Effect Of High-energy Nano Particles On Combustion Performance Of Diesel Engine Based On OpenFOAM

Experimental studies at home and abroad have shown that the addition of high-energy nano particles to diesel fuel can reduce the fuel consumption and partial emissions of diesel engines.In this paper,based on the CFD theory and OpenFOAM software,taking the quarter combustor as the subject,the fuel injection and combustion process are simulated to study effect of high-energy nano particles on combustion performance of diesel engine.In this paper,the injection combustion model of diesel is established according to the sprayH model of Sandia ECN,including the nozzle model,mathematical model(including atomization and break model,phase change model,combustion model and so on),diesel combustion mechanism,etc.The simulation results are compared with the experimental data to verify the accuracy of these models.Then,based on the one-step combustion process,the combustion model of high-energy nano particles is established and coupled with the diesel injection combustion model.In order to realize the simulation in the combustor,this paper also establishes a model of quarter combustor,and completes the mesh generation and the determination of boundary conditions,the conversion from time control to crack angle control,and the change of mesh during the movement of the piston.Based on these models,the diesel injection combustion process of compression-expansion stroke in combustor is simulated.The simulation results show that diesel will burn fully with the addition of high-energy nano particles under high engine load,bringing the increase of the heat of combustion,the reduction of the fuel consumption rate,the increase of temperature and pressure,and the reduction of the emissions of unburnt hydrocarbons,carbon monoxide and soot.But the emissions of nitrogen oxides will increase because of higher temperature.This effect of promoting diesel combustion will decrease as the engine load is reduced,and will increase as the fraction of high-energy nano particles increases or the diameter of the particles decreases.Finally,this paper verifies the rationality and accuracy of the simulation results by comparing with the results of the DSC analysis.