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Review
. 2022;31(1-2):307-314.
doi: 10.1007/s11666-021-01298-5. Epub 2022 Jan 28.

Enhanced High-Temperature YSZ-polyester Abradable Honeycomb Seal Structures

P Pathak  1 , D Dzhurinskiy  1 , A Elkin  1 , P Shornikov  1 , S Dautov  1 , V Ivanov  2
Affiliations
Review

Enhanced High-Temperature YSZ-polyester Abradable Honeycomb Seal Structures

P Pathak et al. J Therm Spray Technol. 2022.

Abstract

The abradable coatings had significantly enhanced turbomachinery performance by acting as a sacrificial seal between rotating blades and stationary casing. Further improvement in seal design to meet the higher energy demand and increase the service time has been the key challenge to solve in the gas turbine industry. Honeycomb seals have become the industry standard clearance seal technique due to their unique design and high structural strength with minimum weight. The present study proposes a concept to form a thermal shock resistance structure to achieve higher temperature capability and improve the reliability of high-temperature abradable seal structures for a hot gas path of turbines. A cavity layer of honeycomb seal structure made of SS 321 alloy was coated with advanced high-temperature ZrO2 + 7.5%Y2O3 + 4% polyester seal material using TriplexPro-210 plasma spray system. The integrity of a seal structure was assessed by a cross-sectional analysis and evaluation of the coating microstructure. Additionally, the micro-hardness test was performed to estimate coating fracture toughness, and finite element analysis was used to assess its thermo-mechanical performance. The concept proposed in this study should be further validated to develop the most capable innovative technology for advanced gas turbine abradable seal structures.

Keywords: APS; YSZ; abradable coating; finite element analysis; gas Turbines; honeycomb Seal.

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Figures

Fig. 1
Fig. 1
Honeycomb dimensions and structure design representation: (a) dimensions of the honeycomb cell; (b) an overall model view
Fig. 2
Fig. 2
Boundary conditions used in FEA analysis: (a) thermal loading; (b) model constraints for stress analysis
Fig. 3
Fig. 3
Microstructure of Metco 2460NS coating layer deposited by APS to the substrate materials: (a) honeycomb substrate; (b) conventional substrate
Fig. 4
Fig. 4
SEM image of Vickers indent at 1 kgf load into Metco 2460NS coating layer. (a) Half of the diagonal indent length, (c) crack length from the indented center, (d) total diagonal length
Fig. 5
Fig. 5
Fracture toughness of deposited Metco 2460NS coating layers
Fig. 6
Fig. 6
The calculated temperature distribution in the honeycomb and conventional structures.
Fig. 7
Fig. 7
Two-dimensional map of the thermal stress distribution: (a) Heating cycle (b) Cooling cycle
Fig. 8
Fig. 8
Distribution of principal stress along Z mid-thickness line (see Fig. 7): (a) Heating cycle (b) Cooling cycle
See this image and copyright information in PMC

References

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