Experimental and Numerical Investigation of the Flow in a Low-Pressure Industrial Steam Turbine With Part-Span Connectors

Häfele, Martin; Traxinger, Christoph; Grübel, Marius; Schatz, Markus; Vogt, Damian M.; Drozdowski, Roman

doi:10.1115/1.4032205

Cited by 5 publications

(8 citation statements)

References 13 publications

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“…Traupel 15 ) are normally used to determine the efficiency losses. More detailed numerical and experimental studies on the flow impact of part-span connectors in LP steam turbine blading have recently been published by Ha¨fele et al [16][17][18] Depending on the size and position of the elements, an efficiency decrease of several percentage points must be expected. 17…”

Section: Damping Elements Developmentmentioning

confidence: 99%

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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:

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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.

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Section: Damping Elements Developmentmentioning

confidence: 99%

“…The test rig setup is shown in Figure 2. Further details can be found in Ha¨fele et al [16][17][18] The turbine is equipped with various temperature and pressure probes for a complete thermodynamic evaluation. Moreover, strain gauges are applied to several moving blades of the rows.…”

Section: Test Rigmentioning

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:

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“…Here, O-grids around blades and PSC profiles are used. Further details can be found in Ha¨fele et al 1,2 In order to perform a study on the aerodynamic effects of geometrical variations of PSCs using hexahedral meshes, the CAD model and meshing procedure which have been formerly used need to be adjusted. Because of the time-consuming grid generation, it is inconvenient to create a new mesh for every single PSC configuration.…”

Section: Parameterization and Grid Generationmentioning

confidence: 99%

“…The impact of PSCs on aero-thermodynamics in wet steam flow has been studied by Ha¨fele et al 1 and details of the hexahedral mesh-generation for LP blades with PSC are shown in Ha¨fele et al 2 These former numerical investigations showed the complexity of the three-dimensional (3D) flow field in LP stages with PSCs mounted between rotor blades. Furthermore, the blockage of the steam flow due to the PSC within the blade channel and related blade design aspects have been discussed.…”

Section: Introductionmentioning

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:

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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.

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“…In these cases boundary conditions are based above all on measurements of experimental steam turbines, e.g. [7].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Research on Flow in the Last Stage of 1090mw Steam Turbine

Hoznedl¹,

Sedlák²

2018

APP

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The paper deals with experimental and numerical research in the last stage of real 1090MW steam turbine with the last steel blade length 1220mm placed in nuclear power station. The last stage was equipped with twelve static pressure taps. It was also possible to probe in two planes - before and behind the last stage using pneumatic or optical probes. A number of last stage flow parameters were determined at the root and tip wall for nominal turbine output. Among those parameters are static pressures, Mach and Reynolds numbers, last stage reactions and steam wetness. All the directly measured and evaluated flow parameters are taken from locally measured points and that is why even 3D CFD calculation of the whole system - last stage, diffuser and exhaust hood was implemented. Measured and calculated parameters are compared. Especially static pressures are in very good agreement; the only steam wetness has bigger difference due to different measurement position. Locally measured values are enough to estimate the flow behavior of the last stage. On the other hand, the CFD simulations with well determined boundary conditions, meshes and geometry and is effective tool to simulate even very complicated flow structures in the last stage and exhaust hood.

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Experimental and Numerical Investigation of the Flow in a Low-Pressure Industrial Steam Turbine With Part-Span Connectors

Cited by 5 publications

References 13 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

Experimental and Numerical Research on Flow in the Last Stage of 1090mw Steam Turbine

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