Brush seal contact force theory and correlation with tests
| Autor: | Ertuğrul Tolga Duran |
|---|---|
| Rok vydání: | 2022 |
| Předmět: |
Materials science
Friction business.industry Rotor (electric) Brush seal General Engineering Brush Structural engineering Bristle Tip Force Engineering (General). Civil engineering (General) Bristle Seal (mechanical) Turbine Contact force law.invention law Heat generation Turbomachinery Contact Force Pressurized rotor interference TA1-2040 business Rotary Test Rig |
| Zdroj: | Alexandria Engineering Journal, Vol 61, Iss 4, Pp 2925-2938 (2022) |
| ISSN: | 1110-0168 |
| Popis: | Brush seals are leakage performance systems that are operating against turbine shafts and bucket tips. Flexible bristle structure can compensate the rotor interference during transients, which enables closer clearance control in turbine and turbo-engine applications. During turbomachinery transients, contacting bristles exert force on turbine shaft, which in turn result in wear, frictional heat generation, counter torque and power loss. Brush seal design with proper stiffness has crucial importance since high bristle tip force levels during rotor contact may result in rotor instability, bristle tip melting or thermo-mechanical fatigue due to large amount of local frictional heat input. Counter torque applied by the contacting brush seal with improperly excessive tip force may result in turbine stall and overall efficiency losses. High levels of bristle contact forces may induce elevated wear rates, which degrades the leakage performance of the brush seal during its life cycle. Brush seal contact force evaluation under operating conditions has critical importance and has to be conducted before turbine integration to avoid performance losses and possible turbine failure in some extreme cases. In this paper, ‘Bristle Contact Force Theory’ is developed and closed form bristle tip force (BTF) function is derived where rotor-bristle, inter-bristle and bristle-back plate interactions are included. BTF measurements under pressurized and unpressurized air environment are conducted for the selected test seals by using the custom ‘Rotary Test Rig’. BTF function of bristle contact force theory show high level of correlation with the test data. The effect of cant angle manufacturing tolerance on bristle tip force levels is also examined through bristle tip contact force theory, and compared with the test seal measurements. Methodology for number of bristle row calculation and comparison with the geometric inspection of test seals are also detailed within the content of this paper. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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