A Precise Full-Dimensional Design System for Multistage Steam Turbines: Part I — Philosophy and Architecture of the System

2007 ◽  
Author(s):  
Hongde Jiang ◽  
Kepeng Xu ◽  
Baoqing Li ◽  
Xinzhong Xu ◽  
Qing Chen
Keyword(s):  
Steam Turbine ◽  
Mechanical Design ◽  
Local Level ◽  
Mechanical Analysis ◽  
Design System ◽  
Steam Turbines ◽  
Aerodynamic Design ◽  
3D Design ◽  
Design And Optimization ◽  
Design Consistency

A new, precise full-dimensional (PFD) design system for multistage steam turbine has been developed in the past decades by the present authors. The remarkable features of PFD system different from conventional 3D design methodology are as followings: a). Taking into account of unsteady aerodynamic impact on steam turbine performance, b). Simulating 3D real structure of blade and non-blade components without geometric simplification, c). Coupling of aerodynamic design with FEM structure- mechanical analysis for blade and non-blade components. Three levels of design and optimization at global, regional and local level for steam turbine cycle and flow path design are described. The PFD design system consists of conceptual (0D), 1D, Q3D, F3D/4D aerodynamic design and optimization codes, structure analysis and mechanical design (MD) tools, and pre- and post-processing software. In this part of present paper a detail description of philosophy and architecture of the PFD design system, function of each design tools, principles for design consistency are given. The PFD design system is a new plateau of present author’s long-term effort to bring multistage steam turbine design from a simple, passive, empirical-based situation toward a comprehensive, active, knowledge-based environment.

Numerical Investigation of Three-Dimensional Wet Steam Flows in an Exhaust Diffuser With Non-Uniform Inlet Flows From the Turbine Stages in a Steam Turbine

2012 ◽  
Author(s):  
Tadashi Tanuma ◽  
Yasuhiro Sasao ◽  
Satoru Yamamoto ◽  
Yoshiki Niizeki ◽  
Naoki Shibukawa ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Numerical Investigation ◽  
Evaluation Method ◽  
High Efficiency ◽  
Mechanical Design ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Steam Turbines ◽  
Wet Steam ◽  
Low Pressure Turbine

The purpose of this paper is to present a numerical evaluation method for the aerodynamic design and development of high-efficiency exhaust diffusers in steam turbines, as well as to present the comparison between the numerical results and measured data in an actual real scale development steam turbine. This paper presents numerical investigation of three-dimensional wet steam flows in a down-flow-type exhaust diffuser that has non-uniform inlet flows from a typical last turbine stage. This stage has long transonic blades designed using recent aerodynamic and mechanical design technologies, including superimposed leakages and blade wakes from several upstream low pressure turbine stages. The present numerical flow analysis showed detail three-dimensional flow structures considering circumferential flow distributions caused by the down-flow exhaust hood geometry and the swirl velocity component from the last stage blades, including flow separations in the exhaust diffuser. The results were compared with experimental data measured in an actual development steam turbine. Consequently, the proposed aerodynamic evaluation method was proved to be sufficiently accurate for steam turbine exhaust diffuser aerodynamic designs.

A Precise Full-Dimensional Design System for Multistage Steam Turbines: Part II — Key Technologies for Blade and Non-Blade Components, Engineering Application and Updating

2007 ◽  
Author(s):  
Xinzhong Xu ◽  
Kepeng Xu ◽  
Baoqing Li ◽  
Qing Chen ◽  
Hongde Jiang
Keyword(s):  
Power Plants ◽  
Performance Test ◽  
Mechanical Design ◽  
Design Method ◽  
Engineering Application ◽  
Control Valve ◽  
Fem Analysis ◽  
Design System ◽  
Steam Turbines ◽  
Key Technologies

In this part of present paper the key technologies for steam turbine blade and non-blade components developed by using the precise, full-dimensional (PFD) system is described firstly. For blade components advanced aerodynamic concept and design method for customized after-loaded profile, compound-lean blade, tandem cascade, contoured endwall, and solid particle erosion protection for HP and IP first nozzle have been developed. For non-blade component including main steam inlet/control valve, LP exhaust hood, packing seal and cavity flow, casing opening and condenser, new aerodynamic and mechanical design has been developed. New blade and non-blade components were experimentally and numerically investigated to verify its performance. Finite element method (FEM) analysis for all key components is also illustrated in this paper. Secondly the approach of validation and updating for the PFD system is introduced. Based on a large amount of on-site performance test data in power plants the statistic accuracy for the PFD system is given. It shows that in comparison with conventional F3D design methodology another 1.5-2 percent of HP and IP overall section efficiency improvement has been achieved.

Mechanical Design of Large Steam Turbine Components for Part Load Conditions

2013 ◽  
Author(s):  
N. Lückemeyer ◽  
F. Qin
Keyword(s):  
Steam Turbine ◽  
Structural Integrity ◽  
Mechanical Design ◽  
Point Of View ◽  
Heat Radiation ◽  
Steam Turbines ◽  
Load Case ◽  
Part Load ◽  
Load Regime ◽  
Load Conditions

Recent developments like the significant introduction of renewable energy sources to the electricity networks worldwide have led to more frequent and extended operation of fossil power plants in part load conditions. As a result the typical load spectrum of large steam turbines used for electricity generation has changed over the last years and will continue to do so. A number of papers has already been published on how to optimize the water-steam cycle and the steam turbine from a thermodynamical and aero-dynamical point of view for this new load regime in order to improve the average efficiency. But the changed load regime also poses a challenge for the mechanical design and structural integrity assessment of steam turbines. Reason for this is that the rated conditions are not necessarily the most challenging boundary conditions and therefore not necessarily a suitable, conservative envelope for all other load cases for mechanical design. Pressures decrease, but steam temperatures in part loads can increase and heat transfer coefficients and the influence of radiation on the component temperatures change. With an increasing demand for and a wider range of part load operation it for this reason becomes more important than ever to consider these load cases in the mechanical design. This paper uses a large, double-flow intermediate pressure steam turbine as an example to investigate the impact of extended part load operation on the design. Both an analytical model and finite element calculations are used to compare from a structural integrity point of view a low part-load load case and the rated load case and to evaluate the significance of heat radiation.

Operation of Steam Turbines to Minimize Shell Cracking

1960 ◽  
Vol 82 (3) ◽  
pp. 227-238
Author(s):  
S. B. Coulter ◽  
R. L. Jackson
Keyword(s):  
Steam Turbine ◽  
Mechanical Design ◽  
Steam Turbines ◽  
Thermal Distribution

Some methods for reducing the tendencies toward cracking in steam-turbine shells are described. Involved are improved operating procedures, application of accessories, and improved mechanical design, all of which aid in properly controlling shell thermal distribution.

scholarly journals Toward Modeling the Concurrent Design of Aircraft Engine Turbines

1993 ◽  
Author(s):  
Hauhua Lee ◽  
Sanjay Goel ◽  
Siu S. Tong ◽  
Brent Gregory ◽  
Scott Hunter
Keyword(s):  
Design Process ◽  
Mechanical Design ◽  
Aircraft Engine ◽  
Design System ◽  
Concurrent Design ◽  
Preliminary Design ◽  
Design Practice ◽  
Aerodynamic Design ◽  
Computer Aided ◽  
Four Levels

This paper describes our approach and experiences in constructing the Turbine Auto–Designer (TAD), an automated concurrent design system for aircraft engine turbines. In TAD, the design process is modeled based on the computer programs of a representative design system. It integrates three domains of the manual design process: preliminary design, detailed aerodynamic design, and detailed mechanical design. The manual design of turbines is an iterative redesign process involving the use of many sets of Computer Aided–Engineering (CAE) programs. The entire design process is modeled at four levels: analysis, automation, optimization, and concurrency. TAD is implemented with Engineous, a generic software shell for engineering design. Parts of TAD are already in use in day–to–day design practice for low–pressure turbines. In many cases of preliminary design, TAD can obtain better results quicker than the optimum obtained manually. Results also show that, for detailed aerodynamic analysis, the system can reduce the cycle time from days to hours.

Mechanical Design of Highly Loaded Large Steam Turbines

2011 ◽  
Author(s):  
N. Lu¨ckemeyer ◽  
H. Almstedt ◽  
T.-U. Kern ◽  
H. Kirchner
Keyword(s):  
Steam Turbine ◽  
Nuclear Power ◽  
Power Plants ◽  
Mechanical Design ◽  
Ductile Failure ◽  
Combined Cycle ◽  
Material Behavior ◽  
Integral Approach ◽  
Steam Turbines ◽  
Creep Fatigue

There are no internationally recognized standards, such as the ASME Boiler and Pressure Vessel Code or European boiler and pipe codes, for the mechanical design of large steam turbine components in combined cycle power plants, steam power plants and nuclear power plants. One reason for this is that the mechanical design of steam turbines is very complex as the steam pressure is only one of many aspects which need to be taken into account. In more than one hundred years of steam turbine history the manufacturers have developed internal mechanical design philosophies based on both experience and research. As the design of steam turbines is pushed to its limits with greater lifetimes, efficiency improvements and higher operating flexibility requested by customers, the validity and accuracy of these design philosophies become more and more important. This paper describes an integral approach for the structural analysis of large steam turbines which combines external design codes, material tests, research on the material behavior in co-operation with universities and experience gained from the existing fleet to derive a substantiated design philosophy. The paper covers the main parameters that need to be taken into account such as pressure, rotational forces and thermal loads and displacements, and identifies the relevant failure mechanisms such as creep fatigue, ductile failure and creep fatigue crack growth. It describes the efforts taken to improve the accuracy for materials already used in power plants today and materials with possible future use such as advanced steels or nickel based alloys.

Comparison of Steam Turbine Pre-Warming and Warm-Keeping Strategies Using Hot Air for Fast Turbine Start-Up

2020 ◽  
Author(s):  
Lukas Pehle ◽  
Piotr Łuczyński ◽  
Taejun Jeon ◽  
Manfred Wirsum ◽  
Wolfgang F. D. Mohr ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Energy Demand ◽  
Energy Use ◽  
Renewable Energy Sources ◽  
Mechanical Analysis ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Steam Turbines ◽  
Hot Air ◽  
Start Up

Abstract Adaptability of coal-based power generating units to accommodate renewable energy sources is becoming increasingly important. In order to improve flexibility, reduce start-up time and extend the life cycle, General Electric has developed solutions to pre-warm/warm-keep steam turbines using hot air. In this paper two main contributions to optimize the warming arrangements are presented. Firstly, the calibrated model of a 19-stage IP steam turbine is analyzed regarding time-dependent mass flow rates in a pre-warming mode. The influences on the duration time of the process and the thermally induced stress are investigated. This investigation utilizes a detailed 3D hybrid (HFEM-numerical FEM and analytical) model of the turbine including the rotor, inner casing and blading for computationally-efficient determination of transient temperature fields in individual components. The thermal boundary conditions are calculated by means of heat transfer correlations developed for this purpose. Moreover, a separate FEM model allows for the implementation of a structural mechanical analysis. As a result of this investigation, the pre-warming time can be further reduced while simultaneously lowering the thermal load in the components. Secondly, selected pre-warming strategies are compared with the warm-keeping scenarios. This analysis is aimed at a minimum thermal energy use required for a reheating of air in a warming arrangement. Hence, the pre-warming and warm-keeping operating strategies are evaluated with regard to their energy demand before start-up. Thus, based on the duration of standstill, the most energy-efficient turbine warming strategy can be chosen to ensure hot start-up conditions.

Aerodynamic Design and Prototype Testing of a New Line of High Efficiency, High Pressure, 50% Reaction Steam Turbines

2007 ◽  
Author(s):  
Joseph A. Cotroneo ◽  
Tara A. Cole ◽  
Douglas C. Hofer
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
Combined Cycle ◽  
Volume Flow ◽  
Steam Turbines ◽  
Aerodynamic Design ◽  
Flow Paths ◽  
Low Volume

The aerodynamic design and prototype performance testing of a new line of high efficiency, high pressure (HP), 50% reaction steam turbines is described in some detail. Three designs were carried out that can be used in a repeating stage fashion to form high efficiency steam paths. The designs were performed employing a blade master concept. The masters can be aerodynamically scaled and cut to cover a wide range of applications while maintaining vector diagram integrity. Three equivalent prototype flow paths, one each for Gen 0, 1 and 2, masters were designed and tested in a Steam Turbine Test Vehicle (STTV). These prototype designs are representative of high pressure steam turbines for combined cycle power plants. Design of experiments is used to optimize the flow path, stage counts and diameters for production designs taking into account multidisciplinary design constraints. Four such Gen 1 steam path designs have been executed to date as part of a structured series of combined cycle power plants. [1-5] There are two A14 HEAT* (High Efficiency Advanced Technology) steam turbine HP flow paths for GE’s 107FA combined cycle power plants and two A15 HEAT HP flow paths for the 109FB. The larger of the A14 HEAT steam turbine HP’s has recently been performance tested at a customer site demonstrating world class efficiency levels of over 90% for this low volume flow combined cycle turbine [1]. HP volume flows are likely to drop even lower in the future with the need to go to higher steam inlet pressure for combined cycle efficiency improvements so steam path designs with high efficiency at low volume flow will be increasingly important.

The Development of Long Last Stage Steam Turbine Blades

2010 ◽  
Author(s):  
Ivan McBean ◽  
Said Havakechian ◽  
Pierre-Alain Masserey
Keyword(s):  
Steam Turbine ◽  
Power Plants ◽  
Mechanical Design ◽  
Turbine Blades ◽  
Operating Experience ◽  
Aerodynamic Design ◽  
Mechanical Reliability ◽  
Last Stage ◽  
And Performance ◽  
High Level

In steam turbine power plants, the appropriate design of the last stage blades is critical in determining the plant efficiency and reliability and competitiveness. A high level of technical expertise combined with many years of operating experience are required for the improvement of last stage designs that increases performance, without sacrificing mechanical reliability. This paper focuses on three main development areas that are key for the development of last stage blades, namely the aerodynamic design, the mechanical design and the validation process. The three different lengths of last stage blade (LSB) were developed of 41in, 45in and 49in (and a number of scaled variants). The aerodynamic design process involves 3D CFD and flow path analysis, considerations such as last stage blade flutter and water droplet erosion, and last stage guide design. The mechanical design includes finite element stress and dynamic analysis, appropriate selection of the blade material, the coupling of the LSB with the rotor and the design of the LSB snubber and shroud. Experimental measurements form a key part of the product validation, from both the mechanical reliability and performance points of view.

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