Maintaining cetane number constantly,for every 3.6%(increase) in oxygen mass fraction,the diffusive combustion duration and total combustion duration decreased by 0.8 crank angle degree,and the position of the center of heat release curve moved close to the top dead center by 0.25 crank angle degree under middle and high loads,which can be regarded as the influence of the ethanol addition as extracting the effect from ignition delay.
The study shows that the premixed combustion prolongs, the diffusive combustion duration and the total combustion duration shorten for ethanol-diesel blends on the condition of CN of blends have been improved to that of neat diesel, when compared to neat diesel.
Firstly, the paper presents the disperse low-temperatured premixed combustion concept, through combining the analyse of the process control and emission reduction principles of HCCI combustion and the research about the heat release characteristics of both diesel diffusive combustion and gasoline sprak-ignited premixed combustion.
The development of diesel engine technology is facing the challenges from both the increasely stringent emission regulations and the shortage of petroleum fuel, so to organize high efficient and clean bombustion on diesel engine, or to replace the conventional diesel diffuse combustion with premixed combustion, becomes an international research focus today.
The numerical simulation of the heat and turbulence burning flow in the arc-plasma ignition of the gas turbine was carried out,with RNGk-ε turbulence model and diffuse combustion model and discrete transfer radiation DTRM modle.
With this mode,the NO x formation mechanism of the DME has been investigated. The results show that NO x formation mainly occurs in the diffuse combustion phase,and the low NO x emissions are due to the low combustion temperature.
The k ε turbulent model, the three gase mixing combustion model and the composite radiosity model are used to simulate numerically the central backflow region of the turbulent diffusion flame in a gas burner with the PHOENICS software.
Using the commercial CFD-code FLUENT,the simulation of the turbulent diffusion flame in flame CVD process for nano-particles is detailedly performed, in which the effect of the boundary conditions, physical properties and radioative heat transfer on the flame temperature profiles is studied. The effect of molecular difusiviity at the low Reynolds number is especially emphasized.
To probe into the effects of the interaction of chemistry and fluid mechanics in the process of flame CVD, the simulation of gas velocity and temperature profile in propane/air turbulent diffusion flame for TiO2 nano-particles production were detailed performed by using the commercial CFD-code Fluent.