Research On Diesel Fuel Atomization Based On Electrohydrodynamics

Compared to gasoline engines, diesel engines have advantages of high thermal efficiency, low emissions of carbon-containing compound, while the problems existing in diesel engine are emissions of nitrogen-containing compounds and more environmental pollution; if diesel impurity particle content is high, it will cause clogging of diesel fuel and uneven air mixture, incomplete combustion. Diesel fuel typically uses pressure atomization, and this method is a waste of energy. If the viscosity of diesel fuel is too high, atomized diesel droplet diameter will be too large so that the surface area of diesel exposed to the air is reduced to cause incomplete combustion.EHD is a disciplines which describes the complex relationships between electric field and hydrodynamic, and EHD has been applied in many fields, including EHD atomization, EHD spray coating, ink jet printing, fuel combustion and electrostatic spinning. Research shows that factors that influence liquid atomization have two main aspects: surface tension of liquid and viscous drag. EHD atomized liquid can reduce the surface tension, while increasing its internal and external pressure differential, and thus significantly improve the atomization. Compared to other atomization methods, EHD atomization can uniformly refine droplet, thereby increasing the surface area of the droplets, improving combustion efficiency, reducing emissions. While the current is small generated in EHD atomization process, EHD atomization is a way of avoiding the energy waste. From this point of view, EHD atomization research has important practical significance.This paper introduces physical and mathematical models by combining status with progress of theoretical EHD atomization technology all over the world. Model includes electric field equations, discrete phase equatio ns, momentum conservation equation and the droplet breakup equation. It does not consider quality changes in the EHD atomization process.In order to obtain the distribution of atomized droplets, it needs Euler-Lagrangian calculation method. Because DPM model has discrete phase Lagrange equation, so this paper chooses DPM model. The solution process needs to add electric field source items in general Navier-Stokes equations.In order to achieve this goal, UDF function is compiled using c language and imported into FLUENT software.This paper achieves the potential field distributions cloud and the distribution of electric field with the selection of Electric modules in the ANSYS software. It is found that the voltage and the electric field strength at the capillary nozzle are higher in favor of liquid atomization.Then this paper uses FLUENT software simulating EHD atomization to give velocity cloud of air flow field distribution. By comparing the speed of the charged and uncharged air flow field distribution, higher liquid velocities can be seen in EHD atomization.In this paper, EHD atomization experimental platform is built to analysis the effect of voltage. According to the simulation results, it can be seen that the voltage can affect atomization. So experiment analyzes influence of voltage, current speed and distance between the electrodes on EHD atomization. Determining the atomization voltage respectively at a flow rate 10 ml / h, 20 ml / h, 30 ml / h, 40 ml / h and 50 ml / h; and required voltage of water and diesel fuel atomization in different electrode spacing. Experimental results show that: at the same flow rate, the voltage atomized water and diesel increased with increasing distance between electrodes; at the same electrode spacing, voltage atomizer lower with the flow rate increases. Therefore increasing the voltage appropriately and decreasing the distance between electrodes is in favor of EHD atomization.