Unsteady Wake and Vortex Interactions in 3-D Steam Turbine Low Pressure Final Three Stages

2014 ◽  
Author(s):  
Satoshi Miyake ◽  
Itsuro Koda ◽  
Satoru Yamamoto ◽  
Yasuhiro Sasao ◽  
Kazuhiro Momma ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Low Pressure ◽  
Future Perspective ◽  
Wet Steam ◽  
Vortex Interactions ◽  
Unsteady Wake ◽  
Pressure Steam ◽  
Three Stages ◽  
Nonequilibrium Condensation ◽  
Wet Steam Flow

A practical unsteady 3-D wet-steam flow through stator-rotor blade rows in a low-pressure steam turbine final three stages is numerically investigated. In ASME Turbo Expo 2013, we presented numerical results of unsteady 3-D wet-steam flows through three-stage stator-rotor low-aspect blade rows in a low-pressure steam turbine model designed by Mitsubishi Heavy Industry (MHI) assuming nonequilibrium condensation. The last study is extended to the final three stages with large aspect blade rows. The discussion in this paper is mainly focused on the effect of unsteady wake and vortex interactions on nonequilibrium condensation computed by our in-house code “Numerical Turbine System (NTS)”. In addition, the NTS and the future perspective are also briefly introduced.

scholarly journals Numerical investigation of condensing flow of low pressure steam turbine at different flow rate conditions

2017 ◽  
Vol 21 (suppl. 1) ◽  
pp. 161-167 ◽  
Author(s):  
Kezhen Huang ◽  
Lin Cai ◽  
Jianshu Gao ◽  
Zhuo Liu ◽  
Xinggang Yu
Keyword(s):  
Steam Turbine ◽  
Numerical Investigation ◽  
Low Pressure ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Wet Steam ◽  
Pressure Steam ◽  
Static Performance ◽  
Wet Steam Flow ◽  
Two Stages

The numerical investigation on the wet steam flow in the last two stages of a 1000 MW fossil-fired low pressure steam turbine is presented in this paper. The non-equilibrium model via the classical nucleation theory is employed to simulate the condensing flow of the wet steam. The characteristics of the flow filed from design condition to low volume flow condition are calculated and the static performance of last stage moving blade is also obtained. The development of the backflow phenomenon is clearly captured through the analysis of the velocity triangle.

Modelling and Validation of Wet Steam Flow in a Low Pressure Steam Turbine

2011 ◽  
Author(s):  
Jo¨rg Starzmann ◽  
M. Schatz ◽  
M. V. Casey ◽  
J. F. Mayer ◽  
Frank Sieverding
Keyword(s):  
Steam Turbine ◽  
Droplet Size ◽  
Low Pressure ◽  
Numerical Results ◽  
Steam Flow ◽  
Droplet Growth ◽  
Wet Steam ◽  
Test Rig ◽  
Pressure Steam ◽  
Wet Steam Flow

Results of numerical investigations of the wet steam flow in a three stage low pressure steam turbine test rig are presented. The test rig is a scale model of a modern steam turbine design and provides flow measurements over a range of operating conditions which are used for detailed comparisons with the numerical results. For the numerical analysis a modern CFD code with user defined models for specific wet steam modelling is used. The effect of different theoretical models for nucleation and droplet growth are examined. It is shown that heterogeneous condensation is highly dependent on steam quality and, in this model turbine with high quality steam, a homogeneous theory appears to be the best choice. The homogeneous theory gives good agreement between the test rig traverse measurements and the numerical results. The differences in the droplet size distribution of the three stage turbine are shown for different loads and modelling assumptions. The different droplet growth models can influence the droplet size by a factor of two. An estimate of the influence of unsteady effects is made by means of an unsteady two-dimensional simulation. The unsteady modelling leads to a shift of nucleation into the next blade row. For the investigated three stage turbine the influence due to wake chopping on the condensation process is weak but to confirm this conclusion further investigations are needed in complete three dimensions and on turbines with more stages.

Study on Effects of Spontaneous Condensation on Performance of Low Pressure Stages in a Steam Turbine

2006 ◽  
Author(s):  
Liang Li ◽  
Zhenping Feng ◽  
Guojun Li
Keyword(s):  
Steam Turbine ◽  
Stokes Equations ◽  
Low Pressure ◽  
Steam Flow ◽  
Vapor Flow ◽  
Wet Steam ◽  
Water Droplets ◽  
Flow Angle ◽  
Spontaneous Condensation ◽  
Wet Steam Flow

The formation of water droplets in low-pressure steam turbine seriously degrades the performance of the turbine. In order to simulate the wet steam flow with spontaneous condensation, an Eulerian/Eulerian model was developed, in which the Navier-Stokes equations for water vapor flow are coupled with two additional equations describing the formation and the distributions of water droplets. The classical condensation theory was used to model the condensation process. With this model, the three dimensional (3D) steady wet steam flow with spontaneous condensation in three low pressure (LP) stages of an industrial steam turbine was numerically investigated and the results were compared with those in superheated flow. The distribution of pressure, the enthalpy drop, the reaction degree, the outflow velocity and flow angle in each wet steam turbine stage obviously change due to the spontaneous condensation in wet steam flow, compare to those in the superheated flow. The re-distribution of flow parameters in condensing flow leads to that the turbine stages run at ‘off-design’ condition actually, which leads to additional efficiency losses besides the well-known non-equilibrium losses.

Unsteady Flow Effect on Nonequilibrium Condensation in 3-D Low Pressure Steam Turbine Stages

2013 ◽  
Author(s):  
Satoshi Miyake ◽  
Satoru Yamamoto ◽  
Yasuhiro Sasao ◽  
Kazuhiro Momma ◽  
Toshihiro Miyawaki ◽  
...  
Keyword(s):  
Unsteady Flow ◽  
Steam Turbine ◽  
Cross Sections ◽  
Rotor Blade ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Low Pressure ◽  
Multi Stage ◽  
Pressure Steam ◽  
Nonequilibrium Condensation

A numerical study simulating unsteady 3-D wet-steam flows through three-stage stator-rotor blade rows in a low-pressure steam turbine model experimentally conducted by Mitsubishi Heavy Industry (MHI) was presented in the last ASME Turbo Expo by our group. In this study, the previous discussion is extended to the discussion how nonequilibrium condensation is influenced by unsteady wakes and corner vortices from prefaced multi-stage blade rows. Unsteady 3-D flows through three-stage stator-rotor blade rows are simulated assuming nonequilibrium condensation. Flows with a different inlet flow condition are calculated and the results are compared with each other. Instantaneous condensate mass fractions are visualized at different spans and cross sections in the three-stage stator and rotor blade rows. Also the time and space dependent values are plotted and the obtained unsteady flow characteristics are explained.

Aerodynamic Interaction Effects From Upstream and Downstream on the Down-Flow Type Exhaust Diffuser Performance in a Low Pressure Steam Turbine

2013 ◽  
Author(s):  
Tadashi Tanuma ◽  
Yasuhiro Sasao ◽  
Satoru Yamamoto ◽  
Yoshiki Niizeki ◽  
Naoki Shibukawa ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Low Pressure ◽  
Interaction Effects ◽  
Wet Steam ◽  
Inlet Flow ◽  
Flow Type ◽  
Diffuser Flow ◽  
Aerodynamic Interaction ◽  
Pressure Steam ◽  
Last Stage

The purpose of this paper is to explain aerodynamic interaction effects from upstream and downstream on the down-flow type exhaust diffuser performance in a low pressure steam turbine. To increase exhaust diffuser performance, design data related to the aerodynamic interaction effects from upstream turbine stages and downstream exhaust hood geometry on the exhaust diffuser performance would be very useful. This paper presents numerical investigation of three dimensional wet steam flows in a down-flow type exhaust diffuser with non-uniform inlet flow from a typical last stage with long transonic blades designed with recent aerodynamic and mechanical design technology. Previous studies show that small scale model tests and CFD analyses of exhaust diffusers with uniform inlet flow conditions are not enough to investigate diffuser efficiency and detail diffuser flow mechanism because inlet flow structures including tip leakage flows and blade wakes superimposed from a last stage and several other upstream turbine stages in low pressure turbines affect flow separations that reduce the exhaust diffuser performance. Recent studies by the authors show that the introduction of radial distributions of velocities and flow angles at the inlet section of exhaust diffuser measured in a full scale development steam turbine increased the accuracy of numerical analysis of diffuser flow. In the present study, the computational domain was enhanced and the method of boundary condition definition was improved to increase the accuracy of boundary layer separation and separation vortex generation in wet steam flows. Using the improved method, the calculation results explained the aerodynamic interaction effects from upstream and downstream on the down-flow type exhaust diffuser performance.

Unsteady Wet-Steam Flows Through Low Pressure Turbine Final Three Stages Considering Blade Number

2015 ◽  
Author(s):  
Satoshi Miyake ◽  
Hironori Miyazawa ◽  
Satoru Yamamoto ◽  
Yasuhiro Sasao ◽  
Kazuhiro Momma ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Low Pressure ◽  
Numerical Results ◽  
Steam Turbines ◽  
Wet Steam ◽  
Flow Simulations ◽  
Low Pressure Turbine ◽  
Blade Number ◽  
Pressure Steam ◽  
Three Stages

Unsteady three-dimensional wet-steam flows through stator–rotor blade rows in the final three stages of a low-pressure steam turbine, taking the blade number into consideration, are numerically investigated. In ASME Turbo Expo 2014, we presented the numerical results of the unsteady flow assuming the same blade number. Here, this previous study is extended to flow simulations using the real blade number. The flows under three flow conditions, with and without condensation and considering the same and real blade numbers are simulated, and the numerical results are compared with each other and with the experimental results. Finally, the effect of the blade number on unsteady wet-steam flows in real low-pressure steam turbines is discussed.

scholarly journals Unsteady Wet Steam Flow Measurements in a Low-Pressure Test Steam Turbine

2016 ◽  
Vol 9 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Chongfei Duan ◽  
Koji Ishibashi ◽  
Shigeki Senoo ◽  
Ilias Bosdas ◽  
Michel Mansour ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Low Pressure ◽  
Steam Flow ◽  
Wet Steam ◽  
Flow Measurements ◽  
Pressure Test ◽  
Wet Steam Flow

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
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