Tip-Shroud Labyrinth Seal Effect on the Flutter Stability of Turbine Rotor Blades

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Roque Corral ◽  
Michele Greco ◽  
Almudena Vega
Keyword(s):  
Rotor Blade ◽  
Labyrinth Seal ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Labyrinth Seals ◽  
Turbine Rotor Blade ◽  
The Stability ◽  
Shrouded Rotor ◽  
Tip Shroud ◽  
The Impact

Abstract The effect of the tip-shroud seal on the flutter onset of a shrouded turbine rotor blade, representative of a modern gas turbine, is numerically tested, and the contributions to the work per cycle of the aerofoil and the tip shroud are clearly identified. The numerical simulations are conducted using a linearized frequency-domain solver. The flutter stability of the shrouded rotor blade is evaluated for an edgewise mode and compared with the standard industrial approach of not including the tip-shroud cavity. It turns out that including the tip shroud significantly changes the stability prediction of the rotor blade. This is due to two facts. First, the amplitude of the unsteady pressure created in the inter-fin cavity due to the motion of the airfoil is much greater than that of the airfoil. The impact of this contribution increases with the frequency. Second, the effect of the outer shroud of the rotor blade, which usually is not included either in the simulations, has an opposite trend with the nodal diameter than the airfoil reducing the maximum and minimum damping. It is concluded that the combined effect of the seal and its platform tends to stabilize the edgewise mode of the rotor blade for all the examined nodal diameters and reduced frequencies. Finally, the numerical results are shown to be consistent with those obtained using an analytical simplified model to account for the effect of the labyrinth seals.

Tip-Shroud Labyrinth Seal Effect on the Flutter Stability of Turbine Rotor Blades

2019 ◽  
Author(s):  
Roque Corral ◽  
Michele Greco ◽  
Almudena Vega
Keyword(s):  
Rotor Blade ◽  
Labyrinth Seal ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Stability Prediction ◽  
Labyrinth Seals ◽  
Turbine Rotor Blade ◽  
The Stability ◽  
Shrouded Rotor ◽  
Tip Shroud

Abstract The effect of the tip-shroud seal on the flutter onset of a shrouded turbine rotor blade, representative of a modern gas turbine, is numerically tested and the contribution to the work-per-cycle of the aerofoil and the tip-shroud are clearly identified. The numerical simulations are conducted using a linearised frequency domain solver. The flutter stability of the shrouded rotor blade is evaluated for an edgewise mode and compared with the standard industrial approach of not including the tip-shroud cavity. It turns out that including the tip shroud significantly changes the stability prediction of the rotor blade. This is due to the fact that the amplitude of the unsteady pressure created in the inter-fin cavity, due to the motion of the airfoil, is much greater than that of the airfoil. It is concluded that the combined effect of the seal and its platform tends to stabilise the rotor blade for all the examined nodal diameters and reduced frequencies. Finally, the numerical results are shown to be consistent with those obtained using an analytical simplified model to account for the effect of the labyrinth seals.

3D Woven Carbon/Glass Hybrid Spar Cap for Wind Turbine Rotor Blade

2006 ◽  
Vol 128 (4) ◽  
pp. 562-573 ◽  
Author(s):  
Mansour H. Mohamed ◽  
Kyle K. Wetzel
Keyword(s):  
Wind Turbine ◽  
Carbon Fibers ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Constant Thickness ◽  
Turbine Rotor Blade ◽  
Parametric Studies ◽  
The Impact ◽  
Wind Turbine Rotor

This paper presents the design and analysis for a spar cap for a wind turbine rotor blade. The cap is formed of an integral, unitary 3D woven material (3WEAVE®) having constant thickness; spar cap weight is varied and controlled by appropriately tapering the cap width from the blade root to tip. This analysis is employed for 24-m and 37-m rotor blades. These studies are conducted parametrically, examining a range of 3WEAVE® materials incorporating varying fractions of glass and carbon fibers, and hence exhibiting a range of structural properties and material costs. These parametric studies are used to determine the impact on blade weight and cost resulting from the various materials studied. Detailed results are presented in the form of tables to enable candidate materials to be evaluated as they are developed.

Investigation of the Impact of Unsteady Turbulence Effects on the Aeroelastic Analysis of a Low-Pressure Turbine Rotor Blade

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Jan Philipp Heners ◽  
Damian M. Vogt ◽  
Christian Frey ◽  
Graham Ashcroft
Keyword(s):  
Rotor Blade ◽  
Numerical Study ◽  
Turbulence Models ◽  
Gibbs Phenomenon ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Filter Method ◽  
Turbine Rotor Blade ◽  
Low Pressure Turbine ◽  
The Impact

Abstract The impact of the unsteadiness in the considered turbulence quantities on the numerical prediction of the aeroelastic behavior of a low-pressure turbine (LPT) rotor blade is evaluated by means of a numerical study. In this context, one of the main objectives of this work is to compare different nonlinear harmonic balance (HB) approaches—one neglecting and one considering the unsteadiness in the employed turbulence models—with a conventional nonlinear solver of the unsteady Reynolds-averaged Navier–Stokes (URANS) equations in the time domain. In order to avoid unphysical oscillations in the turbulence quantities caused by the Gibbs phenomenon in the chosen HB approach, a filter method based on the Lanczos filter is developed. The developed filter method is applied in the course of the HB simulations considering the unsteadiness in the underlying turbulence model. Furthermore, the impact of its application on the solution of the flow field and on the unsteady surface pressure of the rotor blade, in particular, is discussed in the context of this work.

Analysis and Evaluation of the Impact of Different Blade Loadings on a 2-Stage Turbine With Shrouded Blades

2011 ◽  
Author(s):  
Dieter Bohn ◽  
Stephan Schwab ◽  
Michael Sell
Keyword(s):  
Flow Field ◽  
Gas Turbines ◽  
Labyrinth Seal ◽  
Rotor Blades ◽  
Analysis And Evaluation ◽  
Passage Vortex ◽  
Flow Phenomena ◽  
Two Stages ◽  
Shrouded Rotor ◽  
The Impact

An important goal in the development of turbine bladings is to increase the efficiency in order to achieve an optimized use of energy resources. For that purpose a detailed understanding of flow phenomena is required. This paper presents an experimental investigation of the impact of varying blade loadings on the flow field and leakage flow. The investigations were conducted on a 2-stage axial turbine at the Institute of Steam- and Gas Turbines, RWTH Aachen University. The flow field for different blade loadings has been determined at the inlet and outlet as well as between the two stages. Consequently, the inhomogeneity at the outlet of each stage, depending on the blade loading, may be investigated. The homogeneity at the outlet has been evaluated by using the secondary kinetic energy coefficient and the formation of the passage vortex has therefore been emphasized. Furthermore, the loading impact on the leakage mass flow and the leakage main flow interaction has been estimated. On this account, the pressure loss in each cavity within the labyrinth seal of the first shrouded rotor blades is detected. The impact on the efficiency of different loadings has moreover been determined. The efficiency has been ascertained by using 5-hole probes and temperature probes after each stage. The investigations mentioned above have been conducted on a 2D-blade profile and serve as a baseline for future profiled end wall studies. The goal of the endwall contoured blades shall reduce the passage vortex and with it, the under- and overturning which ultimately leads to a more homogeneous outflow from the stage.

scholarly journals Numerical and Experimental Vibration Analysis of a Steam Turbine Rotor Blade

2021 ◽  
Vol 15 (4) ◽  
pp. 462-466
Author(s):  
Marko Katinić ◽  
Marko Ljubičić
Keyword(s):  
Numerical Model ◽  
Modal Analysis ◽  
Steam Turbine ◽  
Vibration Analysis ◽  
Rotor Blade ◽  
High Reliability ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Turbine Rotor Blade ◽  
Computer Environment

Damage to the rotor blade of a steam turbine is a relatively common problem and is one of the leading causes of sudden and unplanned shutdowns of a steam turbine. Therefore, the high reliability of the rotor blades is very important for the safe and economical operation of the steam turbine. To ensure high reliability, it is necessary to perform a vibration analysis of the rotor blades experimentally and in a computer environment. In this paper, a modal analysis was performed on the twisted blade of the last stage of the turbine in the Ansys software. The results of the modal analysis of the stationary rotor blade were compared with the results obtained by the bump test, which confirmed the numerical model of the blade. A modal analysis of a rotating rotor blade was performed on the same numerical model, and Campbell diagrams were plotted to determine the critical speed

Reason Research of the Low Impact Value of 2Cr11Mo1VNbN Ring Forging

2012 ◽  
Vol 184-185 ◽  
pp. 1150-1154
Author(s):  
Lei Gang Wang ◽  
Hong Chen ◽  
Yao Huang ◽  
Xi Gen Qian
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Energy Dispersive Spectroscopy ◽  
Niobium Carbide ◽  
Fracture Morphology ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Precipitated Phase ◽  
The Stability ◽  
The Impact

2Cr11Mo1VNbN steel was mainly used in the manufacture of turbine rotor blades, bolts, nuts and other important parts. However, in actual production, the impact value of their products often failed to meet requirements leaving the material scrapping. In this paper, through observation and analysis of the sample microstructure, fracture morphology and the precipitated phase by electron microscopy and energy dispersive spectroscopy, the results showed that: the low impact value of 2Cr11Mo1VNbN steel ring forgings was caused by the abnormal and large grain, uneven tissue and bulky niobium carbide exhalatted from grain boundary which was serious damage to the stability of grain boundary.

Lateral Forces From Single Gland Rotor Labyrinth Seals in Turbines

2004 ◽  
Vol 126 (3) ◽  
pp. 626-634 ◽  
Author(s):  
Bum Ho Song ◽  
Seung Jin Song
Keyword(s):  
Axial Direction ◽  
Labyrinth Seal ◽  
Turbine Stage ◽  
Labyrinth Seals ◽  
Flow Response ◽  
Lateral Forces ◽  
Downstream Flow ◽  
Shrouded Rotor ◽  
Upstream Flow ◽  
Sealing Gap

Even though interest in labyrinth seal flows has increased recently, an analytical model capable of predicting turbine flow response to labyrinth seals is still lacking. Therefore, this paper presents a new model to predict flow response in an axial turbine stage with a shrouded rotor. A concentric model is first developed, and this model is used to develop an eccentric model. Basic conservation laws are used in each model, and a nonaxisymmetric sealing gap is prescribed for the eccentric model. Thus, the two models can predict the evolution of a uniform upstream flow into a nonuniform downstream flow. In turbines with concentric shrouded rotors, the seal flow is retarded in the axial direction and tangentially underturned. In turbines with eccentric shrouded rotors, flow azimuthally migrates away from and pressure reaches its peak near the maximum sealing gap region. Finally, the rotordynamic implications of such flow nonuniformities are discussed and compared against eccentric unshrouded turbine predictions.

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