Research On The Effect Of Different Alcohol Additives On The Evaporation Characteristics Of Jatropha Curcas Oil Droplets

To solve the problem of energy shortage and environmental pollution,we need to find green and clean energy.Because of its wide economic source and clean emissions,jatropha biodiesel is favored by domestic and foreign researchers.However,because the density and viscosity of pure Jatropha biodiesel are larger than that of diesel,it will affect the fuel atomization and combustion process in the cylinder of the internal combustion engine,thus affecting the performance of the diesel engine.Adding ethanol or pentanol to pure Jatropha biodiesel can improve the atomization process and then affect the evaporation of fuel droplets,and ultimately improve the combustion efficiency and reduce the emission of pollutants.In this thesis,ethanol Jatropha biodiesel and n-pentanol-jatropha biodiesel were used as research objects,and the single drop evaporation characteristic curve,micro explosion mechanism of ethanol Jatropha biodiesel and n-pentanol-jatropha biodiesel as well as the influence of different parameters on them were studied by using the suspended single drop evaporation test device.At the same time,a one-dimensional two-component evaporation model is established.Comparing the theoretical model with the actual average evaporation rate,the evaporation model can be well verified.This thesis first introduces the preparation process of Jatropha biodiesel(by using transesterification method to get pure Jatropha biodiesel under alkaline conditions,and adding ethanol and n-pentanol with different mass fractions to Jatropha biodiesel directly,then the test oil can be obtained)and the operation steps of the experimental equipment,and the data of the droplets can be extracted by batch processing program Error analysis is feasible for the method of extracting diameter data from droplet data processing,and will not have a bad effect on droplet evaporation law.Secondly,the consistency of the experimental device was verified by repeated tests with the suspension single droplet evaporation test device.The droplet evaporation characteristics of E30(Jatropha biodiesel with 30% ethanol)fuel oil were studied,and the evaporation characteristic curve,evaporation time,droplet life,droplet evaporation rate and droplet evaporation shape change process were analyzed The mechanism of micro explosion at 673 k and 973 k.In addition,the factors affecting the droplet evaporation(mass fraction of alcohol added to the droplet,type of alcohol,ambient temperature)were studied.Combined with the D2 curve,the time of each evaporation stage,the evaporation rate and the change process chart of droplet shape,the evaporation characteristics of droplets are analyzed comprehensively.The test results show that the evaporation of E30 droplets is relatively gentle and stable at low temperature,while the micro explosion phenomenon of E30 droplets is obvious at high temperature.With the increase of ethanol content,the droplet life gradually decreases,indicating that the more ethanol content,the more effective the droplet evaporation.For n-pentanol-jatropha biodiesel,the droplet life gradually decreases with the increase of n-pentanol content.Similarly,n-pentanol can promote the droplet evaporation,and the same 30% content of ethanol Jatropha biodiesel and n-pentanol-jatropha biodiesel droplets,E30 droplets evaporate faster.With the increase of the ambient temperature,the evaporation stages of ethanol Jatropha biodiesel and n-pentanol-jatropha biodiesel changed obviously.Therefore,the environmental temperature had the most significant effect on the droplet evaporation.Finally,according to the infinite heat conduction evaporation model and the experiment in this thesis,a one-dimensional two-component evaporation model is proposed to simulate the ethanol-n-hexadecane droplet,and the theoretical simulation value is compared with the experimental value.The results show that the theoretical simulation value and the experimental value are consistent,which shows that the evaporation model can provide the theory for the single droplet evaporation of mixed biodiesel basis.