Experimental and Numerical Investigation of the Nonlinear Vibrational Behavior of Steam Turbine Last Stage Blades With Friction Bolt Damping Elements

Drozdowski, Roman; Völker, L.; Häfele, Martin; Vogt, Damian M.

doi:10.1115/gt2015-42244

Cited by 9 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, an experimental and numerical investigation of the nonlinear vibrational behavior of steam turbine last stage blades with friction bolt damping elements was recently published by Drozdowski et al 14 A comprehensive calculation procedure, including linear and nonlinear FEA to predict maximum vibration amplitudes in a forced response assessment, is shown. According to the authors, the good agreement of calculation results and experimental data, obtained from strain gauge and tip timing measurements in a full-scale test turbine under real steam conditions, is encouraging and gives confidence for applying the method in daily steam turbine blade design processes.…”

Section: Damping Elements Developmentmentioning

confidence: 99%

Numerical and experimental analysis of low-pressure steam turbine blades coupled with lacing wire

Drozdowski¹,

Völker

Häfele

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

Many industrial steam turbine applications require the capability for variable speed operation in combination with high mass flow rates and high back pressure levels. Especially the low-pressure blading has to be designed carefully with respect to the mechanical integrity. An effective way to reduce blade vibration is the introduction of a simple lacing wire to couple the moving blades. In this paper, the structural behavior of blades coupled by a wire is verified by means of linear and nonlinear finite element method. Different modeling techniques for the coupling effects are presented and discussed. Special focus is put on the nonlinear effects of the contact between blade and wire to investigate the frictional damping performance of the system. The obtained numerical results are validated by strain gauge measurements on a full-scale test turbine under real steam conditions in an industrial steam turbine test rig. The experimental data show low blade vibration amplitudes in the whole operational range indicating a high damping performance of the investigated wire design. The calculation results from the forced response analysis including the frictional effects are in good agreement with the experimental data.

show abstract

Section: Damping Elements Developmentmentioning

confidence: 99%

Numerical and experimental analysis of low-pressure steam turbine blades coupled with lacing wire

Drozdowski¹,

Völker

Häfele

et al. 2016

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

show abstract

“…Figure 5 shows a sketch of the investigated LP blade with reinforcements and a conical friction bolt, including all relevant parameters of the PSC model. Besides this, it is noteworthy that information about the mechanical performance of reference configuration V1 is provided by Drozdowski et al, 17 who investigated the vibrational behavior of this LP blade.…”

Section: Parameterization and Grid Generationmentioning

confidence: 99%

Numerical and experimental study on aerodynamic optimization of part-span connectors in the last stage of a low-pressure industrial steam turbine

Häfele

Traxinger

Grübel

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

Industrial steam turbines are operated over an extremely wide range of operating conditions. In order to ensure safe turbine operation, even in blade resonance condition, conical friction bolts are mounted between blade reinforcements of adjacent last stage low-pressure blades. These part-span connectors (PSC) provide blade damping and coupling. However, additional losses are generated, which affect the performance of the turbine. In this paper, a numerical and experimental study on aerodynamic optimization of PSCs is presented. State-of-the-art three-dimensional computational fluid dynamics (CFD) applying a non-equilibrium steam model is used to examine the wet steam flow in coupled last stage blading. The one-passage CFD model with parameterized PSC geometry features structured high-resolution hexahedral meshes. Experimental data of measurements with pneumatic multi-hole probes in an industrial steam turbine test rig are used for validation. According to the good agreement between measured and predicted flow field downstream of the last stage rotor blading, the CFD model is valid to capture the loss induced by the PSC. A numerical study on the aerodynamic effects of geometrical variations of PSCs concerning blockage area and shape is presented in this work. Based on this study, a performance assessment of different PSC designs is discussed and numerical results are compared to the loss coefficients predicted by Traupel's analytical correlation, which is widely used in industry.

show abstract

“…Many experimental studies were performed to identify the key flutter parameters [1,2], and numerical solvers were used to predict turbine blade flutter [3][4][5]. In addition, effective ways to keep steam turbine last stage blades' vibration amplitudes low were also proposed [6]. Since flutter occurrence can lead to severe failures, it is essential to predict this aerodynamic instability when designing modern last-stage steam turbine rotor blades with flexible operating conditions and high backpressures [7].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Flutter Test Rig for a Transonic Flow in a Linear Turbine Blade Cascade and Numerical Data Validation

Tsymbalyuk,

Eret,

Slama

et al. 2023

European Conference on Turbomachinery Fluid Dynamics and Thermodynamics

View full text Add to dashboard Cite

Modern, efficient and robust steam turbines must be designed for large operating ranges and often run at off-design conditions and high backpressures. Therefore, there is a danger that in some operating conditions, last-stage rotor blades can suffer from self-excited vibration known as flutter leading to severe failures of rotor blades or entire turbine units. In order to avoid this, the design of aerodynamically stable last-stage rotor blades became a major topic for all steam turbine manufacturers and a validated numerical model for flutter prediction during the blade preliminary design phase is required. As flutter measurement is difficult in real turbines, controlled flutter tests on simplified experimental models must be used. However, experimental flutter testing facilities are rare. This paper reports on a subsonic flutter test rig enhancement for transonic flow and numerical data validation of aerodynamic stability in a linear turbine blade cascade. A test case for transonic flow is presented at pure bending and torsion modes, and experimental results are compared to numerical simulations performed by commercial code ANSYS CFX. While the test section design upgrade from subsonic to transonic flow proves successful, the discrepancy between the experiment and CFD is found and must be investigated further. KEYWORDSSTEAM TURBINE, LINEAR BLADE CASCADE, FLUTTER, TRANSONIC FLOW NOMENCLATURE 𝐶 coefficient of forces or moments 𝐸 Young's modulus 𝐾 reduced frequency, experimental coefficient 𝑀 Mach number 𝑅 shell curvature radius 𝑅𝑒 Reynolds number 𝑉 velocity of the flow 𝑊 unsteady aerodynamic work 𝑏 blade chord ℎ blade length 𝑖 angle of incidence 𝑝 pressure difference 𝑞 dynamic pressure 𝑠 wall thickness 𝜙 phase shift 𝜔 oscillation frequency

show abstract

Experimental and Numerical Investigation of the Nonlinear Vibrational Behavior of Steam Turbine Last Stage Blades With Friction Bolt Damping Elements

Cited by 9 publications

References 0 publications

Numerical and experimental analysis of low-pressure steam turbine blades coupled with lacing wire

Numerical and experimental analysis of low-pressure steam turbine blades coupled with lacing wire

Numerical and experimental study on aerodynamic optimization of part-span connectors in the last stage of a low-pressure industrial steam turbine

Enhanced Flutter Test Rig for a Transonic Flow in a Linear Turbine Blade Cascade and Numerical Data Validation

Contact Info

Product

Resources

About