scholarly journals New two-tier low pressure turbine for heavy duty steam turbines

2017 ◽  
Vol 891 ◽  
pp. 012257 ◽  
Author(s):  
A E Zaryankin ◽  
A N Rogalev ◽  
S K Osipov ◽  
N M Bychkov
Keyword(s):  
Low Pressure ◽  
Steam Turbines ◽  
Heavy Duty ◽  
Low Pressure Turbine

Sequential vs Multidisciplinary Coupled Optimization and Efficient Surrogate Modelling of a Last Stage and the Successive Axial Radial Diffuser in a Low Pressure Steam Turbine

2014 ◽  
Author(s):  
Kevin Cremanns ◽  
Dirk Roos ◽  
Arne Graßmann
Keyword(s):  
Steam Turbine ◽  
Design Process ◽  
Energy Demand ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Low Pressure ◽  
Steam Turbines ◽  
Low Pressure Turbine ◽  
Pressure Steam ◽  
Last Stage

In order to meet the requirements of rising energy demand, one goal in the design process of modern steam turbines is to achieve high efficiencies. A major gain in efficiency is expected from the optimization of the last stage and the subsequent diffuser of a low pressure turbine (LP). The aim of such optimization is to minimize the losses due to separations or inefficient blade or diffuser design. In the usual design process, as is state of the art in the industry, the last stage of the LP and the diffuser is designed and optimized sequentially. The potential physical coupling effects are not considered. Therefore the aim of this paper is to perform both a sequential and coupled optimization of a low pressure steam turbine followed by an axial radial diffuser and subsequently to compare results. In addition to the flow simulation, mechanical and modal analysis is also carried out in order to satisfy the constraints regarding the natural frequencies and stresses. This permits the use of a meta-model, which allows very time efficient three dimensional (3D) calculations to account for all flow field effects.

Unsteady Wet-Steam Flows Through Low Pressure Turbine Final Three Stages Considering Blade Number

2015 ◽  
Author(s):  
Satoshi Miyake ◽  
Hironori Miyazawa ◽  
Satoru Yamamoto ◽  
Yasuhiro Sasao ◽  
Kazuhiro Momma ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Low Pressure ◽  
Numerical Results ◽  
Steam Turbines ◽  
Wet Steam ◽  
Flow Simulations ◽  
Low Pressure Turbine ◽  
Blade Number ◽  
Pressure Steam ◽  
Three Stages

Unsteady three-dimensional wet-steam flows through stator–rotor blade rows in the final three stages of a low-pressure steam turbine, taking the blade number into consideration, are numerically investigated. In ASME Turbo Expo 2014, we presented the numerical results of the unsteady flow assuming the same blade number. Here, this previous study is extended to flow simulations using the real blade number. The flows under three flow conditions, with and without condensation and considering the same and real blade numbers are simulated, and the numerical results are compared with each other and with the experimental results. Finally, the effect of the blade number on unsteady wet-steam flows in real low-pressure steam turbines is discussed.

Nonequilibrium Throughflow Analyses of Low-Pressure, Wet Steam Turbines

1984 ◽  
Vol 106 (4) ◽  
pp. 716-724 ◽  
Author(s):  
C. C. Yeoh ◽  
J. B. Young
Keyword(s):  
Low Pressure ◽  
Computational Method ◽  
Virial Equation ◽  
Complete Analysis ◽  
Steam Turbines ◽  
Wet Steam ◽  
Streamline Curvature ◽  
Low Pressure Turbine ◽  
Aerodynamic Parameters ◽  
Theoretical Test

The paper describes a throughflow computational method that combines wet steam theory with an axisymmetric streamline curvature technique in order to predict nonequilibrium effects in low-pressure steam turbines. The computer program developed is able to deal with both subsonic and fully choked supersonic flows, and steam properties are represented by a truncated virial equation of state. A number of theoretical test cases have been investigated, including the nonequilibrium flow in the primary nucleating stage of a low-pressure turbine and the complete analysis of a six-stage, 320-MW operational turbine. The calculations are the first of their kind in being able to provide information on the spanwise variation of the Wilson point, the average droplet size nucleated, the degree of supercooling throughout the flowfield, the thermodynamic wetness loss, and the nonequilibrium choking mass flow rate in addition to the aerodynamic parameters which are of interest to the designer.

scholarly journals The applicability of two-tier low pressure turbine in high-power condensing steam turbines

2018 ◽  
Author(s):  
Zaryankin Arkadiy ◽  
Osipov Sergey ◽  
Krutitskii Vladislav
Keyword(s):  
High Power ◽  
Low Pressure ◽  
Steam Turbines ◽  
Low Pressure Turbine

Development of a model for thin films and numerical sensitivity tests

2018 ◽  
Vol 232 (5) ◽  
pp. 525-535 ◽  
Author(s):  
Amélie Simon ◽  
Jean-Marc Dorey ◽  
Michel Lance
Keyword(s):  
Surface Tension ◽  
Shear Stress ◽  
Thin Liquid Film ◽  
Low Pressure ◽  
Liquid Films ◽  
Steam Turbines ◽  
Low Pressure Turbine ◽  
Plane Plate ◽  
Dimensional Version ◽  
The Waves

Because the unsteady behavior of liquid films in steam turbines is a key point for additional friction losses and atomization process (that leads to coarse water generation), the development of a dedicated model has been found necessary. A two-dimensional computational fluid dynamics code for unstructured mesh is being developed using the finite volume method to simulate this thin liquid film. The aim is to predict the formation of the waves in the film since it is suspected to be a key parameter for friction and atomization. Applied as a first step to a plane plate, the code has been verified in a one-dimensional version with analytical solutions and is tested in low-pressure turbine steam conditions. Falling films computations (without gas shear stress) show that the model is capable to reproduce the waves’ shape of experiments from the literature. With steam under low-pressure turbine conditions, and compared to experimental data from the University of Michigan, the model including shear stress and surface tension provides good results for heights. Sensitivity calculations have been undergone showing the crucial influence of the surface tension and the generation of solitary waves for high velocities is captured by the code. The effect of gravity is also quantified.

The Verification of Concentrated Impurities in Low-Pressure Steam Turbines

1983 ◽  
Vol 105 (1) ◽  
pp. 192-198 ◽  
Author(s):  
W. G. Steltz ◽  
P. K. Lee ◽  
W. T. Lindsay
Keyword(s):  
Saturated Vapor ◽  
Field Testing ◽  
Low Pressure ◽  
Steam Turbines ◽  
Expansion Process ◽  
Low Pressure Turbine ◽  
Pressure Steam ◽  
Vapor Line ◽  
Low Levels ◽  
First Time

The problem of corrosion-assisted low-pressure blade failures is discussed from the water chemistry and aerothermodynamic viewpoints. The physical chemistry of particular steam impurities existing in low-pressure steam turbines is reviewed with special applicability to blade path steam conditions. The interaction of the turbine expansion line with the salt solution zone has been verified by field testing which has, for the first time, demonstrated the existence of concentrated impurities within the low pressure turbine blade path. In addition, the existence of low levels of moisture as measured by an optical moisture probe offers strong evidence that the expansion process in low-pressure steam turbines takes place, on the average, in thermodynamic equilibrium, at least in the vicinity of the saturated vapor line.

Survey of Twisted Blading Development in Steam Turbines

1969 ◽  
Vol 184 (1) ◽  
pp. 449-474 ◽  
Author(s):  
A. Smith
Keyword(s):  
Steam Turbine ◽  
Low Pressure ◽  
Scale Model ◽  
Steam Turbines ◽  
Power Station ◽  
Low Pressure Turbine ◽  
Last Stage ◽  
Turbine Blading

The development of steam turbine blading with high tip to hub diameter ratios over the last 50 years has been traced with particular emphasis on the reasons for adopting twisted blading in low pressure turbines. The aerodynamic concepts of the more generally accepted design bases for twisted blading are discussed and comparisons made between the efficiencies of selected twisted designs and straight blading. Current methods in the development of transonic low pressure blading for large 3000 rev/min central power station units are also described and the paper concludes by comparing the theoretical and measured steam angles across the last stage of a one-third scale model of a 136-in tip diameter low pressure turbine.

Droplet deposition in steam turbines

2004 ◽  
Vol 218 (8) ◽  
pp. 859-870 ◽  
Author(s):  
R I Crane
Keyword(s):  
Theoretical Work ◽  
Low Pressure ◽  
Computational Effort ◽  
Steam Turbines ◽  
Work Related ◽  
Low Pressure Turbine ◽  
Fog Deposition ◽  
History Of ◽  
The 1960S ◽  
Theoretical Developments

Research since the 1960s on the deposition of droplets from wet steam is reviewed, concentrating mainly on low-pressure turbines but also covering the limited work related to nuclear high-pressure turbines. The context is first set, outlining the motivation in terms of blade erosion and, to a lesser extent, wetness losses. Details of measurements in turbines and in simulated turbine flows are followed by descriptions of theoretical work on the main inertial and turbulent deposition mechanisms; possible additional contributory mechanisms are summarized. A major combined experimental and computational effort in the 1980s led to broad agreement between measured and calculated fog deposition fractions in low-pressure turbine final stages, attributed largely to the development of more accurate droplet size measurement and computational fluid dynamics techniques. An attempt has been made to correlate advances with the history of steam turbine development and to speculate on the future of deposition studies in the light of recent theoretical developments and trends in power generation.

Using Improved Remote Visual Inspection Tools to Reach Intermediate Stages in Turbomachinery

2004 ◽  
Author(s):  
Christopher P. Brown ◽  
David B. Smith
Keyword(s):  
Visual Inspection ◽  
Axial Direction ◽  
Low Pressure ◽  
Vibration Monitoring ◽  
Steam Turbines ◽  
Foreign Object Damage ◽  
Low Pressure Turbine ◽  
Rotor Imbalance ◽  
Conventional Technology ◽  
Two Stages

Using conventional technology, only the outer stages (the first stage and the last one or two stages) of industrial steam turbines are generally accessible to visual inspection. Signs of problems such as erosion, or native or foreign object damage in the intermediate stages can only be detected by other diagnostic means, such as vibration monitoring. This deficiency can make turbine diagnosis difficult in some circumstances. A remote visual inspection technology that can penetrate to the intermediate stages through access from the first or last stages would provide more complete visual coverage. In a recent inspection of a large cross-compound steam turbine at Detroit Edison’s St. Clair Power Plant, new minimally invasive inspection tools were used to locate the cause of rotor imbalance in the low pressure turbine. Attempts to find the problem using conventional borescopes had failed — they could not be inserted far enough into the intermediate stages to locate the problem. Using the modified inspection tools, a missing shroud band segment was discovered on the L-3 stage of the low pressure turbine. Conventional tools had been unable to reach further than the L-1 stage. The new tools, featuring stiffness in the axial direction and flexibility in the radial direction, were maneuvered through ten stages of turbomachinery and were used to locate the problem and evaluate collateral damage to other turbine stages.

scholarly journals Two-tier low-pressure turbines for heavy duty steam turbines

Vestnik IGEU ◽  
2016 ◽  
pp. 14-20
Author(s):  
A.S. Sedlov ◽  
◽  
A.E. Zaryankin ◽  
A.N. Rogalev ◽  
I.V. Garanin ◽  
...  
Keyword(s):  
Low Pressure ◽  
Steam Turbines ◽  
Heavy Duty
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