Numerical Simulation Study Of Biodiesel Atomization Characteristics

With the development of industry,fossil fuels are almost running out.At the same time,this has caused serious ecological damage and environmental pollution.Biodiesel is considered to be a green alternative with huge potential,attracting the attention of the majority of scholars.In this paper,the biodiesel oil and Jatropha curcas biodiesel were studied.The physicochemical properties of two biodiesel and 0#diesel oil were compared with 0#diesel oil.A fuel atomization model was established and three fuel oils were explored.Differences in atomization,biodiesel viscosity,ambient temperature,and air flow rate affect the atomization of biodiesel.The physical properties such as density,dynamic viscosity,freezing point,flash point,surface tension,calorific value,and moisture content of Jatropha biodiesel,waste oil biodiesel and 0#diesel oil are measured with reference to the measurement methods of physicochemical properties and national standards.The results showed that the density,kinematic viscosity,and surface tension of waste oil biodiesel and Jatropha oil biodiesel were similar but they were all larger than 0#diesel oil;the cold filter points of waste oil biodiesel and Jatropha oil biodiesel are-13°C and-10°C which could meet the standard of China-10#diesel oil;the flash point of waste oil biodiesel and Jatropha oil biodiesel is more than 100°C higher than that of 0#diesel oil,and the former has better safety performance;the calorific value of biodiesel is about 10%lower than that of 0#diesel.Established the model of biodiesel atomization simulation by Fluent.Building the experimental platform by myself and used it to verify the validity of the model.When the air velocity is 12.11m/s and the fuel mass flow rate is 0.00001kg/s,the extraction time is0.01s,0.06s,0.11s,0.16s,0.21s,and 0.26s,contrasted the experimental results and the simulation results.The result show the model is effective.Using the above model,the differences in atomization of waste oil biodiesel,Jatropha biodiesel,and 0#diesel oil were compared.The results show that:The distribution of spray field,velocity field distribution and penetration distance of the three types of fuel are very small.The average diameter and sauter diameter of two biodiesel is not much different from that of sot,which is about 25?m,both nearly 10?m higher than that of 0#diesel.Meanwhile,the influence of viscosity,temperature and air velocity on the atomization performance of biodiesel was analyzed by numerical simulation.The results show that:When the viscosity is increased from 2 mm² s^1-to 8 mm² s^1-,the distribution of the spray field and the change of the penetration range are small.The average diameter is increased from 16?m to 28?m,and the diameter of sot is increased from 24?m to 41?m.When the ambient temperature rises from 300K to 360K,the penetration distance is small.The more particles are distributed in the spray field,the average diameter increases from 23?m to 28?m,and the diameter of sot increases from 36?m to 43?m.By 6.035 m/s air velocity increases to 12.11 m/s,the atomized droplets increase in spray field,through the distance,average diameter by 30?mreduce to 24?m,sauter diameter by 49?m to 37?m.