Relevant bibliographies by topics / Multiple hearth furnace

Academic literature on the topic 'Multiple hearth furnace'

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Published: 1 June 2024

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Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers

Journal articles on the topic "Multiple hearth furnace":

1

Ramı́rez, Mercedes, Rodolfo Haber, Vı́ctor Peña, and Iván Rodrı́guez. "Fuzzy control of a multiple hearth furnace." Computers in Industry 54, no. 1 (May 2004): 105–13. http://dx.doi.org/10.1016/j.compind.2003.05.001.

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Gomez, Fuentes J. V., and S. L. Jämsä-Jounela. "Control Strategy For A Multiple Hearth Furnace." IFAC-PapersOnLine 51, no. 21 (2018): 189–94. http://dx.doi.org/10.1016/j.ifacol.2018.09.416.

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Sapienza, Frank, Thomas Walsh, Karla Sangrey, Louis Barry, Jane Madden, and Robert Gaudes. "Upgrade of UBWPAD's Multiple Hearth Furnace Sludge Incinerators." Proceedings of the Water Environment Federation 2007, no. 3 (January 1, 2007): 880–92. http://dx.doi.org/10.2175/193864707787975642.

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Kukharev, Alexsey, Vyacheslav Bilousov, Ecaterina Bilousov, and Vitaly Bondarenko. "The Peculiarities of Convective Heat Transfer in Melt of a Multiple-Electrode Arc Furnace." Metals 9, no. 11 (October 30, 2019): 1174. http://dx.doi.org/10.3390/met9111174.

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The modern direction of improving the technology of steel production in high-power arc furnaces is the intensification of magnetohydrodynamic effects for mixing the melt. In this article, a furnace design is proposed that contains three roof arc and three bottom electrodes, which provides the formation of additional eddy currents in the melt when the furnace is supplied with direct current or a low-frequency current. For a numerical study of the features of heat transfer in the melt of this furnace, a three-dimensional mathematical model of magnetohydrodynamic and thermal processes was used. The results were processed using the methods of visualization of vortex structures and the Richardson criterion. In an oven with a capacity of 180 tons at currents in the electrodes of 80 kA, the conditions for the interaction of electric vortex and thermogravitational convection were studied. Results showed that thermogravitational convection due to nonuniform heating of the melt led to a decrease in the size of the main electric vortex flow and the formation of an additional flow near the side walls of the furnace. The features of azimuthal flows formed in the areas of electric arcs and hearth electrodes were analyzed. Results showed that the multivortex structure of the flows that formed in the furnace allowed the volume of stagnant zones to be reduced and provided acceptable melt mixing conditions. The results can be used to improve the energy and structural parameters of three-electrode arc furnaces.
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Shekhter, Leonid N., John E. Litz, Nimit M. Shah, and Larry F. McHugh. "Thermodynamic Modelling of Molybdenite Roasting in a Multiple-Hearth Furnace." JOM 73, no. 3 (January 19, 2021): 873–80. http://dx.doi.org/10.1007/s11837-020-04549-y.

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Jämsä-Jounela, Sirkka-Liisa, Jose Valentin Gomez Fuentes, Jonathan Hearle, David Moseley, and Alexander Smirnov. "Control strategy for a multiple hearth furnace in kaolin production." Control Engineering Practice 81 (December 2018): 18–27. http://dx.doi.org/10.1016/j.conengprac.2018.08.020.

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Eskelinen, Aleksi, Alexey Zakharov, Sirkka-Liisa Jämsä-Jounela, and Jonathan Hearle. "Dynamic modeling of a multiple hearth furnace for kaolin calcination." AIChE Journal 61, no. 11 (June 26, 2015): 3683–98. http://dx.doi.org/10.1002/aic.14903.

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Mininni, Giuseppe, Vincenzo Lotito, Roberto Passino, and Ludovico Spinosa. "Influence of sludge cake concentration on the operating variables in incineration by different types of furnaces." Water Science and Technology 38, no. 2 (July 1, 1998): 71–78. http://dx.doi.org/10.2166/wst.1998.0107.

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The influence of cake concentration on fuel consumption, air requirement and flue gas production in incineration of sewage sludge is discussed. Fluidized bed (FBF), multiple hearth (MHF) and rotary kiln (RKF) furnaces are considered as alternatives together with the optional use of an afterburning chamber where exhaust gases are taken at 950°C for 2 s with an oxygen concentration of 6% by volume. It clearly appears that, if an afterburning chamber is used, and total minimum fuel consumption can be achieved at an optimal value of cake concentration (45.9% for FBF and 32.5% for MHF) when autogenous conditions are reached in the furnace and air addition is no longer needed in the afterburning chamber. At higher concentrations, abundant exhaust gas productions, due to the dilution air needed in the furnace, can considerably increase fuel consumption in the afterburning chamber, especially in MHF operation. In the rotary kiln furnace, fuel requirement decreases over the whole range of cake concentration as no conditions for autogenous combustion in the furnace can be achieved.
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Gomez Fuentes, J. V., and S. L. Jämsä-Jounela. "Simplified Mechanistic Model of the Multiple Hearth Furnace for Control Development." SNE Simulation Notes Europe 28, no. 3 (September 2018): 97–100. http://dx.doi.org/10.11128/sne.28.sn.10426.

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He, Hongsheng, Xiaofang Lv, and Liying Huang. "Enhanced reduction of multiple layers carbon containing pellets in rotary hearth furnace." Metallurgical Research & Technology 120, no. 4 (2023): 410. http://dx.doi.org/10.1051/metal/2023054.

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To enhance the reduction of multiple layers carbon containing pellets in rotary hearth furnace (RHF) process, a three-layer bed pellets were investigated using an electric furnace by simulating the RHF process. It was found that the metallization rate of the pellets on the upper layer was greatly higher than that on the middle and lower layers due to the low reduction efficiency and heat transfer efficiency. Various types and amount of reducing agent in carbon containing pellets showed different metallization rate and shrinkage rate, which affected the reduction efficiency and heat transfer efficiency of pellets. By optimization the type and amount of reducing agent, the metallization rates of reduced pellets for each layer of the bed all achieved more than 85% at 1300 °C and holding 20min, the metallization rates of reduced pellets for each layer of the bed reached over 90% at 1300 °C and holding 25 min.
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Journal articles

Dissertations / Theses on the topic "Multiple hearth furnace":

1

Lacombe, Elie. "Modélisation de la torréfaction de biomasse dans un four à soles multiples." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. https://thares.univ-grenoble-alpes.fr/2023GRALI086.pdf.

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Dans le contexte énergétique actuel, la biomasse est une ressource abondante et renouvelable qui peut être valorisée énergétiquement directement sous forme de chaleur ou indirectement sous forme de gaz ou de biocarburants. Pour cela, plusieurs procédés thermochimiques de dégradation de la biomasse sèche tels que la gazéification, la pyrolyse ou la combustion sont mis en œuvre. Cependant, la biomasse exploitable (forestière ou agricole) est caractérisée par un fort taux d'humidité, une broyabilité énergivore, une mauvaise coulabilité de sa poudre ainsi qu’une faible densité énergétique par rapport au charbon. La torréfaction est un prétraitement thermique entre 200 et 300 °C sous atmosphère inerte permettant d’améliorer la qualité de la biomasse en vue de sa valorisation énergétique. La biomasse torréfiée obtenue est hydrophobe, sèche et son pouvoir calorifique est plus élevé que la ressource brute.La description des mécanismes de dégradation de la biomasse au cours de la torréfaction a fait l’objet de nombreux travaux scientifiques. Cependant, il y a un manque d’études sur des procédés pilotes et de démonstration qui se limitent pour la plupart à l’analyse du produit principal : le solide.En considérant les phénomènes prépondérants influençant la dégradation thermique de la biomasse, l’objectif de ce travail est d’approcher cette problématique du passage à l’échelle, en cherchant à modéliser les rendements de torréfaction dans un four à soles multiples, qui constitue l’une des technologies de référence. Pour mener à bien ce travail, une étude cinétique réalisée à partir de mesures dans un analyseur thermogravimétrique a permis de valider sur les biomasses étudiées (le chêne et noyaux d’olives) le schéma semi-détaillé de dégradation développé par Ranzi et Anca-Couce. Ensuite, des mesures de distribution de temps de séjour dans ce four ont permis d’estimer l’influence des paramètres opératoires sur le mouvement des particules et d’identifier les principaux mécanismes en jeu. Si la vitesse de rotation de l’axe du four est le levier principal pour contrôler le temps de séjour de la ressource, le débit d’alimentation et l’espacement entre les dents d’un même bras ont une influence importante sur la distribution de temps de séjour. Le transport des particules dans le four est fortement dispersif. Sur l’ensemble des essais, le temps de séjour des particules dans le four est compris entre 50 % et 150 % du temps de séjour moyen. La dernière étape consiste à développer un modèle thermique complet du four à soles multiples intégrant la cinétique chimique et un modèle de transport de la biomasse. Les résultats sont alors confrontés à des mesures expérimentales réalisées dans un four à soles multiples traitant entre 40 et 80 kg/h de ressource de 250 à 300 °C. Le modèle développé décrit de manière satisfaisante les tendances observables expérimentalement. Le rendement solide est correctement décrit par le modèle mais le rendement en gaz permanent est sous-estimé de 34 % en moyenne. L’erreur relative sur le pouvoir calorifique supérieur de la ressource torréfiée est inférieure à 8 %. Expérimentalement, comme attendu, la température de torréfaction influence significativement les rendements et produits de torréfaction. Plus rarement rapporté dans la littérature, l’impact du taux d’humidité de la ressource traitée sur les rendements obtenues est également considérable
In the current energy context, biomass is an abundant and renewable resource that can be energetically recovered directly into heat or indirectly into gas or biofuels. Several thermochemical processes, such as gasification, pyrolysis or combustion can be implemented. However, biomass is characterized by a high humidity rate, a high grinding energy and a low energy density compared to coal. Torrefaction is a thermal pre-treatment between 200 and 300 °C under an inert atmosphere that improves biomass quality for energy uses. The torrefied biomass obtained is hydrophobic, dry and has a higher calorific value than raw biomass.Researchers have put a lot of effort into understanding the mechanisms of biomass degradation during torrefaction on small-scale experiments for various resources. Those works are useful for investigating chemical kinetics during torrefaction. However, there is a lack of studies on pilot and demonstration processes, which are limited for the most part to the analysis of the main product: the torrefied solid.By considering predominant phenomena influencing the thermal degradation of biomass, this work aims to model torrefaction yields in a multiple hearth furnace, which constitutes one of the reference technologies. To carry out this work, a kinetic study based on thermogravimetric measurements aims to validate the Ranzi Anca-Couce degradation scheme on two biomasses (oak and olive stones). Then, residence time distribution measurements in this furnace are achieved to estimate the influence of operating parameters on particle transport and identify the main mechanisms involved. The shaft speed of the furnace is the main parameter to control the residence time of the resource. The feed rate and the spacing between the teeth of an arm also have an important influence on the distribution of the residence time of particles. Particle transport in the furnace is dispersive. The particles' residence time is comprised between 50 % and 150 % of the average residence time. The last step consists of developing a complete thermal model of this furnace, integrating a chemical kinetic and a biomass transport model. Results are compared with experimental measurements achieved in a semi-industrial multiple hearth furnace processing between 50 and 70 kg/h of biomass at 250 to 300 °C. The model satisfactorily describes experimentally observable trends. Solid yield is correctly described by the model but the dry gas yield is underestimated by 34 %. The relative error on the higher calorific value of the solid product is less than 8 %. Experimentally, torrefaction temperature influences torrefaction yields and products as expected. More rarely reported in the literature, the impact of the moisture content of raw biomass on yields is also significant

Books on the topic "Multiple hearth furnace":

1

Office, General Accounting. Air pollution: Emission sources regulated by multiple Clean Air Act provisions : report to the Chairman, Subcommittee on Clean Air, Wetlands, Private Property, and Nuclear Safety, Commmittee on Environment and Public Works, U.S. Senate. Washington, D.C. (P.O. Box 37050, Washington, D.C. 20013): U.S. General Accounting Office, 2000.

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Book chapters on the topic "Multiple hearth furnace":

1

Spellman, Frank R. "Description of Multiple-Hearth Furnace." In Incinerating Biosolids, 59–103. CRC Press, 2020. http://dx.doi.org/10.1201/9781003075875-6.

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Spellman, Frank R. "Operation of Multiple-Hearth Furnace." In Incinerating Biosolids, 105–41. CRC Press, 2020. http://dx.doi.org/10.1201/9781003075875-7.

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Spellman, Frank R. "Preventive Maintenance Practices: Multiple-Hearth Furnace." In Incinerating Biosolids, 143–52. CRC Press, 2020. http://dx.doi.org/10.1201/9781003075875-8.

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Conference papers on the topic "Multiple hearth furnace":

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Fuentes, Jose Valentin Gomez, Sirkka-Liisa Jamsa-Jounela, David Moseley, and Tom Skuse. "Control strategy of a Multiple Hearth Furnace enhanced by machine learning algorithms." In 2019 4th Conference on Control and Fault Tolerant Systems (SysTol). IEEE, 2019. http://dx.doi.org/10.1109/systol.2019.8864797.

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Wu, Puyuan, Weixiao Shang, and Jun Chen. "Study of Flow Field of a Residential Gas Furnace With Particle Image Velocimetry." In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83471.

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Nearly 45% of the residential site energy in the US is consumed by the gas furnace for space heating. The design practice of next-generation product often refers to CFD-based design tool, in order to reduce the development cost and cycle. In the present study, Particle Image Velocimetry (PIV) is applied to measure the detailed flow field inside a general gas furnace model for establishing a benchmark database and validating CFD predictions. The furnace model is equipped with multiple observation windows and is connected to an air circulation system with seeding particles introduced, simulating different well-controlled operation conditions. The flow field around the four primary heat exchangers and at the outlet of the furnace is measured and analyzed statistically. The mean velocity displays symmetric patterns as the differential pressure between inlet and outlet of the furnace is low. The symmetry is transiently lost as the differential pressure increases. Statistical analysis also shows turbulence in regions with flow separation and vortex shedding. The results provide a clear understanding of the change of flow characteristics under different operation conditions.
3

Jian, Christopher Q. "CFD Modeling of a Fiberglass Furnace." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1664.

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Abstract In the fiberglass production process, glass is produced from various batch ingredients in a glass furnace. The molten glass is then delivered, through a delivery system that is often called the front-end system, to the various downstream forming operations. Multiple complex processes take place in the glass furnace, which include the turbulent reacting flow in the combustion space; laminar flow dominated by natural convection in the molten glass; fusion of raw batch materials to form molten glass; radiation and convective heat transfer between the combustion space and the molten glass; bubbling flows in the glass; and Joule heating within the molten glass, etc. The main task of the glass furnace is to convert raw batch materials into glass and thermally and chemically condition the glass before being delivered to the front-end system. One of the major tasks of a front-end system is to insure that the glass is conditioned to the specifications required by the forming operations while maintaining the highest glass quality. Improperly designed and/or operated furnace and front end delivery system can cause a number of problems to the forming operations, ranging from poor glass quality with defects to shortened furnace service life. CFD has become an increasingly important tool for glass manufacturers to guide and optimize such system designs and operations. The current work is part of an effort to leverage CFD resources in the decision-making processes in engineering, operations, and businesses. The furnace modeling was performed using the recently implemented batch melting model jointly developed by Owens Corning and Fluent, Inc., which features three-dimensional simulation of an entire glass furnace including combustion, bubbling, and electrical boosting. The thermal coupling procedure between the combustion space, batch, and the melting tank along with the associated convergence issues are discussed. The modeling results are presented along with comparison with field measurements.
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Mammoser, John H., and Aldo Jimenez. "Comparison of Temperature Measurements in Fire Test Furnaces Using Aspirated Thermocouples." In ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72548.

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There are numerous thermocouple types which are used to measure temperature in experimental fire environments including bare bead, plate, sheathed (grounded and ungrounded) and aspirated thermocouples (suction pyrometers). Furnaces used to test fire resistive construction, as specified in the Standards ANSI/UL 263, ASTM E119 and NFPA 251 employ sheathed, ungrounded thermocouples to measure gas temperatures, while room fire experiments, such as ASTM E603-01, employ bare bead and aspirated thermocouples to measure hot gas temperature layers. Shielded, aspirated thermocouples are quite inexpensive and easy to make, however, the suction needed to create velocities in excess of 10 m/s at the tip is quite a difficult challenge. A commonly used method to create suction includes multiple gas traps to cool and dehumidify the hot gas before passing through a pump rated for high temperatures. This method can be costly, time consuming to maintain and cannot operate for multiple hours at high temperature without damaging the pump. An investigation has been undertaken to determine a cost effective method to measure gas temperatures in fire test furnaces for long durations at high temperatures. A comparison of bear bead, plate and double shielded, aspirated thermocouples will be presented. A low cost, durable aspirated thermocouple will be shown to continuously endure temperatures in excess of 1040°C for multiple hours.
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Heuer, Volker, Klaus Löser, and Bill Gornicki. "New Applications for Synchronized Vacuum Heat Treatment." In HT 2015. ASM International, 2015. http://dx.doi.org/10.31399/asm.cp.ht2015p0631.

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Abstract A recently introduced new vacuum furnace design allows the total integration of heat treatment into the manufacturing line. This compact unit can be implemented into the heart of the production chain and provides heat-treatment processes which can be fully synchronized with the green and hard machining-operations. When performing case hardening, the components are low pressure carburized at high temperatures (1050°C) followed by gas quenching. Using this technology, the components are treated in most cases in a single layer of parts (“2D-treatment”) which allows for an easy automated loading and unloading of the fixture-trays. Furthermore this “small batch – treatment” leads to an optimum in quality regarding quench homogeneity and distortion control. By using the small batch concept, a continuous flow of parts can be established. There is no need to wait until enough parts are collected to build a large batch with multiple layers (“3D-batch”). Therefore excessive costs are avoided for inventory, part storage and transportation within the plant. Typical components for this technology come from the automotive, aerospace and tool industry. The paper shows several new results from case hardening applications.
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Amritkar, Amit Ravindra, Danesh Tafti, and Surya Deb. "Particle Scale Heat Transfer Analysis in Rotary Kiln." In ASME 2012 Heat Transfer Summer Conference collocated with the ASME 2012 Fluids Engineering Division Summer Meeting and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ht2012-58137.

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Rotary furnaces have multiple applications including calcination, pyrolysis, carburization, drying, etc. Heat transfer through granular media in rotary kilns is a complex phenomenon and plays an important role in the thermal efficiency of rotary furnaces. Thorough mixing of particles in a rotary kiln determines the bed temperature uniformity. Hence it is essential to understand the particle scale heat transfer modes through which the granular media temperature changes. In this study, numerical simulations are performed using coupled Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) to analyze heat transfer in a non-reacting rotary kiln. The microscopic models of particle-particle, particle-fluid, particle-surface and fluid-surface heat transfer are used in the analysis. The heat transfer simulations are validated against experimental data. The effect of particle cascading on the bed temperature is measured and contributions from various modes of particle scale heat transfer mechanisms are reported. Particles are heated near the rotary kiln walls by convection heat transfer as they pass through the thermal boundary layer of the heated fluid. These particles are transported to the center of the kiln where they transfer heat to the cooler particles in the core of the kiln and back to the cooler fluid at the center of the kiln. It is found that 90% of the heat transferred to particles from the kiln walls is a result of convection heat transfer, whereas only 10% of the total heat transfer is due to conduction from the kiln walls.
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Nunes, Edmundo M., Mohammad H. N. Naraghi, Hui Zhang, and Vishwanath Prasad. "A Volume Radiation Heat Transfer Model for Czochralski Crystal Growth Processes." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-1485.

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Abstract Thermal modeling of Czochralski (CZ) crystal growth processes is a challenging task owing to the complex interaction of heat conduction, convection, thermal radiation, fluid flow, and other transport phenomena. A highly innovative, general-purpose computer model for phase-change and free-surface problems, utilizing a multi-zone adaptive grid generation and curvilinear finite volume scheme, is linked to a spectral, volume and surface thermal radiation algorithm to predict the temperature distribution within a Czochralski growth furnace. The radiative transfer model, based upon the Discrete Exchange Factor (DEF) method, is capable of addressing the complexities due to irregularly-shaped axisymmetric geometries and shadowing effects. A unified exchange factor model is used to account for multiple reflection/scattering of radiation within the enclosure. Several numerical trials are performed to simulate the CZ growth of yttrium aluminum garnet (YAG). The effect of the top surface boundary condition on temperature profile, crystal/melt interface shape, and process stability is studied to examine the applicability of this model to control the growth conditions and interface shape. The results show that there exists a temperature range for this surface for which the desirable conditions for crystal growth are possible. This limiting temperature range is, however, dynamic and changes as the growth progresses.
8

Crane, Nathan B. "Low-Cost Pyrometric Temperature Measurement in Concentrated Sunlight With Emissivity Determination." In ASME 2008 2nd International Conference on Energy Sustainability collocated with the Heat Transfer, Fluids Engineering, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/es2008-54258.

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A method for correcting pyrometric temperature measurements of high temperature objects with unknown emissivity is presented. The method also estimates surface emissivity a the pyrometer wavelengths. It is particularly useful for correcting errors due to reflected light in solar heating applications. The method requires two or more narrow band pyrometers and can be applied to low-cost commercial instruments. The method analyzes the temperature measurements of multiple pyrometers operating at different wavelengths across a range of sample temperatures to solve for the surface emissivities that minimize the differences in temperature measurements. The temperature measurements are corrected using the new emissivities values. Simulated temperature data with both random noise and systematic errors is used to assess the robustness of the analysis method. When applied to temperature data from a solar furnace, it is shown to significantly decrease the difference in the temperature measurements of two single-color pyrometers. This method provides a potential low cost solution for pyrometric temperature measurement of solar-heated objects.
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Nakate, Prajakta, Domenico Lahaye, Cornelis Vuik, and Marco Talice. "Systematic Development and Mesh Sensitivity Analysis of a Mathematical Model for an Anode Baking Furnace." In ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/fedsm2018-83131.

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The anode baking process is developed and improved since the 1980s due to its importance in Aluminium industry. The process is characterized by multiple physical phenomena including turbulent flow, combustion process, conjugate heat transfer, and radiation. In order to obtain an efficient process with regards to quality of anodes, soot-free combustion, reduction of NOx and minimization of energy, a mathematical model can be developed. A mathematical model describes the physical phenomena and provides a deeper understanding of the process. Turbulent flow is one of the important physical phenomena in an anode baking process. In the present work, isothermal turbulent flow is studied in detail with respect to two turbulence models in COMSOL Multiphysics software. The difference between wall boundary conditions for these models and their sensitivity towards the boundary layer mesh is investigated. A dimen-sionless distance in viscous scale units is used as a parameter for comparison of models with and without a boundary layer mesh. The investigation suggests that the boundary layer mesh for both turbulence models increase the accuracy of flow field near walls. Moreover, it is observed that along with the accuracy, the numerical convergence of Spalart-Allmaras turbulence model in COMSOL Multiphysics is highly sensitive to the boundary layer mesh. Therefore, development of converged Spalart-Allmaras model for the complete geometry is difficult due to the necessity of refined mesh. Whereas, the numerical convergence of k-ε model in COMSOL Multiphysics is less sensitive to the dimen-sionless viscous scale unit distance. A converged solution of the complete geometry k-ε model is feasible to obtain even with less refined mesh at the boundary. However, a comparison of a developed solution of k-ε model with another simulation environment indicates differences which enhance the requirement of having converged Spalart-Allmaras model for complete geometry.
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Ryu, Sang-gil, David J. Hwang, Eunpa Kim, Jae-hyuck Yoo, and Costas P. Grigoropoulos. "Laser-Assisted on Demand Growth of Semiconducting Nanowires." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-65696.

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We present laser-assisted direct synthesis of nanowires with site-, composition-, and shape-selectivity on a single substrate by employing a spatially confined laser heat source. Laser-assisted nanowire growth based on vapor-liquid-solid mechanism is conveniently studied with multiple growth parameters such as temperature, time, and illumination direction. On-demand direct integration of silicon and germanium nanowires are demonstrated in a hetero-array configuration by simply switching the reactant gases as the growth of nanowires is limited within the heat-affected zone induced by the laser. Since laser-induced local temperature field is able to drive the individual growth, each germanium nanowire is successfully synthesized with distinctively different geometric features from cylindrical to hexagonal pyramid shape. By regularly patterning gold catalysts prepared by electron beam lithography on Si(111), especially, we accomplished site- and shape-selective direct integration of germanium nanowires on a single substrate in vertical architecture. Considering that blanket furnace heating only produce nanowires with uniform size and shape, therefore, our work shows a route toward the facile fabrication of multifunctional nanowire based devices.

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