Increasing the fatigue strength and operational reliability of the critical elements of a steam turbine

Engineering ◽  
2018 ◽  
Vol 21 ◽  
pp. 91-97
Author(s):  
T. Fursova ◽  
Keyword(s):  
Fatigue Strength ◽  
Steam Turbine ◽  
Operational Reliability ◽  
Critical Elements

scholarly journals Effect of Corrosion on the Low-cycle Fatigue Strength of Steels used in Frequent Start-up Power Generation Steam Turbine

2015 ◽  
Vol 133 ◽  
pp. 528-534 ◽  
Author(s):  
Mohamed EL May ◽  
Nicolas Saintier ◽  
Olivier Devos ◽  
Alexia Rozinoer
Keyword(s):  
Power Generation ◽  
Fatigue Strength ◽  
Steam Turbine ◽  
Low Cycle Fatigue ◽  
Cycle Fatigue ◽  
Start Up

Design Philosophy and Dynamic Calculation Method for Optimized Load Rejection Characteristics of Steam Turbines

2012 ◽  
Author(s):  
Christoph Schindler ◽  
Gerta Zimmer
Keyword(s):  
Steam Turbine ◽  
Dynamic Equilibrium ◽  
Reaction Times ◽  
Operational Reliability ◽  
Steam Turbines ◽  
Electrical Grid ◽  
Counter Measures ◽  
Failure Conditions ◽  
Turbine Speed ◽  
The Impact

A load rejection disconnects the generator from the electrical grid. The resulting power excess accelerates the turbo set. Reacting to the load rejection, the turbine governor rapidly closes the steam admission valves. The remaining entrapped steam expands, thereby continuing to power the turbine. Thus the turbine speed rises till a dynamic equilibrium of accelerating and braking forces is reached. Thereafter the turbine speed decreases. If the maximally attained turbine speed remains below the trip threshold, immediate re-synchronization to the electrical grid is possible. Consequently, a forced outage of the steam turbine can be avoided and operational reliability is increased. Furthermore, functional safety requirements demand that the maximum turbine speed remains below test speed under all failure conditions. Accordingly, steam turbine design has to account for the impact of overspeed for a reliable and safe operation of the turbo set. In order to manage load rejection requirements for steam turbine operation, the design engineer applies standard rules and overspeed calculation methods. These rules limit standardized overspeed estimation by defining maximum steam volumes, valve closing times, and I&C reaction times, as well as type and number of non-return valves. A more thorough turbine overspeed investigation is necessary for several reasons, such as to evaluate this behavior under undesired failure conditions e.g. failure of non-return valves or blocking of control valves. A second justification for this investigation would be to predict changes resulting from turbine modifications — e.g. turbine upgrade or change at I&C systems. In this paper, basic and advanced overspeed calculation tools are illustrated and compared, with respect to required effort as well as accuracy of prediction. It is shown how system parameters which are most sensitive with respect to overspeed can be identified and their influence assessed. Thus, firstly it is already possible to identify and improve critical overspeed behavior during design. Secondly, the impact of particular failures can be accurately predicted, thus allowing for due implementation of appropriate counter measures. The methods, presented in this paper, were developed by the authors and their predecessors at SIEMENS AG for large steam turbo sets with a power range between 100 MW and 1500 MW.

scholarly journals Analysis of Fretting Fatigue Strength of Integral Shroud Blade for Steam Turbine

2008 ◽  
Vol 2 (3) ◽  
pp. 909-920
Author(s):  
Yasutomo KANEKO ◽  
Masayuki TOMII ◽  
Hiroharu OHYAMA ◽  
Takayuki KURIMURA
Keyword(s):  
Fatigue Strength ◽  
Steam Turbine ◽  
Fretting Fatigue

Factors That Affect the Fatigue Strength of Power Transmission Shafting and Their Impact on Design

1986 ◽  
Vol 108 (1) ◽  
pp. 106-114 ◽  
Author(s):  
S. H. Loewenthal
Keyword(s):  
Residual Stress ◽  
Fatigue Strength ◽  
Stress Concentration ◽  
Power Transmission ◽  
Design Method ◽  
Surface Condition ◽  
Operational Reliability ◽  
Torsional Loading ◽  
Variable Amplitude ◽  
Limited Life

A long-standing objective in the design of power transmission shafting is to eliminate excess shaft material without compromising operational reliability. A shaft design method is presented which accounts for variable amplitude loading histories and their influence on limited life designs. The effects of combined bending and torsional loading are considered, along with a number of application factors known to influence the fatigue strength of shafting materials. Among the factors examined are surface condition, size, stress concentration, residual stress, and corrosion fatigue.

Reliability Analysis of Steam Turbine Blade Using Monte Carlo Simulation

2004 ◽  
Vol 261-263 ◽  
pp. 549-554
Author(s):  
Chul Su Kim ◽  
Jung Kyu Kim
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Fatigue Strength ◽  
Reliability Analysis ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Applied Stress ◽  
Element Analysis ◽  
Bending Load ◽  
Steam Turbine Blade

In this study, the reliability analysis of the low pressure steam turbine blade was performed using the Monte Carlo simulation considering variations of applied stress and strength. Applied stress under the service condition of steady state was obtained by finite element analysis. The fatigue strength under rotating bending load was evaluated by the staircase method. The most appropriate probabilistic distribution of the fatigue strength is 3-parameter Weibull distribution, which is determined by the comparative analysis. The failure probability under various loading conditions was derived from the strength-stress interference model.

scholarly journals Stress Strain State of Steam Turbine Components under Plastic Deformation

2020 ◽  
pp. 14-17
Author(s):  
I. Palkov ◽  
S. Palkov
Keyword(s):  
Plastic Deformation ◽  
Steam Turbine ◽  
Calculation Method ◽  
Power Plants ◽  
Turbine Unit ◽  
Strain State ◽  
Operational Reliability ◽  
Stress Strain ◽  
Stress Strain State ◽  
Pressure Cylinder

Reliable operation of secondary equipment of PWR nuclear power plants is an integral part of nuclear and radiation safety of the entire NPP unit. The problem of stress strain state of steam turbine structural components under plastic deformation is considered. The theory of elastic-plastic deformations is used to solve the problem along with the finite element method. The paper presents the results of computer assessment of stress strain state of locking joint of working blades of the first stage of a intermediate-pressure cylinder (IPC) and high-pressure cylinder (HPC) body of a steam turbine, which makes it possible to characterize the degree of relaxation and stress redistribution in the structure in comparison with obtained earlier results. It is provided that the use of the presented calculation method in designing new structures of steam turbine components operating in the area of high thermal and power loads, taking into account the contact interaction of components, as well as different mechanical and physical properties of materials, and their changes depending on operating temperature, at this stage of software development allows one to identify problem areas in the design and prevent further breakdowns in the turbine. Based on the comparison of operational data of the developed design solutions and calculation assessment, it is proved that the chosen calculation method can significantly increase the operational reliability not only of the turbine unit but also the nuclear unit as a whole, as well as reduce economic costs caused by turbine unit downtime during maintenance.

Analysis of Fretting Fatigue Strength of Integral Shroud Blade for Steam Turbine

2007 ◽  
pp. 263-269 ◽  
Author(s):  
Yasutomo Kaneko ◽  
Masayuki Tomii ◽  
Hiroharu Ohyama ◽  
Takayuki Kurimura
Keyword(s):  
Fatigue Strength ◽  
Steam Turbine ◽  
Fretting Fatigue

Correlative microscopy in distrubuted (client/server) computing environments: tools for catalyzing the rapid dissemination of information about the cell biology of the human prostate

1995 ◽  
Vol 53 ◽  
pp. 682-683
Author(s):  
A. Hakam ◽  
J.T. Gau ◽  
M.L. Grove ◽  
B.A. Evans ◽  
M. Shuman ◽  
...  
Keyword(s):  
United States ◽  
Cell Biology ◽  
Tissue Bank ◽  
The United States ◽  
Prostate Adenocarcinoma ◽  
Correlative Microscopy ◽  
Client Server ◽  
Critical Elements ◽  
Transplant Organ

Prostate adenocarcinoma is the most common malignant tumor of men in the United States and is the third leading cause of death in men. Despite attempts at early detection, there will be 244,000 new cases and 44,000 deaths from the disease in the United States in 1995. Therapeutic progress against this disease is hindered by an incomplete understanding of prostate epithelial cell biology, the availability of human tissues for in vitro experimentation, slow dissemination of information between prostate cancer research teams and the increasing pressure to “ stretch” research dollars at the same time staff reductions are occurring.To meet these challenges, we have used the correlative microscopy (CM) and client/server (C/S) computing to increase productivity while decreasing costs. Critical elements of our program are as follows:1) Establishing the Western Pennsylvania Genitourinary (GU) Tissue Bank which includes >100 prostates from patients with prostate adenocarcinoma as well as >20 normal prostates from transplant organ donors.

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