scholarly journals Simulation of unsteady flows through three-stage middle pressure steam turbine in operation

2020 ◽  
Vol 7 (4) ◽  
pp. 20-00068-20-00068 ◽  
Author(s):  
Akihiro UEMURA ◽  
Hironori MIYAZAWA ◽  
Takashi FURUSAWA ◽  
Satoru YAMAMOTO ◽  
Koichi YONEZAWA ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Unsteady Flows ◽  
Pressure Steam

Simulation of Unsteady Flows in Intermediate Pressure Steam Turbine with Cutback Stator Blade Row

2020 ◽  
Vol 2020 (0) ◽  
pp. J05102
Author(s):  
Hironori MIYAZAWA ◽  
Akihiro UEMURA ◽  
Takashi FURUSAWA ◽  
Satoru YAMAMOTO ◽  
Shuichi UMEZAWA ◽  
...  
Keyword(s):  
Steam Turbine ◽  
Unsteady Flows ◽  
Intermediate Pressure ◽  
Blade Row ◽  
Pressure Steam ◽  
Stator Blade

Effect of Blade Secular Change on Unsteady Flows in Middle Pressure First-Stage Steam Turbines

2019 ◽  
Author(s):  
Akihiro Uemura ◽  
Hironori Miyazawa ◽  
Takashi Furusawa ◽  
Satoru Yamamoto ◽  
Koichi Yonezawa ◽  
...  
Keyword(s):  
Power Plant ◽  
Steam Turbine ◽  
Rotor Blade ◽  
Unsteady Flows ◽  
Secular Change ◽  
Steam Turbines ◽  
Secular Changes ◽  
Pressure Steam ◽  
The Difference ◽  
Over Time

Abstract This paper presents the effect of blade secular changes in stator and rotor blade passages on unsteady flows through the first-stage in a middle pressure steam turbine. The scales from the boilers may collide with the stator and rotor blade surfaces, and the blades could become gradually thinned or adhered over time because of the collision. The secular-changed blades influence the performance of steam turbines and may further induce unexpected accidents. Therefore, the maintenance, repair, and overhaul (MRO) of steam turbines is essential. The optimization of MRO scheduling is quite crucial for electric power companies. We simulated unsteady steam flows through an actual middle pressure steam turbine working at a coal-fired power plant while setting manufactured and secular-changed blades. The shape of the secular-changed blades was measured from actual blades during overhaul. The numerical method developed at Tohoku University was employed for the simulation. The difference in the results between the manufactured and secular-changed blades is shown, and the effect of secular changes on unsteady flows is investigated. In addition, the possibility of utilizing the results in the MRO of real turbines is highlighted.

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

Using CFD to Enhance the Preliminary Design of High-Pressure Steam Turbines

2013 ◽  
Author(s):  
Juri Bellucci ◽  
Federica Sazzini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Design Tool ◽  
Tip Clearance ◽  
Large Set ◽  
Preliminary Design ◽  
Steam Turbines ◽  
High Pressure Steam ◽  
Wide Range ◽  
Pressure Steam

This paper focuses on the use of the CFD for improving a steam turbine preliminary design tool. Three-dimensional RANS analyses were carried out in order to independently investigate the effects of profile, secondary flow and tip clearance losses, on the efficiency of two high-pressure steam turbine stages. The parametric study included geometrical features such as stagger angle, aspect ratio and radius ratio, and was conducted for a wide range of flow coefficients to cover the whole operating envelope. The results are reported in terms of stage performance curves, enthalpy loss coefficients and span-wise distribution of the blade-to-blade exit angles. A detailed discussion of these results is provided in order to highlight the different aerodynamic behavior of the two geometries. Once the analysis was concluded, the tuning of a preliminary steam turbine design tool was carried out, based on a correlative approach. Due to the lack of a large set of experimental data, the information obtained from the post-processing of the CFD computations were applied to update the current correlations, in order to improve the accuracy of the efficiency evaluation for both stages. Finally, the predictions of the tuned preliminary design tool were compared with the results of the CFD computations, in terms of stage efficiency, in a broad range of flow coefficients and in different real machine layouts.

Development of a Hydrogen-Fueled Combustion Turbine Cycle for Power Generation

1998 ◽  
Vol 120 (2) ◽  
pp. 276-283 ◽  
Author(s):  
R. L. Bannister ◽  
R. A. Newby ◽  
W. C. Yang
Keyword(s):  
Steam Turbine ◽  
Rankine Cycle ◽  
Energy System ◽  
Cryogenic Liquid ◽  
Pure Oxygen ◽  
Pure Hydrogen ◽  
Development Organization ◽  
Cell Conversion ◽  
Pressure Steam ◽  
Near Term

Consideration of a hydrogen based economy is attractive because it allows energy to be transported and stored at high densities and then transformed into useful work in pollution-free turbine or fuel cell conversion systems. Through its New Energy and Industrial Technology Development Organization (NEDO) the Japanese government is sponsoring the World Energy Network (WE-NET) Program. The program is a 28-year global effort to define and implement technologies needed for a hydrogen-based energy system. A critical part of this effort is the development of a hydrogen-fueled combustion turbine system to efficiently convert the chemical energy stored in hydrogen to electricity when the hydrogen is combusted with pure oxygen. The full-scale demonstration will be a greenfield power plant located seaside. Hydrogen will be delivered to the site as a cryogenic liquid, and its cryogenic energy will be used to power an air liquefaction unit to produce pure oxygen. To meet the NEDO plant thermal cycle requirement of a minimum of 70.9 percent, low heating value (LHV), a variety of possible cycle configurations and working fluids have been investigated. This paper reports on the selection of the best cycle (a Rankine cycle), and the two levels of technology needed to support a near-term plant and a long-term plant. The combustion of pure hydrogen with pure hydrogen with pure oxygen results only in steam, thereby allowing for a direct-fired Rankine steam cycle. A near-term plant would require only development to support the design of an advanced high pressure steam turbine and an advanced intermediate pressure steam turbine.

Detailed Numerical Study of the Main Sources of Loss and Flow Behavior in Low Pressure Steam Turbine Exhaust Hoods

2017 ◽  
Author(s):  
Dickson Munyoki ◽  
Markus Schatz ◽  
Damian M. Vogt
Keyword(s):  
Steam Turbine ◽  
Numerical Study ◽  
Flow Behavior ◽  
Low Pressure ◽  
Operating Conditions ◽  
Pressure Recovery ◽  
Exhaust Hood ◽  
Recovery Coefficient ◽  
Pressure Steam ◽  
Underlying Mechanisms

The performance of the axial-radial diffuser downstream of the last low-pressure steam turbine stages and the losses occurring subsequently within the exhaust hood directly influences the overall efficiency of a steam power plant. It is estimated that an improvement of the pressure recovery in the diffuser and exhaust hood by 10% translates into 1% of last stage efficiency [11]. While the design of axial-radial diffusers has been the object of quite many studies, the flow phenomena occurring within the exhaust hood have not received much attention in recent years. However, major losses occur due to dissipation within vortices and inability of the hood to properly diffuse the flow. Flow turning from radial to downward flow towards the condenser, especially at the upper part of the hood is essentially the main cause for this. This paper presents a detailed analysis of the losses within the exhaust hood flow for two operating conditions based on numerical results. In order to identify the underlying mechanisms and the locations where dissipation mainly occurs, an approach was followed, whereby the diffuser inflow is divided into different sectors and pressure recovery, dissipation and finally residual kinetic energy of the flow originating from these sectors is calculated at different locations within the hood. Based on this method, the flow from the topmost sectors at the diffuser inlet is found to cause the highest dissipation for both investigated cases. Upon hitting the exhaust hood walls, the flow on the upper part of the diffuser is deflected, forming complex vortices which are stretching into the condenser and interacting with flow originating from other sectors, thereby causing further swirling and generating additional losses. The detailed study of the flow behavior in the exhaust hood and the associated dissipation presents an opportunity for future investigations of efficient geometrical features to be introduced within the hood to improve the flow and hence the overall pressure recovery coefficient.

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