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Published: 4 June 2021
Last updated: 31 July 2024

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1

Harish, J. "Computational Modelling Of Heat Transfer In Reheat Furnaces." Thesis, Indian Institute of Science, 2000. https://etd.iisc.ac.in/handle/2005/234.

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Furnaces that heat metal parts (blooms) prior to hot-working processes such as rolling or forging are called pre-forming reheat furnaces. In these furnaces, the fundamental idea is to heat the blooms to a prescribed temperature without very large temperature gradients in them. This is to ensure correct performance of the metal parts subsequent to reheating. Due to the elevated temperature in the furnace chamber, radiation is the dominant mode of heat transfer from the furnace to the bloom. In addition, there is convection heat transfer from the hot gases to the bloom. The heat transfer within the bloom is by conduction. In order to design a new furnace or to improve the performance of existing ones, the heat transfer analysis has to be done accurately. Given the complex geometry and large number of parameters encountered in the furnace, an analytical solution is difficult, and hence numerical modeling has to be resorted to. In the present work, a numerical technique for modelling the steady-state and transient heat transfer in a reheat furnace is developed. The work mainly involves the development of a radiation heat transfer analysis code for a reheat furnace, since a major part of the heat transfer in the furnace chamber is due to radiation from the roof and combustion gases. The code is modified from an existing finite volume method (FVM) based radiation heat transfer solver, The existing solver is a general purpose radiation heat transfer solver for enclosures and incorporates the following features: surface-to-surface radiation, gray absorbing-emitting medium in the enclosure, multiple reflections off the bounding walls, shadowing effects due to obstructions in the enclosure, diffuse reflection and enclosures with irregular geometry. As a part of the present work, it has now been extended to include the following features that characterise radiation heat transfer in the furnace chamber · Combination of specular and diffuse reflection as is the case with most real surfaces · Participating non-gray media, as the combustion gases in the furnace chamber exhibit highly spectral radiative characteristics Transient 2D conduction heat transfer within the metal part is then modelled using a FVM-based code. Radiation heat flux from the radiation model and convection heat flux calculated using existing correlations act as boundary conditions for the conduction model. A global iteration involving the radiation model and the conduction model is carried out for the overall solution. For the study, two types of reheat furnaces were chosen; the pusher-type furnace and the walking beam furnace. The difference in the heating process of the two furnaces implies that they have to be modelled differently. In the pusher-type furnace, the heating of the blooms is only from the hot roof and the gas. In the walking beam furnace, the heating is also from the hearth and the blooms adjacent to any given bloom. The model can predict the bloom residence time for any particular combination of furnace conditions and load dimensions. The effects of variations of emissivities of the load, thickness of the load and the residence time of billet in the furnaces were studied.
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2

Harish, J. "Computational Modelling Of Heat Transfer In Reheat Furnaces." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/234.

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Furnaces that heat metal parts (blooms) prior to hot-working processes such as rolling or forging are called pre-forming reheat furnaces. In these furnaces, the fundamental idea is to heat the blooms to a prescribed temperature without very large temperature gradients in them. This is to ensure correct performance of the metal parts subsequent to reheating. Due to the elevated temperature in the furnace chamber, radiation is the dominant mode of heat transfer from the furnace to the bloom. In addition, there is convection heat transfer from the hot gases to the bloom. The heat transfer within the bloom is by conduction. In order to design a new furnace or to improve the performance of existing ones, the heat transfer analysis has to be done accurately. Given the complex geometry and large number of parameters encountered in the furnace, an analytical solution is difficult, and hence numerical modeling has to be resorted to. In the present work, a numerical technique for modelling the steady-state and transient heat transfer in a reheat furnace is developed. The work mainly involves the development of a radiation heat transfer analysis code for a reheat furnace, since a major part of the heat transfer in the furnace chamber is due to radiation from the roof and combustion gases. The code is modified from an existing finite volume method (FVM) based radiation heat transfer solver, The existing solver is a general purpose radiation heat transfer solver for enclosures and incorporates the following features: surface-to-surface radiation, gray absorbing-emitting medium in the enclosure, multiple reflections off the bounding walls, shadowing effects due to obstructions in the enclosure, diffuse reflection and enclosures with irregular geometry. As a part of the present work, it has now been extended to include the following features that characterise radiation heat transfer in the furnace chamber · Combination of specular and diffuse reflection as is the case with most real surfaces · Participating non-gray media, as the combustion gases in the furnace chamber exhibit highly spectral radiative characteristics Transient 2D conduction heat transfer within the metal part is then modelled using a FVM-based code. Radiation heat flux from the radiation model and convection heat flux calculated using existing correlations act as boundary conditions for the conduction model. A global iteration involving the radiation model and the conduction model is carried out for the overall solution. For the study, two types of reheat furnaces were chosen; the pusher-type furnace and the walking beam furnace. The difference in the heating process of the two furnaces implies that they have to be modelled differently. In the pusher-type furnace, the heating of the blooms is only from the hot roof and the gas. In the walking beam furnace, the heating is also from the hearth and the blooms adjacent to any given bloom. The model can predict the bloom residence time for any particular combination of furnace conditions and load dimensions. The effects of variations of emissivities of the load, thickness of the load and the residence time of billet in the furnaces were studied.
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3

Moros, A. "Magnetohydrodynamics of channel induction furnaces." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383311.

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4

Chiu-Webster, Sunny. "Horizontal convection and glass furnaces." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611923.

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5

Correia, Sara Alexandra Chanoca. "Development of improved mathematical models for the design and control of gas-fired furnaces." Thesis, University of South Wales, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369080.

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6

Carlson, Kurt B. "Development of a mathematical model to determine the temperature distribution in the metal layer and hearth of an electrical resistance smelter /." Online version of thesis, 1987. http://hdl.handle.net/1850/10219.

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7

Hixson, Scott. "Rapid industrial furnace thermal modeling for improved fuel efficiency." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5091.

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Thesis (M.S.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 9, 2009) Includes bibliographical references.
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8

Aula, M. (Matti). "Optical emission from electric arc furnaces." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526210926.

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Abstract The main cause of temperature and composition fluctuations in the electric arc furnace (EAF) process is the scrap used as a raw material. Process conditions in EAF can vary significantly from heat to heat because there is no accurate information of scrap composition. Due to harsh process conditions, there are currently few sensors available for direct on-line measurement of the EAF process. In this work new information about stainless steelmaking EAF process conditions is sought with optical emission spectrum measurement. The measurement system relies on transportation of the light emitted from the measured furnace to a remotely situated spectrometer. Analysing the slag composition from the arc emission spectrum was tested in the laboratory and on a pilot scale. The laboratory measurements indicate that changes in the amount of CrOx and MnO in the slag have the highest impact on optical emission spectra. The pilot scale measurements show that the Cr2O3 content of the slag can be measured from the arc emission spectrum using suitable reference lines with an average absolute error of 0.62 %-points and a standard deviation of 0.49 %-points. The results from measurements at Outokumpu Stainless Oy, Tornio Works, indicate that measurement of the optical emission spectrum from industrial EAF is feasible in a practical sense, and can be used in analysing of EAF atmosphere, scrap melting and slag surface. Furthermore, the results of industrial measurements indicate that the atoms in the arc plasma mainly originate from the slag. The measurement of scrap melting could be potentially used in EAF control in optimization of arc voltages and second scrap bucket charging. The potential use of slag CrOx measurements is in optimization of reductant additions as well as defining the further processing of EAF slag
Tiivistelmä Valokaariuunien ohjaus on perinteisesti ollut uunioperaattorin käsissä. Valokaaariuuniprosessin on-line mittaukseen on olevassa vähän menetelmiä johtuen uunin hyvin haastavaista olosuhteista. Tässä työssä on tutkittu optiseen emissiospektroskopiaan perustuvaa menetelmää uuden jatkuva-aikaisen tiedon tuottamisessa valokaariuuniprosessista. Mittausjärjestelmä perustuu valon keräämiseen mitattavasta uunista valokuidun avulla, joka johtaa valon analysoitavaksi etäälle prosessista sijoitettuun spektrometriin. Mittauksia suoritettiin laboratorio-, pilot- ja tehdas-mittakaavassa. Valokaariuunin kuonan koostumuksen analysointia testattiin laboratorio- ja pilot-mittakaavan uuneilla. Laboratoriomittaukset osoittivat että kuonan komponenteista CrOx ja MnO ja vaikuttavat eniten mitattuun emissiospektriin. Pilot-mittakaavan kokeissa havaittiin, että kuonan Cr2O3-pitoisuutta voidaan mitata valokaaren emissiospektristä 0,62 %-yksikön keskimääräisellä absoluuttisella virheellä ja 0,49 %-yksikkön hajonnalla. Teollisella valokaariuunilla suoritetuista mittauksista havaittiin että optisen emissiospektrin mittaus voidaan suorittaa ilman ylitsepääsemättömiä teknisiä esteitä. Mittauksen tuloksia voidaan puolestaan käyttää kaasufaasin reaktioiden, romun sulamisen ja kuonapinnan ominaisuuksien arvioinnissa. Valokaaren emissiospektrin analyysi osoitti, että valokaaren plasman komponentit ovat pääosin peräisin kuonasta, joka mahdollistaa kuonan koostumuksen arvioinnin valokaaren emissiospektrin perusteella. Romun sulamisen mittausta voidaan prosessinohjauksessa käyttää jänniteportaiden ja toisen korin panostuksen optimointiin. Kuonan kromipitoisuuden mittaamista voidaan puolestaan käyttää pelkistinaineiden lisäyksen optimointiin ja kuonan jatkokäsittelyn valintaan
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9

Morris, Heath A. "Advanced modeling for small glass furnaces." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5066.

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Thesis (M.S.)--West Virginia University, 2007.
Title from document title page. Document formatted into pages; contains vii, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 70-71).
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10

Woodfield, Peter Lloyd. "Combustion instability in bagasse-fired furnaces." Thesis, The University of Sydney, 2001. https://hdl.handle.net/2123/27860.

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With rapidly increasing interest in a cleaner world environment, biomass com­bustion is becoming a very real alternative energy source to the more traditional coal-fired power stations. Sugar cane bagasse is one such material that is readily available and moreover, has been used as a fuel in the Australian sugar industry for well over thirty years. Today, the most widely utilised bagasse-fired furnace is the 'pneumatic spreader suspension fired furnace'. In this particular design, the solid bagasse particles are blown into the furnace by high velocity air jets, where the majority of the fuel is entrained vertically by a large flow of pre-heated air. This stream is termed 'combustion air' and enters the furnace via a grate spanning the entire furnace floor. Combustion of bagasse in these furnaces has its own special set of problems which appear to be due largely to the high moisture content of the fuel (45 - 55% as fired (wet basis)). Combustion instability in bagasse-fired furnaces is a key issue for operation but is presently not well understood. During periods of instability, there is a con­siderable dulling of the flame, the furnace pressure oscillates, large mounds of wet fuel accumulate on the grate and it becomes impossible to maintain the mill steam requirements. Dixon (1984) describes this as the 'single factor limiting the further development of bagasse suspension firing'. Since the early eighties, the majority of the research into this problem has been on a 'trial and error' basis with only lim­ited success. More recently an in-depth theoretical and computational investigation was undertaken into modelling of bagasse-furnaces (Luo, 1993; Luo and Stanmore, 1994). The work of Luo and Stanmore (1994) and the work of Dixon (1983,1984) provide the starting point for this current research.
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11

MacRosty, Richard Swartz Christopher L. E. "Modelling, optimization and control of an electric arc furnace." *McMaster only, 2005.

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12

Elmedhem, Bashir A. "Modelling of liquid fuel combustion in furnaces." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325303.

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13

SOBRAL, SERGIO CORDEIRO. "SERIES LIMITING CURRENT REACTOR FOR ARC FURNACES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9424@1.

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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Esta tese apresenta os principais fenômenos eletromecânicos, que ocorrem durante a operação do forno a arco, com ênfase especial nos fenômenos elétricos e magnéticos envolvidos. Apresenta também uma simulação computacional, que tem por objetivo verificar que a utilização de um reator série limitador de corrente no circuito de alimentação do forno, visando estabilizar o arco, não reduz significativamente a potência operacional do mesmo à 60Hz. A tese apresenta ainda os resultados de uma simulação analógica, que permite verificar que a impedância do reator série limitador, vista pelo circuito do forno, é pequena à 60 Hz e relativamente elevada em outras freqüências. Desta forma, tem-se um efetivo amortecimento das flutuações de corrente e tensão, causadas pela operação do forno, sem restringir a potência operacional do mesmo.
This thesis presents the main electromechanical phenomena, occuring during the operating of an arc furnace, focusing the electric and magnetic ones. It also presents a digital simulation aiming to verify that the utilization of a series limiting current reactor included into the furnace feeding circuit, for arc stabilization purposes, does not reduce its operational capacity at 60 Hz. It is also presented the results of an analogic simulation, which shows that the reactor impedance seen by the furnace circuit is small at 60 Hz and relatively large at other frequencies. Hence, an effective damping of the current and voltage variations, caused by the furnace operation, can be achieved.
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14

Ballard, Norman. "Electrode length measurement in electric arc furnaces." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/18232.

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Accurate measurement of electrode length in electric arc furnaces will result in decreased maintenance time, and improved plant productivity. This thesis describes the development of a microwave-based Soderberg electrode length-measurement system. Various methods of electrode-length measurement were investigated, and it was found that a microwave measurement system based on a conventional frequency modulated continuous wave (FMCW) radar presented the most feasible technique. In this system, microwaves are propagated down a waveguide placed in the electrode. As the waveguide melts, they continue propagating in the resulting cavity until they are reflected by the discontinuity at the bottom of the electrode. The time taken for the return journey to the bottom of the electrode and back is measured, and the electrode length calculated.
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15

Boyd, Rodney Kenneth. "Computer modelling of a coal fired furnace." Phd thesis, Mechanical Engineering, 1986. http://hdl.handle.net/2123/5337.

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16

Levy, Jean-Francois. "Prediction of flow, combustion and heat transfer in coal fired cement kilns." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46886.

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17

Fogarty, Terence C. "Adaptive rule-based optimisation of combustion in muliple burner installations." Thesis, Open University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259989.

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18

Khan, Irshad. "Automatic frequency control of an induction furnace." Thesis, Cape Technikon, 2000. http://hdl.handle.net/20.500.11838/1092.

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Thesis (MTech(Electrical engineering))--Cape Technikon, Cape Town, 2000
The development of an automatic frequency control system for a miniature high frequency induction furnace is described. A background study into the fields of induction-heating, resonance, power electronic resonant converters and phase locked-loops are performed with relevance to this research. An analysis of the resonant load circuit is performed by means of a combination of measurement and numerical simulations. The study of the load behavior and power source is used as a :001 to aid effective implementation of the automatic frequency control system. This Jimulation data is used to detenninc the operating frequency range of the RLL system. A background study is performed in whieh several frequency-control schemes for power electronic converters are investigated. A brief summary, in which the basic requirements for a frequency control system with regards to this research are presented. Two revisions of the Automatic Frequency Control system (RLL) were implemented, on the induction furnace. Experimental results on both systems (Revl and Rev2), illustrating the necessity for frequency control are also presented. Future suggestions for optimizing the loop performance are presented. Further steps in the developmental process of the miniature high frequencj induction furnace are also discussed.
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19

Kadkhodabeigi, Mehdi. "Modeling of Tapping Processes in Submerged Arc Furnaces." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-13240.

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20

Valderhaug, Aasgeir Mikael. "Modelling and control of submerged-arc ferrosilicon furnaces." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 1992. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19565.

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21

Dahlqvist, v. "Increase the capacityof continuous annealing furnaces at Ovako." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161909.

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The capacity of soft annealing of low alloyed tubes at Ovako’s continuous annealing furnaces have been evaluated by comparing how it is done today with information from published and internal articles on the subject. It was found that it is possible to reduce the cycle time by 30 % for one furnace, 55 % for one furnace and 72 % for two furnaces. Two separate fullscale tests were made to assess whether the faster soft annealing procedure was feasible. The tests were performed without any reconstruction of the furnace and were made by continuously vary the speed of the batch inside thefurnace. The temperature in the batch was measured and compared with results from computer simulations of the heating/cooling sequences. The computer simulations were performed in COMSOL. The soft annealing was evaluated according to the SEP-520 standard ,which means evaluating the microstructure and hardness. The results show that the faster heat treatment could yield lower grades than today but still meet it’s requirements. In order to achieve this increase  a reconstruction of the furnaces is needed and the reconstruction is  briefly treated in the report. Ideas to further increase the speed of the soft annealing procedure are also presented.
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22

Cokrojoyo, Handi. "Analysis of flame images in gas-fired furnaces." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4759.

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Thesis (Ph.D.)--University of Missouri-Columbia, 2007.
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 19, 2009) Vita. Includes bibliographical references.
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23

Guevara, Fernando Irons Gordon A. "A study of slag freezing in metallurgical furnaces." *McMaster only, 2007.

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24

Grant, Michael G. K. "Factors affecting the mechanical properties of blast furnace coke." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26702.

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The influence of coking conditions, with respect to position in a commercial coke-oven, on the mechanical behaviour of blast furnace coke has been studied. This involved the determination of density, porosity, the characterization of microstructure and assessing the influence of all three on the compressive strength of coke. The plastic flow properties were also investigated at temperatures greater than 1000°C. Three coke batches, originating in a 5m commercial coke-oven at three different positions with respect to height (0.8m, 3.3m and 5m below the coal line), along with three coke batches produced in a 460mm test-oven, were supplied by Energy, Mines and Resources (CANMET) in Ottawa. A warf coke batch was also provided as a control sample. Several hundred core-drilled specimens (≃1.3cm diameter and 1.3cm length) were produced from the seven coke batches. The bulk density of each cylindrical coke specimen was determined. Also, a detailed microstructural analysis, using a Leitz Image Analyzer, of the flat faces of the coke cylinders was performed to quantitatively characterize the pore and cell wall size, and the pore geometry. The compressive strength of each coke cylinder was determined both at ambient temperature and at 1400°C. In addition, the plastic flow behaviour of the commercially produced coke batches was studied. Results indicate that the coke product bulk density was affected by the coke-oven pressure (static load). Studies of the test-oven coke batches revealed that coke bulk density increased with higher oven pressure. Furthermore, the pore size was found to be larger for cokes produced at lower oven pressures. The cell wall size did not appear to be affected by coke-oven pressure. The bulk density of the commercially produced samples increased with depth below the coal line. This was attributed to a higher temperature and static load that existed at the bottom of the battery. The pore size was larger in cokes extracted from higher regions. No correlation of cell wall size with depth below the coal line was found. However, an oven size effect on the pore and wall size was noticed. Both the pore and wall size was smaller in the test-oven coke batches. The compressive strength of coke was higher in batches subjected to higher coke-oven pressures. Similarly,' the compressive strength of commercial coke batches was higher for coke batches extracted from regions near the sole of the coke-oven, than that for coke batches extracted from higher regions. It was concluded that high oven pressures resulted in cokes exhibiting a lower porosity and small pores which had the combined effect of producing stronger coke. Coke strength was generally shown to be higher at 1400°C than at room temperature. The test-oven cokes were always stronger than cokes produced in the 5m commercial coke-oven. Constant load tests revealed that coke exhibited plastic flow behaviour at temperatures above 1000°C. The time dependent strain data was described using an interactive-double-Kelvin element visco-elastic model.
Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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25

Debrincat, David Paul. "Disintegration of powder agglomerates in a flash furnace shaft /." Connect to thesis, 2002. http://eprints.unimelb.edu.au/archive/00000766.

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Thesis (Ph.D.)--University of Melbourne, Dept. of Chemical Engineering, 2003.
System requirements: Windows PC, CD-Rom drive. CD-Rom contains the appendices, experimental data, and various video clips. Typescript (photocopy). Includes bibliographical references (leaves 209-216).
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26

Duffield, Roger John. "Direct atomisation furnace atomic absorption." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236310.

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27

Salzmann, Roger. "Fuel staging for NOx reduction in automatic wood furnaces /." [S.l.] : [s.n.], 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13531.

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28

Dong, Wei. "Design of advanced industrial furnaces using numerical modeling method." Doctoral thesis, KTH, Materials Science and Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2900.

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This doctoral thesis describes the fundamentals ofmathematical modeling for the industrial furnaces and boilersand presents the results from the numerical simulations of sometypical applications in advanced industrial furnaces andboilers. The main objective of this thesis work is to employcomputational fluid dynamics (CFD) technology as an effectivecomputer simulation tool to study and develop the newcombustion concepts, phenomena and processes in advancedindustrial furnaces and boilers. The applications concern onfrom retrofitted conventional grate boilers to the mostadvanced highly preheated and diluted air combustion (HPDAC)furnaces. In this work, several topics are specially concernedwhen applying CFD technology to combustion cases. These topicsare including grate bed model, NOxmodeling, mixing problem, air staging system, andhighly preheated and diluted air combustion technology. In thiswork, a black-box grate bed model is developed and used inmodeling of grate fired furnaces and boilers. It is based onthe thermodynamic calculations and a set of conservationequations of mass, energy of fuel and air on the grate bed. Oneof benefits of this bed model is simple and feasible to be putinto use in industry. For NOxmodeling, besides the thermal NO and prompt NO,the HCN route fuel NO has been employed to predict the fuel NOemissions in coal/biomass fired furnaces. In addition, based onNH3route of fuel NO formation, a SNCR scheme for NOxabatement has been proposed also. For mixingproblem, the concepts of global degree of mixing and individualdegree of mixing have been proposed and used successfully inpractical applications. The new definition of degree of mixingovercomes some shortages of existed mixing parameters, such asthe mixing factor and the degree of non-mixing, which arenon-normalized and may lose physical meaning in some regions ofthe system. A new air staging system has been studied. It isused to improve the secondary or over-fire air configuration,thus to reduce the pollutant emissions and to enhance thecombustion facilities' efficiencies. In this work, the airstaging system has been employed in coal and biomass combustionfor grate fired furnaces/boilers. The performance of the newair staging system has been evaluated and optimized by usingnumerical modeling method together with physical modelingmethod. Results show that the new air staging system has a goodpotential of improving the combustion quality and reducing thepollutant emissions in industrial furnaces and boilers.Recently, the highly preheated and diluted air combustiontechnology has been regarded as the new generation energytechnology for advanced industrial furnaces and boilers. Inthis work, the highly preheated and diluted air combustionphenomena have been studied by using different numericalmodels. A hybrid procedure of both the large eddy simulationusing subgrid-scale stress Smagorinsky model and the Reynoldsstress model with eddy dissipation model has been alsoinvestigated to study the dynamic combustion process under theconditions of highly preheated and diluted air combustion.Results show that HPDAC technology possesses advantages ofsaving energy and low NOxemission, thus it has high potential to be usedfor the next generation of industrial furnaces and boilers. Thelarge eddy simulation using subgrid-scale stress Smagorinskymodel together with Reynolds stress model / eddy dissipationmodel are possible to study the HPDAC dynamic process. Finally,this work shows that numerical modeling method is a verypromising tool to deal with the complicated combustionprocesses even for practical applications in industry.

Keywords: air staging, bed model, boiler, burner,computational fluid dynamics (CFD), Ecotube, fuel staging,furnace, grate combustion, highly preheated and diluted aircombustion (HPDAC), large eddy simulation (LES), mathematicalmodeling, nitrogen oxides (NOx), numerical simulation

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29

Arzpeyma, Niloofar. "Modeling of electric arc furnaces (EAF) with electromagnetic stirring." Thesis, KTH, Materialvetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-43906.

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The influence of electromagnetic stirring in an electric arc furnace (EAF) has been studied. Using numerical modeling the effect of electromagnetic stirring on the thermal stratification and fluid flow has been investigated. The finite element method (FEM) software was used to compute the electromagnetic forces, and the fluid flow and heat and mass transfer equations were solved using a finite volume method (FVM) software. The results show that electromagnetic stirring has a significant effect on temperature homogenization and mixing efficiency in the bath. The important part of this study was calculation of heat transfer coefficient. The results show, electromagnetic stirring improves the heat transfer from the melt to scrap which is dependent on the stirring direction and force magnitudes.
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JUNIOR, JOSE HENRIQUE NOLDIN. "THERMO-CHEMICAL MODELING OF SELF-REDUCTION BASED SHAFT FURNACES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2007. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=10881@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
O presente trabalho consiste de um modelo matemático termoquímico de simulação do processo Tecnored de produção de ferro primário, construído através do estudo e equacionamento da fenomenologia do processo, levando em consideração os aspectos termodinâmicos e operacionais, bem como a geometria do reator. Apesar de ser um modelo estático, considerações cinéticas de laboratório e de planta piloto foram usadas para estimar a extensão das principais reações químicas nas diferentes regiões do forno. Para construção do modelo o reator foi dividido em três zonas, a saber: cuba superior, zona de amolecimento e fusão, e cuba inferior. Para cada uma das zonas foram descritas as fenomenologias e reações químicas envolvidas, condicionadas ao balanço global das espécies químicas presentes no processo. As saídas do programa permitiram uma análise da engenharia de processo global e estagiada. Através do modelo construído é possível prever o comportamento do processo com diferentes tipos de matériasprimas e em diferentes condições operacionais. Adicionalmente, o modelo servirá para a checagem da operação do primeiro forno industrial desta tecnologia, atualmente em construção, comparando com os dados obtidos através da operação da planta piloto. Os resultados obtidos mostraram que a técnica de modelagem utilizada constitui-se em uma poderosa ferramenta de análise global e estagiada, confirmando as vantagens de consumo de combustível, eficiência energética e de geração de gases do processo Tecnored em relação à tecnologia tradicional do alto-forno.
The present work consists of a Tecnored ironmaking process oriented thermo-chemical modeling, built after a thorough assessment of the process phenomena and considering besides the peculiarities of the reactor, a number of applicable thermodynamic and operational aspects. In spite of being a thermochemical model, bench scale and pilot plant based kinetics considerations have been taken in account in order to estimate the extension of the main reactions in different parts of the furnace. The framework involved the division of the furnace in three main zones, namely Solid-state Reduction Zone (SRZ), Softening and Melting Zone (SMZ) and Dripping and Hearth Zone (DHZ). In each of the zones the existing chemical processes and overall process phenomena have been evaluated conditional to the global mass balance ruling the process. The model developed shall be used onwards to predict the behavior of the process under different conditions of raw material usage and operational modes. Moreover, the model shall be applied to compare the results of the industrial plant (under construction) with the available bench and pilot plant data, with the intention of gathering information to be used in the optimization of the model and subsequently the process. The results obtained thus far show that the applied modeling technique is a powerful tool for the global and stage-wise analysis of the process, confirming the advantageous performance of the technology as far as fuel-rate, thermal efficiency and environmental soundness are concerned.
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31

Fong, Douglas S. 1970. "Evaluation of continuous batch processing for vertical diffusion furnaces." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50399.

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Thesis (M.S.)--Massachusetts Institute of Technology, Sloan School of Management; and, Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1998.
Includes bibliographical references (p. 68-69).
by Douglas S. Fong.
M.S.
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32

Mbiock, Aristide. "Radiative heat transfer in furnaces : elliptic boundary value problem." Rouen, 1997. http://www.theses.fr/1997ROUEA002.

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33

Misra, Mahendra Kumar. "Modeling of pulverized-coal flames in plug flow furnaces /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487685204970189.

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34

Matar, Hattan Saleh. "Evaluating dust exposure from steel manufacturing electrical arc furnaces." Online version, 2009. http://www.uwstout.edu/lib/thesis/2009/2009matarh.pdf.

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35

Kenbar, Asaad M. A. "Combustion aerodynamics and pollution formation in gas-fired furnaces." Thesis, University of Glasgow, 1991. http://theses.gla.ac.uk/38026/.

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This thesis presents a combined experimental and theoretical study of the combustion aerodynamics and pollutant formation in confined swirling flames. The fuel used in this study was natural gas. In the experimental part of the work, two fuel injection modes are examined as alternatives to the conventional central axial fuel injection mode. These alternatives are (a) introducing the fuel around the periphery of the swirled air jet, and (b) injection radially outwards from the central axis, across the entering swirled air flow. The measurements were performed in a semi-industrial size furnace with a movable-block swirl generator. Four swirl settings were examined, covering swirl number range of 0 to 2.25. The flow patterns (as defined by three time-averaged velocity components and static pressure), combustion patterns (as defined by temperature and species concentrations) and pollutant formation (CO and NOx) were investigated for these two alternative injection modes as well as for the conventional central axial mode to assess the merits of the three systems. The formation of NOx has been studied in greater detail in these three systems. For the flow and combustion patterns, measured along the furnace, the main input variable was swirl, while for the pollutants, measured in the stack, the main input variables were fuel equivalence ratio and swirl. The investigations showed that with the radial fuel injection system, a stable flame was achieved without swirl, while for the peripheral and central axial injection systems, a minimum swirl number of 0.8 was required to establish a stable flame. By introducing some of the combustion air radially outward through a central gun with the peripheral fuel injection system, a stable flame was achieved without swirl. With the central radial and peripheral fuel injection modes, complete combustion can be guaranteed with 5% excess air, while for the central axial fuel injection at least 10% excess air was required to achieve complete combustion. The results of flow and combustion patterns demonstrate that the highest rates of mixing, combustion efficiency and heat transfer from the flame were achieved with the peripheral fuel injection. Increasing the degree of swirl was found to improve these characteristics by producing a more uniform and intense flame. The measurements of NOx at lean and rich conditions showed that this system offers wider scope for NOx reduction through lean combustion and staged combustion (ie both air and fuel staging). The radial fuel injection has also produced much improved mixing and combustion efficiency compared with the central axial fuel injection. However, with this system and with the central axial injection, only air staging can be used to reduce NOx formation. In all fuel injection modes, the strong dependence of NOx generation on flame temperature confirms that its principal formation is by the thermal mechanism. Locally, the effect of swirl on NOx formation was significant, however, its effect on the overall values was small. In the theoretical part of the work, predictions of the overall NOx formation are made using a well-stirred reactor model based on the extended Zeldovich mechanism. The model takes account of the fluctuations of the concentrations of fuel and oxidant in NOx reaction zone. A stochastic analysis has been introduced by the author to calculate the effect of these fluctuations on the NOx formation rate. The results of these predictions compare satisfactorily with the experimental measurements for the three methods of fuel injection. As part of the validation process of existing computational fluid dynamics (CFD) codes, an assessment is made of the ability of a CFD code to model swirling flames. The peripheral fuel injection mode applied to natural gas swirling flame is a novel test case (Beltagui and Maccallum (1988)). The predictions were made using the PHOENICS code, with turbulence and combustion represented by the k-e and the 'eddy break-up' models respectively. The main changes in the combustion patterns caused by switching from central axial to peripheral fuel injection were qualitatively well predicted. For the peripheral fuel injection system, the predicted flow patterns were in reasonable agreement with those previously measured. The quantitative agreement for combustion patterns, however, was good for the non-swirled flow only. This is attributed to the simplified turbulence and combustion models used.
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36

Dimitriou, Dimitrios. "Applied mathematical modelling of NO abatement in pulverised fuel furnaces." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409410.

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37

Yehia, Mohamed Ahmed Aly. "Modelling of pulverised coal swirling flames in axi-symmetric furnaces." Thesis, Imperial College London, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245761.

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38

Khan, Yasir Urfat. "Modelling of spectral effects in radiative heat transfer in furnaces." Thesis, Coventry University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337097.

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39

Cooke, J. A. "Mathematical modelling and identification of the control characteristics of furnaces." Thesis, Swansea University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636288.

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Slab reheating furnaces have two important control variables. One is an operating temperature such as wall temperature and the other is the combustion gas composition which must be kept within close limits to maintain the metallurgical properties of the metal. The manipulated variables are air and fuel flow. Conventional control of these furnaces utilizes a single temperature control loop with an air/fuel ratio controller to maintain the combustion product composition. Closed loop control of both temperature and gas composition may give better performance but results in a dual input/dual output system. Its design requires detailed knowledge of the dynamic behaviour of the furnace which is very non-linear. Such a dual loop scheme has been investigated using a mathematical model of a reheating furnace. The control system uses feedback of wall temperature to modulate fuel flow and feedback of excess oxygen to modulate air flow. The transfer function method of analysis was employed and it was found that the wall temperature response, which is distributed parameter in nature, could be modelled successfully using a transfer function consisting of a zero and two poles (lead/lag/lag). Further evidence to support this was obtained by system identification, using pseudo-random binary sequence signals, on an experimental boiler rig and also on the furnace model. This system identification work was performed in order to determine the applicability of the method to this type of system and showed that it could be used for identifying transfer function models of a real furnace. Investigations into the excess oxygen control loop revealed a very non-linear system which could destabilise at certain operating conditions and this made the dual loop system unsatisfactory. The investigations also revealed an unusual characteristic in the transient response of the non-linear dual loop system in that it had the ability to recover from a period of instability during a transient.
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40

Butt, A. R. "The generation of high temperature gases from fluidised bed furnaces." Thesis, University of the West of England, Bristol, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259330.

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41

SIQUEIRA, ELIS REGINA LIMA. "NATURAL GAS SIMULATION INJECTED FOR TUYERES OF BLAST FURNACES STEEL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2014. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25322@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O alto forno é um reator metalúrgico cujo objetivo consiste na produção de ferro-gusa. O consumo de combustível/redutor no processo de redução de minério de ferro em altos fornos, representa mais de 50 por cento do custo do gusa. No sentido de aumentar a produtividade e reduzir o consumo de combustível/redutor são empregadas técnicas de injeção de combustíveis auxiliares pelas ventaneiras dos altos fornos. A combustão de gás natural (GN) injetado nas ventaneiras produz grande quantidade de hidrogênio, esse gás é melhor redutor se comparado ao monóxido de carbono, pois ele possui velocidade de reação maior com os óxidos de ferro e, além disso, a geração de CO2 no processo de redução é diminuída quando comparado ao uso do carvão pulverizado (PCI), que é atualmente o material de injeção mais usado no Brasil. Este trabalho propõe a simulação da combustão de GN injetado pelas ventaneiras de um alto forno, utilizando o software CHEMKIN. As simulações provenientes deste software são amplamente utilizadas para otimização da combustão, sendo possível explorar rapidamente o impacto das variáveis de projeto sobre o desempenho do processo. Os resultados provenientes dessa simulação computacional em condições típicas de alto forno permitiram a previsão da temperatura de chama adiabática e a quantificação dos gases redutores de óxidos de ferro: H2 e CO. A partir da variação dos parâmetros de processo foi possível obter resultados úteis para a tomada de decisão, visando controlar e otimizar o processo.
The blast furnace is a metallurgical reactor whose goal is to produce pig iron. The fuel / reductant in the reduction of iron ore in the blast furnace process, represents more than 50 percent of the cost of the iron. In order to increase the productivity of the blast furnace and reduce fuel consumption / reducer injection techniques are employed by tuyeres of materials that act as fuel / reducer. The combustion of natural gas injected into the tuyeres produces large amounts of hydrogen, which replaces part of the carbon monoxide as reducing gas in the tank. The hydrogen gas is better compared to the reductant carbon monoxide, because it has reaction rate with the iron oxides and, moreover, the CO2 generation in the process of reduction is decreased when compared to the use of pulverized coal (PCI), which is currently the material most commonly used injection by tuyeres in Brazil. This paper proposes the simulation of combustion of natural gas injected into the tuyeres of a blast furnace, using the CHEMKIN software package. Simulations from this software are widely used for optimization of combustion, which can quickly explore the impact of design variables on the performance of the process, using accurate models of chemical kinetics. The computer simulation results from the combustion of natural gas at typical conditions of blast furnaces allowed the prediction of the adiabatic flame temperature and the reaching of the reducing gases of iron oxides: H2 and CO. From the variation of process parameters was possible to obtain useful results in order to control and optimize the process.
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42

Ma, Guojun. "Cr(VI)-containing electric furnace dust and filter cake characteristics, formation, leachability and stabilisation /." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-10182006-163226.

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43

Sumnicht, Daniel W. "A computer model of a kraft char bed." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/5476.

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44

Dong, Xuefeng Materials Science &amp Engineering Faculty of Science UNSW. "Modelling of gas-powder-liquid-solid multiphase flow in a blast furnace." Awarded by:University of New South Wales. School of Materials Science and Engineering, 2004. http://handle.unsw.edu.au/1959.4/20808.

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The ironmaking blast furnace (BF) is a complex reaction vessel involving counter-, coand/ or cross-current flows of gas, powder, liquid, and solids. However, the interactions of these multiphase flows have not been completely understood. The objective of this thesis is to develop a suitable model to simulate the powder flow and accumulation in packed beds and then extend it to numerically investigate the multiphase flow in the furnace. Gas-powder flow in a slot type packed bed has been experimentally studied in order to understand the flow and accumulation behaviour of powder in systems like an ironmaking blast furnace. A variety of variables including gas flowrate, powder flowrate and packing properties have been taken into consideration. It is found that a clear and stable accumulation region can form in the low gas-powder velocity zone at the bottom of the bed. The accumulation region is stable and shows strong hysteresis. The distribution of softening-melting layers in the blast furnace known as the cohesive zone (CZ) is modelled by inserting solid blocks into the bed. The results indicate that the inverse-V cohesive zone shape leads to low powder accumulation within the CZ and at the corner of the bed. A mathematical model is proposed to describe gas-powder flow in a bed packed with particles. The model is the same as the two fluid model developed on the basis of the space-averaged theorem in terms of the governing equations but extended to consider the interactions between gas, powder and packed particles, as well as the static and dynamic holdups of powder. In particular, a method is proposed to determine the boundary between dynamic and stagnant zones with respect to powder phase, i.e. the profile of the powder accumulation zone. The validity of numerical modelling is examined by comparing the predicted and measured distributions of powder flow and accumulation under various flow conditions. With high PCI rate operations, a large quantity of unburned coal/char fines flow together with the gas into the blast furnace. Under some operating conditions, the holdup of fines results in deterioration of furnace permeability and lower production efficiency. Therefore, the proposed model is applied to simulate the powder (unburnt coal/char) flow and accumulation inside the blast furnace when operating with different cohesive zone (CZ) shapes. The results indicate that powder is likely to accumulate at the lower part of W-shaped CZs and the upper part of V- and inverse V-shaped CZs. In addition, for the same CZ shape, a thick cohesive layer can lead to a large pressure drop while the resistance of narrow cohesive layers to gas-powder flow is found to be relatively small. Gas-powder flow in moving beds of solid particles has been numerically investigated, under conditions related to the ironmaking blast furnace and high rate pulverized coal injection. A new correlation, which is formulated to describe static powder holdup in a moving packed bed, is incorporated into the previous mathematical model and applied to a description of gas-powder flow in a blast furnace. Compared with the results of fixed beds, the results show that the solids descent due to the consumption of ore, coke and unburnt char in various regions, together with the non-uniform structural distribution, significantly affects powder flow and accumulation in a blast furnace. Finally, liquid flow is simulated through force balance approach and numerical results are compared with the different liquid inlet distribution under the iron-making blast furnace conditions with gas flow. The results show that the effect of inlet distribution on liquid flow is significant in the upper part of coke region in BF and possible loading and dry zone can be numerically identified. Then, this part of work is incorporated to the developed gas-powder-solid modelling system to investigate the influence of liquid phase on other phases flow in the blast furnace although heat transfer and chemistry are not considered in the model.
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45

Chen, Matthew Lidong Materials Science &amp Engineering Faculty of Science UNSW. "Multiphase flow in packed beds with special reference to ironmaking blast furnace." Awarded by:University of New South Wales. Materials Science & Engineering, 2008. http://handle.unsw.edu.au/1959.4/41354.

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Multi-phase flows can be found in a range of processes in vanous industries. Ironrnaking blast furnace is one of the typical examples. With high pulverized coal injection rates, complete combustion within the raceway of blast furnace becomes difficult, giving rise to a large amount of powder flow together with gases into the furnace. Thus, the performance of a modern blast furnace with high PCI strongly depends on the characteristics of a multiphase system which involves gas, powder, and liquid superimposed on the motion of solid particles. For this multiphase flow system, the solid (coke, sinter/pellets, etc) movement and liquids (hot metal and slag) and powders (unbumt coal and coke ash) accumulation in the lower region of the furnace are believed to play an important role. This thesis presents an experimental study focus on quantifying the hydrodynamics of gas-powder and gas-powder-liquid flows through packed beds with special reference to blast furnace. The effects of process variables including fluid flowrate and some material properties on powder hold-up, pressure gradient and phase interaction are examined. An experimental study of the hydrodynamics of gas-powder flow in packed beds has been carried out. Glass powder and spherical/non-spherical particles are used to simulate pulverized coal and coke particle respectively. It is found that solid motion, powder flowrate and particle spericity affect powder hold-up and pressure gradient significantly. New correlations are proposed for static and dynamic powder hold-ups to account for these effects based on experimental results. A hydrodynamic model is proposed for gas-powder flow in packed beds with spherical and non-spherical particles. Incorporation these correlations and porosity function into the existed Fanning and Ergun equations, the pressure gradients in fixed and moving beds can be reasonably estimated. The gas-powder-liquid flow through the moving beds is studied. The effects of fluid variables and some material properties on total powder hold-up and pressure gradients have been examined experimentally within the so-called operational regime. The normal and non-wetting treated glass beads, glass powder and water or mixture of water and glycerin are used to simulate coke, pulverized coal and hot metal/slag in a blast furnace. The results indicates that steady-state gas-powder-liquid flow in moving packed beds can be achieved under certain flow conditions since particle motion gives main contribution while it provides a higher bed porosity, enhances powder and liquid flow and removes the accumulation of the powder. The fluid variables and liquid viscosity significantly affect the total powder hold-up and hence pressure gradient but the wettability does not. Based on the experimental results, new correlations for powder hold-up and pressure gradient are proposed for blast furnace modelling in terms of dimensionless number of flowrates for different phases. Incorporation of these correlations and the existed empirical correlations of phase interactions, a hydrodynamic model is proposed to quantify the interaction force between liquid and powder. The results show that this force plays an important role for stable gas-powder-liquid flow in moving beds though it is ignored by most of the previous researchers.
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46

Morris, Brian. "A model test methodology for the fire testing of compartment walls." Thesis, University of Ulster, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245800.

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47

Lucca-Negro, Oona. "Modelling of swirling flow instabilities." Thesis, Cardiff University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310677.

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This research concentrates on the swirl motion, and in particular the flow structure which develops under its action, in swirl burner/furnace systems. Although the Reynolds numbers for such systems are usually large and well into the turbulent regime, periodic oscillations and associated instabilities are still prevalent. The predominant coherent structure is the so-called precessing vortex core (PVC) which is a three-dimensional, time-dependent phenomenon. It is helical in shape, twisted against the flow, and precesses around the geometric centre of the system, in the sense of the flow. The aim of this work was to numerically model this instability in a 2MW industrial-size system, under isothermal conditions. A fully three-dimensional, time-dependent model was developed using the CFD (Computational Fluid Dynamics) software FLUENT. This study first presents an overview of publications on vortex breakdown, a similar phenomenon observed initially on delta wings, in order to highlight its significant features. A summary was also made of various recent studies, experimental and theoretical, carried out at Cardiff University, in the same equipment as used in the present work. This review allows a better understanding of the phenomenon and constitutes a basis for further validation of the mathematical model. Numerous flow pattern characteristics have- been predicted, which agree qualitatively with different published studies, such as crescent shaped regions of maximum axial and tangential velocities, off-centred reverse flow zone, and spiralling vortex core. Quantitatively, the agreement is good, in terms of range of velocities and frequency. However, the predicted flow pattern could. not be maintained in time and tended back to axisymmetry, possibly due to numerical diffusion. Grid refinement could not, however, be envisaged due to the practical limits of the available machines. Nevertheless, these results are encouraging and prove that mathematical modelling of these complex flows is a realistic objective.
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48

Tait, Peter. "Simulation of bagasse-fired furnaces incorporating energy recycling to stabilise combustion /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17066.pdf.

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49

Rafidi, Nabil. "Thermodynamic aspects and heat transfer characteristics of HiTAC furnaces with regenerators." Doctoral thesis, KTH, Materials Science and Engineering, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-541.

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Oxygen-diluted Combustion (OdC) technology has evolved from the concept of Excess Enthalpy Combustion and is characterized by reactants of low oxygen concentration and high temperature. Recent advances in this technology have demonstrated significant energy savings, high and uniform thermal field, low pollution, and the possibility for downsizing the equipment for a range of furnace applications. Moreover, the technology has shown promise for wider applications in various processes and power industries.

The objectives of this thesis are to analyze the thermodynamic aspects of this novel combustion technology and to quantify the enhancement in efficiency and heat transfer inside a furnace in order to explore the potentials for reduced thermodynamic irreversibility of a combustion process and reduced energy consumption in an industrial furnace. Therefore, theoretical and experimental investigations were carried out.

The 2nd law of thermodynamics analyses of OdC systems have been carried out for cases in which the oxidizer is either oxygen (Flameless-oxy-fuel) or air (High Temperature Air Combustion, HiTAC). The analyses demonstrate the possibilities of reducing thermodynamic irreversibility of combustion by considering an oxygen-diluted combustion process that utilizes both gas- and/or heat-recirculation. Furthermore, the results showed that an oxygen-diluted combustion system that utilizes oxygen as an oxidizer, in place of air, results in higher 1st and 2nd law efficiencies.

Mathematical models for heat regenerators were developed to be designing tools for maximized heat recovery. These models were verified by heat performance experiments carried out on various heat regenerators.

Furthermore, experiments were performed in a semi-industrial test furnace. It was equipped with various regenerative burning systems to establish combustion and heat transfer conditions prevailing in an industrial furnace operating based on HiTAC. The tests were carried out at seven firing configurations, two conventional and five HiTAC configurations, for direct and indirect heating systems.

Measurements of energy balance were performed on the test furnace at various configurations in order to obtain the 1st law efficiency. Moreover, local measurements of temperature, gas composition, and heat fluxes in the semi-industrial test furnace were performed to find out the main characteristics of HiTAC flame and the effects of these characteristics on the heating potential, i.e., useful heating in the furnace. In the case of HiTAC, these measurements showed uniformities of chemistry, temperature, temperature fluctuation, and heat fluxes profiles. The values of fluctuations in temperature were small. The high speed jets of the fuel and air penetrated deep into the furnace. The fuel gradually disappeared while intermediate species gradually appeared in relatively high concentrations and at broader regions inside the furnace. These findings indicate: a large reaction zone, low specific combustion intensity in the flame, low specific fuel energy release, and high heat release from this large flame. In addition to the thermodynamic limitations to the maximum temperature of the Oxygen-diluted Combustion, the low specific energy release of the fuel and the high heat release from the flame to its surroundings cause this uniform and relatively moderate temperature profile in a HiTAC flame, consequently suppressing thermal-NO formation.

Heat flux and energy balance measurements showed that heating potential is significantly increased in the case of HiTAC compared to that in the conventional case, implying much more energy savings than the apparent heat recovery from the heat regenerators, and consequently much less pollutants emissions. Therefore, it is certain that this large HiTAC flame emits more thermal radiation to its surroundings than the conventional flame does, in spite of the moderate-uniform temperature profile of the flame. This intense heat flux was more uniform in all HiTAC configurations, including the indirect heating configuration, than that of the conventional-air combustion configuration.

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Rafidi, Nabil Elias. "Thermodynamic aspects and heat transfer characteristics of HiTAC furnaces with regenerators /." Stockholm : KTH, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-541.

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