Based on the grea field investigation and experiment in laboratory, four fuel types wer classified for all broad-leaved/Korean pine forests and its plantations in northeast China in this paper. Various kinds of fuel l...Based on the grea field investigation and experiment in laboratory, four fuel types wer classified for all broad-leaved/Korean pine forests and its plantations in northeast China in this paper. Various kinds of fuel loads, combuStibility and potential energy are calculated and discussed.The relationships between fuel types, fire environment and fire behavior are also widely expounds,and some researh results and management suggestion on Konan pine forests are also given in the paper.展开更多
Based on a large number field investigation and experiment inlaboratory and the corresponding qualitative and quantitetive analysis, 6 fuel type groups and 12 fuel types were classitied to the east mountains in northe...Based on a large number field investigation and experiment inlaboratory and the corresponding qualitative and quantitetive analysis, 6 fuel type groups and 12 fuel types were classitied to the east mountains in northeast China in this paper. The characteristics, distribution and fire behavior of these fuel types are also widely discussed.展开更多
This paper presents three-dimensional numerical simulations of the hybrid rocket motor with hydrogen peroxide (HP) and hy-droxyl terminated polybutadiene (HTPB) propellant combination and investigates the fuel regress...This paper presents three-dimensional numerical simulations of the hybrid rocket motor with hydrogen peroxide (HP) and hy-droxyl terminated polybutadiene (HTPB) propellant combination and investigates the fuel regression rate distribution charac-teristics of different fuel types. The numerical models are established to couple the Navier-Stokes equations with turbulence,chemical reactions, solid fuel pyrolysis and solid-gas interfacial boundary conditions. Simulation results including the temper-ature contours and fuel regression rate distributions are presented for the tube, star and wagon wheel grains. The results demonstrate that the changing trends of the regression rate along the axis are similar for all kinds of fuel types, which decrease sharply near the leading edges of the fuels and then gradually increase with increasing axial locations. The regression rates of the star and wagon wheel grains show apparent three-dimensional characteristics, and they are higher in the regions of fuel surfaces near the central core oxidizer flow. The average regression rates increase as the oxidizer mass fluxes rise for all of the fuel types. However, under same oxidizer mass flux, the average regression rates of the star and wagon wheel grains are much larger than that of the tube grain due to their lower hydraulic diameters.展开更多
Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hy...Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 （where Lm is La-richened mischmetal） alloy （LNM） by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.展开更多
This paper summarizes the fuel type systems currently adopted by the fire danger rating systems or fire behavior prediction systems of some countries, such as Canada, the United States, Australia, Greece, and Switzerl...This paper summarizes the fuel type systems currently adopted by the fire danger rating systems or fire behavior prediction systems of some countries, such as Canada, the United States, Australia, Greece, and Switzerland. As an example, the Canadian Forest Fire Danger Rating System organizes fuel types into five major groups, with a total of 16 discrete fuel types recognized. In the United States National Fire Danger Rating System, fuel models are divided into four vegetation groups and twenty fire behavior fuel models. The Promethus System （Greece） divides fuels into 7 types, and Australia has adopted only three distinct fuel types： open grasslands, dry eucalyptus forests, and heath/shrublands. Four approaches to mapping fuels are acceptable： field reconnaissance, direct mapping methods, indirect mapping methods, and gradient modeling. Satellite remote-sensing techniques provide an alternative source of obtaining fuel data quickly, since they provide comprehensive spatial coverage and enough temporal resolution to update fuel maps in a more efficient and timely manner than traditional aerial photography or fieldwork. Satellite sensors can also provide digital information that can be easily tied into other spatial databases using Geographic Information System （GIS） analysis, which can be used as input in fire behavior and growth models. Various fuel-mapping methods from satellite remote sensing are discussed in the paper. According to the analysis of the fuel mapping techniques worldwide, this paper suggests that China should first create appropriate fuel types for its fire agencies before embarking on developing a national fire danger rating system to improve the current data situation for it＇s fire management programs.展开更多
The variation of fuel loads after a fire for three forest types, phododendron -Larix gmetinii forest, herb--Larix gmelinii forest and herb--Betula plalyphlla forest , in the northern forest area of Daxing’anling regi...The variation of fuel loads after a fire for three forest types, phododendron -Larix gmetinii forest, herb--Larix gmelinii forest and herb--Betula plalyphlla forest , in the northern forest area of Daxing’anling region was discussed. The dynamic models were developed by gray theory for estimating the fuels loads of arbor- shrub, herbs’ grass, litter, and semi-decomposed litter, inflamma ble fuel and the total fuels in each forest type. After a fire, the inflammabIe fuel loads in phododendron-- Larix gmelinii forest and in the herb- - Betula platyphlla fores was estimated at 10.958 t/hm2and 10.473 t/hm2 respectively’ by 13 years later. and that was 12.297 t/hm 2 in herb--Larix gmeliniiforest by 7 years later.. It was predicated that a big fire may occur after 10 years based on inflammable fuel biomass accumulated.展开更多
The demand for nuclear fuel for research reactors is rising worldwide. Thus, the production facilities of this kind of fuel need reliable guidance on how to augment their production in order to meet the increasing dem...The demand for nuclear fuel for research reactors is rising worldwide. Thus, the production facilities of this kind of fuel need reliable guidance on how to augment their production in order to meet the increasing demand efficiently and safely. We proposed a specific procedure for increasing production capacity. That procedure was tested with data from a real plant, which produces plate-type fuel elements loaded with LEU U3Si2-Al fuel. The test was made by means of discrete event simulation, and the results indicated the proposed procedure is efficient in raising production capacity.展开更多
池式研究型反应堆是全球多用途研究堆中的重点类型,因其在安全特性、多用途性和运行维护等方面的突出表现而备受关注。在池式堆中,热功率为1~10 MW的小型研究堆方案设计最为成熟,应用场景最为广泛。为了探索未来池式研究堆堆芯设计及其...池式研究型反应堆是全球多用途研究堆中的重点类型,因其在安全特性、多用途性和运行维护等方面的突出表现而备受关注。在池式堆中,热功率为1~10 MW的小型研究堆方案设计最为成熟,应用场景最为广泛。为了探索未来池式研究堆堆芯设计及其应用场景的发展趋势,首先,根据全球开展RERTR(Reduced Enrichment Research and Test Reactor)低浓化项目并进行堆芯重新设计的小型池式研究堆不同的堆芯方案进行对比,研究分析未来小型池式研究堆堆芯可采用的燃料类型和组件结构,以及目前全球小型池式研究堆的应用情况。其次,总结了小型池式研究堆在燃料类型和堆芯结构两个方面的发展现状,汇总了研究堆各类中子应用场景的技术指标。最终,通过横向对比探究分析推判:未来小型池式研究堆将采用紧凑型堆芯设计,采用高密度的低浓缩铀燃料,以紧凑可移动式小堆芯为基础,以大水池内中子源应用设施为主要发展方向。展开更多
文摘Based on the grea field investigation and experiment in laboratory, four fuel types wer classified for all broad-leaved/Korean pine forests and its plantations in northeast China in this paper. Various kinds of fuel loads, combuStibility and potential energy are calculated and discussed.The relationships between fuel types, fire environment and fire behavior are also widely expounds,and some researh results and management suggestion on Konan pine forests are also given in the paper.
文摘Based on a large number field investigation and experiment inlaboratory and the corresponding qualitative and quantitetive analysis, 6 fuel type groups and 12 fuel types were classitied to the east mountains in northeast China in this paper. The characteristics, distribution and fire behavior of these fuel types are also widely discussed.
文摘This paper presents three-dimensional numerical simulations of the hybrid rocket motor with hydrogen peroxide (HP) and hy-droxyl terminated polybutadiene (HTPB) propellant combination and investigates the fuel regression rate distribution charac-teristics of different fuel types. The numerical models are established to couple the Navier-Stokes equations with turbulence,chemical reactions, solid fuel pyrolysis and solid-gas interfacial boundary conditions. Simulation results including the temper-ature contours and fuel regression rate distributions are presented for the tube, star and wagon wheel grains. The results demonstrate that the changing trends of the regression rate along the axis are similar for all kinds of fuel types, which decrease sharply near the leading edges of the fuels and then gradually increase with increasing axial locations. The regression rates of the star and wagon wheel grains show apparent three-dimensional characteristics, and they are higher in the regions of fuel surfaces near the central core oxidizer flow. The average regression rates increase as the oxidizer mass fluxes rise for all of the fuel types. However, under same oxidizer mass flux, the average regression rates of the star and wagon wheel grains are much larger than that of the tube grain due to their lower hydraulic diameters.
文摘Fuel cell using borohydride as the fuel has received much attention. AB5-type hydrogen storage alloy used as the anodic material instead of noble metals has been investigated. In order to restrain the generation of hydrogen and enhance the utilization of borohydride, Ti/Zr metal powders has been added into the parent LmNi4.78Mn0.22 （where Lm is La-richened mischmetal） alloy （LNM） by ball milling and heat treatment methods. It is found that the addition of Ti/Zr metal powders lowers the electrochemical catalytic activity of the electrodes, at the same time, restrains the generation of hydrogen and enhances the utilization of the fuel. All the results show that the hydrogen generation rate or the utilization of the fuel is directly relative to the electrochemical catalytic activity or the discharge capability of the electrodes. The utilization of the fuel increases with discharge current density. It is very important to find a balance between the discharge capability and the utilization of the fuel.
基金This paper was supported by the Beijing Fund of Nature Science (No. 6042025), China NKBRSF Project (No. 2001CB409600) and Laboratory of Forest Protection, State Forestry Administration
文摘This paper summarizes the fuel type systems currently adopted by the fire danger rating systems or fire behavior prediction systems of some countries, such as Canada, the United States, Australia, Greece, and Switzerland. As an example, the Canadian Forest Fire Danger Rating System organizes fuel types into five major groups, with a total of 16 discrete fuel types recognized. In the United States National Fire Danger Rating System, fuel models are divided into four vegetation groups and twenty fire behavior fuel models. The Promethus System （Greece） divides fuels into 7 types, and Australia has adopted only three distinct fuel types： open grasslands, dry eucalyptus forests, and heath/shrublands. Four approaches to mapping fuels are acceptable： field reconnaissance, direct mapping methods, indirect mapping methods, and gradient modeling. Satellite remote-sensing techniques provide an alternative source of obtaining fuel data quickly, since they provide comprehensive spatial coverage and enough temporal resolution to update fuel maps in a more efficient and timely manner than traditional aerial photography or fieldwork. Satellite sensors can also provide digital information that can be easily tied into other spatial databases using Geographic Information System （GIS） analysis, which can be used as input in fire behavior and growth models. Various fuel-mapping methods from satellite remote sensing are discussed in the paper. According to the analysis of the fuel mapping techniques worldwide, this paper suggests that China should first create appropriate fuel types for its fire agencies before embarking on developing a national fire danger rating system to improve the current data situation for it＇s fire management programs.
文摘The variation of fuel loads after a fire for three forest types, phododendron -Larix gmetinii forest, herb--Larix gmelinii forest and herb--Betula plalyphlla forest , in the northern forest area of Daxing’anling region was discussed. The dynamic models were developed by gray theory for estimating the fuels loads of arbor- shrub, herbs’ grass, litter, and semi-decomposed litter, inflamma ble fuel and the total fuels in each forest type. After a fire, the inflammabIe fuel loads in phododendron-- Larix gmelinii forest and in the herb- - Betula platyphlla fores was estimated at 10.958 t/hm2and 10.473 t/hm2 respectively’ by 13 years later. and that was 12.297 t/hm 2 in herb--Larix gmeliniiforest by 7 years later.. It was predicated that a big fire may occur after 10 years based on inflammable fuel biomass accumulated.
文摘The demand for nuclear fuel for research reactors is rising worldwide. Thus, the production facilities of this kind of fuel need reliable guidance on how to augment their production in order to meet the increasing demand efficiently and safely. We proposed a specific procedure for increasing production capacity. That procedure was tested with data from a real plant, which produces plate-type fuel elements loaded with LEU U3Si2-Al fuel. The test was made by means of discrete event simulation, and the results indicated the proposed procedure is efficient in raising production capacity.
文摘池式研究型反应堆是全球多用途研究堆中的重点类型,因其在安全特性、多用途性和运行维护等方面的突出表现而备受关注。在池式堆中,热功率为1~10 MW的小型研究堆方案设计最为成熟,应用场景最为广泛。为了探索未来池式研究堆堆芯设计及其应用场景的发展趋势,首先,根据全球开展RERTR(Reduced Enrichment Research and Test Reactor)低浓化项目并进行堆芯重新设计的小型池式研究堆不同的堆芯方案进行对比,研究分析未来小型池式研究堆堆芯可采用的燃料类型和组件结构,以及目前全球小型池式研究堆的应用情况。其次,总结了小型池式研究堆在燃料类型和堆芯结构两个方面的发展现状,汇总了研究堆各类中子应用场景的技术指标。最终,通过横向对比探究分析推判:未来小型池式研究堆将采用紧凑型堆芯设计,采用高密度的低浓缩铀燃料,以紧凑可移动式小堆芯为基础,以大水池内中子源应用设施为主要发展方向。
