Analysis and experimental study of leakage characteristics of rotating seal ring
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摘要:
旋转密封环在航空发动机中阻隔轴承腔低温引气与涡轮高温引气。为获得转速和进出口压比对密封效果的影响规律,搭建了高压比、高转速的实验台。通过多截面参数测量,结合密封间隙、接触面润滑对比实验,分析了泄漏特性演变规律。结果表明,转速由0 r/min升至
10000 r/min(压比2.5)时泄漏量减少36.4%,而压比从1.1增至2.5(10000 r/min)导致泄漏量增长91.8%;装配间隙在0.5 mm公差范围内影响小于5%,增加润滑涂层使泄漏量降低15~60%。数值仿真表明,实验工况下转速提升导致平均接触应力增加最大1.24 MPa,改善了密封效果,摩擦因数增大会使平均接触应力降低超过1.35 MPa,不利于密封。研究揭示了转速与密封性能的定量关系及润滑的增效机制,为航空发动机旋转密封设计提供了依据。Abstract:Rotating seal ring are used in aero engines to block low-temperature bleed air in the bearing cavity from high-temperature bleed air in the turbine. In order to obtain the influence of rotation speed and inlet and outlet pressure ratio on the sealing effect, an experimental system with high pressure ratio and high speed was built. Through the measurement of multi-section parameters, combined with the comparative experiments of sealing clearance and contact surface lubrication, the evolution law of leakage characteristics was analyzed. The results show that the leakage is reduced by 36.4% when the rotation speed is increased from 0 to
10000 r/min (pressure ratio 2.5), and the leakage increases by 91.8% when the pressure ratio is increased from 1.1 to 2.5 (10000 r/min). The assembly clearance affects less than 5% within the 0.5mm tolerance, and the addition of lubricating coatings reduces leakage by 15-60%. Numerical simulations show that the average contact stress increases by up to 1.24 MPa under the experimental conditions, which improves the sealing effect, and the increase of friction coefficient reduces the average contact stress by more than 1.35 MPa, which is not conducive to sealing. The quantitative relationship between rotational speed and seal performance and the efficiency mechanism of lubrication are revealed, which provides a basis for the design of rotary seals for aero engines.-
Key words:
- secondary air system /
- rotating seal ring /
- leakage characteristics /
- rotational speed /
- contact stress
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表 1 主要参数的不确定度
Table 1. Uncertainty of the main parameters
参数 不确定度(%) 密封环泄漏量mr 4.4 有效泄漏面积Aeff 4.6 换算流量$ \lambda $ 4.5 -
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