基于能量法的篦齿封严环气弹稳定性数值研究

Numerical study on aeroelastic stability of labyrinth seal ring based on energy method

关键词:  篦齿封严环  气弹稳定性  能量法  进气畸变  气动功

Key words:  Labyrinth seal ring  Aeroelastic stability  Energy method  Intake distortion  Aerodynamic power

摘要:

针对航空发动机篦齿封严环气弹稳定性问题，采用基于三维插值及非定常动网格技术的能量法，建立了篦齿封严环气弹稳定性数值求解模型。在验证数值方法准确性的基础上，研究了供气压力、转速和进气畸变对篦齿封严环气弹稳定性的影响，分析了篦齿封严环气动力、气动功分布特性，揭示了进气畸变对篦齿封严环气弹稳定性的影响机理。研究表明：在本文研究中，外篦齿封严环相对于内篦齿封严环更易发生气弹失稳；随供气压力增加，外篦齿封严环气弹稳定性呈现降低趋势，当供气压力为0.55 MPa和0.7 MPa时，外篦齿封严环存在气弹失稳的风险；转速2 000 r/min和4 000 r/min相对于6 000 r/min具有更大的气弹失稳风险。相比于360°圆周进气，90°圆周进气的外篦齿封严环气动力存在相互抵消的耦合作用，所以90°圆周进气的外篦齿封严环具有较高的气弹稳定性。篦齿封严环在发生气弹失稳时，齿腔底部做功占总气动功百分比会显著增加，故在进行结构优化时，可改变齿腔底部的结构参数以对篦齿封严环气弹稳定性进行改善。

Abstract:

Aiming at the aeroelastic stability problem of labyrinth seal ring of aero-engine， a numerical solution model for the aeroelastic stability of the labyrinth seal ring was established by using the energy method based on three-dimensional interpolation and unsteady dynamic grid technology. On the basis of verifying the accuracy of the numerical method， the effects of supply pressure， rotational speed and intake distortion on the aeroelastic stability of the labyrinth seal ring were studied. The aerodynamic force and aerodynamic power distribution characteristics of labyrinth seal ring were analysed. The influence mechanism of intake distortion on the aeroelastic stability of labyrinth seal ring was revealed. The results show that the outer labyrinth seal ring is more prone to aeroelastic instability than the inner labyrinth seal ring in this study. With the increase of gas supply pressure， the aeroelastic stability of the outer labyrinth seal decreases. When the gas supply pressure is 0.55 MPa and 0.7 MPa， the outer labyrinth seal ring has the risk of aeroelastic instability. Compared with 6 000 r/min， 2 000 r/min and 4 000 r/min have greater risk of aeroelastic instability. Compared with outer labyrinth seal ring of 360° circumferential gas intake， the aerodynamic force of the 90° circumferential gas intake offsets each other. Therefore， the labyrinth seal ring of 90° circumferential gas intake has higher aeroelastic stability. When the aeroelastic instability occurs， the percentage of the work done by cavities’ bottom wall in the total aerodynamic work change obviously. Therefore， the aeroelastic stability of the labyrinth seal ring can be improved by changing the structure parameters of cavities’ bottom wall in the structural optimization.