Dynamic analysis of C/C composite finger seal

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2016

Self Cite

With the development of science and technology, the performance of an aero-engine has been given more rigorous requirements. Seal device is an important component part of an aero-engine, and the improvement in its performance may be an efficient way to further improve the performance of an aero-engine. Finger seal is a flexible seal and has higher performance price ratio, therefore it gets more attention and research recently. The phenomenon of noncontact state converting to contact state will occur in every working cycle of finger seal that inevitably lead to the finger seal bearing the impact effect of rotor. But so far, the influence of impact on the finger seal performance has not been discussed and researched. To overcome this shortcoming, the stress–strain curves of C/C composite under different impact velocities are obtained by the Gleeble3500 thermo-simulator system in the paper, and then the elastic modulus of C/C composite in three directions is calculated by experimental data. The effects of impact velocity and impact damping on the impact force are analyzed by means of the impact theory. The new structural stiffness of finger seal and the impact displacement excitation of the rotor are built through impact effect analysis. On this basis, the equivalent dynamic model of C/C composite finger seal with distributed mass is established to evaluate the impact effect. By the model, the difference of calculated results is analyzed under whether considering the impact effect or not. And the effect of impact velocity and coefficient of restitution on the dynamic performance of the finger seal is also analyzed under considering the impact effect, respectively. The above results show that the impact effect has significant influence on the leakage and wear of finger seal, therefore when the performance of the finger seal was analyzed, it is necessary to consider the impact effect.

Section: Equivalent Dynamic Model Of Finger Sealmentioning

confidence: 99%

Impact dynamic analysis of C/C composite finger seal

Wang

Proceedings of the Institution of Mechanical Engineers, Part G:

et al. 2016

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“…Each sheet element is rotated relative to its adjacent element so that the gaps between the fingers of one element are covered by the fingers of the adjacent element to eliminate gas leakage. In Figure 1(b), the finger seal assembly consists of the back plate (8), the forward plate (9), the high pressure finger laminate (10) and the low pressure finger laminate (11), fixed with rivet (7) throughout the seal. The back plate serves as an axial support against bending when the finger laminates are under pressure differential (P H > P L ).…”

Section: Structural Fe Model Of Finger Sealmentioning

confidence: 99%

“…in aircraft, because of their low weight, excellent thermal and mechanical properties, and selflubricating capability. [5][6][7][8][9][10] Therefore, Chen et al 11 investigated the influence of material design parameters on leakage and contact pressure of the C/C composites finger seal without considering the seal wear. However, during the continuous rotation, the finger seal and the rotor are in contact and seal wear occurs.…”

Section: Introductionmentioning

confidence: 99%

“…29 For the finger seal, the Archard equation was used to predict seal wear, and the seal dynamic performances were obtained without considering the material loss. 11,30 In this study, the progressive wear of finger seal is investigated and the effects of material loss on seal performances are analyzed. First, a FE model for the C/C composite finger seal dynamic motion is presented and a modified Archard wear model is adopted to calculate the local wear rate of nodes on finger foot bottom.…”

Section: Introductionmentioning

confidence: 99%

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Progressive wear prediction of C/C composite finger seal based on ALE adaptive meshing strategy

Proceedings of the Institution of Mechanical Engineers, Part J:

et al. 2016

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Leakage clearance between the finger seal and the rotor is influenced by the seal wear, and a large leakage clearance may cause sealing failure. The aim of this study is to develop a predictive method to simulate the progressive wear of C/C composite finger seal. A finite element model is presented for the finger seal dynamic motion. A wear model is built by calculating the local wear rate for the nodes on finger foot bottom and by introducing an Arbitrary Lagrangian Eulerian adaptive meshing strategy. Progressive wear analysis is implemented by integrating the finger dynamic motion and the wear model. The results show that the contact pressure of finger seal is decreased and the leakage clearance is increased with operating time due to progressive wear. Compared to the case that the non-woven cloth is parallel to rotor surface (O1) and the case that the non-woven cloth is perpendicular to rotor surface but the laminated direction is perpendicular to sliding direction (O2), low leakage and low wear are obtained when the non-woven cloth is perpendicular to rotor surface and the laminated direction is the same as sliding direction (O3). In addition, the wear depth of finger foot and the leakage clearance between the finger seal and rotor are both increased with pressure differential and rotor speed.

“…Chen et al 10 studied the impacts of yarn density and yarn braided structure of C/C composite on the dynamic performance of finger seal, where the work supported the possibility of application of C/C composite in finger seal. Chen et al 11 analyzed the influence of structural parameters of C/C composite on the dynamic performance of finger seal with the distributed mass equivalent dynamic model, where a comparison was made with the performance of the Co-based alloy finger seal, and the result indicated that the C/C composite finger seal with low seal leakage and low wear could be acquired by reducing the leakage through the structure optimization design as the wear life was guaranteed. Wang et al 12 used the distributed mass equivalent dynamic model to study the effects of temperature on the finger seal, and found that the leakage rate decreased with the increase in temperature, but the wear increased.…”

Section: Introductionmentioning

confidence: 99%

Dynamic analysis of finger seal in the complex working state

Zhao

Proceedings of the Institution of Mechanical Engineers, Part G:

Wang

et al. 2017

Self Cite

With the development of aero-engine industry technology, the operating conditions for finger seal become more horrible, including that high temperature, assembly type of finger seal, rotor tilt, and impact of rotor coexist. Unfortunately, the coupled effect on the dynamic performance of finger seal is not studied in previous works for the dynamic of finger seal. In this paper, the parameters of equivalent dynamic model for finger seal, including the equivalent structure stiffness of finger stick, the contact stiffness between finger stick and rotor, the friction heat between finger boot and rotor and the rotor displacement excitation, are corrected when the coupled effect of rotor tilt, assembly condition, temperature, and impact are considered. In addition, the distributed mass equivalent dynamic model is developed for considering the complex working conditions (including rotor tilt, assembly condition, temperature effect, and impact effect). Based on this model, the dynamic performance of finger seal in the complex working state is analyzed, and the influence of the complex working state on the dynamic performance is also studied. The results indicate that effect of the complex working state on the leakage performance and wear performance of finger seal is complex. The work in this paper demonstrates the necessity of considering the complex working conditions in the analysis of the dynamic performance of finger seal.