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Tuesday, July 21, 2020 | History

2 edition of Vibrations of shrouded turbine blades. found in the catalog.

Vibrations of shrouded turbine blades.

Kraus, Paul.

Vibrations of shrouded turbine blades.

by Kraus, Paul.

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Published .
Written in English


Edition Notes

ContributionsManchester Polytechnic. Department of Mechanical Engineering, Design and Manufacture.
ID Numbers
Open LibraryOL20070247M

Abstract. The tip leakage flow losses of the shrouded rotor blade contribute significantly to overall losses of the turbine stage. Effects of the shrouded rotor blade tip leakage flow in stator blade/shrouded rotor blade/stator blade on the aerodynamic performance of a axial turbine stage were numerical investigated using commercial CFD software CFX-TASCflow. In order to predict the resulting vibration amplitudes, a reduced order model of a shrouded turbine blading is presented including a contact model to determine the nonlinear contact forces. To compute the forced response, the resulting nonlinear equations of motion are solved in the frequency domain using the multiharmonic balance method.

FIGURE 5 is a perspective view of the shrouded blade tip of a gas turbine blade with a further form of shroud for receiving vibration-resisting wires, FIGURE 6 is, on a smaller scale, a view of the upstream face of a bladed turbine disc provided with shrouded rotor blades according to FIGURE 5, and. Meherwan P. Boyce, in Gas Turbine Engineering Handbook (Fourth Edition), Turbines. The first-stage turbine nozzle vanes can be superficially inspected by the use of a borescope for bowing by entering the turbine through the combustion chamber areas or by removing inspection plates. In certain size turbines (and by somewhat difficult maneuvering) the last row of turbine rotating blades.

A 'shrouded', 'cowled', 'ducted' or 'wind lens' turbine is one that is housed in a ring-shaped aerofoil that increases airflow through the turbine blades' swept area by generating a localised ring vortex. Such systems can increase the power of a Horizontal-Axis Wind Turbine by times, for a given blade diameter and the use of an engine duct in aircraft design is considered a. 4. The method of claim 1, wherein determining the vibration characteristic of the shrouded turbine blade comprises determining whether the shrouded turbine blade has a vibration mode shape with an anti-node at the corner. 5. The method of claim 1, wherein the corner is cut substantially adjacent a curved fillet connecting the airfoil to the.


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Vibrations of shrouded turbine blades by Kraus, Paul. Download PDF EPUB FB2

Primary function of the shroud is to reduce blade vibration by limiting the motion of the blade tip. During turbine operation the centrifugal force of the blade is large enough to consider the blade as built-in at the root.

Also, there is generally a small gap between adjacent shrouds due to centrifugal and thermal growth of the blades and rotor. Therefore, the blades vibrate. this paper, this character of the interlocked shroud structure was utilized for measuring blade vibrations based on the BTT technique.

Sensors19, x FOR PEER REVIEW 3 of 17 Figure 1. Shrouded blades of the last stage in a steam turbine. The interlocked shroud structure of steam turbine blades is shown in Figure 2.

The edge between. Turbine blades are subjected to high static and dynamic loads. In order to reduce the vibration amplitude means of friction damping devices have been developed, e.g.

damping wires, interblade friction dampers and shrouds. This paper presents both numerical and experimental results for investigating the dynamical behavior of shrouded turbine by: 1. In this context, many researchers developed efficient numerical methods to calculate the vibration Vibrations of shrouded turbine blades.

book of bladed disks. In particular, shrouded bladed disks with frictional contacts present a major challenge in the design process. Beside efficient simulations, the validation process plays an important role in most recent : Ferhat Kaptan, Lars Panning-von Scheidt, Jörg Wallaschek.

On Forced Vibration of Shrouded Turbine Blades Numerical predictions of the forced vibration of a disc assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process. Assuming a tuned disc assembly, numerical static, free and then forced vibration analyses of a shrouded.

Abstract. translated from. A shrouded turbine blade vibration monitoring system is comprised of a plurality of sensors for sensing a profile of a turbine blade row. A microprocessor compares the. Numerical predictions of the forced vibration of a disk assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process.

Assuming a tuned disk assembly, numerical static, free, and then forced vibration analyses of a shrouded turbine blade measured in the spin pit are performed.

The nonlinear dynamic analysis of shrouded turbine blade with combination effect of impact and friction between shrouds is presented in this paper. Adding shrouds to blade is for vibration reduction. It is very complex to analyze nonlinear dynamics in the presence of nonlinearities such as nonlinear resilience of springs and piecewise linearity.

Abstract The impact vibration between shrouded turbine blades in an aero-engine is analyzed in this paper to study the influence of the parameters on the dynamic behavior.

To investigate the impact vibration, a model composed of springs and a cantilever beam carrying a mass is developed to simulate the shrouded turbine blade in aero-engines.

Numerical predictions of the forced vibration of a disc assembly including frictional effects between the shrouds are presented concerning engineering needs for the blade design process.

Assuming a tuned disc assembly, numerical static, free and then forced vibration analyses of a shrouded turbine blade measured in the spin pit are performed.

A system for monitoring the vibration of a plurality of shrouded turbine blades carried by a rotor and configured in a row includes a stationary sensor for inducing eddy currents in each shroud segment as each shroud segment passes the sensor.

A target is located on each shroud segment for causing variations in the induced eddy currents. However, the apparatus disclosed in that patent cannot be used on shrouded turbine blades because the shroud located at the periphery of the blades shields the blade tips from the sensors. Another technique for monitoring blade vibration designed for monitoring the vibration of shrouded turbine blades is disclosed in U.S.

Pat. 4,   High cycle fatigue damage caused by resonance and forced vibration can significantly affect the life and reliability of turbine rotor blades in aero-engines. The friction damper has been widely used to reduce the resonant stress of blades, on which the turbine blade shroud dampers are highly used.

In order to solve the problems of vibration damping analysis and design of shrouded blades dampers, an analytical method without complex and time-consuming nonlinear vibration.

The blade tip timing (BTT) technique could resolve this problem because it has the advantage of measuring all blades’ vibrations. This article proposed an improved BTT technique for measuring synchronous vibrations of shrouded blades in a steam turbine based on.

turbine shrouded blades. The proposed method utilizes the time-frequency processing (cross spectra) to analyse the data from the optical and magnetoresistive sensors, which are mounted in the stator radially above the rotor blades.

Fundamentally, the blade vibrations are detected during the blade passages under the sensors and the. Janecki, S. and Krawczuk, M. () The reciptance effect in the integral shroud interfaces on the eigen vibration of the steam turbine blade packets, in J.

Badur et al. (eds). Modelling and Design in Fluid-Flow MachineryInstitute of Fluid-Flow Machinery, Gdańsk, pp– Google Scholar. A Non-intrusive Stress Measurement (NSMS) was developed to measure coupled vibration on turbine blades.

These systems can report the actual stresses seen on the blades; detect synchronous resonances that are the source of High Cycle Fatigue (HCF) in blades; measure individual blade mistuning and even help separate complicated, coupled resonances in bladed disks.

Turbine trips on high vibrations This event had occurred approximately 1 month before the failure of the turbine blade. 0 0 20 40 60 80 (Focused on first or last blade of shroud group / 1st bearing).

The blade tip timing (BTT) technique could resolve this problem because it has the advantage of measuring all blades' vibrations. This article proposed an improved BTT technique for measuring synchronous vibrations of shrouded blades in a steam turbine based on fiber optical sensors with lenses.

The analysis and simulation of turbomachinery blade vibration is outside the scope of the book, but a simplified description can be helpful. The main sources of blade vibration are the vibration of the shaft and vibration-inducing mechanisms of the flow, such as surge or stall.

The test rig, which accommodates a group of 4 shrouded blades of a low pressure steam turbine, has been accurately analysed by means of linear and non linear finite element analyses, in order to explore different operating conditions that the blades could experience during operation.

The main results of this analysis are here presented.The forced excitation of the rotor blades of a single-stage turbine due to rotorstator interaction is calculated with an in-house unsteady flow solver and a general purpose finite element code. A scaled configuration is used in order to reduce the amount of computational effort.

The unsteady flow solution is obtained on three blade-to-blade cuts.The invention discloses a turbine blade vibration characteristic testing and measuring device with a shroud damping block and a blade root wedged damping block. The device comprises a test foundation rack, a blade root contact surface pressure load applying mechanism, a centrifugal force applying mechanism for the blade root wedged damping block and the shroud damping block, an exciting .