scholarly journals Application of numerical modelling for determining the optimal position of the suction slot in the steam turbine vane cascade

2020 ◽  
Vol 1683 ◽  
pp. 022067
Author(s):  
V G Gribin ◽  
A A Tishchenko ◽  
R A Alekseev ◽  
I Yu Gavrilov ◽  
V V Popov ◽  
...  
Author(s):  
Yasutomo Kaneko ◽  
Kazushi Mori ◽  
Hiroharu Ohyama

The vane used in a low pressure end of steam turbine is usually fixed to shroud and casing by welding both ends. In such a vane structure, the damping in loading operation is comprised of the material damping and the aerodynamic damping, because the structural damping is very small. In this paper, first, the vane is modeled by the uniform beam fixed at both ends, and the effect of the material damping on the vane flutter is studied. In the stability analysis, the simple one-degree-of-freedom model is applied, where the linear aerodynamic model is used. In other words, it is assumed that the aerodynamic force due to the working fluid is proportional to the vane velocity and the negative damping coefficient does not change with amplitude. The allowable aerodynamic damping for the vane flutter is calculated and compared for the solid vane and the hollow vane. In addition, the vibration analysis of the actual steam turbine vane is carried out by 3D FEA (Finite Element Analysis), and the material damping of the solid and hollow vane is calculated by use of the results by FEA. The stability of the solid vane and the hollow vane on the flutter is also evaluated by use of the results calculated by FEA. From these results, the material damping characteristics of the steam turbine vane are clarified, as well as the effect of the material damping of the steam turbine vane on the flutter suppression.


Author(s):  
Yasutomo Kaneko ◽  
Hiroyuki Yamashita ◽  
Hiroharu Ooyama

A vane used in a low pressure end of a steam turbine is usually fixed to a shroud and a casing by welding both ends. In such a vane structure, the damping in loading operation is comprised of the material damping and the aerodynamic damping, because the structural damping is very small. In the blade and vane of high-capacity steam turbine units, the aerodynamic damping may become negative under the high loading operation, and some papers reported the self-excited vibration of the blade and vane caused by the negative aerodynamic damping. Recently, in order to increase the reliability of the steam turbine vane, a hollow vane with a friction damper has been proposed. In such a steam turbine vane, the curved damper piece made of the thin plate is inserted into the hollow vane, and the structural damping is added by use of the friction between the damper piece and the vane. In this paper, for the purpose of clarifying the damping characteristics of the hollow vane with the friction damper, first, the excitation test of the model vane is carried out. In the excitation test of the model vane, the damping characteristics of the model vane consisting of two flat plates and the thin curved damper piece are measured, changing the excitation force. Second, the analysis method for predicting the damping characteristics of the hollow vane with the friction damper, which utilizes the conventional modal analysis method and the harmonic balance method, is proposed. The validity of the analysis method is verified by comparing the measured damping with the calculated ones. After verifying the analysis method, the actual steam turbine hollow vane with the friction damper is also analyzed, and the effect of the damper stiffness on the damping characteristics is examined. Finally, the actual hollow vane with the friction damper for the high-capacity steam turbine unit is designed and manufactured, and the excitation test of the actual hollow vane is carried out. From these results, the damping characteristics of the hollow vane with the friction damper are clarified.


Author(s):  
D. J. Ryley ◽  
G. J. Parker

This paper reports an experimental research undertaken to explore the performance of a suction slot located in the trailing edge of a representative low-pressure steam turbine fixed blade. Tests have been made on a 1-in wide section of a full-size hollow blade mounted in a single-blade test section. Typical turbine pressures were reproduced down to 3 inHg (abs.), and blade exit Mach numbers varied in the range 0·57–1·10. With round entry lips, the slot operated satisfactorily in any blade orientation, as it completely removed quantities of water that were in excess of the amount expected under operating conditions. Square entry lips gave somewhat poorer performance.


Author(s):  
Xinjun Wang ◽  
Pengfei Su ◽  
Luke Chou ◽  
Panlong Guan ◽  
Chunguo Li ◽  
...  

Water droplets dispersion through a stationary cascade channel and their deposition on the blade surface in the last-stage of a 600MW steam turbine have been simulated with CFD software FLUENT. So the deposition on stationary blades along the axial and radial direction was determined. In the experiment, the performance of water removal by suction slots on stationary blades surface was investigated. The results showed that: 12.2% of water at the inlet still existed as droplets, depositing on the concave side of the airfoils in contrast with only 1.6% on the convex side. The volume of the water removed by the suction slots on the concave side was bigger than that on the convex side. The closer the slot position was to the trailing edge, the bigger the volume was. The volume became smaller and then larger with the increase in slot width; the minimum value occurred when slots were about 3.0 mm in width. The bigger suction pressure difference would initiate a bigger volume of water removed by suction slots, but the increase in main flow rate would quickly initiate a smaller volume.


2014 ◽  
Vol 6 (12) ◽  
pp. 1282-1286
Author(s):  
Feng Zi-Ming ◽  
Ding Huanhuan ◽  
Li Chunhong ◽  
Xu Ping

Author(s):  
Srikanth Deshpande ◽  
Marcus Thern ◽  
Magnus Genrup

Vortexing methods implemented on an industrial steam turbine vane in order to reduce secondary losses are discussed. Three vortexing methods presented are prismatic blade design, inverse vortex and parabolic forced vortex. Baseline industrial vane considered for study is a prismatic blade design. Modifications are analysed numerically using commercial code CFX. Modified vanes along with baseline rotor as a complete stage is considered for analysis. Steady state Reynolds averaged Navier Stokes equations are solved. Total pressure loss (TPL) is used as target functions to monitor reduction in secondary losses. Rotor considered for the study is the baseline industrial rotor for all design modifications of vane.


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