In the present study a modified CFD code KIVA3V was used to simulate the spray combustion in a small DI diesel engine fueled with DME. The improved spray models consider more spray phenomena such as cavitation flow in...In the present study a modified CFD code KIVA3V was used to simulate the spray combustion in a small DI diesel engine fueled with DME. The improved spray models consider more spray phenomena such as cavitation flow in nozzle hole, jet atomization, droplet second breakup and spray wall interaction. Otherwise, a reduced DME reaction mechanism is implemented in the combustion model, and a new turbulent combustion model?Partial Stirred Reactor (PaSR) model is selected to simulate the spray combustion process, the effects of turbulent mixing on the reaction rate are considered. The results of engine modeling based on those models agreed well with the experimental measurements. Study of temperature fields variation and particle traces in the combustion chamber revealed that the engine combustion system originally used for diesel fuel must be optimized for DME.展开更多
In this study, the Gibbs-Duhem equation was applied to make the thermodynamic consistency test and thermodynamic model estimation for systems of CO2-DME (dimethyl ether), DME-CH3OH, CO2-CH3OH and DME-C2H5OH systems on...In this study, the Gibbs-Duhem equation was applied to make the thermodynamic consistency test and thermodynamic model estimation for systems of CO2-DME (dimethyl ether), DME-CH3OH, CO2-CH3OH and DME-C2H5OH systems on the basis of the vapor-liquid equilibrium (VLE) experimental data in published reports. And the NRTL binary interaction parameters of the systems mentioned above were regressed by the VLE data and were subjected to a thermodynamic consistency test because the study showed that PR-NRTL model combination was appropriate for the four systems mentioned above. The regressed binary interaction parameters were used to es-timate the VLE for DME-CO2-CH3OH at temperatures of 313.15K and 333.15K, and the estimated result was coin-cident with the experimental data. On the basis of the predicted VLE data for systems of DME-CO2-CH3OH and DME-CO2-C2H5OH, the VLE behaviors of the two systems were studied by the phase diagrams of these two ter-nary systems, with the forms of both the two dimensional and three dimensional phase diagrams, respectively.展开更多
A mathematical model for a bubble column slurry reactor is presented for dimethyl ether synthesis from syngas. Methanol synthesis from carbon monoxide and carbon dioxide by hydrogenation and the methanol dehydration a...A mathematical model for a bubble column slurry reactor is presented for dimethyl ether synthesis from syngas. Methanol synthesis from carbon monoxide and carbon dioxide by hydrogenation and the methanol dehydration are considered as independent reactions, in which methanol, dimethyl ether and carbon dioxide are the key components. In this model, the gas phase is considered to be in plug flow and the liquid phase to be in partly back mixing with axial distribution of solid catalyst. The simulation results show that the axial dispersion of solid catalysts, the operational height of the slurry phase in the bubble column slurry reactor, and the reaction results are influenced by the reaction temperature and pressure, which are the basic data for the scale-up of reactor.展开更多
基金Project supported by the National Basic Research Program (973)of China(No. 2001CB209207)and the National Natural Science Foundation of China (No. 50376018)
文摘In the present study a modified CFD code KIVA3V was used to simulate the spray combustion in a small DI diesel engine fueled with DME. The improved spray models consider more spray phenomena such as cavitation flow in nozzle hole, jet atomization, droplet second breakup and spray wall interaction. Otherwise, a reduced DME reaction mechanism is implemented in the combustion model, and a new turbulent combustion model?Partial Stirred Reactor (PaSR) model is selected to simulate the spray combustion process, the effects of turbulent mixing on the reaction rate are considered. The results of engine modeling based on those models agreed well with the experimental measurements. Study of temperature fields variation and particle traces in the combustion chamber revealed that the engine combustion system originally used for diesel fuel must be optimized for DME.
基金Supported by the National Natural Science Foundation of China (No.90210032, No.50576001).
文摘In this study, the Gibbs-Duhem equation was applied to make the thermodynamic consistency test and thermodynamic model estimation for systems of CO2-DME (dimethyl ether), DME-CH3OH, CO2-CH3OH and DME-C2H5OH systems on the basis of the vapor-liquid equilibrium (VLE) experimental data in published reports. And the NRTL binary interaction parameters of the systems mentioned above were regressed by the VLE data and were subjected to a thermodynamic consistency test because the study showed that PR-NRTL model combination was appropriate for the four systems mentioned above. The regressed binary interaction parameters were used to es-timate the VLE for DME-CO2-CH3OH at temperatures of 313.15K and 333.15K, and the estimated result was coin-cident with the experimental data. On the basis of the predicted VLE data for systems of DME-CO2-CH3OH and DME-CO2-C2H5OH, the VLE behaviors of the two systems were studied by the phase diagrams of these two ter-nary systems, with the forms of both the two dimensional and three dimensional phase diagrams, respectively.
文摘A mathematical model for a bubble column slurry reactor is presented for dimethyl ether synthesis from syngas. Methanol synthesis from carbon monoxide and carbon dioxide by hydrogenation and the methanol dehydration are considered as independent reactions, in which methanol, dimethyl ether and carbon dioxide are the key components. In this model, the gas phase is considered to be in plug flow and the liquid phase to be in partly back mixing with axial distribution of solid catalyst. The simulation results show that the axial dispersion of solid catalysts, the operational height of the slurry phase in the bubble column slurry reactor, and the reaction results are influenced by the reaction temperature and pressure, which are the basic data for the scale-up of reactor.
