Experimental research of flow parameters on the last stage of the steam turbine 1090 MW

Author(s):  
Kamil Sedlák ◽  
Michal Hoznedl ◽  
Lukáš Bednář ◽  
Lukáš Mrózek ◽  
Robert Kalista
2018 ◽  
Vol 20 ◽  
pp. 43-50
Author(s):  
Michal Hoznedl ◽  
Kamil Sedlák

The paper deals with experimental and numerical research in the last stage of real 1090MW steam turbine with the last steel blade length 1220mm placed in nuclear power station. The last stage was equipped with twelve static pressure taps. It was also possible to probe in two planes - before and behind the last stage using pneumatic or optical probes. A number of last stage flow parameters were determined at the root and tip wall for nominal turbine output. Among those parameters are static pressures, Mach and Reynolds numbers, last stage reactions and steam wetness. All the directly measured and evaluated flow parameters are taken from locally measured points and that is why even 3D CFD calculation of the whole system - last stage, diffuser and exhaust hood was implemented. Measured and calculated parameters are compared. Especially static pressures are in very good agreement; the only steam wetness has bigger difference due to different measurement position. Locally measured values are enough to estimate the flow behavior of the last stage. On the other hand, the CFD simulations with well determined boundary conditions, meshes and geometry and is effective tool to simulate even very complicated flow structures in the last stage and exhaust hood.


Author(s):  
Michal Hoznedl ◽  
Michal Kolovratník ◽  
Ondřej Bartoš ◽  
Kamil Sedlák ◽  
Robert Kalista ◽  
...  

This paper presents the experimental research for the flow of the last stage of a turbine for saturated steam with the nominal output 1090 MW. In addition, the flows in 600, 800, and 1070 MW output turbines were also measured. Pneumatic probes were used to determine the distribution of static pressures and absolute angles at the outlets from the penultimate and the last stages of the turbine. Optical probes were used to measure wetness distribution and were placed in positions similar to the pneumatic probes. The courses of static pressures, angles, and wetness for all outputs respectively were compared and discussed. The difference between wetness courses on the left and right side of the turbine as well as before and behind last stage was minimal. Absolute angles of steam behind the last stage are strongly influenced by the vacuum level in the condenser. Big difference between the outlet angles from last stage on the left and right side of the turbine is confirmed. The influence of the tie-boss was evident in both pneumatic and wetness measurements. Differences of the flow field on the left and right sides of the turbine behind the penultimate stage are noted and discussed. These differences lead to a dynamic loading of the penultimate rotor blades and could reduce the service life.


Author(s):  
Robert Kalista ◽  
Lukáš Mrózek ◽  
Václav Sláma ◽  
Kamil Sedlák

Abstract Exhaust casings are one of the most important steam turbine components. The main purpose of the exhaust casing is to increase the last stage enthalpy drop, which results in an increase of the whole turbine output. It plays a significant role especially in turbines with lower outputs and in turbines whose condenser is cooled by air. In such cases, the exhaust casings with an axial diffuser is usually used. This paper deals with the investigation of the axial diffuser outlet part based on experimental measurements performed on a test rig installed in a wind tunnel in the Doosan Skoda Power laboratories and numerical simulations. The first part of the paper is about the general issues appearing the exhaust diffusers. Then, the design of the experimental test rig which aim is to simulate the flow conditions in real turbines is described. The last part of the paper is about experimental measurement as well as numerical results. The main observed phenomenon which is the effect of the circumferential angle on the inlet of the diffuser is described on different designs which were tested from the static pressure recovery factor point of view. For measuring flow parameters, a static wall pressure measurement was used together with multi-hole pneumatic probes. For numerical simulations, the commercial code ANSYS CFX 18.2 was used.


2021 ◽  
Vol 1096 (1) ◽  
pp. 012097
Author(s):  
A M Kongkong ◽  
H Setiawan ◽  
J Miftahul ◽  
A R Laksana ◽  
I Djunaedi ◽  
...  

1976 ◽  
Vol 98 (3) ◽  
pp. 573-577 ◽  
Author(s):  
J. Krzyz˙anowski ◽  
B. Weigle

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.


Author(s):  
Eric Liese

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.


Author(s):  
Fabian F. Müller ◽  
Markus Schatz ◽  
Damian M. Vogt ◽  
Jens Aschenbruck

The influence of a cylindrical strut shortly downstream of the bladerow on the vibration behavior of the last stage rotor blades of a single stage LP model steam turbine was investigated in the present study. Steam turbine retrofits often result in an increase of turbine size, aiming for more power and higher efficiency. As the existing LP steam turbine exhaust hoods are generally not modified, the last stage rotor blades frequently move closer to installations within the exhaust hood. To capture the influence of such an installation on the flow field characteristics, extensive flow field measurements using pneumatic probes were conducted at the turbine outlet plane. In addition, time-resolved pressure measurements along the casing contour of the diffuser and on the surface of the cylinder were made, aiming for the identification of pressure fluctuations induced by the flow around the installation. Blade vibration behavior was measured at three different operating conditions by means of a tip timing system. Despite the considerable changes in the flow field and its frequency content, no significant impact on blade vibration amplitudes were observed for the investigated case and considered operating conditions. Nevertheless, time-resolved pressure measurements suggest that notable pressure oscillations induced by the vortex shedding can reach the upstream bladerow.


Author(s):  
Kai Cheng ◽  
Zeying Peng ◽  
Gongyi Wang ◽  
Xiaoming Wu ◽  
Deqi Yu

In order to meet the high economic requirement of the 3rd generation Pressurized Water Reactor (PWR) or Boiling Water Reactor (BWR) applied in currently developing nuclear power plants, a series of half-speed extra-long last stage rotating blades with 26 ∼ 30 m2 nominal exhaust annular area is proposed, which covers a blade-height range from 1600 mm to 1900 mm. It is well known that developing an extra long blade is a tough job involving some special coordinated sub-process. This paper is dedicated to describe the progress of creating a long rotating blade for a large scaled steam turbine involved in the 3rd generation nuclear power project. At first the strategy of how to determine the appropriate height for the last-stage-rotating-blade for the steam turbine is provided. Then the quasi-3D flow field quick design method for the last three stages in LP casing is discussed as well as the airfoil optimization method. Furthermore a sophisticated blade structure design and analyzing system for a long blade is introduced to obtain the detail dimension of the blade focusing on the good reliability during the service period. Thus, except for CAD and experiment process, the whole pre-design phase of the extra-long turbine blade is presented which is regarded as an assurance of the operation efficiency and reliability.


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