. A. Gurin. "Study of transient processes in a blast furnace based on the heat exchange scheme analysis." Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 76, no. 2 (March 19, 2020): 132–38. http://dx.doi.org/10.32339/0135-5910-2020-2-132-138.

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A blast furnace is a complicated metallurgical facility, which is characterized by considerable delay and inertia in the flow of heat and mass exchange. Therefore, the analysis of transient processes based on modern ideas about heat transfer is an important issue in solving technological problems of blast furnace smelting managing. A two-stage heat transfer scheme along the height of a blast furnace of modern technology presented. When studying the thermal state of a blast furnace as a control object, it is advisable to divide it into two thermal zones - the upper zone and the lower zone. The border between the zones is located in the upper part of the mixed reduction region, between the start level of coke carbon gasification and the horizon below which iron oxides are directly reduced. It was shown, that the upper and lower thermal zones have fundamental differences in heat exchange conditions and are interconnected through the index of iron direct reduction degree. The transient processes of silicon variation in the hot metal studied at variation of iron ore load, natural gas flow rate, temperature and humidity of the hot blast, oxygen content in the hot blast and slag basicity. It was shown that the oscillatory transition process is observed in case, after applying the perturbation, it will have the opposite effect on the thermal conditions of the lower and the upper stages of heat exchange in the blast furnace. The iron ore load, hot blast humidity and slag basicity were found to be the most predictable input parameters affecting the concentration of silicon in hot metal. Change in oxygen concentration in hot blast and natural gas consumption have an alternating character of influence on thermal conditions of the blast-furnace hearth. At that, the characteristics of the transient processes of blast furnaces through various channels of action vary and depend significantly on the properties of the smelted raw materials, design and operational parameters of the furnaces

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Urióstegui-Hernández, Antonio, Pedro Garnica-González, José Ángel Ramos-Banderas, Constantin Alberto Hernández-Bocanegra, and Gildardo Solorio-Díaz. "Multiphasic Study of Fluid-Dynamics and the Thermal Behavior of a Steel Ladle during Bottom Gas Injection Using the Eulerian Model." Metals 11, no. 7 (July 6, 2021): 1082. http://dx.doi.org/10.3390/met11071082.

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In this work, the fluid dynamic and thermal behavior of steel was analyzed during argon gas stirring in a 140-t refining ladle. The Eulerian multiphase mathematical model was used in conjunction with the discrete ordinates (DO) thermal radiation model in a steel-slag-argon system. The model was validated by particle image velocimetry (PIV) and the analysis of the opening of the oil layer in a physical scale model. The effect of Al2O3 and Mg-C as a refractory in the walls was studied, and the Ranz-Marshall and Tomiyama models were compared to determine the heat exchange coefficient. The results indicated that there were no significant differences between these heat exchange models; likewise, the radiation heat transfer model adequately simulated the thermal behavior according to plant measurements, finding a thermal homogenization time of the steel of 2.5 min for a gas flow of 0.45 Nm3·min−1. Finally, both types of refractory kept the temperature of the steel within the ranges recommended in the plant; however, the use of Al2O3 had better heat retention, which would favor refining operations.

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Makarov, A. N. "HEAT EXCHANGE IN HIGH POWER ARC STEEL FURNACES Part III. INTERCONNECTION OF HEAT EXCHANGE, HEIGHT OF SLAG LAYER, EFFICIENCY OF ARCS AND SPECIFIC ELECTRICITY CONSUMPTION." Metallurg, no. 11 (2022): 41–46. http://dx.doi.org/10.52351/00260827_2022_11_41.

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Shubov, L. Ya, I. G. Doronkina, O. N. Borisova, L. M. Tyger, and T. R. Lyubetskaya. "Analytical evaluation and systematization of technologies for extraction of rare metals from production waste." E3S Web of Conferences 311 (2021): 09005. http://dx.doi.org/10.1051/e3sconf/202131109005.

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The article is a message containing systematized information on resource-saving technologies as the basic for involving metal-containing secondary raw materials in the economic turnover. The set of independent technologies arranged in a certain sequence that solve the problems of resource saving allows us to compare the specific features and effectiveness of the use of each of them, the details and features of the processes. It is shown that the following can be the main sources of rare metals and REE: phosphogypsum (REE, Sr); ash and slag waste from TPPs, ash and slag waste (REE, Ti, Sc); metallurgical slags (Ge, Be, Se, Te, V); sulfuric acid dust (Se, Te); alumina production waste - red mud (Sc, REE); liquid waste from sulphate production of titanium dioxide (Sc, Ti); refinery dust bins (Se, Te); wastes from production of permanent magnets (Nd, Sm). It is noted that the technology uses beneficiation methods, acid leaching and ion-exchange concentration, biotechnology, electrolysis, heat treatment, a combination of different methods. To assess the quality of man-made raw materials and their suitability for complex processing and utilization, the article uses the methodology of analytical research of a set of patented technological solutions (technological samples were taken from real man-made deposits).

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Makarov, A. N., and A. V. Krupnov. "Heat Exchange in High-Power Arc Steel Furnace when the Height of the Slag Layer Changes." IOP Conference Series: Materials Science and Engineering 969 (November 13, 2020): 012059. http://dx.doi.org/10.1088/1757-899x/969/1/012059.

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Zvegintsev, Valery. "Penetration of a Pulsed Gas Jet through a Package of Heat Exchange Tubes." Aerospace 9, no. 8 (July 27, 2022): 404. http://dx.doi.org/10.3390/aerospace9080404.

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The slagging of heating surfaces by fly ash significantly complicates the long term operation of solid-fuel boilers. Gas pulse technologies offer a potentially convenient, inexpensive, yet efficient way for online slag deposits removal. The creation and application of real boiler cleaning systems using gas pulse technologies is a relatively new direction in the energy sector and requires scientific research on various aspects. In this work, the numerical investigation of the gas-dynamic flow arising when the package of heat-exchange tubes is blown with single air jet created by a pneumopulse cleaning system has been carried out. The forces acting on the heat-exchange tubes located at distances 1.0 m and 2.0 m from the exhaust nozzle with various configurations of tubes in the package have been determined. It is shown that an increase in the pressure of the generated air jet makes it possible to significantly increase the acting forces at large distances from the exhaust nozzle. The results of this study and similar calculations for real geometry will increase the validity of engineering solutions used in the development of pneumopulse cleaning systems for large power boilers.

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Ezhov, V. S., N. E. Semicheva, A. P. Burtsev, V. I. Zenchenkov, and D. A. Ermakov. "Study of the Process of Generation of Thermoelectricity in Low Grade Heat Recovery of Waste Gases." Proceedings of the Southwest State University 23, no. 2 (July 9, 2019): 74–84. http://dx.doi.org/10.21869/2223-1560-2019-23-2-74-84.

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Purpose of research. The purpose of the study is to develop an experimental design of an integrated air heater, conduct and analyze experiments as well as to determine the main characteristics of a thermoelectric generator in low-grade heat recovery of waste gases.Methods. The experimental unit consists of two blocks – a thermoelectric generator operating on the principle of cross heat exchange for heat recovery with concurrent heating of the incoming air, which is supplied as a mixture to the burner device of the boiler unit; and an adsorber block filled with blast furnace slag for cleaning the waste gases from nitrogen, sulphur and carbon oxides. To achieve these goals, the work is based on the proposed thermoelectricity effect, which works on the principle of converting thermal energy into electricity at a temperature difference between hot and cold junctions in thermoelectric sections consisting of two metals different in their electronegativity. At the same time, in an integrated air heater, the intensification of the process of adsorption of harmful components by granulated blast furnace slag takes place, which reduces the heat content and temperature of waste gases, reduces emissions of flue gases and, as a result, increases environmental safety of the area adjacent to the boiler. In particular, the study of countercurrent heat exchange in the design of the thermoelectric generator was carried out.Results. The main result of the research work is the development of an experimental design of an integrated air heater, an experimental technique and the determination of the main characteristics of the thermoelectricity generation process.Conclusion. The use of such an integrated air heater can improve the efficiency of heat-generating units of low, medium and high power installed in the central heating stations, multi-family and single-family houses. The gained electric power with the subsequent transformation can be used for power supply of automatiс equipment of boilers of low, medium and high power, and for power supply of the stations of cathodic protection against electrochemical corrosion of back-end surfaces formed as a result of the presence of water vapors in waste gases.

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Chang, Hong, and Lihan Jin. "Preparation and Heat Transfer Performance of Steel Ball Phase Change Concrete." Journal of New Materials for Electrochemical Systems 23, no. 3 (September 30, 2020): 204–12. http://dx.doi.org/10.14447/jnmes.v23i3.a08.

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Accompanied by a large amount of heat absorption and release during the phase change process, phase change concrete has the advantages of high energy storage density, low volume expansion ratio and approximate isotherm in the heat exchange. It is widely used in the building field. For this, using steel balls as the carrier material and butyl stearate as the phase change material (PCM), the authors combined the phase change energy storage material with the energy pile to prepare a new type of concrete energy pile enhanced with the PCMs. Then, the tests and numerical simulations were conducted to study the optimal mix ratio and thermal conductivity of the phase change concrete. The results show that adding steel balls (10% of the coarse aggregate volume), and slag and fly ash (5% of the cementitious material mass) to the ordinary concrete C30 can greatly improve the heat transfer efficiency of the energy pile. The research findings provide a guidance for engineering practice.

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Akhmedov, R. B., Z. L. Miropolsky, E. V. Samuilov, and G. P. Stelmakh. "Direct-contact heat exchange, shale production, and slag processing as examples of new efficient technologies for power generation." Energy 12, no. 10-11 (October 1987): 1097–105. http://dx.doi.org/10.1016/0360-5442(87)90065-x.

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Makarov, A. N. "INFLUENCE OF ATMOSPHERIC SMOKE AND SLAG HEIGHT ON HEAT EXCHANGE IN ARC STEEL MELTING FURNACES. PART II. INFLUENCE OF SLAG HEIGHT ON WALL THERMAL LOADS AND ELECTRICITY CONSUMPTION." Bulletin of the Tver State Technical University Series «Building Electrical engineering and chemical technology», no. 4 (2021): 80–88. http://dx.doi.org/10.46573/2658-7459-2021-4-80-88.

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Laktyushin, A. N., V. L. Sergeev, and I. V. Khvedchin. "Analysis of the processes of heat and mass exchange in a slag-lined plasma reactor in production of microfibers from powder minerals." Journal of Engineering Physics and Thermophysics 70, no. 4 (July 1997): 616–19. http://dx.doi.org/10.1007/bf02663582.

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Firsbach, Felix, Dieter Senk, and Alexander Babich. "Process Concept for the Dry Recovery of Thermal Energy of Liquid Ferrous Slags." Journal of Sustainable Metallurgy 7, no. 3 (June 24, 2021): 783–93. http://dx.doi.org/10.1007/s40831-021-00391-x.

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AbstractSlags are valuable by-products of iron- and steelmaking processes. Their efficient reutilization and the recuperation of their thermal energy are key for improving the overall efficiency of these processes. With the innovative approach presented in this work, it is possible to recover thermal heat from liquid slags. The process concept consists of a slag tundish and four subsequent heat exchangers. The liquid slag is poured into the slag tundish which homogenizes the slag and guarantees a constant mass flow. The heat exchangers extract thermal energy from the slag and transfer it to water or oil. The first module cools the slag from the tapping temperature of about 1500 °C down to 850 °C. Inside the second module, more thermal energy is gathered from the already solidified slag cooling the slag down to ambient temperature. The captured energy can be used for various processes, such as gas preheating or generation of steam. The solidified slag is volume stable and forms amorphous phases, depending on its basicity. The process was designed, and the concept was tested on lab-scale demonstrators with an overall heat recovery rate of 42%. Some applications of the recovered slag heat are also presented in this work. Graphical Abstract Scheme of the process concept with the three heat exchangers and buffer unit.

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Andreev, A. S., and N. N. Sinitsyn. "A MODEL OF THE DYNAMICS OF HEAT EXCHANGE AND CONTROL OF THE COOLING PROCESS MOVING BY A DENSE LAYER OF HOT BLAST FURNACE SLAG." Metallurg, no. 12 (2021): 19–23. http://dx.doi.org/10.52351/00260827_2021_12_19.

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Makarov, A. N. "INFLUENCE OF ATMOSPHERIC SMOKING AND SLAG HEIGHT ON HEAT EXCHANGE IN ARC STEEL MELTING FURNACES. PART I. INFLUENCE OF ATMOSPHERIC HUMIDITY ON LOSSES WITH GASES AND WATER." Bulletin of the Tver State Technical University Series «Building Electrical engineering and chemical technology», no. 2 (2021): 67–77. http://dx.doi.org/10.46573/2658-7459-2021-67-77.

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Matiukhin, V. I., Y. G. Yaroshenko, and K. V. Bulatov. "On Modernization of Air Supply Systems for Improvement of Gas Distribution in Shaft Furnaces." Solid State Phenomena 284 (October 2018): 1390–97. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.1390.

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The paper presents a developed method for assessment of gas distribution over the cross section of a shaft furnace working in the countercurrent conditions. This method is scientifically based on the fundamental principles of the countercurrent heat exchange theory in shaft furnaces, i.e. dependences of the temperature field throughout the burden bed height on the ratio between heat capacities of gas and burden flows. The ratio between the gas flow heat capacity and burden flow heat capacity at the stock line level is determined by the averaged gas temperature at the burden bed output. By comparing these data, we estimated directions for improving the gas distributing system. Efficiency of this method was assessed when analyzing the system of air supply to the shaft furnace at one of the Ural plants. The analysis showed the main drawbacks of the existing gas distributing system and enabled to determine the main directions for reconstruction of this system. On the basis of the analysis results related to operation of the tuyeres and distribution manifold, we proposed more efficient options of their parameters, i.e. manifold cross-section area, tuyere number and diameter, angle of tuyere inclination to the horizontal. These changes provided a uniform distribution of gases across the furnace and improved conditions for melt flow in the furnace. Thus, we established virtually equal conditions for development of heat and mass transfer processes in the work space of the shaft furnace. The modernized system of air supply to MMSK’s shaft furnace increased the furnace performance by 14.14% in terms of burden, by 23.27% in terms of matte, by 15.15% in terms of slag and by 6.65% in terms of thermal efficiency. At the same time, the following parameters were reduced: specific fuel consumption (anthracite) by 17.46% and dust discharge by 40.5%. When supplying air to the furnace through the inclined tuyeres, it became possible to reduce formation of accretions and provide new working conditions for operating personnel due to a more uniform gas distribution across the horizontal section of the furnace. Within six months of furnace operation the personnel had no problems related to its operation.

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Safavi Nick, Reza, Virpi Leinonen, Juha Mäyrä, and Johan Björkvall. "Towards Greener Industry: Modelling of Slag Heat Recovery." Metals 11, no. 7 (July 20, 2021): 1144. http://dx.doi.org/10.3390/met11071144.

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The steel industry, in accordance with the momentum of greener industry, has welcomed the changes and is actively pursuing that objective. One such activity is the commitment to energy recovery from by-products such as slag since the average energy content of ferrous slags is around 1 to 2 GJ/tslag. The recovered energy could, then, be used in heating or drying process among others. The RecHeat was designed and modelled iteratively to achieve an optimised heat recovery apparatus. The model shows that the temperature of different sections of the heat exchanger part varies from 170 to 380 °C after slag pouring while the average air temperature at the entrance of the heat exchanger is less than 150 °C. Furthermore, the temperature of the fluid medium changes from 125–140 °C to 260–340 °C from one end of the heat exchanger part to the other at the end of the simulation. The outlet temperature at the end of the simulation is calculated to be around 340 °C, which shows an increase by at least 200 °C in the temperature of the air entering the apparatus.

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Lee, Seokjae, Sangwoo Park, Minkyu Kang, and Hangseok Choi. "Field Experiments to Evaluate Thermal Performance of Energy Slabs with Different Installation Conditions." Applied Sciences 8, no. 11 (November 10, 2018): 2214. http://dx.doi.org/10.3390/app8112214.

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The energy slab is a novel type of horizontal Ground Heat Exchanger (GHEX), where heat exchange pipes are encased in building slab structures. The thermal performance of energy slabs is usually inferior to the conventional closed-loop vertical GHEX because its installation depth is relatively shallow and therefore affected by ambient air temperature. In this paper, heat exchange pipes were made of not only conventional high-density polyethylene (HDPE), but also stainless steel (STS), which is expected to enhance the thermal performance of the energy slabs. In addition to a floor slab, a side wall slab was also used as a component of energy slabs to maximize the use of geothermal energy that can be generated from the underground space. Moreover, a thermal insulation layer in the energy slabs was considered in order to reduce thermal interference induced by ambient air temperature. Consequently, two different field-scale energy slabs (i.e., floor-type and wall-type energy slabs) were constructed in a test bed, and two types of heat exchange pipes (i.e., STS pipe and HDPE pipes) were installed in each energy slab. A series of thermal response tests (TRTs) and thermal performance tests (TPTs) were conducted to evaluate the heat exchange performance of the constructed energy slabs. Use of the STS heat exchange pipe enhanced the thermal performance of energy slabs. Additionally, the wall-type energy slab had a similar thermal performance to the floor-type energy slab, which infers the applicability of the additional use of the wall-type energy slab. Note that if an energy slab is not thermally cut off from the building’s interior space with the aid of thermal insulation layers, heat exchange within the energy slabs should be significantly influenced by fluctuations in ambient temperature.

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Golub, T., L. Molchanov, S. Semykin, and V. Vakulchuk. "STUDY OF THE PHYSICAL CHARACTERISTICS OF STREAMS EMERGING FROM COHERENT-TYPE NOZZLES." Collection of scholarly papers of Dniprovsk State Technical University (Technical Sciences) 2, no. 41 (December 19, 2022): 19–25. http://dx.doi.org/10.31319/2519-2884.41.2022.2.

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The main controlling factor in oxygen converting with top blowing is the stream of oxygen, which penetrate the metal bath and promotes the flow of heat, mass exchange and chemical processes. The inherent characteristics of the oxygen jet are created by the nozzle tip with nozzles that may differ in design depending on the issue they solve. In the electrometallurgical industry, coherent nozzles consisting of a central nozzle for supplying the main oxygen jet and a surrounding annular nozzle for supplying shielding gas, mainly methane, are used to ensure deep penetration of the oxygen jet into the melt and to improve the mixing processes of the bath. This design of the nozzle, according to available published data, ensures the elongation of the main jet while preserving its momentum. The paper presents the results of a study using a modified liquid manometer of the features of the action of jets flowing out of nozzles of a coherent type of different designs (the ratio of the outer and central parts of 25%, 50% and 75%) under blowing conditions that correspond to the conditions of top blowing during industrial oxygen conversion. The conducted research made it possible to establish that when the share of the peripheral part is more than 50%, the main controlling link of the jet is the central nozzle, and when the share is smaller, it is the peripheral slotted part. The jets flowing out of the nozzles of the coherent type with the share of the peripheral part more than 50% have a greater force of action on the liquid compared to the force of action of the corresponding central nozzle, by the amount from 33 to 74%relatively. The design of nozzles with a share of the peripheral part of the order of 25% practically does not create conditions for improving the power characteristics of the jet. According to the results of the established conclusions, it is possible to recommend the use of nozzles of the coherent type with a share of the peripheral part of more than 50% as nozzles, for example, of the second row for top blowing lance, which have a slag-forming effect, contributing to better penetration into the melt compared to the corresponding cylindrical ones, that will intensify the processes of mixing and slag formation in the bath

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Zhou, Yang Min, Chao Li, Li Li Xu, Si Yi Luo, and Chui Jie Yi. "Experimental Study of Self-Cleaning Plate Shell Heat Exchanger." Advanced Materials Research 339 (September 2011): 176–79. http://dx.doi.org/10.4028/www.scientific.net/amr.339.176.

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A heating experimental system using waste heat from washing Blast Furnace Slag (BFS) water is designed. The effect of corrugated angle, on the property of self-cleaning plate shell heat exchanger and the system typical working conditions was investigated. The results show that: the corrugated angle, as the key factor for the heat transfer property of self-cleaning plate shell heat exchanger, produces intense turbulent flows. It enhances the heat exchanger efficiency and reduces the scaling on the plate.

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Wang, Gu, Qu, Shi, Luo, Yang, and Dai. "Mechanism of CaF2 under Vacuum Carbothermal Conditions for Recovering Nickel, Iron, and Magnesium from Garnierite." Metals 10, no. 1 (January 15, 2020): 129. http://dx.doi.org/10.3390/met10010129.

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Nickel laterite ore is divided into three layers and the garnierite examined in this study belongs to the third layer. Garnierite is characterized by high magnesium and silicon contents. The main contents of garnierite are silicates, and nickel, iron, and magnesium exist in silicates in the form of lattice exchange. Silicate minerals are difficult to destroy so are suitable for smelting using high-temperature pyrometallurgy. To solve the problem of the large amounts of slag produced and the inability to recycle the magnesium in the traditional pyrometallurgical process, we propose a vacuum carbothermal reduction and magnetic separation process to recover nickel, iron, and magnesium from garnierite, and the behavior of the additive CaF2 in the reduction process was investigated. Experiments were conducted under pressures ranging from 10 to 50 Pa with different proportions of CaF2 at different temperatures. The experimental data were obtained by various methods, such as thermogravimetry, differential scanning calorimetry, scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy. The analysis results indicate that CaF2 directly reacted with Mg2SiO4, MgSiO3, Ni2SiO4, and Fe2SiO4, which were isolated from the bearing minerals, to produce low-melting-point compounds (FeF2, MgF2, NiF2, etc.) at 1315 and 1400 K. This promoted the conversion of the raw materials from a solid–solid reaction to a liquid–liquid reaction, accelerating the mass transfer and the heat transfer of Fe–Ni particles, and formed Si–Ni–Fe alloy particles with diameters of approximately of 20 mm. The smelting materials appeared stratified, hindering the reduction of magnesium. The results of the experiments indicate that at 1723 K, the molar ratio of ore/C was 1:1.2, the addition of CaF2 was 3%, the recovery of Fe and Ni reached 82.97% and 98.21% in the vacuum carbothermal reduction–magnetic separation process, respectively, and the enrichment ratios of Fe and Ni were maximized, reaching 3.18 and 9.35, respectively.

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Chen, Xia, Yun Xiang Zhang, Qing Ming Chang, Chang Jun Chen, and Jiu Lang Xiong. "Finite Element Analsysis of Deformation during Continuopus Rolling on CSP." Key Engineering Materials 480-481 (June 2011): 707–11. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.707.

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In this paper, the CSP (compact strip production) technology was studied with the aid of elastic-plastic and thermal-mechanical coupled FEM using commercial software ABAQUS. The distribution and change of temperature, stress and strain field in rolling process were analyzed. In the view of boundary conditional influence on temperature, some factors such as thermal exchange between the work-roll and the thin slab, plastic deforming quantity of heat, cooling flux, convection and radiation heat exchange were considered during simulation. The results show contact heat conduction and deformation heat are the main factors that influence the temperature change of the thin slab. A good agreement was found between the predicted and the experimental data.

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Kareem, Bashir E., Ahmed M. Adham, and Banipal N. Yaqob. "Performance Enhancement of a Ventilation System in Hot and Dry Climate Using Air-PCM Heat Exchanger." International Journal of Heat and Technology 40, no. 3 (June 30, 2022): 773–80. http://dx.doi.org/10.18280/ijht.400316.

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The building projects' power consumption and CO2 emissions are 40% and 33%, respectively. It is a viable strategy to use phase change material in energy storage to provide free cooling. There are few studies on free cooling in hot climates, so the proposed system uses paraffin as a thermal storage material for free cooling and ventilation. The project contains a cooling tower, a horizontal slab heat exchanger between air and phase change material, and an indirect compact heat exchanger between air and water. The energy equation is computed using Engineering Equation Solver software to assess the overall system perform properly. The model investigated the parameters that affect the system's performance under various climate conditions. The system has improved indoor air quality by providing ventilation and extending the period of thermal comfort. The system's performance is determined by the cooling tower's performance and the Air to PCM and Air to water heat exchangers. The Air to PCM heat exchanger reduces supply temperature by 2°C with a slight pressure drop < 20Pa and does not affect system power consumption.

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Den Braven, K., and E. Nielson. "Performance Prediction of a Sub-Slab Heat Exchanger for Geothermal Heat Pumps." Journal of Solar Energy Engineering 120, no. 4 (November 1, 1998): 282–88. http://dx.doi.org/10.1115/1.2888132.

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A large portion of the installation cost of a ground-coupled heat pump system is for the excavation necessary for ground coil placement. One possible method of reducing this cost is to place the ground coils beneath the slab floor of the building. This configuration of ground coil placement has not been specifically addressed in previous research. Freezing of the soil must be avoided in such a system. To simulate the temperature response of the surrounding soil to heat pump operation, a computer model was developed which incorporates line source theory in the form of a system of rings. The fluid temperature change along the length of the coil was used to determine the distribution of the ground load throughout the ring system. The model includes an adiabatic upper boundary, seasonal soil temperature variation, and thermal interference throughout the system. Using these results, the minimum soil temperature over a season was predicted. Based on these results, design recommendations for ground coil installation are provided based on available area, soil type, heat extraction rate, depth of coil beneath the slab floor, and depth of slab floor below grade. These include recommendations for pipe spacing, flow direction, and a method to determine whether this type of system is feasible for installation in a particular location.

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Glushkov, Dmitrii, Kristina Paushkina, Ksenia Vershinina, and Olga Vysokomornaya. "Slagging Characteristics of a Steam Boiler Furnace with Flare Combustion of Solid Fuel When Switching to Composite Slurry Fuel." Applied Sciences 13, no. 1 (December 29, 2022): 434. http://dx.doi.org/10.3390/app13010434.

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Two interconnected mathematical models have been developed to describe slagging of a steam boiler furnace at the macro and micro levels. The macro-level model is implemented in Ansys Fluent. Using the fuel characteristics and temperature in the furnace, this model can predict the characteristics of ash formation on heat exchanger tubes when the melting temperature of the mineral part of solid fossil fuel is exceeded. The obtained values of slagging rates are used as initial data in the software implementation of the original Matlab microlevel model. Under conditions of dynamic change in the thickness of the slag layer, this model can evaluate the heat transfer characteristics in the hot gas/slag layer/tube wall/water coolant system. The results showed that switching a coal-fired boiler from a solid fossil fuel to a fuel slurry will improve stability and uninterrupted boiler operation due to a lower slagging rate. The combustion of coal water slurries with petrochemicals compared with coal–water fuel is characterized by higher maximum temperatures in the furnace (13–38% higher) and a lower average growth rate of slag deposits (5% lower), which reduces losses during heat transfer from flue gases to water coolant by 2%.

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Staszczuk, Anna, Tadeusz Kuczyński, Magdalena Wojciech, and Piotr Ziembicki. "Comparative Calculation of Heat Exchange with the Ground in Residential Building Including Periodes of Heat Waves." Civil And Environmental Engineering Reports 21, no. 2 (June 1, 2016): 109–19. http://dx.doi.org/10.1515/ceer-2016-0026.

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Abstract The paper provides verification of 3D transient ground-coupled model to calculation of heat exchange between ground and typical one-storey, passive residential building. The model was performed with computer software WUFI®plus and carried out to estimate the indoor air temperatures during extending hot weather periods. For verifying the results of calculations performed by the WUFI®plus software, the most recent version of EnergyPlus software version was used. Comparison analysis of calculation results obtained with the two above mentioned calculation method was made for two scenarios of slab on ground constructions: without thermal insulation and with thermal insulation under the whole slab area. Comprehensive statistical analysis was done including time series analysis and descriptive statistics parameters.

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Acharya, Shiladitya, and Krishnendu Mukherjee. "Heat transport in an anharmonic crystal." International Journal of Modern Physics B 32, no. 11 (April 16, 2018): 1850126. http://dx.doi.org/10.1142/s0217979218501266.

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We study transport of heat in an ordered, anharmonic crystal in the form of slab geometry in three dimensions. Apart from attaching baths of Langevin type to two extreme surfaces, we also attach baths of same type to the intermediate surfaces of the slab. Since the crystal is uninsulated, it exchanges energy with the intermediate heat baths. We find that both Fourier’s law of heat conduction and the Newton’s law of cooling hold to leading order in anharmonic coupling. The leading behavior of the temperature profile is exponentially falling from high to low temperature surface of the slab. As the anharmonicity increases, profiles fall more below the harmonic one in the log plot. In the thermodynamic limit thermal conductivity remains independent of the environment temperature and its leading order anharmonic contribution is linearly proportional to the temperature change between the two extreme surfaces of the slab. A fast crossover from one-dimensional (1D) to three-dimensional (3D) behavior of the thermal conductivity is observed in the system.

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Choi, Jong-Min, and Byong-Hu Sohn. "Performance Analysis of Energy-Slab Ground-Coupled Heat Exchanger." Korean Journal of Air-Conditioning and Refrigeration Engineering 24, no. 6 (June 10, 2012): 487–96. http://dx.doi.org/10.6110/kjacr.2012.24.6.487.

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Manni, Mattia, Claudia Fabiani, Andrea Nicolini, Anna Laura Pisello, Federico Rossi, and Franco Cotana. "Assessment of operating temperature within the new pavilion for slag management in Terni." Journal of Physics: Conference Series 2177, no. 1 (April 1, 2022): 012008. http://dx.doi.org/10.1088/1742-6596/2177/1/012008.

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Abstract The whole metallurgic sector produces up to 200 million tons of slag, which are tapped from the blast furnace (at a temperature of 1,500°C), and then need to be cooled down before disposal. These cooling processes are generally conducted open-air, significantly affecting local environmental quality of the surroundings. The present study aims at investigating the potential of an innovative slag cooling system housed within a pavilion, designed in order to minimize the emission of dust and pollutants out from the metallurgic plant. Such a system consists of a depressurized environment whose top surface is treated with black pigments and cooled down by water streams above it. Air is continuously extracted and then adequately filtered before being released outdoor. A numerical model was elaborated for evaluating the main heat flows developed within and through the pavilion’s envelope for the case study in Terni, central Italy. Once the physical and geometrical properties of the slag and the pavilion were defined, the heat exchanged with the air and water due to convection, as well as the latent heat dissipated through water evaporation was quantified. Results demonstrated the effectiveness of the water-based cooling system in keeping the roof temperature lower than 328 K without compromising the mechanical properties of the material. The evaporated water mass ranged between 4.2 kg h−1 and79.6 kg h−1 and was strongly influenced by seasonal weather conditions.

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Toghraie, Davood, Maboud Hekmatifar, and Niyusha Adavoodi Jolfaei. "Investigation of heat transfer and fluid flow behaviors of CuO/(60:40)% ethylene glycol and water nanofluid through a serpentine milichannel heat exchanger." International Journal of Numerical Methods for Heat & Fluid Flow 30, no. 4 (June 19, 2019): 1603–36. http://dx.doi.org/10.1108/hff-10-2018-0560.

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Purpose This paper aims to investigate the three-dimensional (3D) numerical simulations, based on the Navier–Stokes equations and the energy equation. Forced convection of a mixture of (60:40) percent ethylene glycol and water, was used as the base fluid and CuO nanoparticles, through a serpentine minichannel. Design/methodology/approach In this simulation, a serpentine mini-channel heat exchanger was simulated. The fluid studied in this simulation was composed of a mixture of (60:40) per cent ethylene glycol and water, was used as the base fluid and CuO nanoparticles. Four slabs and three serpentines were used in this study. The serpentine section is connected to the slab. Three equidistant circular channels (1 mm in diameter) were implemented inside the slab. Findings Results show that nanoparticles increase the fluid pressure drop and by changing volume fraction of nanoparticles from 0 to 1 per cent, the pressure drop of nanofluids increases between 42and 47 per cent, for Reynolds numbers from 100 to 500. The existence of serpentine bend in the minichannel heat exchanger causes the heat transfer rate to increase. Increase the volume fraction of nanoparticles reduces the fluid temperature at the outlet of the heat exchanger. The numerical results show that in Re = 500, at the beginning of the last slab in middle channel by changing volume fraction of nanoparticles from 0 to 2 per cent, local Nusselt number 57.40 per cent increase. The existence of the serpentine bend causes the heat transfer rate to increase. Originality/value Forced convection of a mixture of (60:40) per cent ethylene glycol and water by using of 3D numerical simulations, based on the Navier–Stokes equations.

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Garcia-Cadena, Carlos. "Optical device for thermal effusivity estimation of liquids." Revista Mexicana de Física 64, no. 2 (March 14, 2018): 101. http://dx.doi.org/10.31349/revmexfis.64.101.

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We determined the thermal effusivity of liquids using an optical sensor based on the laser beam deflection technique, without directly heat the samples and thus minimally altering them. Applying a heat pulse in a thermo-optical slab we generate a unidimensional temperature distribution. This temperature distribution modifies the refractive index in the slab that finally causes the deflection of a laser beam that propagates perpendicularly to the direction of the heat propagation. The deflection of the laser beam depends on the interaction of the thermal energy with the sample at the slab interface. The exchange of thermal energy between the thermo-optical slab and the sample depends, on the thermal properties of both of them, being the thermal effusivity of our particular interest. Utilizing a theoretical model, we estimate the thermal effusivity of liquids using tridistilled-water and glycerine as reference.We present a simplified version of a past sensor proposal as well as the theoretical analysis of the sensor response. We obtain the thermal effusivity of tridistilled water and glycerine samples with a maximum error of 3%. Finally, we estimate the thermal effusivity of dissolutions of NaCl in tridistilled-water with maximum error of 7.3%.

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Jassim, E. I. "Experimental study on transient behavior of embedded spiral-coil heat exchanger." Mechanical Sciences 6, no. 2 (September 11, 2015): 181–90. http://dx.doi.org/10.5194/ms-6-181-2015.

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Abstract. Spiral coil offers a substantial amount of heat transfer area at a considerably low cost as it does not only have a lower wall resistance but it also achieves a better heat transfer rate in comparison to conventional U-tube arrangement. The general aim of the study is to assess different configurations of spiral coil heat exchangers that can eventually operate in a highly efficient manner. The paper documents the transient behavior of spiral-shaped tubes when the coil is embedded in a rectangular conducting slab. Different arrangements and number of turns per unit length, with fixed volumes, are considered in order to figure out the optimal configuration that maximizes the performance of the heat transfer. The implementation presented in the study is conducted to demonstrate the viability of the use of a large conducting body as supplemental heat storage. The system uses flowing water in the coil and stagnant water in the container. The copper-made coils situated in the center of the slab carries the cold fluid while the container fluid acts as a storage-medium. The water temperature at several depths of the container was measured to ensure uniformity in the temperature distribution of the container medium. Results have shown that the coil orientation, the number of loops, and the Reynolds number, substantially influence the rate of the heat transfer. The vertically-embedded spiral coil has a better performance than the horizontally-embedded spiral coil. Doubling the number of loops is shown to enhance the performance of the coil. Increasing Reynolds Number leads to better coil performance.

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Chiba, Ryoichi. "An Analytical Solution for Transient Heat Conduction in a Composite Slab with Time-Dependent Heat Transfer Coefficient." Mathematical Problems in Engineering 2018 (2018): 1–11. http://dx.doi.org/10.1155/2018/4707860.

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An analytical solution is derived for one-dimensional transient heat conduction in a composite slab consisting of n layers, whose heat transfer coefficient on an external boundary is an arbitrary function of time. The composite slab, which has thermal contact resistance at n-1 interfaces, as well as an arbitrary initial temperature distribution and internal heat generation, convectively exchanges heat at the external boundaries with two different time-varying surroundings. To obtain the analytical solution, the shifting function method is first used, which yields new partial differential equations under conventional types of external boundary conditions. The solution for the derived differential equations is then obtained by means of an orthogonal expansion technique. Numerical calculations are performed for two composite slabs, whose heat transfer coefficient on the heated surface is either an exponential or a trigonometric function of time. The numerical results demonstrate the effects of temporal variations in the heat transfer coefficient on the transient temperature field of composite slabs.

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39

King, A. Douglas. "Heat resistance of Talaromyces flavus ascospores as determined by a two phase slug flow heat exchanger." International Journal of Food Microbiology 35, no. 2 (April 1997): 147–51. http://dx.doi.org/10.1016/s0168-1605(96)01213-5.

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Askar, Serena, Amir Fartaj, Engr Sarbadaman Dasgupta, and Abdul Quayium. "Second law analysis of a multiport serpentine Micro-Channel Slab Heat Exchanger." International Journal of Exergy 10, no. 4 (2012): 379. http://dx.doi.org/10.1504/ijex.2012.047509.

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41

Cherkaoui, M., J. L. Dufresne, R. Fournier, J. Y. Grandpeix, and A. Lahellec. "Monte Carlo Simulation of Radiation in Gases With a Narrow-Band Model and a Net-Exchange Formulation." Journal of Heat Transfer 118, no. 2 (May 1, 1996): 401–7. http://dx.doi.org/10.1115/1.2825858.

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The Monte Carlo method is used for simulation of radiative heat transfers in nongray gases. The proposed procedure is based on a Net-Exchange Formulation (NEF). Such a formulation provides an efficient way of systematically fulfilling the reciprocity principle, which avoids some of the major problems usually associated with the Monte Carlo method: Numerical efficiency becomes independent of optical thickness, strongly nonuniform grid sizes can be used with no increase in computation time, and configurations with small temperature differences can be addressed with very good accuracy. The Exchange Monte Carlo Method (EMCM) is detailed for a one-dimensional slab with diffusely or specularly reflecting surfaces.

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Xiao, Suguang, Muhannad T. Suleiman, Clay J. Naito, and Sudhakar Neti. "Use of Geothermal Deep Foundations for Bridge Deicing." Transportation Research Record: Journal of the Transportation Research Board 2363, no. 1 (January 2013): 56–65. http://dx.doi.org/10.3141/2363-07.

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Winter deicing practices reduce the longevity of bridge infrastructure and make it difficult to achieve the national goal of a bridge service life of 100 years or more, which was set by SHRP 2. The vast majority of these bridges are supported on deep foundations. The goal of this study was to evaluate the concept of employing geothermal deep foundations (energy piles) to heat the bridge slab and thereby minimize or eliminate the use of deicing salt. This concept had the advantage of using required foundation elements to function also as heat exchangers with the surrounding soil, which approximated a constant temperature below a depth of 1 to 3 m (depending on the region). This paper describes a two-dimensional (2-D) finite element model used to assess the power demands to heat a typical bridge slab. Initially, the 2-D model of a conventional bridge (not incorporating the geothermal system) was validated by using a case study for a bridge in Rhode Island for which the temperature of the bridge slab was monitored for about 1 year. Once validated, the model was extended to include the effects of geothermal deep foundations for weather conditions in Philadelphia, Pennsylvania, as an example. Analyses were conducted to simulate the performance of the geothermal system with and without preheating of the bridge slab before the snow or ice formation event.

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Makinde, O. D., T. Chinyoka, and R. S. Lebelo. "Numerical Investigation into Emission, Depletion, and Thermal Decomposition in a Reacting Slab." Mathematical Problems in Engineering 2011 (2011): 1–19. http://dx.doi.org/10.1155/2011/208426.

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The emission of carbon dioxide (CO2) is closely associated with oxygen (O2) depletion, and thermal decomposition in a reacting stockpile of combustible materials like fossil fuels (e.g., coal, oil, and natural gas). Moreover, it is understood that proper assessment of the emission levels provides a crucial reference point for other assessment tools like climate change indicators and mitigation strategies. In this paper, a nonlinear mathematical model for estimating the CO2emission, O2depletion, and thermal stability of a reacting slab is presented and tackled numerically using a semi-implicit finite-difference scheme. It is assumed that the slab surface is subjected to a symmetrical convective heat and mass exchange with the ambient. Both numerical and graphical results are presented and discussed quantitatively with respect to various parameters embedded in the problem.

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Houšová, J., and K. Hoke. "Temperature profiles in microwave heated solid foods of slab geometry: Influence of process parameters." Czech Journal of Food Sciences 19, No. 3 (February 7, 2013): 111–20. http://dx.doi.org/10.17221/6586-cjfs.

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A simple 1-D mathematical model for prediction of local temperatures in a layer of solid material during microwave heating (Hou&scaron;ová et al. 1998) and a sensitivity analysis were used to evaluate the influence of process and material parameters on vertical temperature profiles in a layer of material during heating. The results of calculations are presented in graphs and discussed. The incident microwave power and heat capacity and density of heated material are parameters with great effect on all local and average temperatures and local and average heating rates. The shape of temperature profile is influenced only to a small extent by a change in the value of applied microwave power and also in the value of heat capacity or density of heated material. The whole profiles shift to higher or lower temperature values when the incident microwave power is changing. The distribution of applied microwave power between the upper and bottom layer surface very much influences the shape of the profile and the values and position of the highest and the lowest temperature in the layer. Depth of penetration and thermal conductivity of heated material influence on the shape of temperature profiles and the temperature spread in the layer (evenness of temperature distribution). Effect of penetration depth also depends on the relation to the layer thickness – its effect increases with the increasing layer thickness. At the low values of penetration depth relative to the layer thickness, an uneven temperature profile is to be expected. Effect of thermal conductivity value on temperature profile depends on the time of heating. Because of a short time of microwave heating, the effect of this parameter on temperature distribution is smaller compared to the conventional heating methods. At the beginning of heating its influence is quite negligible. Temperature of the air surrounding the layer and intensity of heat exchange between the air and layer surface are parameters with only small local effect on temperature distribution.

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Yan, Bin, Ruiqi Cheng, Haoran Xie, and Xiangmin Zhang. "Vertical Nonlinear Temperature Gradient and Temperature Load Mode of Ballastless Track in China." Mathematics 10, no. 1 (January 1, 2022): 120. http://dx.doi.org/10.3390/math10010120.

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In the process of heat exchange with the external environment, the internal temperature of ballastless track structure presents a nonlinear distribution. The vertical temperature gradient will cause repeated warping and deformation of track slab, resulting in mortar layer separation, which will affect driving comfort and track durability. The traditional temperature field analysis method of concrete structure based on thermodynamics has the disadvantages of too many assumptions, difficult parameter selection and too much calculation of energy consumption. In this paper, based on the finite element software ANSYS, the heat exchange was transformed into the boundary condition of heat flux, which was applied to the thermodynamic analysis model to study the nonlinear temperature distribution law of ballastless track. The accuracy of the analysis method was verified by the measured data. On this basis, the regional distribution law of temperature gradient of ballastless track under different geographical coordinates and climatic conditions was studied. By adding a regional adjustment coefficient, the vertical temperature load model of ballastless track suitable for typical areas in China was proposed. The proposed temperature load model makes up for the lack of refinement of climate division and temperature load model in relevant specifications, and has strong engineering application and popularization value.

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Charach, C., M. Conti, and C. Bellecci. "Thermodynamics of Phase-Change Storage in Series With a Heat Engine." Journal of Solar Energy Engineering 117, no. 4 (November 1, 1995): 336–41. http://dx.doi.org/10.1115/1.2847888.

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This paper addresses thermodynamics of phase-change storage elements in series with heat engines. It is assumed that the duration of the heat storage and the discharge are equal. It is also assumed that the same heat transfer fluid (HTF) with a constant flow rate is used for the whole cycle. The major constraint imposed on these systems is the stability of the temperature of the HTF supplied to the engine during the storage-discharge cycle. It is shown, for this setup, that the freezing point of the phase-change material (PCM) is defined by the First Law. Maximal stability corresponds to the freezing point equal to the arithmetic mean of the inlet temperatures of the hot and the cold streams. An analytic expression is developed for the Second Law efficiency of the heat storage-removal cycle for the phase-change element in series with an engine. It yields maximal entropy production in the absolute stability limit. Two analytically tractable models of a phase-change storage in series with a heat engine are studied in detail. One involves a PCM slab, and the second involves a PCM tube-and-shell heat exchanger.

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Romanska-Zapala, Anna, Mark Bomberg, Miroslaw Dechnik, Malgorzata Fedorczak-Cisak, and Marcin Furtak. "On Preheating of the Outdoor Ventilation Air." Energies 13, no. 1 (December 19, 2019): 15. http://dx.doi.org/10.3390/en13010015.

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The growing popularity of buildings with integrated sub-systems requires a review of methods to optimize the preheating of ventilation air. An integrated system permits using geothermal heat storage parallel to the direct outdoor air intake with additional treatment in the mechanical room as a part of building an automatic control system. The earth–air heat exchanger (EAHX) has many advantages but also has many unanswered questions. Some of the drawbacks are: A possible entry of radon gas, high humidity in the shoulder seasons, and the need for two different air intake sources with a choice that depends on the actual weather conditions. In winter the EAHX may be used continuously to ensure thermal comfort, while in other seasons its operation must be automatically controlled. To generate missing information about EAHX technology we examined two nearly identical EAHX systems, one placed in the ground next to a building and the other under the basement slab. In another project, we reinforced the ground storage action by having a heat exchanger placed on the return pipes of the hydronic heating system. The information provided in this paper shows advantages of merging both these approaches, while the EAHX could be placed under the house or near the basement foundation that is using an exterior basement insulation.

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Zhang, Qing, Yunfeng Li, Jian Hua, Xiaonan Niu, Lili Hou, Zongfang Chen, and Weiya Ge. "Assessment of Energy Potential and Benefit under the Ground Source Heat Pump Air Conditioning System in Anqing Area of Eastern China." Geofluids 2021 (November 9, 2021): 1–14. http://dx.doi.org/10.1155/2021/3271884.

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Now ground source heat pump is a more efficient way to develop and utilize shallow geothermal energy because it is clean and environmentally friendly and has a relatively low energy cost. In order to optimize the planning layout and geographical space development in the eastern new town of Anqing city, which can realize the transformation and upgrading of real space and urban sustainable development, the exploration for shallow geothermal energy will be carried out in this area, so as to find out the comprehensive thermophysical parameters of the shallow rock-soil body and the heat transfer capacity of the vertical heat exchanger, etc. This paper takes the CBD in the eastern new town of Anqing as an example to provide the basis for the feasibility construction of the ground source heat pump project in the study area and evaluate the economic and environmental benefits of the expected project. According to the simulation test data of 5 working conditions of 4 geothermal exploration holes in the study area, we can clearly know that the energy cost per square meter of the ground source heat pump is 11.8 yuan for a building of one hundred thousand square meters in which the heat removal power is expected to be 9481 kW in summer and 3070 kW in winter. And the annual emission of carbon dioxide, sulfur dioxide, nitrogen oxides, suspended dust, and other air pollutants to the atmosphere can be reduced by 1442.5 t, and the solid waste ash and slag can be reduced by 59.7 t. The annual environmental treatment cost will be saved by 166000 yuan.

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Ji, Wenchao, Guojun Li, Linyang Wei, and Zhi Yi. "Modeling and determination of total heat exchange factor of regenerative reheating furnace based on instrumented slab trials." Case Studies in Thermal Engineering 24 (April 2021): 100838. http://dx.doi.org/10.1016/j.csite.2021.100838.

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Semykin, S. I., and T. S. Golub. "Investigation of electric potential difference during the top oxygen blowing in converter." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 88 (May 1, 2018): 35–40. http://dx.doi.org/10.5604/01.3001.0012.5869.

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Abstract:

Purpose: of this paper is to investigate the method of monitoring the course of the main oxidation-reduction processes and dust depression during the top oxygen blowing, based on the registration of natural electric potential difference on the lance-metal melt site during the blowing. Design/methodology/approach: Exchange processes in the converter bath take place with exchange of electrons and ions between metal and slag melts and gas phase. Since the processes are far from equilibrium, if to complete the circuit it will be possible to register the potential difference. Investigation was conducted in industrial converters of 60-t capacity at medium-carbon steel smelting. During the blowing the potential difference in the lancemetal bath site, the position of the lance and the dust level after gas cleaning were recorded. Findings: It was revealed that the level and sign of variation of the potential difference in the lance-metal bath site reflects the course of the main oxidation-reduction processes in the sub lance area during melting periods: oxidation of silicon, carbon and iron. The probable course of gaseous oxygen interaction with the metal fusion was discussed. Practical implications: In order to reduce the dust level without slowing down the carbon oxidation process, it was recommended to place the lance at a level corresponded to the potential difference during the active carbon oxidation period 30 % lower than 200-210 mV. The results of heats, conducted with the proposed mode of lance position, showed that the level of dust emission was 16% lower than on the comparative melting. Originality/value: The level and sign of the potential difference is possible to use to select the lance position during the blowing for longer slag foamed state without overflow that ensures a lower level of dust emission.

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Journal articles on the topic 'Slag heat exchange'

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