| The aircraft engine is known as the "heart" of the aircraft and consists of thousands of precision parts.The air bleed valve is an important component of the bleed air system in the aircraft engine.Its function is to draw out the extra air in the compressor to prevent engine surging,and at the same time use the extracted air for the downstream air system of the aircraft.Accurate and rapid adjustment and stable and reliable operation are necessary functions and characteristics for the air bleed valve,and its performance improvement is of great significance to the overall performance of the bleed air system.In this dissertation,aiming at the complex working environment high temperature and high pressure of the air bleed valve,the multi-field coupling simulation method is adopted to study the flow field characteristics,structural deformation and dynamic characteristics of the air bleed valve,dedicating to provide theoretical and technical support for the optimal design of the air bleed valve.Mainly carried out the following work:(1)The force analysis of the air bleed valve is carried out,considering the compressibility of the gas medium and the influence of the vent on the air pressure in the dynamic process of the spool,the air pressure model of the middle cavity of the spool and the flow model of the vent is established,and then the release is derived.The dynamic model of the valve core of the air valve lays the foundation for the study of the dynamic characteristics of the air bleed valve.(2)Aiming at the problem that the force of the bleed valve spool changes with the opening of the air bleed valve,the force is unknown.Using the Fluent flow field modeling and simulation method,the flow field characteristics of the bleed valve under different openings are analyzed,and the bleed volume and the valve are obtained.The quantitative relationship of the opening degree of the port,and at the same time,the gas pressure change law of the working chamber when the valve core changes with the opening degree of the valve port is obtained.(3)Considering the comprehensive effect of the external environment and internal medium of the air bleed valve,a one-way thermal-fluid-solid coupling simulation model of the air bleed valve is established,Focus on the analysis of the change law of the clearance between the air bleed valve core and the shell under high temperature and high pressure environmental conditions,providing theoretical and technical support for the optimization of the anti-blocking design of the bleed valve structure.(4)Based on AMESim platform,on the basis of mathematical modeling and flow field simulation,setting up the air bleed valve dynamic characteristic simulation model of valve core quality,control cavity leakage flow,the size of the air holes,the parameters of the spring and the valve core diameter ratio on the valve dynamic characteristic were analyzed,clarifying the key factors and influence rule affecting the air bleed valve dynamic characteristic,and the influence of structural deformation on dynamic performance,providing technical support for the forward design and structural optimization of the air bleed valve. |
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