Heat Transfer: Volume 4 — Combustion and Energy Systems最新文献_第5页

Forest Fire Propagation in Inclined Terrains 倾斜地形下森林火灾的传播

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24247

K. Satoh, K. T. Yang

{"title":"Forest Fire Propagation in Inclined Terrains","authors":"K. Satoh, K. T. Yang","doi":"10.1115/imece2001/htd-24247","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24247","url":null,"abstract":"\u0000 Forest fires are of common occurrence all over the world, causing the loss of precious natural resources. The propagation of forest fires depends on many factors, notably local weather conditions. Additionally, the local terrain such as mountainous areas also plays an important role. For instance, forest fires may propagate from mountain ridges to ridges due to locally strong wind by means of firebrands and hot air flows. While much is known cm the methodologies on the forest fire control, they are largely empirical and may not be totally effective. Therefore, scientific studies based on fundamental physical understanding of the underlying phenomena are needed to provide definitive data on cause-effect relationships in various forest fire scenarios, so that the collective database can be used to suggest control strategies and preventive measures for forest fires. The present study is motivated by this approach, and specifically focuses on the phenomena of rapid forest-fire propagation from mountain slqpes to other similar mountain slopes in the direction of the wind. The study deals with both laboratory experiments and numerical simulations by the use of a CFD-based fire field model.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128047562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Apparent Radiative Properties and Radiation Scattering by a Semitransparent Hemispherical Shell 半透明半球形壳体的表观辐射特性和辐射散射

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/1.1497357

T. Fan, A. Fedorov

引用次数: 3

Large-Scale Laboratory Fire Whirls and Their Numerical Simulations 大型实验室火涡及其数值模拟

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24242

K. Satoh, M. Shinohara, Liu Nai-an

{"title":"Large-Scale Laboratory Fire Whirls and Their Numerical Simulations","authors":"K. Satoh, M. Shinohara, Liu Nai-an","doi":"10.1115/imece2001/htd-24242","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24242","url":null,"abstract":"\u0000 Fire whirls have been observed in large-scale forest and city fires, which are likely accompanied by strong winds and heavy damages such as loss of lives and physical properties. Despite the general interest in the research of fire whirls, their detailed mechanisms and physical effects still remain largely unknown. One reason is that such real fire whirls are of large size and their direct studies are obviously not feasible. On the other hand, CFD-based fire field models, despite their inherent deficiencies, do provide a rational means to scale the fire sizes. It is desirable, or even necessary, to study larger-scale fire whirls with higher whirling flames in the laboratory, along with their numerical simulations. If success in the numerical simulations for the larger fire whirls can again be demonstrated, we will then approach more closely to have a quantitative tool in the use of the fire field model to simulate and study the truly large real-life fire whirls. The purpose of the present study is to attempt to create a stable six-meter class whirling flame in the laboratory, and then compare the measured data with what can be simulated with a fire field model.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117342828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A New LES Pool Fire Simulation Tool 一个新的LES池火灾模拟工具

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24245

R. Rawat, J. Spinti, Wing Yee, Philip J. Smith

{"title":"A New LES Pool Fire Simulation Tool","authors":"R. Rawat, J. Spinti, Wing Yee, Philip J. Smith","doi":"10.1115/imece2001/htd-24245","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24245","url":null,"abstract":"\u0000 In a large-scale pool fire simulation, the processes that must be modeled are complex and coupled. The flow is often highly turbulent, dynamic vortical structures are present, the chemical reactions involve several thousand elementary steps and hundreds of species/intermediates, and radiation, the dominant mode of heat transfer, is strongly affected by the presence of soot. The range of length and time scales associated with all these processes cannot be simulated on even the most powerful supercomputers available today. Our approach to making this intractable problem tractable has been twofold: one, to improve the models used at all levels in the simulation (i.e., transport models and subgrid scale models) and two, to parallelize the simulation tool to run on massively parallel machines. We have employed Large Eddy Simulation (LES) to model the fluid dynamics and the convection-diffusion scalar transport. LES successfully captures the transient nature of the coherent vortical structures present in a pool fire. We have integrated these improved models into a computational framework that provides support for parallelization. Preliminary validation results show the capability of the fire simulation tool to capture the puffing nature of pool fires. In addition, scalability studies of the simulation tool reveal close to linear scalability up to 500 processors.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117343919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Study of the NOx Emission in a Regenerative Industrial Furnace 蓄热式工业炉NOx排放研究

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24227

Qing Jiang, Chao Zhang

引用次数: 0

Application of a New CFD Analysis Tool for SOFC Technology 一种新型CFD分析工具在SOFC技术中的应用

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24270

M. Prinkey, R. Gemmen, W. Rogers

{"title":"Application of a New CFD Analysis Tool for SOFC Technology","authors":"M. Prinkey, R. Gemmen, W. Rogers","doi":"10.1115/imece2001/htd-24270","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24270","url":null,"abstract":"\u0000 FLUENT™, a commercial computational fluid dynamics (CFD) package, has been modified to include fuel cell electrochemistry. The model is being developed to account for three loss mechanisms present in fuel cells: ohmic overpotential, concentration overpotential, and electrochemical overpotential, each capable of temperature dependency. Because we envision this model to be applied to a wide range of geometries, the present model is also being developed to directly assess the electric potential field. This paper presents some preliminary results from the present model, and provides a summary status of our development.\u0000 The main results from the present study arise from an analysis of a single monolithic SOFC geometry. Several cases were analyzed in order to generate a typical steady-state V-I curve for the cell, which summarizes its performance. Results on the detailed distribution of various conserved quantities are also presented. The preliminary results are encouraging, and show that for the geometry under study, simple scale-up relations may hold. Additionally, the newly developed tool no longer requires the modeler to manually input approximate current flow information, which will be seen to be of great benefit in fuel cell analysis.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"158 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116560456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Modeling of Transport Processes Within a Molten Carbonate Fuel Cell Stack 熔融碳酸盐燃料电池堆内传输过程的建模

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24268

Z. Ma, S. Jeter, S. Abdel-Khalik

引用次数: 0

Fire Behavior in a Poorly Ventilated Compartment 通风不良的隔间内的火灾行为

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24244

K. Wakatsuki, B. Ringwelski, J. Quintiere

{"title":"Fire Behavior in a Poorly Ventilated Compartment","authors":"K. Wakatsuki, B. Ringwelski, J. Quintiere","doi":"10.1115/imece2001/htd-24244","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24244","url":null,"abstract":"\u0000 The fire behavior of heptane burning in a poorly ventilated compartment was studied. The diameter of the heptane pan fires were varied and the ventilation opening size and location were adjusted. Two kinds of compartment fire experiment were conducted: (1) horizontal slits at the top and bottom of a wall, and (2) a single vent at the roof. Temperature, oxygen, fuel mass loss rate and differential pressure were measured. Extinction was studied with an oxygen meter to find the minimum oxygen concentration in the compartment achieved in ventilation-controlled fires. Extinguishments due to ventilation or complete fuel consumption was distinguished. Flow exchange was measured by differential pressure transducers. Particularly, flow exchange of ceiling vent was examined by calculation of flooding pressure difference, which will allow bi-directional flow. The wall vent case had oscillatory combustion (puffing), which sometimes leads to an increase in fire amplitude followed by extinction. This was not observed for the ceiling vent case. Video recording of the flame was conducted through a glass on sidewall. The fire behavior varied from conditions in which the flame extinguishes to cases of steady burning. In some cases, “ghosting flames” were observed.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126524435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Self-Preserving Properties of Unsteady Round Nonbuoyant Turbulent Starting Jets and Puffs in Still Fluids 静止流体中非定常圆形非浮力湍流启动射流和泡波的自保性质

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/1.1421047

R. Sangras, O. Kwon, G. Faeth

引用次数: 58

NOx Emissions in a Steel Reheat Furnace Firing By-Product Fuels 燃烧副产燃料的钢加热炉NOx排放

Heat Transfer: Volume 4 — Combustion and Energy Systems Pub Date : 2001-11-11 DOI: 10.1115/imece2001/htd-24229

B. Adams, David H. Wang

{"title":"NOx Emissions in a Steel Reheat Furnace Firing By-Product Fuels","authors":"B. Adams, David H. Wang","doi":"10.1115/imece2001/htd-24229","DOIUrl":"https://doi.org/10.1115/imece2001/htd-24229","url":null,"abstract":"\u0000 A DOE-funded program was used to understand the mechanisms that control the formation of NOx during the combustion of steelmaking by-product fuels and to investigate possible low-cost control options to minimize the NOx emissions. This paper discusses the CFD modeling results of NOx emissions in a reheat furnace. The reheat furnace has a total of 20 burners distributed over three firing zones. The furnace is fired at a rate of 250 × 106 Btu/hr and an overall stoichiometric ratio of 1.06 (fuel lean). Fuels with heating values of approximate 500 Btu/SCF were examined, including coke oven gas (COG), blast furnace gas (BFG) and a blend of COG, BFG, natural gas (NG) and nitrogen. A good range of process variables was modeled to examine effects of fuel type, air preheat, stoichiometric ratio, firing rate and burner stoichiometry distribution on NOx emissions.\u0000 Modeling results indicated that NOx formation in the reheat furnace is dominated by thermal NO, with some variation depending on the fuel fired. Temperature profiles showed an effective separation of the furnace interior into top and bottom zones as a result of the steel slab barrier. Higher temperatures characterized the bottom zone and elevated NOx levels as a result of the confined space and enhanced fuel air mixing provided by the slab supports. Results also showed that reburning of NOx plays a significant role in final NOx emissions with 30–40% of NOx formed being reduced by reburning in most cases. Modeling identified that operating the side burners in each burner zone slightly substoichiometric (while maintaining the overall furnace stoichiometry at 1.06) provided significant NOx reduction via reburning. NOx reductions of 23% and 30% were predicted when firing with COG and COG-NG-Air fuels, respectively. Overall furnace exit temperatures and heat flux profiles were not significantly affected by the biased firing.","PeriodicalId":426926,"journal":{"name":"Heat Transfer: Volume 4 — Combustion and Energy Systems","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123237529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1