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01766 Pressure and concentration dependences of the autoignition temperature for normal butane + air mixtures in a closed vessel
00
Combustion (burners, c0mbustion systems)
Oslo1754 NO and N,O decompoaltlon over coal char at tluldlxod-hod combuatlon oondltbna Rodri cx-Mirhsal, J. cf aL, Combustion & Flame, Dec. 1994,99, (3), 499-s f 7. l%e dccompositon of NO and NJ0 by chars has been studied in a fixed bed reactor under steady state conditions. The reactions were studied at tempcraturcs tirn 673 to 1223 K and at partial NO and N,O pressures in the range of 0.62-3.08 and 0.19-1.92 mbar, respectively. %/017% NO raductlon In a flukilzad bad combuator wlth prlmary moaauroa and wloctlva non-wtal Ic raductlon. A acroonlng atudy ualng atatlatlwl ?? xporlmentar doalgna Nordin, A. et al., FueL Jan. 1995, 74, (1). 128-135. Screening experiments were carried out to stud the reduction of NO cmissions &om a 2OMW circulating fluidixcd bed r CFB) boiler, c uipd with an installation for selective non-catalytic rrduction (SNR). lL tiucnce of both rimary measures and SNR were evaluated, using 2~’ and 2s*2 fractlona P factorial designs for the two fuels, crushed peat and wood waste, respectively. Polynomial models were deducted from statistical analysis of the experiments, and a good agreement between models and measured data was obtained. The evaluation showed that, by using a designed experimental mocedure. CFB oocratinn conditions vieldimz an NO reduction of 6080% could be identifi&, w&both primg mea&es and the SNR being of approximately equal importance. %I01 758 The nonllnur dynamlw of Intrlnalc acouatlc oaclllatlona In a modal pulw oombuator Margolis, S. B. Combustion & Flame, Nov. 1994, 99, (2), 311-322. The appearance of nonlinear acoustic oscillations in pulse combustors and other unsteady combustion devices arises from combustion-driven instabilides that excde one or more classical acoustic modes of the system. For sufficiently strong acoustic driving relative to various damping processes, these disturbances grow to finite amolitudcs and. owing to the nonlinear coupling bchveen l&early unstable ahd stable m&es, a-stable limit-cycle oscillation is typically established. %I01 757 NO= and CO ?? mlaalona from II pulu owratlna In a loan onmbad mod0 Killer, J. 0. et al., Cornbusrion % Flame, Dec. 1994, 99, Control over the combustion fluid dynamics was used to emission of NO. and CO. The combustion kinetics were
combuator (3), 460466. minimixe the controlled by
periodic &t&flow in a pulse combushr. It v&s pound th& co&olling the flame tern raturc, chemical kinetics, and residence time at high tempcraturc was 7cst accomplished by controlling the e$uivalcncc.ratio yd the degree of macro~lc mixing rather than controllm~ the mwrosco IC mixing over the dynamic range obtainable by the techniques used in tR*IS study. Numorlwl wlculatlon of gas-paftlcle. two-phaaa %I01 7% flow In a pulvorlxod coal burnor wlth Jota In croaallow Xu, M. and Han, C. Huazhong Ligong Daxue Xuebao, 1994, 22, (3), 69-73. (In Chinese) Prcscnts the numerical scales of the gas-particle two-phase flow in a pulverixed coal burner witb jets in crossflow using a k-c two-equation turbulent model for the as-phase and an algebraic formula model for the particle-base. The ve‘3ocity components and mass flow distribution of gas and particles in the burner were obtained and the results compared with experimental data. Discusses the influence of particle diameter on particle mixii. Numarlcal Invwtlgatlon of steady lamlnar flamr %/Ql759 propagatlon In a circular tub0 z4SkT. and Tsai, C. H. Combusrion & Flame, Dec. 1994, 99, (3), The stcadv orooaaation of a memixed laminar flame in circular tubes with adiabatic ;r’kl‘&~z isotbcd wall is numerically investigated in the present study. It is assumed that the flow ls axisymmetric and the flame chemistry is mod&d by a one-step overall reaction which simulates tbe reaction of a lean methane-air mixture. The numerical results show that the flame propagating steadily in a tube can take hvo distinct shapes: tulip shape and mushroom-shape. It is found that, in a insulated tube, the tulipshaped flame is a more robust manifestation than the rnern$art flame, and is tbC primary mode Of the SOhtiOII. ThC 0 tube with isothermal wall. The effect of gravity along $”e tube axis is also studied.
120
Fuel and Enargy Abatracta March 1995
951017% Numorlwl modalln of flow and pattlolo hoatlng In a reactor wlth lamlnar ?? ntralno8 flow
Chcn. C. et aL, Huazhong Ligong Daxue Xuebao, 1994, 22, (3), 30-35. (Ill Chinese)
Describes a study of the flow and particle heating charactcritics of a reactor with laminar entrained flow for experiments on fhe dcvolatilixation and combustion of coal. A fmitc difference model was used to predict the gas flow and tern rature fields as well as article heating rate and residence time. Of the rcaturcs to be modelled, tge gas flow field had the greatest effect on the residence time. %I01 761 Numerlcal modeling of spark lgnltbn and flama Inltlatbn In a qulrswnt mathaneslr mlxtura Kravchik, T. and Sher, E. Combudon & Flame, Dec. 1994, 99, (3), 635-643.
scheme for a methane-air mixture which contains 29 chemical species and
97 reaction steps.
95101762 Numorlwl rlmulatlona of burner-atablllxod hydrogan-alr flames In mlcrogravlty Patnaik, G. and Kailasanath, K. Comburrion & Flame, NOV. 1994,99, (2). . 247-2.53. Detailed two-dimensional, time-dependent numerical simulations have been ncrformcd to pain undcrstandinp of the similarities and differences in the &ucturc and s’tability of burne&abilixed flames in xcro and earth avity. These simulations include the effects of fluid convection, detailed $ _ ydrogen oxygen chemistry, multispecies diffusion, thermal conduction, viscosity, and heat losses to the burner. A series of simulations for a range of mixtures and inlet velocities have been performed. %I01763 Ovarvlaw of traw aloment partltlonlng In flamaa and furnawa of utlllty coal-fIrad bollora Ratafia-Brown. J. A. Fkl Process. TechnoL, 1994, 39, (1). 139-157. The oaocr discusses oartitioninn of trace elements in flames and furnaces of cdal&cd utility b&lcrs, as {ti of an effort to character& the combusdon process as it affects the release, transformation and partitioning of trace elements in the combustion zone and heat transfer sections of the boiler. Trace element partitioning is initiated at the burner front and condnucs in the high-temperature radiant section of the furnace as the coal particles are pyrolyzed and burned, and the the fly ash, bottom ash, and flue gases, xation eochemical mode of occurrence in the coal, an physl&/I or chemical bonding to the carbon matrix or primary aluminosilicate minerals. %I01764 Predlctlon of atagod coal combuatbn In throwdlmenalonal furnawa Papadakii, G. and Bergclcs, G. .I. Insrirrcte of Berm, Dec. 1994, 67, (473), 156-167. A 3-D numerical method was used for the stud of staged coal combustion in a semi-industrial-scale furnace cxpcrlmcn t,iyly investigated in the Intcrnational Flame Research Foundation. Detailed evaluation of the 3-D code against cx@mcntal data for temperahue, oxygen and nitrogen monoxide concentration is presented. In the numerical algorithm is inco~rated a higher-order finite-differencing scheme for all quations, along wrth a general dcvolatilisation model. In order to minim& time and memory rcquircmen& the computational domain was limited lo one quarter of the furnace with the aid ofcyclic boundary conditions. A rcasontible degree of agreement is indicated by comparison of predicted and experimental results. %I01 7% Pndlctlona of motala ?? mlaalona and partltlonlng In coal-flrod combuatlon ayatama Rixeq, R. G. et aL, Fuel Process. TechnoL, 1994, 39 1) 219-236. A computer modclling approach was developed to pr&G metals bchaviour and emissions in coal-fired combustion systems. To test the orcdictivc applicability of the modelling approach, predictions of the ‘overall partitioning of metals in a pulverized bituminous coal-fired combustor were compared with measured data from full-scale facilities in tbc Nethcrlands. In general, the comparison between predicted and measured values was favourable. %I01 7% Proaaun and conwntratlon doPondenwa of the autolgnltlon kmporaturr for normal butano + air mlxturaa In a cloud vaaaol Chandraratna, M. R. and Griffiths, J. F. Combustion % Flame, Dec. 1994, 99, (3), 626-634. The conditions at which autoignition occurs in lean premixed n-butane + air mixtures over the composition range 0.2%2.5% n-butane b volume were investigated experimentally. Total ICaCtMt pressure from B.1 to 0.6 MPa (1-6 atm) were studied in a spherical. stainless-steel, closed vessel (0.5 dm’).
Combustion (burners, c0mbustion systems)
Oslo1754 NO and N,O decompoaltlon over coal char at tluldlxod-hod combuatlon oondltbna Rodri cx-Mirhsal, J. cf aL, Combustion & Flame, Dec. 1994,99, (3), 499-s f 7. l%e dccompositon of NO and NJ0 by chars has been studied in a fixed bed reactor under steady state conditions. The reactions were studied at tempcraturcs tirn 673 to 1223 K and at partial NO and N,O pressures in the range of 0.62-3.08 and 0.19-1.92 mbar, respectively. %/017% NO raductlon In a flukilzad bad combuator wlth prlmary moaauroa and wloctlva non-wtal Ic raductlon. A acroonlng atudy ualng atatlatlwl ?? xporlmentar doalgna Nordin, A. et al., FueL Jan. 1995, 74, (1). 128-135. Screening experiments were carried out to stud the reduction of NO cmissions &om a 2OMW circulating fluidixcd bed r CFB) boiler, c uipd with an installation for selective non-catalytic rrduction (SNR). lL tiucnce of both rimary measures and SNR were evaluated, using 2~’ and 2s*2 fractlona P factorial designs for the two fuels, crushed peat and wood waste, respectively. Polynomial models were deducted from statistical analysis of the experiments, and a good agreement between models and measured data was obtained. The evaluation showed that, by using a designed experimental mocedure. CFB oocratinn conditions vieldimz an NO reduction of 6080% could be identifi&, w&both primg mea&es and the SNR being of approximately equal importance. %I01 758 The nonllnur dynamlw of Intrlnalc acouatlc oaclllatlona In a modal pulw oombuator Margolis, S. B. Combustion & Flame, Nov. 1994, 99, (2), 311-322. The appearance of nonlinear acoustic oscillations in pulse combustors and other unsteady combustion devices arises from combustion-driven instabilides that excde one or more classical acoustic modes of the system. For sufficiently strong acoustic driving relative to various damping processes, these disturbances grow to finite amolitudcs and. owing to the nonlinear coupling bchveen l&early unstable ahd stable m&es, a-stable limit-cycle oscillation is typically established. %I01 757 NO= and CO ?? mlaalona from II pulu owratlna In a loan onmbad mod0 Killer, J. 0. et al., Cornbusrion % Flame, Dec. 1994, 99, Control over the combustion fluid dynamics was used to emission of NO. and CO. The combustion kinetics were
combuator (3), 460466. minimixe the controlled by
periodic &t&flow in a pulse combushr. It v&s pound th& co&olling the flame tern raturc, chemical kinetics, and residence time at high tempcraturc was 7cst accomplished by controlling the e$uivalcncc.ratio yd the degree of macro~lc mixing rather than controllm~ the mwrosco IC mixing over the dynamic range obtainable by the techniques used in tR*IS study. Numorlwl wlculatlon of gas-paftlcle. two-phaaa %I01 7% flow In a pulvorlxod coal burnor wlth Jota In croaallow Xu, M. and Han, C. Huazhong Ligong Daxue Xuebao, 1994, 22, (3), 69-73. (In Chinese) Prcscnts the numerical scales of the gas-particle two-phase flow in a pulverixed coal burner witb jets in crossflow using a k-c two-equation turbulent model for the as-phase and an algebraic formula model for the particle-base. The ve‘3ocity components and mass flow distribution of gas and particles in the burner were obtained and the results compared with experimental data. Discusses the influence of particle diameter on particle mixii. Numarlcal Invwtlgatlon of steady lamlnar flamr %/Ql759 propagatlon In a circular tub0 z4SkT. and Tsai, C. H. Combusrion & Flame, Dec. 1994, 99, (3), The stcadv orooaaation of a memixed laminar flame in circular tubes with adiabatic ;r’kl‘&~z isotbcd wall is numerically investigated in the present study. It is assumed that the flow ls axisymmetric and the flame chemistry is mod&d by a one-step overall reaction which simulates tbe reaction of a lean methane-air mixture. The numerical results show that the flame propagating steadily in a tube can take hvo distinct shapes: tulip shape and mushroom-shape. It is found that, in a insulated tube, the tulipshaped flame is a more robust manifestation than the rnern$art flame, and is tbC primary mode Of the SOhtiOII. ThC 0 tube with isothermal wall. The effect of gravity along $”e tube axis is also studied.
120
Fuel and Enargy Abatracta March 1995
951017% Numorlwl modalln of flow and pattlolo hoatlng In a reactor wlth lamlnar ?? ntralno8 flow
Chcn. C. et aL, Huazhong Ligong Daxue Xuebao, 1994, 22, (3), 30-35. (Ill Chinese)
Describes a study of the flow and particle heating charactcritics of a reactor with laminar entrained flow for experiments on fhe dcvolatilixation and combustion of coal. A fmitc difference model was used to predict the gas flow and tern rature fields as well as article heating rate and residence time. Of the rcaturcs to be modelled, tge gas flow field had the greatest effect on the residence time. %I01 761 Numerlcal modeling of spark lgnltbn and flama Inltlatbn In a qulrswnt mathaneslr mlxtura Kravchik, T. and Sher, E. Combudon & Flame, Dec. 1994, 99, (3), 635-643.
scheme for a methane-air mixture which contains 29 chemical species and
97 reaction steps.
95101762 Numorlwl rlmulatlona of burner-atablllxod hydrogan-alr flames In mlcrogravlty Patnaik, G. and Kailasanath, K. Comburrion & Flame, NOV. 1994,99, (2). . 247-2.53. Detailed two-dimensional, time-dependent numerical simulations have been ncrformcd to pain undcrstandinp of the similarities and differences in the &ucturc and s’tability of burne&abilixed flames in xcro and earth avity. These simulations include the effects of fluid convection, detailed $ _ ydrogen oxygen chemistry, multispecies diffusion, thermal conduction, viscosity, and heat losses to the burner. A series of simulations for a range of mixtures and inlet velocities have been performed. %I01763 Ovarvlaw of traw aloment partltlonlng In flamaa and furnawa of utlllty coal-fIrad bollora Ratafia-Brown. J. A. Fkl Process. TechnoL, 1994, 39, (1). 139-157. The oaocr discusses oartitioninn of trace elements in flames and furnaces of cdal&cd utility b&lcrs, as {ti of an effort to character& the combusdon process as it affects the release, transformation and partitioning of trace elements in the combustion zone and heat transfer sections of the boiler. Trace element partitioning is initiated at the burner front and condnucs in the high-temperature radiant section of the furnace as the coal particles are pyrolyzed and burned, and the the fly ash, bottom ash, and flue gases, xation eochemical mode of occurrence in the coal, an physl&/I or chemical bonding to the carbon matrix or primary aluminosilicate minerals. %I01764 Predlctlon of atagod coal combuatbn In throwdlmenalonal furnawa Papadakii, G. and Bergclcs, G. .I. Insrirrcte of Berm, Dec. 1994, 67, (473), 156-167. A 3-D numerical method was used for the stud of staged coal combustion in a semi-industrial-scale furnace cxpcrlmcn t,iyly investigated in the Intcrnational Flame Research Foundation. Detailed evaluation of the 3-D code against cx@mcntal data for temperahue, oxygen and nitrogen monoxide concentration is presented. In the numerical algorithm is inco~rated a higher-order finite-differencing scheme for all quations, along wrth a general dcvolatilisation model. In order to minim& time and memory rcquircmen& the computational domain was limited lo one quarter of the furnace with the aid ofcyclic boundary conditions. A rcasontible degree of agreement is indicated by comparison of predicted and experimental results. %I01 7% Pndlctlona of motala ?? mlaalona and partltlonlng In coal-flrod combuatlon ayatama Rixeq, R. G. et aL, Fuel Process. TechnoL, 1994, 39 1) 219-236. A computer modclling approach was developed to pr&G metals bchaviour and emissions in coal-fired combustion systems. To test the orcdictivc applicability of the modelling approach, predictions of the ‘overall partitioning of metals in a pulverized bituminous coal-fired combustor were compared with measured data from full-scale facilities in tbc Nethcrlands. In general, the comparison between predicted and measured values was favourable. %I01 7% Proaaun and conwntratlon doPondenwa of the autolgnltlon kmporaturr for normal butano + air mlxturaa In a cloud vaaaol Chandraratna, M. R. and Griffiths, J. F. Combustion % Flame, Dec. 1994, 99, (3), 626-634. The conditions at which autoignition occurs in lean premixed n-butane + air mixtures over the composition range 0.2%2.5% n-butane b volume were investigated experimentally. Total ICaCtMt pressure from B.1 to 0.6 MPa (1-6 atm) were studied in a spherical. stainless-steel, closed vessel (0.5 dm’).