R5 Procedure Based Damage Estimation in a Steam Turbine Valve Under In-Service Conditions

2016 ◽  
Author(s):  
Zhenwei Cai ◽  
Weizhe Wang ◽  
Hui Hong ◽  
Yingzheng Liu
Keyword(s):  
Steady State ◽  
Steam Turbine ◽  
Influential Factor ◽  
Recent Analysis ◽  
Assessment Procedure ◽  
Stress Strain ◽  
Thermal Transients ◽  
Steady State Operation ◽  
Service Data ◽  
Steam Parameter

The fatigue behavior in steam turbine valve is generally considered to be associated with thermal transients during start and stop phase. However, the recent analysis has shown that steam parameter fluctuations under in-service steady state operation could induce significant increase in the damage. In this paper, the effect of in-service steam parameter fluctuations on stress-strain behavior in the valve was analyzed based on FE analysis under in-service data. The rain-flow cycle counting method was applied to get effective stress-strain cycle numbers and cycle amplitudes to classify the types of fatigue cycle based on in-service data. The creep-fatigue damage during steady state operation of the valve was estimated by using R5 (Volume 2/3) high temperature assessment procedure together with the FE results. Frequent steam pressure fluctuations at steady state operation were identified as the most influential factor for the fatigue life of the steam turbine valve.

scholarly journals Steady state operation simulation of the Francis-99 turbine by means of advanced turbulence models

2017 ◽  
Vol 782 ◽  
pp. 012006
Author(s):  
A Gavrilov ◽  
A Dekterev ◽  
A Minakov ◽  
D Platonov ◽  
A Sentyabov
Keyword(s):  
Steady State ◽  
Turbulence Models ◽  
Steady State Operation

Fluid turbulence simulations of divertor heat load for ITER hybrid scenario using BOUT++

2021 ◽  
Author(s):  
Xueyun Wang ◽  
Xueqiao Xu ◽  
Philip B Snyder ◽  
Zeyu Li
Keyword(s):  
Heat Flux ◽  
Steady State ◽  
Energy Loss ◽  
Heat Load ◽  
Type I ◽  
Fluid Turbulence ◽  
Drift Model ◽  
Steady State Operation ◽  
Different Types ◽  
The One

Abstract The BOUT++ six-field turbulence code is used to simulate the ITER 11.5MA hybrid scenario and a brief comparison is made among ITER baseline, hybrid and steady-state operation (SSO) scenarios. Peeling-ballooning instabilities with different toroidal mode numbers dominate in different scenarios and consequently yield different types of ELMs. The energy loss fractions (ΔWped/Wped) caused by unmitigated ELMs in the baseline and hybrid scenarios are large (~2%) while the one in the SSO scenario is dramatically smaller (~1%), which are consistent with the features of type-I ELMs and grassy ELMs respectively. The intra ELM divertor heat flux width in the three scenarios given by the simulations is larger than the estimations for inter ELM phase based on Goldston’s heuristic drift model. The toroidal gap edge melting limit of tungsten monoblocks of divertor targets imposes constraints on ELM energy loss, giving that the ELM energy loss fraction should be smaller than 0.4%, 1.0%, and 1.2% for ITER baseline, hybrid and SSO scenarios, correspondingly. The simulation shows that only the SSO scenario with grassy ELMs may satisfy the constraint.

Measured Torsional Vibration Characteristics of a 100 Megawatt Wind Tunnel Drive Line

1999 ◽  
Author(s):  
James M. Corliss ◽  
H. Sprysl
Keyword(s):  
Steady State ◽  
Damping Ratio ◽  
Forced Response ◽  
Operating Conditions ◽  
Pulse Load ◽  
Torsional Vibrations ◽  
Variable Frequency Drive ◽  
Steady State Operation ◽  
Torque Measurements ◽  
Torsional Analysis

Abstract A new 100 MW (135,000 Hp) adjustable speed drive system has recently been installed in the NASA Langley National Transonic Facility. The 100 MW system is the largest of its kind in the world and consists of a salient pole synchronous motor powered by a 12-pulse Load Commutated Inverter variable frequency drive. During system commissioning the drive line torsional vibrations were measured with strain gages and a telemetry-based data acquisition system. The torque measurements included drive start-up and steady-state operation at speeds where the drive motor’s pulsating torques match the drive line’s torsional natural frequency. Rapid drive acceleration rates with short dwell times were effective in reducing torsional vibrations during drive starts. Measured peak torsional vibrations during steady-state operation were comparable to predicted values and large enough to produce noticeable lateral vibrations in the drive line shafting. Cyclic shaft stresses for all operating conditions were well within the fatigue limits of the drive line components. A comparison of the torque measurements to an analytical forced response model concluded that a 0.5% critical damping ratio was appropriately applied in the drive line’s torsional analysis.

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