喷嘴抗冲蚀磨损研究及梯度模型设计

分析喷嘴冲蚀磨损特点，指出喷嘴的不同部位同时受到不同角度的冲击；磨料颗粒在喷嘴内部加速运动，喷嘴沿长度方向的磨损程度不同，喷嘴人口磨损最严重，出口次之，而中间区域磨损相对较轻。阐述陶瓷喷嘴冲蚀磨损机理，说明陶瓷喷嘴两端承受以高冲击角为主的冲蚀，磨损机理以应力疲劳断裂和脆性断裂为主；喷嘴中部承受低角冲蚀，微切削冲蚀磨损为其主要磨损机理，得到喷嘴磨损属于多冲蚀磨损机理并存的结论。在此基础上，提出均质材料难以适应喷嘴冲蚀磨损特点，不易满足喷嘴高抗冲蚀磨损性能要求的观点。基于梯度功能技术思想首次提出梯度功能喷嘴设计方法，并建立梯度功能喷嘴设计模型。

RESEARCH FOR THE RESIST WAYS OF NOZZLES EROSION WEAR AND DESIGN GRADIENT MODELS

The nozzle erosion wear characteristics were analysed. Different positions of the nozzle are bear with blast by different impact angles.Sports within the nozzle of abrasive particle are a course accelerated,and speed is a variable.The erosion wear degree of nozzle is different along the length direction.The nozzle erosion wear is most serious at the entrance.In the middle,the erosion wear is not very obvious.The erosion wear of nozzle exit is a bit more serious than of the middle of nozzle.Ceramic nozzle was regarded as research object to explain nozzle erosion wear mechanisms.Nozzle both entrance and exit were proved to bear with high impact angles,and the main erosion wear mechanisms is the stress fatigue and brittle fracture.Nozzle bear the low impact angles in the middle of it,and micro-machining is its main erosion wear mechanism.The results show that the nozzle erosion wear mechanisms belongs to coexisting of more erosion wear mechanisms.On this basis,the ways to control and reduce the nozzle erosion wear were researched by combining the mechanism and the characteristics of the nozzle erosion wear closely.It was found that the same kind nozzle material is difficult to be fit for the characteristic of nozzle erosion wear,and to meet the need of high resisting the erosion wear.Based on the technological idea of the function gradient material(FGM),it is firstly have proposed the design method and set up the design model of the function gradient nozzle.