单 位：
华南农业大学工程基础教学与训练中心;华南理工大学电力学院
关键词：
微尺度燃烧;锥-射流;场强分布;荷电喷雾;组合电场
摘 要：
荷电喷雾燃烧技术对于促进微小尺度条件下液体燃料稳定与充分燃烧具有重要意义。基于喷嘴内径为0.9 mm的新型结构小尺度荷电喷雾燃烧器,开展了单电场及组合电场作用下乙醇燃料的荷电喷雾实验,测量了稳定"锥-射流"雾化模式下雾化区的雾化角。实验结果发现在相同乙醇流量下,采用组合电场燃烧器时的雾化角大于采用单电场时的雾化角,表明环形电极的引入可提高乙醇的雾化效果。荷电喷雾空间电场是由高压组合电极和空间电荷共同作用产生的,电极参数和空间电荷对空间电场分布均有重要影响。根据均匀带电细圆环电势和场强公式,将有限长薄圆柱面视为均匀带电细圆环的集合,利用叠加定理和椭圆积分的方法,计算出组合电极诱导电场在雾化区的场强分布。空间电荷作用产生的电场由喷嘴形成的雾锥区形状和带电量决定。计算结果表明,环形电极在雾化区产生的场强是轴对称的极不均匀的场强。当喷嘴电压处于一定值时,增大极距和环形电极的电压,组合电极的诱导电场强度大小有明显增强的作用,场强角度有明显变化。空间电荷产生的场强也是轴对称的极不均匀的电场强度,与电极诱导电场相比其作用不容忽视,尤其靠近金属网附近,空间电荷产生的电场起主导作用。组合电极条件下的荷电喷雾空间电场强度比喷嘴单电极作用下的荷电喷雾空间场强有明显的增强。选择1 mm的极距和环形电极的电压有利于荷电喷雾系统形成稳定的"锥-射流"雾化模式。
译 名：
Analysis on Electric Field Strength Distribution in Spraying Region of Small-scale Electro-spraying System
作 者：
Shi Yanling;Luo Zhibin;Gan Yunhua;Li Hua;Yang Zeliang;Engineering Basis for Teaching and Training Center,South China Agricultural University;School of Electric Power,South China University of Technology;Guangdong Province Key Laboratory of Efficient and Clean Energy Utilization;
关键词：
micro-scale combustion;;cone-jet;;distribution of electric field strength;;electro-spraying;;combined electric field
摘 要：
Electro-spraying is an effective technique to enhance combustion of liquid fuel in micro / smallscale. A new combustor using a stainless steel capillary tube with inner diameter of 0. 9 mm was designed. Electro-spraying experiments using ethanol as fuel were carried out under single electric field and combined electric field,and the spraying angels in the spraying region were measured under stable cone-jet mode. The experimental results found that the spraying angel under the combined electric field was bigger than that under single electric field at the same flow rate of 1. 6 m L / h. It can be inferred that the ring electrode can enhance the spraying process of ethanol. The space electric field during the electrospraying process was established by the combination of the combined electrodes and space charges. Both the electrode parameters and space charges play great roles in the electric field distribution. According tothe uniformly charged ring electric potential and field strength formula,the limited long and thin cylinder was regarded as a set of uniformly charged ring. Based on superposition theorem,the distribution of electric field strength in the spraying region was calculated using ellipse integral method and the relationship between Cartesian coordinates and polar coordinates. The electric field established by the space charges depends on the form of spraying region and the quantity of electric charge. The results show that the electric field strength was an axial symmetry and extremely nonuniform when using the ring electrode only. When keeping the voltage of nozzle as a constant,the electric field strength in the spraying region varies greatly along with increasing the electrode spacing and voltage of ring electrode.The electric field strength from the space charges was also an axial symmetry and extremely nonuiform,which cannot be ignored. Especially near to the steel mesh,the space charge dominated the whole electric field. The electric field strength under combined electrodes was enhanced greatly when comparing with that under single electrode. The selection of suitable electrode spacing and voltage is very important for the form of stable cone-jet mode. The present study can supply some guidelines for the design and operation of small-scale combustor.
