Investigation of Moisture Removal on Last Stage Stationary Blade in Actual Steam Turbine

2020 ◽  
Author(s):  
Hideaki Sato ◽  
Soichiro Tabata ◽  
Naoto Tochitani ◽  
Yasuhiro Sasao ◽  
Ryo Takata ◽  
...  
Keyword(s):  
Power Systems ◽  
Water Level ◽  
Steam Turbine ◽  
Pressure Ratio ◽  
Internal Flow ◽  
Moisture Removal ◽  
Operating Environment ◽  
Choked Flow ◽  
Measurement Result ◽  
Last Stage

Abstract This paper presents an investigation for wet steam flow through the slit on the last stage hollow stationary blades of a steam turbine. The aim of this investigation is to evaluate the moisture removal performance by measuring the quantity of drain and “Motive steam” from some kinds of slit configurations under the actual turbine operating environment. Motive steam is effective steam sucked from the slit and removed together with drain. The measurement was carried out on a 105 MW class steam turbine at “T-point”, a verification power plant owned by Mitsubishi Hitachi Power Systems, Ltd. [MHPS]. The measurement system was constructed right under the turbine. Even though both drain and steam were sucked from the slit on the stationary blade, drain was separated by the cyclone separator and measured by detecting the water level accumulated in the water level tank by the optical pulse sensor. For the measurement of the motive steam quantity, the choked flow rate measured by the critical nozzle was used to obtain the slit characteristic data of pressure ratio (ratio of blade surface static pressure to outer ring inner pressure). The critical nozzles were arranged in parallel, and the measurement was carried out by adopting a multi-valve switching system. And CFD slit analysis, in which the drain discharge path inside the last stage hollow stationary blade is modeled, was also carried out. The CFD slit analysis was compared with the measurement result to examine the internal flow. The corresponding CFD was calculated by ANSYS CFX. And the coarse water droplets analysis by the kinetic equation of the discrete droplet model was also carried out. From the measurement result and the evaluation, it was confirmed that the slit with groove configuration is more effective than the normal slit under the actual turbine operating environment.

Modeling of a Steam Turbine Including Partial Arc Admission for Use in a Process Simulation Software Environment

2011 ◽  
Author(s):  
Eric Liese
Keyword(s):  
Steam Turbine ◽  
Process Simulation ◽  
Process Model ◽  
Constant Pressure ◽  
Pressure Ratio ◽  
Simulation Software ◽  
State Variables ◽  
Steam Turbines ◽  
Software Environment ◽  
Last Stage

A dynamic process model of a steam turbine, including partial arc admission operation, is presented. Models were made for the first stage and last stage, with the middle stages presently assumed to have a constant pressure ratio and efficiency. A condenser model is also presented. The paper discusses the function and importance of the steam turbines entrance design and the first stage. The results for steam turbines with a partial arc entrance are shown, and compare well with experimental data available in the literature, in particular, the “valve loop” behavior as the steam flow rate is reduced. This is important to model correctly since it significantly influences the downstream state variables of the steam, and thus the characteristic of the entire steam turbine, e.g., state conditions at extractions, overall turbine flow, and condenser behavior. The importance of the last stage (the stage just upstream of the condenser) in determining the overall flowrate and exhaust conditions to the condenser is described and shown via results.

Modeling of a Steam Turbine Including Partial Arc Admission for Use in a Process Simulation Software Environment

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Eric Liese
Keyword(s):  
Steam Turbine ◽  
Flow Rate ◽  
Process Model ◽  
Constant Pressure ◽  
Pressure Ratio ◽  
Simulation Software ◽  
State Variables ◽  
Steam Turbines ◽  
Software Environment ◽  
Last Stage

A dynamic process model of a steam turbine, including partial arc admission operation, is presented. Models were made for the first stage and last stage, with the middle stages assumed to have a constant pressure ratio and efficiency. A condenser model is also presented. The paper discusses the function and importance of the steam turbine's entrance design and the first stage. The results for steam turbines with a partial arc entrance are shown and compare well with experimental data available in the literature; in particular, the “valve loop” behavior as the steam flow rate is reduced. This is important to model correctly since it significantly influences the downstream state variables of the steam, and thus the characteristic of the entire steam turbine, e.g., state conditions at extractions, overall turbine flow, and condenser behavior. The importance of the last stage (the stage just upstream of the condenser) in determining the overall flow rate and exhaust conditions to the condenser is described and shown via results.

Study on Service Life of Last Stage Blade with Damped Structure in Large Power Steam Turbine

2008 ◽  
Vol 44-46 ◽  
pp. 803-808
Author(s):  
Di Zhang ◽  
Yong Hui Xie
Keyword(s):  
Numerical Model ◽  
Service Life ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Dynamic Stress ◽  
Aerodynamic Load ◽  
Operating Environment ◽  
Large Power ◽  
Last Stage ◽  
Blade Failure

Blade which transfers thermal energy of steam into power, is a basic component in steam turbine. The reliability of blade is heavily influenced by the operating environment. The rotating blade experiences large inertial load and the wake of nozzle flow impose large variations of aerodynamic load on blade, in addition, the last stage blade is also affected by corrosion, so accidents of blade happen from time to time. Preventing blade failure has become one of the major objectives of turbine design and in-service maintenance. It is said that the reason for most of blade failure is fatigue fracture. In this study, a synthetical numerical model has been developed to evaluate service life of blade. At first, a numerical model to analyze the excitation force, dynamic frequency and dynamic stress of steam turbine blade has been developed, based on the results of dynamic stress analysis, a model to evaluate the service life of turbine blade has been developed. Many factors such as manufacturing technology of blade and erosion operating environment are considered to get more accurate results for service life of blade. At last, a last stage blade group of a large power steam turbine is analyzed in detail. It is shown clearly that the numerical model can give some rational quantitative results, and it is suitable for its engineering application to the improvement of the blade reliability.

A Numerical Investigation of Rotating Instability in Steam Turbine Last Stage

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
L. Y. Zhang ◽  
L. He ◽  
H. Stüer
Keyword(s):  
Steam Turbine ◽  
Dynamic Instability ◽  
Computational Study ◽  
Fluid Dynamic ◽  
Pressure Ratio ◽  
Separated Flow ◽  
Test Model ◽  
Steam Turbines ◽  
Last Stage ◽  
Rotating Instability

The unsteady flow phenomenon (identified as rotating instability) in the last stage of a low-pressure model steam turbine operated at very low mass flow conditions is numerically studied. This kind of instability has been observed previously in compressors and can be linked to the high structural stress levels associated with flow-induced blade vibrations. The overall objective of the study is to enhance the understanding of the rotating instability in steam turbines at off design conditions. A numerical analysis using a validated unsteady nonlinear time-domain CFD solver is performed. The 3D solution captures the massively separated flow structure in the rotor-exhaust region and the pressure ratio characteristics around the rotor tip of the test model turbine stage in good comparison with the experiment. A computational study with a multi-passage whole annulus domain on two different 2D blade sections is subsequently carried out. The computational results clearly show that a rotating instability in a turbine blading configuration can be captured by the 2D model. The frequency and spatial modal characteristics are analyzed. The simulations seem to be able to predict a rotating fluid dynamic instability with the similar characteristic features to those of the experiment. In contrast to many previous observations, the results for the present configurations suggest that the onset and development of rotating instabilities can occur without 3D and tip-leakage flows, although a quantitative comparison with the experimental data can only be expected to be possible with fully 3D unsteady solutions.

A Numerical Investigation of Rotating Instability in Steam Turbine Last Stage

2011 ◽  
Author(s):  
L. Y. Zhang ◽  
L. He ◽  
H. Stu¨er
Keyword(s):  
Steam Turbine ◽  
Dynamic Instability ◽  
Computational Study ◽  
Fluid Dynamic ◽  
Pressure Ratio ◽  
High Stress ◽  
Test Model ◽  
Steam Turbines ◽  
Last Stage ◽  
Rotating Instability

In the present study, the unsteady flow phenomenon (identified as rotating instability) in the last stage of a low-pressure model steam turbine operated at very low mass flow conditions is studied through numerical investigations. This kind of instability has been observed previously in compressors and is believed to be the cause of high stress levels associated with the corresponding flow-induced blade vibrations. The overall purpose of the study is to enhance the understanding of the rotating instability in steam turbines at off design conditions. A numerical analysis using a validated unsteady nonlinear time-domain CFD solver is adopted. The 3D solution captures the massively separated flow structure in the rotor-exhaust region and the pressure ratio characteristics around the rotor tip of the test model turbine stage, which compare well with those observed in the experiment. A computational study with a multi-passage whole annulus domain on two different 2D blade sections is subsequently carried out. The computational results clearly show that a rotating instability in a turbine blading configuration can be captured by the 2D model. The frequency and spatial modal characteristics are analyzed. The simulations seem to be able to predict a rotating fluid dynamic instability with the similar characteristic features to those of the experiment. In contrast to the previous observations and conventional wisdom, the present work reveals that the formation and movement of the disturbance can occur without 3D and tip-leakage flows, even though a quantitative comparison with the experimental data can only be expected to be possible with full 3D unsteady solutions.

Experimental and Numerical Investigations of Steam Turbine Exhaust Hood Flow Field With Two Types of Diffusers

2019 ◽  
Author(s):  
Soichiro Tabata ◽  
Hisataka Fukushima ◽  
Kiyoshi Segawa ◽  
Koji Ishibashi ◽  
Yoshihiro Kuwamura ◽  
...  
Keyword(s):  
Flow Field ◽  
Flow Pattern ◽  
Steam Turbine ◽  
Three Dimensional ◽  
Internal Flow ◽  
Exhaust Hood ◽  
Scaled Model ◽  
Last Stage ◽  
Verification Test ◽  
Lp Turbine

Abstract The exhaust hood performance of LP turbine plays an important role in the efficiency of steam turbine. By improving the exhaust performance, the kinetic energy of the last stage rotating blades can be converted to the potential energy and it becomes possible to improve the turbine efficiency. However, the flow field in the diffuser is closely related to the flow pattern of the last stage rotating blade, and the flow field inside the exhaust chamber afterward has a complicated three dimensional flow field. Therefore, in this study, it conducted a scaled model steam turbine test using two types of diffusers and CFD, and evaluated exhaust performance and flow pattern. The verification test was carried out using a test turbine (4 stages) of × 0.33 scale, the velocity field and the pressure field were evaluated by traverse and the wall pressure measurements. The corresponding CFD was calculated by ANSYS CFX. All four stages of blades and seals, exhaust chambers were accurately modeled. Due to the detailed CFD, the internal flow of the exhaust chamber exhibiting complicated three-dimensionality was visualized and the flow pattern was evaluated. The verification test results and the corresponding CFD results were compared and evaluated, and it has been found that the overall performance predicted by CFD is well showing the verification test result. Therefore, it has been found that CFD can help to understand the internal flow of the exhaust chamber exhibiting complex three-dimensional characteristics.

scholarly journals 5 MW Closed Cycle Gas Turbine

1984 ◽  
Author(s):  
John L. Mason ◽  
Anthony Pietsch ◽  
Theodore R. Wilson ◽  
Allen D. Harper
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Oil Recovery ◽  
Low Cost ◽  
Pressure Ratio ◽  
Commercial Application ◽  
Solid Fuels ◽  
Closed Cycle ◽  
Emission Standards ◽  
Fluidized Bed Combustor

A novel closed-cycle gas turbine power system is now under development by the GWF Power Systems Company for cogeneration applications. Nominally the system produces 5 megawatts (MW) of electric power and 80,000 lb/hr (36,287 kg/hr) of 1000 psig (6895 kPa) steam. The heat source is an atmospheric fluidized bed combustor (AFBC) capable of using low-cost solid fuels while meeting applicable emission standards. A simple, low-pressure ratio, single spool, turbomachine is utilized. This paper describes the system and related performance, as well as the development and test efforts now being conducted. The initial commercial application of the system will be for Enhanced Oil Recovery (EOR) of the heavy crudes produced in California.

scholarly journals Failure Analysis in Lacing Wire Of Last Stage Low Pressure Steam Turbine Blade

2021 ◽  
Vol 1096 (1) ◽  
pp. 012097
Author(s):  
A M Kongkong ◽  
H Setiawan ◽  
J Miftahul ◽  
A R Laksana ◽  
I Djunaedi ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Steam Turbine ◽  
Turbine Blade ◽  
Low Pressure ◽  
Pressure Steam ◽  
Steam Turbine Blade ◽  
Last Stage

Some Experiments on Wet Steam Flow Visualization in Large Steam Turbine Blading

1976 ◽  
Vol 98 (3) ◽  
pp. 573-577 ◽  
Author(s):  
J. Krzyz˙anowski ◽  
B. Weigle
Keyword(s):  
Steam Turbine ◽  
Steam Flow ◽  
Light Sources ◽  
Phase Flow ◽  
Wet Steam ◽  
Experimental Conditions ◽  
Advantages And Disadvantages ◽  
Primary Droplet ◽  
Last Stage ◽  
Wet Steam Flow

In a series of experiments aimed at the visualization of the wet steam flow in the exhaust part of a 200 MW condensing steam turbine a set of periscopes and light sources was used. The aim of the experiment was: 1 – The investigation of the liquid-phase flow over the last stage stator blading of the turbine mentioned. 2 – The investigation of the gaseous-phase flow through the last stage blading at full and part load. The first part of the program partially failed due to the opaqueness of the wet steam atmosphere for the turbine load higher than 10–20 MW. The detailed experimental conditions will be described. An assessment of the primary droplet size will also be given. The preliminary results of the second part of the program will be outlined. The advantages and disadvantages of the equipment used will be discussed.

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