摘要
针对应用于航空发动机的高速气膜镶装式浮环密封,探究密封在不同结构参数、启动方式、材料结合等多因素下的开启性能。建立镶装环-石墨环-跑道的固体域模型和气膜流体域模型,得到了工作气膜厚度、气膜流场压力分布;计算密封受力,得到了密封上浮力、闭合力和开启转速等密封开启性能参数。分析镶装环与石墨环的厚度比和宽度比、镶装环-石墨环配对材料、镶装环-跑道配对材料等因素对密封开启转速的影响。搭建浮环密封试验台和浮环位移监测系统,通过试验验证了数值模拟结果。研究结果表明:浮环的镶装结构能有效改善升温时石墨环与跑道间隙减小而导致密封失效的问题;镶装环材料是影响密封开启性能的敏感参数,密封开启性能随材料线膨胀系数的升高而快速降低;镶装环与跑道的材料配对情况是影响密封开启性能的重要因素,镶装环与跑道材料相同时,石墨环与跑道处于“恒间隙”状态,在复杂温度工况下密封的开启性能更加稳定;不同的工作机组启动方式对密封开启性能影响较大,发动机采用将转速增加至工况转速再增压的启动方式时密封开启性能最好;浮环密封在高转速、高压力工况下因转速、压力变化产生的密封扰动值更大,浮环密封应避免在较高压力和转速下长时间调节工况参数。研究结果为航空发动机镶装式浮环密封的结构设计、材料选用、系统设计的研究提供了参考。
This study investigates the inlaid floating ring seal with high-speed gas films in aeroengines,focusing on the opening performance of the seal with different structural parameters,starting modes,and material combinations.The solid domain model and the gas film fluid domain numerical analysis model of the inlay ring-graphite ring-runway are established,and the working gas film thickness and the pressure distribution of the gas film flow field are obtained.By calculating the seal force,the seal opening performance parameters,such as buoyancy,closing force and opening speed,are obtained.This study analyzes the effects of many factors on seal opening speed,such as the inlay-graphite ring thickness ratio and width ratio,and material matchings between the inlay and graphite rings and between the inlay ring and runway.A floating ring seal test bench and a floating ring displacement monitoring system are built,and the numerical simulation results are verified by experiments.Results show that the inlaid structure of the floating ring can effectively improve the sealing failure caused by the decrease of the gap between the graphite ring and runway when temperature rises.The material of the insert ring is a sensitive parameter,which affects the opening performance of seals.This performance decreases rapidly with the increase of the linear expansion coefficient of the material.The material matching between the inlay ring and runway is an important factor for the opening performance.When the inlay ring and runway have the same material,the graphite ring and runway are in a state with a “constant gap”,and the opening performance of the seal is more stable at complex temperatures.Results also show that start-up mode has great influence on the opening performance of seals,and that this performance is best when the engine is started by increasing the speed to the working speed and then pressurized.Therefore,floating ring seals should avoid adjusting operating parameters for a long time with higher pressure and speed.The resul
作者
郑娆
陈潇竹
李双喜
赵祥
施任杰
宋子锋
ZHENG Rao;CHEN Xiaozhu;LI Shuangxi;ZHAO Xiang;SHI Renjie;SONG Zifeng(College of Mechanical and Electrical Engineering,Beijing University of Chemical Technology,Beijing 100029,China)
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2022年第11期2111-2120,共10页
Journal of Beijing University of Aeronautics and Astronautics
基金
国家重点研发计划(2018YFB2000800)。
关键词
轴承腔密封
浮环密封
开启特性
恒间隙
运行稳定性
bearing cavity seal
floating ring seal
opening characteristics
constant gap
operation stability
