The flame structure of gasoline engine is complicated and has the characteristic of fractal geometry. A fractal combustion model was used to simulate the engine working cycle. Based on this model, the fractal dimensio...The flame structure of gasoline engine is complicated and has the characteristic of fractal geometry. A fractal combustion model was used to simulate the engine working cycle. Based on this model, the fractal dimension and laminar flame surface area of turbulent premixed flames were studied under different working conditions. The experimental system mainly includes an optical engine and a set of photography equipment used to shoot the images of turbulent flame of spark-ignition engine. The difference box-counting method was used to process 2D combustion images. In contrast to the experimental results, the computational results show that the fractal combustion model is an effective method of simulating the engine combustion process. The study provides a better understanding for flame structure and its propagation.展开更多
Turbulent reacting flows in a generic swirl gas turbine combustor model are investigated both numerically and experimentally.In the investigation,an emphasis is placed upon the external flue gas recirculation,which is...Turbulent reacting flows in a generic swirl gas turbine combustor model are investigated both numerically and experimentally.In the investigation,an emphasis is placed upon the external flue gas recirculation,which is a promising technology for increasing the efficiency of the carbon capture and storage process,which,however,can change the combustion behaviour significantly.A further emphasis is placed upon the investigation of alternative fuels such as biogas and syngas in comparison to the conventional natural gas.Flames are also investigated numerically using the open source CFD software OpenFOAM.In the numerical simulations,a laminar flamelet model based on mixture fraction and reaction progress variable is adopted.As turbulence model,the SST model is used within a URANS concept.Computational results are compared with the experimental data,where a fair agreement is observed.展开更多
基金Supported by National Natural Science Foundation of China (No. 50876072) Tianjin Municipal Science and Technology Commission (No. 07JCYBJC03900 )
文摘The flame structure of gasoline engine is complicated and has the characteristic of fractal geometry. A fractal combustion model was used to simulate the engine working cycle. Based on this model, the fractal dimension and laminar flame surface area of turbulent premixed flames were studied under different working conditions. The experimental system mainly includes an optical engine and a set of photography equipment used to shoot the images of turbulent flame of spark-ignition engine. The difference box-counting method was used to process 2D combustion images. In contrast to the experimental results, the computational results show that the fractal combustion model is an effective method of simulating the engine combustion process. The study provides a better understanding for flame structure and its propagation.
文摘Turbulent reacting flows in a generic swirl gas turbine combustor model are investigated both numerically and experimentally.In the investigation,an emphasis is placed upon the external flue gas recirculation,which is a promising technology for increasing the efficiency of the carbon capture and storage process,which,however,can change the combustion behaviour significantly.A further emphasis is placed upon the investigation of alternative fuels such as biogas and syngas in comparison to the conventional natural gas.Flames are also investigated numerically using the open source CFD software OpenFOAM.In the numerical simulations,a laminar flamelet model based on mixture fraction and reaction progress variable is adopted.As turbulence model,the SST model is used within a URANS concept.Computational results are compared with the experimental data,where a fair agreement is observed.
