Research On Fuel Micro-Nozzle Atomization Performance And Processing Technology

The micro atomizing nozzle enhances the interaction between the liquid working medium and the air to atomize the liquid spray to form droplets achieving spraying dust reduction and improving combustion efficiency.However,the micro atomizing nozzle is facing difficulties and challenges in improving the atomization performance and the surface quality and accuracy.In this paper,the influence of the surface roughness value,machining residue and burr of the fuel micro-nozzle on the atomization performance is studied.Reasonable value range of surface roughness are summarized to ensure the comprehensive atomization performance of the micro-nozzle.The micro-milling processing technology of the working part of the contraction and expansion section of the micro-nozzle is optimized.Processing parameters are optimized by orthogonal experiment.The burr removal technology,processing residue suppression technology and micro-sandblasting post-treatment technology are presented.The micro-nozzles with reasonable roughness are obtained.The relationship between manufacturing process,surface quality and atomizing performance of micro-nozzle is studied,which is helpful for the better application of micro-nozzle in various fields.Firstly,CFD simulation technology was used to study the effects of surface roughness,machining residue and burr on atomization performance of micro-nozzle.The surface quality requirements of the contraction and expansion section of the micro-nozzle is summarized to ensure atomization performance.The surface roughness value must be within the range of 0.4 μm～0.8 μm,processing residues and burrs must be removed.The negative effects on the atomization performance can be avoided.Secondly,the structure of the micro-nozzle is analyzed.According to the structural characteristics of the micro-nozzle atomization working part,the micro-milling processing technology was formulated.Orthogonal experiment of micro-nozzle finishing cutting parameters is designed.The influence of spindle speed,feed per tooth,and axial cutting depth on the surface quality of the micro-nozzle is studied,and the best cutting parameter combinaton is selected.PMMA burr suppression technology and secondary finishing technology are proposed,and the two processing technology can significantly improve the surface quality is proved.Finally,according to the surface quality requirements of the micro-nozzle atomization performance,PMMA burr suppression technology,secondary finishing technology and sandblasting post-treatment technology are proposed.The overall processing of the contraction and expansion section of the micro-nozzle was generated.The results found that PMMA burr suppression technology can reduce the surface roughness by more than 40%,the secondary finishing process can reduce the surface roughness by 33%-36%,and the surface roughness of the contraction and expansion section of the micro-nozzle obtained by the sandblasting post-treatment technology up to 0.44 μm.