Assessment of Analytical Predictions for Radial Growth of Rotating Labyrinth Seals
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Sivakumar Subramanian
und
B. V. S. S. S. Prasad
Abstract
Radial growth predictions of rotating labyrinth seals are conventionally obtained from one-dimensional analytical models. However, these predictions quantitatively differ within themselves by about 5-500 %. Simulations using three-dimensional finite element method (FEM) are carried out in this paper for a typical labyrinth seal, subjected to high rotational speed and temperature, for a range of radius-to-length ratio of the rotor. Taking the predicted values by FEM as reference, four analytical models are assessed and their errors are quantified. These errors are found to be independent of rotational speed and temperature but significantly vary with the radius-to-length ratio of the rotor. Based on this finding, simple analytical models, together with correction factor charts, are suggested.
Acknowledgement
The authors acknowledge the support of the Centre for Computational Fluid Dynamics and High Performance Computing Facility, IIT Madras. Also, the authors express their gratitude to the reviewers for the encouraging and insightful comments.
Nomenclature
- Abbreviation
- CG
centrifugal growth of rotor/seal
- FE
finite element
- FEA
finite element analysis
- LTE
linear thermal expansion
- RF
Roark’s formula
- RSD
rotating solid disk
- RTC
rotating thick cylinder
- SEPC
structural percentage error in energy norm
- TG
thermal growth of rotor/seal
- Notation
- b
width of the seal tooth (mm)
- C
initial clearance (mm)
- E
modulus of elasticity of the rotor material (GPa)
- h
height of the seal tooth (mm)
- L
length of the rotor/seal (mm)
- p
pitch of the seal tooth (mm)
- R
radius of the shaft (also inner radius of seal) (mm)
- R/L
radius-to-length ratio of rotor/seal
- RL
correction factor
- Ro
outer radius of rotor/seal (mm); Ro=R+h
- T
air temperature (°C)
- Ts
surface temperature of rotor/seal (°C); Ts=T
- Tref
reference temperature of rotor/seal (°C); Tref = 21 °C
- ΔT
thermal gradient (°C); ΔT=T‒Tref.
- UCG
radial deformation due to CG (mm)
- UTG
radial deformation due to TG (mm)
- α
thermal expansion coefficient for rotor/seal material (1/°C)
- Ν
Poisson’s ratio of the rotor/seal material
- Ρ
density of the rotor/seal material (kg/mm3)
- ω
angular speed of the rotor/seal (rad/s)
- Δ
percentage error (%)
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© 2018 Walter de Gruyter GmbH, Berlin/Boston
Artikel in diesem Heft
- Frontmatter
- Original Research Articles
- The Effect of Pulsed Injection on Supersonic Shear Layer Mixing in a Scramjet Combustor
- Entropy Generation Calculation of a Turbofan Engine: A Case of CFM56-7B
- Separation Control by Slot Jet in a Critically Loaded Compressor Cascade
- An Impingement Cooling Using Swirling Jets Induced by Helical Rod Swirl Generators
- Studies on Stepped Air Ejector Diffusers incorporating Heat Transfer Effects
- Assessment of Analytical Predictions for Radial Growth of Rotating Labyrinth Seals
- Ground Simulation of High Altitude Test of Turbo-Refrigeration Cycle
- Investigations on the Film Cooling of Counter-Inclined Film-Hole Row Structures for Turbine Vane Leading Edge
Artikel in diesem Heft
- Frontmatter
- Original Research Articles
- The Effect of Pulsed Injection on Supersonic Shear Layer Mixing in a Scramjet Combustor
- Entropy Generation Calculation of a Turbofan Engine: A Case of CFM56-7B
- Separation Control by Slot Jet in a Critically Loaded Compressor Cascade
- An Impingement Cooling Using Swirling Jets Induced by Helical Rod Swirl Generators
- Studies on Stepped Air Ejector Diffusers incorporating Heat Transfer Effects
- Assessment of Analytical Predictions for Radial Growth of Rotating Labyrinth Seals
- Ground Simulation of High Altitude Test of Turbo-Refrigeration Cycle
- Investigations on the Film Cooling of Counter-Inclined Film-Hole Row Structures for Turbine Vane Leading Edge
