The purpose of this study is to investigate the effect of fuel properties on liquid and vapor penetrations in evaporating spray systems. A recently developed model, which can simultaneously account for the finite ther...The purpose of this study is to investigate the effect of fuel properties on liquid and vapor penetrations in evaporating spray systems. A recently developed model, which can simultaneously account for the finite thermal conductivity, finite mass diffusivity and turbulence effects within atomizing multi-component liquid fuel sprays, is utilized for the numerical predictions. Two different multi-component fuels with different boiling temperatures,densities and other thermal properties are implemented in the KIVA-3V computational fluid dynamics(CFD)code to study the evaporation behaviors. A six-component surrogate fuel is used to emulate the relevant volatility property of the real diesel fuel, and a second bi-component fuel is chosen to represent a low boiling-temperature fuel. The numerical results are compared with the experimental data, and the representative results are obtained.For a lower density and lower boiling temperature fuel, the liquid penetration length is shorter. However, the vapor penetration lengths are not affected by the fuel type in terms of fuel volatility. Available experimental data are used for validation and appraisal of the multi-component evaporation model.展开更多
Under the condition of absolute dry, more than thirty forest fuel pararneters,ash content. extract and burning point were measured. By the method of regression step by step. we found an experience formula which can es...Under the condition of absolute dry, more than thirty forest fuel pararneters,ash content. extract and burning point were measured. By the method of regression step by step. we found an experience formula which can estimate effective fuel high combusti on value of forest community from the Daxingan Mountain,and then,By means of modifying moisture content. we gave an approximate formula about actual heat releasing of forest fuels in the forest fire behavior.展开更多
The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent structure of active...The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent structure of active sites but also by the properties of the interfacial structures at catalytic surfaces. Ionic liquids（ILs）, as a unique class of metal salts with melting point below 100 ℃, present themselves as ideal modulators for manipulations of the interfacial structures. Due to their excellent properties such as good chemical stability, high ionic conductivity, wide electrochemical windows and tunable solvent properties the performance of electrocatalysts can be substantially improved through ILs. In the current minireview, we highlight the critical role of the IL phase at the microenvironments created by the IL, the liquid electrolyte, catalytic nanoparticles and/or support materials, by detailing the promotional effect of IL in electrocatalysis as reaction media, binders, and surface modifiers. Updated exemplary applications of IL in electrocatalysis are given and moreover, the latest developments of IL modified electrocatalysts following the ＂Solid Catalyst with Ionic Liquid Layer（SCILL）＂ concept are presented.展开更多
Effects of liquid fuel composition variations on characteristics of self-excited thermo-acoustic instabilities in a lean premixed,pre-vaporized gas turbine model combustor were experimentally studied.Test fuels includ...Effects of liquid fuel composition variations on characteristics of self-excited thermo-acoustic instabilities in a lean premixed,pre-vaporized gas turbine model combustor were experimentally studied.Test fuels included practical RP-3 jet fuel and its blending with iso-octane and n-dodecane,which were branched and linear alkanes respectively.Under the test conditions,dynamic pressure measurements indicated that the dominant instability frequency was highest for RP-3 flame,while RP-3/ndodecane flame exhibited the strongest instability strength.A further analysis showed that the instability frequency correlated well with the profiles of adiabatic flame temperature,and the strength of the instability highly depended on the ignition delay times of the fuels.Measurements of the flame structure and flow field with OH*chemiluminescence (CL) imaging and twodimensional particle image velocimetry (PIV) techniques indicated that changes in the fuel composition did not alter the unstable modes and general sequences of flame-flow structure oscillations.Further power spectra and proper orthogonal decomposition(POD) analysis suggested that axial oscillations along with precessing vortex core (PVC) induced helical motion predominated periodic flame structure and flow field oscillations.展开更多
基金the Third Round"985 Project"Through the University of Michigan-Shanghai Jiao Tong University Joint Institute(No.TS0321337001)
文摘The purpose of this study is to investigate the effect of fuel properties on liquid and vapor penetrations in evaporating spray systems. A recently developed model, which can simultaneously account for the finite thermal conductivity, finite mass diffusivity and turbulence effects within atomizing multi-component liquid fuel sprays, is utilized for the numerical predictions. Two different multi-component fuels with different boiling temperatures,densities and other thermal properties are implemented in the KIVA-3V computational fluid dynamics(CFD)code to study the evaporation behaviors. A six-component surrogate fuel is used to emulate the relevant volatility property of the real diesel fuel, and a second bi-component fuel is chosen to represent a low boiling-temperature fuel. The numerical results are compared with the experimental data, and the representative results are obtained.For a lower density and lower boiling temperature fuel, the liquid penetration length is shorter. However, the vapor penetration lengths are not affected by the fuel type in terms of fuel volatility. Available experimental data are used for validation and appraisal of the multi-component evaporation model.
文摘Under the condition of absolute dry, more than thirty forest fuel pararneters,ash content. extract and burning point were measured. By the method of regression step by step. we found an experience formula which can estimate effective fuel high combusti on value of forest community from the Daxingan Mountain,and then,By means of modifying moisture content. we gave an approximate formula about actual heat releasing of forest fuels in the forest fire behavior.
基金supported by the funding of the German Research Council (DFG), which, within the framework of its Excellence Initiative, supports the Cluster of Excellence “Engineering of Advanced Materials” (www.eam.uni-erlangen.de) at the University of Erlangen-Nürnberg
文摘The performance of an electrocatalyst, which is needed e.g. for key energy conversion reactions such as hydrogen evolution, oxygen reduction or CO2 reduction, is determined not only by the inherent structure of active sites but also by the properties of the interfacial structures at catalytic surfaces. Ionic liquids（ILs）, as a unique class of metal salts with melting point below 100 ℃, present themselves as ideal modulators for manipulations of the interfacial structures. Due to their excellent properties such as good chemical stability, high ionic conductivity, wide electrochemical windows and tunable solvent properties the performance of electrocatalysts can be substantially improved through ILs. In the current minireview, we highlight the critical role of the IL phase at the microenvironments created by the IL, the liquid electrolyte, catalytic nanoparticles and/or support materials, by detailing the promotional effect of IL in electrocatalysis as reaction media, binders, and surface modifiers. Updated exemplary applications of IL in electrocatalysis are given and moreover, the latest developments of IL modified electrocatalysts following the ＂Solid Catalyst with Ionic Liquid Layer（SCILL）＂ concept are presented.
基金the National Natural Science Foundation of China(Grant Nos.91641202 and 501100001809)the Program of Shanghai Subject Chief Scientist(Grant No.19XD1401800)。
文摘Effects of liquid fuel composition variations on characteristics of self-excited thermo-acoustic instabilities in a lean premixed,pre-vaporized gas turbine model combustor were experimentally studied.Test fuels included practical RP-3 jet fuel and its blending with iso-octane and n-dodecane,which were branched and linear alkanes respectively.Under the test conditions,dynamic pressure measurements indicated that the dominant instability frequency was highest for RP-3 flame,while RP-3/ndodecane flame exhibited the strongest instability strength.A further analysis showed that the instability frequency correlated well with the profiles of adiabatic flame temperature,and the strength of the instability highly depended on the ignition delay times of the fuels.Measurements of the flame structure and flow field with OH*chemiluminescence (CL) imaging and twodimensional particle image velocimetry (PIV) techniques indicated that changes in the fuel composition did not alter the unstable modes and general sequences of flame-flow structure oscillations.Further power spectra and proper orthogonal decomposition(POD) analysis suggested that axial oscillations along with precessing vortex core (PVC) induced helical motion predominated periodic flame structure and flow field oscillations.
