Toughness of Cr-Mo-V Steels for Steam Turbine Rotors

1983 ◽  
Vol 105 (4) ◽  
pp. 286-294 ◽  
Author(s):  
R. Viswanathan ◽  
R. I. Jaffee
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Major Influence ◽  
Steam Turbines ◽  
Factors Affecting ◽  
Intermediate Pressure ◽  
Research Programs ◽  
Operation And Maintenance ◽  
Better Than ◽  
Broad Overview

Cr-Mo-V steels are used extensively as the rotor material in the High Pressure and Intermediate Pressure Sections of modern steam turbines. The toughness of these rotors has a major influence on the reliability and efficiency of the turbine and the overall economy of operation and maintenance of the plant. The metallurgical factors affecting the toughness of the rotors and the methods to improve the toughness are now understood better than ever before. This paper will present a broad overview of the materials and design aspects of the toughness of Cr-Mo-V rotors with emphasis on the salient results of recent research programs aimed at improving their toughness.

Using CFD to Enhance the Preliminary Design of High-Pressure Steam Turbines

2013 ◽  
Author(s):  
Juri Bellucci ◽  
Federica Sazzini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Design Tool ◽  
Tip Clearance ◽  
Large Set ◽  
Preliminary Design ◽  
Steam Turbines ◽  
High Pressure Steam ◽  
Wide Range ◽  
Pressure Steam

This paper focuses on the use of the CFD for improving a steam turbine preliminary design tool. Three-dimensional RANS analyses were carried out in order to independently investigate the effects of profile, secondary flow and tip clearance losses, on the efficiency of two high-pressure steam turbine stages. The parametric study included geometrical features such as stagger angle, aspect ratio and radius ratio, and was conducted for a wide range of flow coefficients to cover the whole operating envelope. The results are reported in terms of stage performance curves, enthalpy loss coefficients and span-wise distribution of the blade-to-blade exit angles. A detailed discussion of these results is provided in order to highlight the different aerodynamic behavior of the two geometries. Once the analysis was concluded, the tuning of a preliminary steam turbine design tool was carried out, based on a correlative approach. Due to the lack of a large set of experimental data, the information obtained from the post-processing of the CFD computations were applied to update the current correlations, in order to improve the accuracy of the efficiency evaluation for both stages. Finally, the predictions of the tuned preliminary design tool were compared with the results of the CFD computations, in terms of stage efficiency, in a broad range of flow coefficients and in different real machine layouts.

Validation of Advanced Steam Turbine Technology: A Case Study of an Ultra Super Critical Steam Turbine Power Plant

2011 ◽  
Author(s):  
Rainer Quinkertz ◽  
Thomas Thiemann ◽  
Kai Gierse
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Steam Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
State Of The Art ◽  
Cooling System ◽  
Operational Experience ◽  
Internal Cooling ◽  
Steam Turbines

High efficiency and flexible operation continue to be the major requirements for power generation because of the benefits of reduced emissions and reduced fuel consumption, i.e. reduced operating costs. Ultra super critical (USC) steam parameters are the basis for state of the art technology of coal fired power plants with highest efficiency. An important part of the development process for advanced steam turbines is product validation. This step involves more than just providing evidence of customer guaranteed values (e.g. heat rate or electric output). It also involves proving that the design targets have been achieved and that the operational experience is fed back to designers to further develop the design criteria and enable the next step in the development of highly sophisticated products. What makes product validation for large size power plant steam turbines especially challenging is the fact that, due to the high costs of the required infrastructure, steam turbine manufacturers usually do not have a full scope / full scale testing facility. Therefore, good customer relations are the key to successful validation. This paper describes an extensive validation program for a modern state of the art ultra supercritical steam turbine performed at an operating 1000 MW steam power plant in China. Several measuring points in addition to the standard operating measurements were installed at one of the high pressure turbines to record the temperature distribution, e.g. to verify the functionality of the internal cooling system, which is an advanced design feature of the installed modern high pressure steam turbines. Predicted 3D temperature distributions are compared to the actual measurements in order to verify and evaluate the design rules and the design philosophy applied. Conclusions are drawn regarding the performance of modern 3D design tools applied in the current design process and an outlook is given on the future potential of modern USC turbines.

Development and Operating Experience of a Two-Casing 600MW Ultra-Super-Critical Steam Turbine

2005 ◽  
Author(s):  
Yoshinori Tanaka ◽  
Hiroharu Ohyama ◽  
Naoto Tochitani ◽  
Tamiaki Nakazawa
Keyword(s):  
Electric Power ◽  
Steam Turbine ◽  
Operating Experience ◽  
Low Pressure ◽  
Steam Turbines ◽  
Design Features ◽  
Intermediate Pressure ◽  
Commercial Operation ◽  
Compact Design ◽  
Maintenance Requirements

600MW class steam turbines are typically manufactured in three casing configurations with two low-pressure casings. Mitsubishi Heavy Industries (MHI) has developed and manufactured a 600MW two-casing Ultra Super Critical turbine for the Hirono No.5, Tokyo Electric Power Co. in Japan, which comprises one combined high- and intermediate-pressure casing and one double-flow low-pressure casing. This unit started the commercial operation in July 2004. Two-casing design simplifies construction and maintenance requirements and saves capital cost of the plant. This compact design was realized mainly due to the development of 3000 rpm 48 inch steel low-pressure end blades, the longest steel blade in the industries for 3000 rpm machines. In addition, a highly efficient and compact design in achieving 600°C steam condition was realized by employing a combined high- and intermediate-pressure frame. This paper addresses the design features of the 600MW two-casing USC turbine, operating condition of the Hirono No.5 and the results of the verification tests performed.

scholarly journals Influence of Intercept Valves on Control of Multiple Stages Steam Turbines During the Switching into the Island Operation

2015 ◽  
Vol 66 (2) ◽  
pp. 103-107
Author(s):  
Ladislav Laštovka ◽  
Pavla Hejtmánková
Keyword(s):  
High Pressure ◽  
Control System ◽  
Steam Turbine ◽  
Dynamic Load ◽  
The Other ◽  
Steam Turbines ◽  
Electrical Grid ◽  
Operation Status ◽  
Hydraulic Valves ◽  
Multiple Stages

Abstract This paper presents control of a multiple stages steam turbine which is switched into the island operation. The frequency in an electrical grid is stated on nominal value which is in UCTE grid 50 Hz. When deviation of frequency is higher then 0.2 Hz, the switching of particular steam units into the island operation is only the chance how to maintain the supply of, at least, some small grids. The other possibility how to keep power units in operation, to be prepared for the next synchronization to the grid, is to switch them to operation status in which they supply only their self-consumption. This change of the operating state is the most dynamic load change for the control system of the unit. The multiple stages turbines are equipped with high pressure hydraulic valves for steam turbine governing. Influence of the intercept valve on steam turbine control during the switching process into the island operation is examined in Matlab Simuling software.

Numerical Calculation of Seal Clearance Change in Installation Process of a 1000MW Nuclear Steam Turbine HIP Casing

2020 ◽  
Author(s):  
Daohui Ji ◽  
Ziyue Mei ◽  
Wei Jiang ◽  
CaiYan Xiang ◽  
Danmei Xie ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Nuclear Power ◽  
Complex Structure ◽  
Steam Turbines ◽  
Maximum Deformation ◽  
Intermediate Pressure ◽  
Geometry Model ◽  
Whole Process ◽  
Calculation Results ◽  
Clearance Change

Abstract During installation process, most of 1000MW-class nuclear power steam turbines will undergo certain deformations due to their own big size and heavy weight, which will change seal clearances in the steam passage. The clearance change will affect steam turbine’s efficiency, and may cause rubbing faults and even strong abnormal vibration, affecting the safety of the steam turbine. Moreover, limited by the complex structure and measurement method, it is difficult to measure deformation and seal clearance accurately, so it is necessary to study the change tendency of the clearance in the installation process. In this paper, a HIP (High and Intermediate Pressure) casing of a 1000MW nuclear steam turbine was taken as the research object, and its 3D geometry model is established based on Pro/E software. By using ANSYS WORKBENCH, we calculated the deformation of the HIP casing during installation with five steps, which are named as: ① lower casing with lower diaphragms, ② step ① + upper diaphragms, ③ step ② + upper casing, ④ step ③ + bolting, and ⑤ replacing the support. Then we analyzed the change of the seal clearance during the installation process by deformation differences of some points under different conditions. The calculation results show that the maximum deformation of the HIP Casing during the installation process occurs in the middle of casing close to the IP (Intermediate Pressure) casing. The relative change of the clearance during the whole process is 0.6–0.8 mm. The change of seal clearance is largest at the first-stage of IP casing, and it can be 0.8mm during replacement of the support.

Aerodynamic Flutter of Turbine Brush Seals

2017 ◽  
Author(s):  
Samuel J. Borgueta ◽  
Nicholas R. Bach ◽  
Jared J. Correia ◽  
Brendan G. J. Egan ◽  
Joshua S. Horton ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Reynolds Numbers ◽  
Working Fluid ◽  
Steam Turbines ◽  
High Pressure Steam ◽  
Modes Of Failure ◽  
Brush Seal ◽  
Pressure Steam ◽  
Brush Seals

With global energy demands continually growing and environmental impacts a major concern in power production, maximizing the efficiencies of power plants is of top priority. EthosEnergy2 has sponsored a project at the University of Massachusetts Dartmouth to study and analyze the brush seals in steam turbines in pursuit of increasing steam turbine thermodynamic efficiency. Brush seals are incorporated circumferentially around the turbine blades in their housing. The brush seals provide a very minimal clearance height that compensates for start-up rotor deviation and minimizes high-pressure steam blow-by around the edges of the blades. Brush seals minimize the clearance height between the blades and housing, which allows the turbine to produce more work. However, overtime brush seals can be damaged, greatly reducing efficiency. The seals that are repeatedly showing excessive wear and damage, occur in the high-pressure sections of steam turbines with high Reynolds numbers. The bristle breakdown is attributed to high Reynolds numbers and aerodynamic flutter. The purpose of this research is to design a prototype and empirically model steam turbine conditions with air to map out the fluid-solid interaction, determine the modes of bristle failure, and ultimately reproduce and record bristle flutter. A pressure vessel and pressure system was designed to test linear strips of brush seals with air as the working fluid. The pressure vessel accommodates varying clearance heights to identify the correlation of clearance height and the effects on fluid flow. The system also incorporates a high-speed camera that can capture the phenomena of flutter, precisely identify the modes of failure, and record fluid-solid interaction and the interaction of the bristles with each other. Designing a prototype to empirically model this problem serves as a fundamental and critical step in understanding the fluid interaction with seals in high-pressure steam turbines and will identify brush seal modes of failure. The prototype’s ability to model steam turbine conditions and rapidly test various seal designs will facilitate better brush seal designs to be constructed and will ultimately increase the thermal efficiencies of steam turbines, aid in accommodating the increase in global energy demands, and reduce the detrimental environmental impacts of producing power. The system successfully produced and recorded brush-seal-bristle flutter while modeling high-pressure steam turbine conditions. Matching Reynolds and Euler numbers of the steam turbine stages provided the ability to scale the steam turbine to our prototype, with air as the working fluid. Brush seal breakdown was occurring in steam turbines at Reynolds numbers above 20,000. The prototype repeatedly produced brush seal flutter at Reynolds numbers above 25,000, validating the theory that brush seal breakdown is dependent predominantly on the Reynolds number.

Stress Corrosion Cracking and Corrosion Fatigue Analysis of Nuclear Steam Turbine Rotor

2014 ◽  
Author(s):  
Gang Chen ◽  
Puning Jiang ◽  
Xingzhu Ye ◽  
Junhui Zhang ◽  
Yifeng Hu ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Steam Turbine ◽  
Corrosion Fatigue ◽  
Stress Corrosion Cracking ◽  
Nuclear Power ◽  
Power Plants ◽  
Fatigue Cracking ◽  
Corrosion Cracking ◽  
Major Influence ◽  
Steam Turbines

Although stress corrosion cracking (SCC) and corrosion fatigue cracking can occur in many locations of nuclear steam turbines, most of them initiate at low pressure disc rim, rotor groove and keyway of the shrunk-on disc. For nuclear steam turbine components, long life endurance and high availability are very important factors in the operation. Usually nuclear power plants operating more than sixty years are susceptible to this failure mechanism. If SCC or corrosion fatigue happens, especially in rotor groove or keyway, it has a major influence on nuclear steam turbine life. In this paper, established methods for the SCC and corrosion fatigue-controlled life prediction of steam turbine components were applied to evaluating a new shrunk-on disc that had suffered local keyway surface damage during manufacture and loss of residual compressive stress.

Creep Deformation of High Pressure Steam Turbine Part

2015 ◽  
Vol 732 ◽  
pp. 187-190
Author(s):  
František Straka ◽  
Pavel Albl ◽  
Pavel Pánek
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Steam Turbine ◽  
Creep Deformation ◽  
Steam Turbines ◽  
High Pressure Turbine ◽  
High Pressure Steam ◽  
Pressure Steam ◽  
Temperature Levels ◽  
Steam Parameters

Steam turbines are complex rotating machines working at high pressure and high temperature levels. Their high-pressure parts, which are subjected to the highest steam parameters, are most affected by these conditions and may suffer from creep deformation. Permanent changes in geometry become visible in high-pressure turbine casings when they are disassembled after certain time in operation.

Influence of Shroud Cavity Jet and Steam Admission Through a Circumferential Slot on the Flow Field in a Steam Turbine

2012 ◽  
Author(s):  
David Engelmann ◽  
Tobias J. Kalkkuhl ◽  
Thomas Polklas ◽  
Ronald Mailach
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Steam Turbine ◽  
Test Facility ◽  
Incoming Flow ◽  
Specific Flow ◽  
Intermediate Pressure ◽  
Steam Admission ◽  
Flow Through ◽  
Pressure Part

Steam turbines for industrial application are often constructed according to modular design concepts. This allows interchangeable combinations of modules including steam admission and extraction. Prior to field tests the flow in a typical stage configuration of such a steam turbine is predicted numerically. Focus of the current work is the axial gap between high pressure and intermediate pressure part containing a circumferential slot. Mass flow used for axial thrust balancing re-enters the blade channel through this slot. Another exceptional feature appears at the high pressure vane carrier: For manufacturing reasons the last rotor shroud next to and upstream of the gap is not fully enclosed by the vane carrier. This results in a turbulent jet at the exit of the rotor shroud cavity mixing with both the blade channel flow as well as the incoming flow from the slot. A commercial 3D RANS CFD-solver (ANSYS CFX 12) is used to predict the mixing of the different flow partitions within the stage gap. Therefore, the last stage of the high pressure part, the gap with the slot and the first stage of the intermediate pressure part are modeled and solved numerically. The amount of flow through the circumferential slot is varied to discern the influences of the specific flow partitions. Additionally, a modification of the vane carrier helps to analyze radial distribution of incoming flow for the downstream vane row as well as scoring global loss characteristics. As the simulation results indicate, flow parameters up- and downstream and also fluctuations crossing the gap are affected by flow through the slot. Furthermore, the computed flow field shows locations appropriate for a traversing probe system to be used in the test facility.

Performance Analysis of Transcritical CO2 Two Stage Compression Cycle with an Intercooler (TSCC+IC) and the Cycle with an Expander (TSCE+IC)

2012 ◽  
Vol 538-541 ◽  
pp. 1998-2002 ◽  
Author(s):  
Jing Rui Tian ◽  
Hong Li Wang ◽  
Hui Qin Liu
Keyword(s):  
High Pressure ◽  
Heat Pumps ◽  
Cycle Performance ◽  
Outlet Temperature ◽  
Two Stage ◽  
Intermediate Pressure ◽  
Discharge Temperature ◽  
Compression Cycle ◽  
Increasing Trend ◽  
Better Than

In range of high pressure, the performance of two stage compression cycle with an expander (TSCE+IC) is better than the two stage cycle with an intercooler (TSCC+IC). In the cycle (TSCE+IC), the optimum discharge temperature is 42°C and the highest COP is 3.3, in the cycle (TSCC+IC), the optimum discharge temperature is 50°C and the highest COP is 3.07. In the cycle (TSCC+IC), the optimum intermediate pressure is 5.8MPa and the highest COP is 3.08, in the cycle (TSCE+IC), the optimum intermediate pressure is 6.2MPa and the highest COP is 3.33. With increasing of evaporating temperature or decreasing outlet temperature of gas cooler, the performance of cycle (TSCE+IC) or cycle (TSCC+IC) is an increasing trend. Under the same conditions, expander cycle performance superior to the throttle valve performance. Some fundamental data were obtained for improving cycle performance and developing the products of CO2 refrigeration air condition and heat pumps.

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