Static and Dynamic Analysis of 48″ Steel Last Stage Blade for Steam Turbine

2009 ◽  
Author(s):  
Tomas Misek ◽  
Zdenek Kubin ◽  
Karel Duchek
Keyword(s):  
Steam Turbine ◽  
Centrifugal Force ◽  
High Speed ◽  
Structural Damping ◽  
Static And Dynamic Analysis ◽  
Speed Test ◽  
Rotational Vibration ◽  
Eigen Frequencies ◽  
Last Stage ◽  
Vibration Tests

The 3000 rpm 48 inch blade for steam turbine has been developed with the application of new design features. The last stage moving blade was designed with integral cover, mid-span tie-boss connection, and fir-tree dovetail. Blades are continuously coupled by the blade untwist due to the centrifugal force, so vibration control and increased structural damping are provided. The last stage airfoil was optimized from view of minimization of its centrifugal force which helped to reach higher safety factors. The blade was well tuned in order to have eigen-frequencies safely away from possible excitation. Because of connection members, the number of the resonant vibration modes can be reduced by virtue of the vibration characteristics of the circumferentially continuous blades. In order to develop the 3000 rpm 48 inch blade, the latest analysis methods were applied to predict dynamic behavior of the bladed structure. Coupled rotor-blade analysis was also aim of the attention. To validate calculated results the verification measurement such as rotational vibration tests was carried out in the high-speed test rig. The test rotor was fitted with the actual full scale 48″ blades. Relation of the friction damping of the bladed structure on amount of excitation level was also monitored and evaluated.

Comparison of Blade Tip Timing With Strain Gauge Data for Evaluation of Dynamic Characterization of Last Stage Blade With Interlocked Shroud for Steam Turbine

2018 ◽  
Author(s):  
Jiamin Zhang ◽  
Peng Shan ◽  
Kai Cheng ◽  
Dechao Ye
Keyword(s):  
Steam Turbine ◽  
Strain Gauge ◽  
High Speed ◽  
Aircraft Engine ◽  
Dynamic Strain ◽  
Dynamic Characterization ◽  
Speed Test ◽  
Gauge Data ◽  
Last Stage

The tip-timing technology has been widely developed and has become an industry standard in aircraft engine and gas turbine over past decade. The main application of the tip-timing method is to verify safe operation of blades and monitor the health of blades. But tip-timing technology gets rarely used to the last stage blade of steam turbine. Particularly the blade is designed with an integral shroud, snubber and fir-tree root. The article mainly describes the process of identifying the dynamic characterization of last stage blade with an integral shroud and snubber by contactless measurements provided by tip-timing technology. Attention is focused on the comparison of tip-timing results with the results from strain gauge data. Firstly, the frequency response of the bladed blisk is calculated by using Computer-Aided-Engineering (CAE) technologies. Secondly, according to the results of finite element modal calculation, the location of strain gauge is confirmed. The dynamic strain of blade is measured by utilizing telemetry technology. Finally, according to the design features of integral shroud, the tip-timing probe locations must be accurately confirmed in order to acquire the valid data. All probes are positioned along the radial direction of blades. The rotating vibration test of the bladed blisk has been carried out in the high-speed test rig. In order to validate the tip-timing measurement, all the results from the tip-timing, especially the resonant frequencies and damping ratios, are compared with results from the strain gauges with which only a few blades were equipped.

Development and Verification of 3000 rpm 48 Inch Integral Shroud Blade for Steam Turbine

2005 ◽  
Author(s):  
Yasutomo Kaneko ◽  
Kazushi Mori ◽  
Hiroharu Ohyama
Keyword(s):  
Steam Turbine ◽  
Field Test ◽  
High Speed ◽  
Vibration Characteristics ◽  
Operating Conditions ◽  
Blade Design ◽  
Vibration Stress ◽  
Rotational Vibration ◽  
Verification Test ◽  
Vibration Tests

The 3000 rpm 48 inch blade for steam turbine was developed as one of the new standard series of LP end blades. The new LP end blades are characterized by the ISB (Integral Shroud Blade) structure. In the ISB structure, blades are continuously coupled by blade untwist due to centrifugal force when the blades rotate at high speed. Therefore, the number of the resonant vibration modes can be reduced by virtue of the vibration characteristics of the circumferentially continuous blades, and the resonant stress can be decreased due to the additional friction damping generated at shrouds and stubs. In order to develop the 3000 rpm 48 inch blade, the latest analysis methods to predict the vibration characteristics of the ISB structure were applied, after confirming their validity to the blade design. Moreover, the verification tests such as rotational vibration tests and model turbine tests were carried out in the shop to confirm the reliability of the developed blade. As the final verification test, the field test of the actual steam turbine was carried out in the site during the trial operation, and the vibration stress of the 3000 rpm 48 inch blade was measured by use of telemetry system. In the field test, the vibratory stress of the blade was measured under various operating conditions for more than one month. This paper first presents the up-to-date design technology applied to the design of the 3000 rpm 48 inch blade. In the second place, the results of the various verification tests carried out in the shop are presented as well as their procedure. Lastly, the results of the final verification tests of 3000 rpm 48 inch blade carried out in the site are presented.

Clearance and Seals Design for New Heat™ Steam Turbine

2006 ◽  
Author(s):  
Bernard A. Couture ◽  
Leslie B. Keeling ◽  
Mark W. Kowalczyk
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
High Efficiency ◽  
Labyrinth Seal ◽  
Mechanical Analysis ◽  
Advanced Technology ◽  
Speed Test ◽  
Steady State Operation ◽  
Thermal Mechanical Analysis ◽  
Abradable Coatings

The HEAT™ (High Efficiency Advanced Technology) steam turbine utilizes high reaction technology [1], which is significantly influenced by the effectiveness of sealing between the stages. The thermal-mechanical analysis based clearance design and the combination of labyrinth sealing with abradable coatings offer an effective solution to minimize bucket and nozzle tip leakage through transient and steady state operation of the turbine. The aim of this paper is to describe the clearance design process and the development of abradable-labyrinth seal configurations. The paper describes extensive testing and detailed analysis conducted to evaluate seal properties and behaviors. Properties investigated included corrosion, erosion and in particular, rub characteristics. Rub behavior is investigated in a high temperature, high speed test apparatus designed to simulate clearance changes during transient periods of start-up, shutdown and hot re-start which often result in interference between the sealing components. This paper will discuss the method to predict differential rotor to stator movements and the resulting abradable incursion during the various operating transients. The seal tooth to coating contact is then simulated with component testing for multiple incursion modes (i.e. radial, axial and a combination of the two) and rates. The discussion will also include the application of the clearance design and sealing technology to a reaction type steam turbine.

scholarly journals Turbine Cascades of Last Stage Blades for Wide Range of Operating Conditions

2019 ◽  
Vol 4 (4) ◽  
pp. 33 ◽  
Author(s):  
Ondrej Novak ◽  
Marek Bobcik ◽  
Martin Luxa ◽  
Jaroslav Fort ◽  
Bartolomej Rudas ◽  
...  
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Power Plants ◽  
Electric Energy ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Biomass Waste ◽  
Wide Range ◽  
Last Stage ◽  
Turbine Cascades

Recent trends in the electric energy market such as biomass, waste incineration or combined cycle power plants require innovative solutions in steam turbine design. Variable operating conditions cause significant changes in flow field surrounding the steam turbine last stage blades. Therefore, the enlargement of operating range for last stage blades presents new challenges in design of turbine cascades. Several turbine cascades were designed and analyzed by commercial and in-house software of CTU Prague. Selected profiles were experimentally validated in the high-speed wind tunnel for 2D cascade measurements of the Institute of Thermomechanics of the Czech Academy of Sciences which is equipped by an adjustable supersonic inlet nozzle, perforated inserts at side walls and adjustable perforated tailboard. Comparisons are presented of numerical results with optical and pneumatic measurements for a wide range of inlet and outlet Mach numbers for optimized hub and tip profile cascades.

Development of a Robust LP Blade Family for Variable Speed Applications

2018 ◽  
Author(s):  
Martin Schubert ◽  
Johannes Tusche
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Design Method ◽  
Suction Side ◽  
Operating Conditions ◽  
Subsequent Paper ◽  
Variable Speed ◽  
Design Changes ◽  
Last Stage ◽  
High Flexibility

Industrial steam turbine applications require a high flexibility in terms of aerodynamically as well as mechanically operating conditions. Mechanical drives run at variable rotor speeds and often face high backpressure levels, which is a particularly challenging aspect for the last-stage moving blade (LSMB) row of a low-pressure (LP) steam turbine. As speed synchronous blade resonances cannot be excluded over the entire operating speed range, the LSMB needs to be designed resonance proof from viewpoint of dynamics and mechanical strength. The subsequent paper describes a new developed LP stage group for variable speed applications, which is available as fully scaled blade family with distinct exhaust area and rotational speed limit reaching from conventional 3000rpm up to high speed utilities for special purposes. It consists of two standard stages, which can be operated at off resonance as well as resonance conditions. For that reason frictional elements were implemented in both moving blade rows. They are loosely assembled into pockets, which are placed on the pressure as well as suction side of each airfoil. Basically, this feature was already introduced for certain Siemens LP blades, see [1], [2], [3] and [4]. However, the recent development on this field utilizes several design changes for the benefit of robustness and reliability. The present paper focuses on the non-linear dynamic behavior of the friction damped, coupled blade rows and outlines the underlying design method as well as calculation process.

scholarly journals Failure Analysis in Lacing Wire Of Last Stage Low Pressure Steam Turbine Blade

2021 ◽  
Vol 1096 (1) ◽  
pp. 012097
Author(s):  
A M Kongkong ◽  
H Setiawan ◽  
J Miftahul ◽  
A R Laksana ◽  
I Djunaedi ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Low Pressure ◽  
Pressure Steam ◽  
Steam Turbine Blade ◽  
Last Stage

Paper 23: The Collision of Drops with Dry and Wet Surfaces in an Air Atmosphere

1969 ◽  
Vol 184 (7) ◽  
pp. 57-63
Author(s):  
G. J. Parker ◽  
E. Bruen
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
Size Range ◽  
Drop Surface ◽  
Wet Steam ◽  
Air Atmosphere ◽  
Made In

This paper describes an investigation into the behaviour of drops which impinge upon dry and wet surfaces. This is of particular interest in the context of the wet steam turbine. Two approaches have been made in the studies; these are: (1) Drops were made to impinge normally on to various types of dry, stationary surfaces. The drops were in the size range 300–1500 μm diameter with velocities of 2–9 m/s. (2) Drops were made to impinge on to surfaces moving with considerable velocity at right angles to the motion of the drop. Surface velocities ranged up to 45 m/s. The latter study is of direct interest for the splashing of drops on turbine casings at small glancing angles, as occurs near drainage belts. Analysis of the mechanisms involved is made from the records of high-speed ciné photography.

Some Experiments on Wet Steam Flow Visualization in Large Steam Turbine Blading

1976 ◽  
Vol 98 (3) ◽  
pp. 573-577 ◽  
Author(s):  
J. Krzyz˙anowski ◽  
B. Weigle
Keyword(s):  
Steam Turbine ◽  
Steam Flow ◽  
Light Sources ◽  
Phase Flow ◽  
Wet Steam ◽  
Experimental Conditions ◽  
Advantages And Disadvantages ◽  
Primary Droplet ◽  
Last Stage ◽  
Wet Steam Flow

In a series of experiments aimed at the visualization of the wet steam flow in the exhaust part of a 200 MW condensing steam turbine a set of periscopes and light sources was used. The aim of the experiment was: 1 – The investigation of the liquid-phase flow over the last stage stator blading of the turbine mentioned. 2 – The investigation of the gaseous-phase flow through the last stage blading at full and part load. The first part of the program partially failed due to the opaqueness of the wet steam atmosphere for the turbine load higher than 10–20 MW. The detailed experimental conditions will be described. An assessment of the primary droplet size will also be given. The preliminary results of the second part of the program will be outlined. The advantages and disadvantages of the equipment used will be discussed.

Modeling of a Steam Turbine Including Partial Arc Admission for Use in a Process Simulation Software Environment

2011 ◽  
Author(s):  
Eric Liese
Keyword(s):  
Steam Turbine ◽  
Process Simulation ◽  
Process Model ◽  
Constant Pressure ◽  
Pressure Ratio ◽  
Simulation Software ◽  
State Variables ◽  
Steam Turbines ◽  
Software Environment ◽  
Last Stage

A dynamic process model of a steam turbine, including partial arc admission operation, is presented. Models were made for the first stage and last stage, with the middle stages presently assumed to have a constant pressure ratio and efficiency. A condenser model is also presented. The paper discusses the function and importance of the steam turbines entrance design and the first stage. The results for steam turbines with a partial arc entrance are shown, and compare well with experimental data available in the literature, in particular, the “valve loop” behavior as the steam flow rate is reduced. This is important to model correctly since it significantly influences the downstream state variables of the steam, and thus the characteristic of the entire steam turbine, e.g., state conditions at extractions, overall turbine flow, and condenser behavior. The importance of the last stage (the stage just upstream of the condenser) in determining the overall flowrate and exhaust conditions to the condenser is described and shown via results.

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