基于微小尺度荷电喷雾燃烧系统,进行了组合电场下乙醇的荷电雾化实验,得出了稳定的锥-射流雾化模式,并基于该模式,进行了理论分析计算。借助直角坐标系与极坐标的关系,采用椭圆积分的方法,求解出组合电场下射流区的场强分布。研究结果表明:环形电极在射流区产生的场强在喷嘴中心处产生的电场强度最大,环形电极圆心处的场强为0 V/m,当其他条件相同时,场强随着半锥角的增大而增大。环形电极的半径远大于喷嘴半径,极距较小,环形电极在射流区产生的场强与喷嘴电极所产生的场强相比可以忽略。在球坐标系φ为0°~49.3°范围内,射流区的电场强度电场分布是轴对称的极不均匀的场强,喷嘴中心处值较小,周围场强较高,利于雾滴荷电,改变环形电极电压参数,对射流区的场强分布没有影响,但对雾化区的场强起到了明显增强作用。
Experiments on electro-spraying were carried out under a combined electric field based on micro-scale combustion system by using ethanol as fuel. A stable cone-jet mode was obtained. And theoretical calculation was performed based on the cone-jet mode. The distribution of electric field strength was calculated by using ellipse integral method and the relationship between Cartesian coordinates and polar coordinates. The results showed that the electric field strength produced by the ring electrode alone at the center of nozzle reached its maximum value, which was 0 V/m at the position of the center of ring electrode. It increased with the increase of cone angle when all the other conditions were kept the same. The electric field strength produced by the ring electrode could be ignored compared with that produced by the nozzle electrode due to the much bigger diameter of ring electrode and smaller electrode spacing. The distribution of electric field strength in the jet region was axis-symmetry and extremely non-uniform in the angle range φ of 0° -49.3°. The strength in the center of nozzle was very small while it was bigger around the outer side of nozzle, which enhanced the electric induction. Changing the voltage of the ring electrode put little effect on the electric field distribution in the jet region, but the electric field strength in the spraying region was greatly increased.