In-Scale and Up-Scale Full Turbine Stage Measurements as a Support for Small Turbine Units Development

2012 ◽  
Author(s):  
Martin Němec ◽  
Tomáš Jelínek ◽  
Martin Babák
Keyword(s):  
Flow Field ◽  
Channel Height ◽  
Turbine Stage ◽  
Performance Study ◽  
Gas Generator ◽  
Time Resolved ◽  
Jet Engine ◽  
Cool Flow ◽  
Stage Performance ◽  
Flow Field Measurement

This paper summarizes experimental results of an aerodynamic performance study carried out on two full stage turbine test rigs. The stage under investigation was designed as a gas generator turbine for a small jet engine produced by PBS (the TJ100 engine with thrust of 1100 N and turbine tip diameter of 141 mm). The investigation was carried out alternatively on two full-stage test rigs (in-scale and scaled-up) integrated into a cool flow closed-loop wind tunnel located at VZLU. Firstly, the in-scale testing, focusing on an overall stage performance measured by means of a hydraulic dynamometer was arranged. Furthermore, some time-averaged flow field parameters in terms of total pressure, velocity and angles were acquired along the channel height upstream and downstream of the stage. The flow path authenticity and construction simplicity were strictly followed during the rig design phase and therefore original parts of the engine were mostly used. Then, the verification of results was performed with the stage scaled-up by factor 2.27. The overall stage performance was measured and compared with results of the in-scale measurement. Moreover, detail unsteady flow field measurement at the rotor exit was performed. Time-resolved data were analysed in order to study the influences of the stage load on the stage performance.

Comparison of Steady and Unsteady Coupled Heat-Transfer Simulations of a High-Pressure Turbine Blade

2015 ◽  
Author(s):  
Markus Schmidt ◽  
Christoph Starke
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Steady State ◽  
Flow Field ◽  
Film Cooling ◽  
Strong Increase ◽  
Pressure Side ◽  
Turbine Stage ◽  
High Pressure Turbine ◽  
Time Resolved

This article presents results for the coupled simulation of a high-pressure turbine stage in consideration of unsteady hot gas flows. A semi-unsteady coupling process was developed to solve the conjugate heat transfer problem for turbine components of gas turbines. Time-resolved CFD simulations are coupled to a finite element solver for the steady state heat conduction inside of the blade material. A simplified turbine stage geometry is investigated in this paper to describe the influence of the unsteady flow field onto the time-averaged heat transfer. Comparisons of the time-resolved results to steady state results indicate the importance of a coupled simulation and the consideration of the time-dependent flow-field. Different film-cooling configurations for the turbine NGV are considered, resulting in different temperature and pressure deficits in the vane wake. Their contribution to non-linear effects causing the time-averaged heat load to differ from a steady result is discussed to further highlight the necessity of unsteady design methods for future turbine developments. A strong increase in the pressure side heat transfer coefficients for unsteady simulations is observed in all results. For higher film-cooling mass flows in the upstream row, the preferential migration of hot fluid towards the pressure side of a turbine blade is amplified as well, which leads to a strong increase in material temperature at the pressure side and also in the blade tip region.

Three-Dimensional Time-Resolved Flow Field in the First and Last Turbine Stage of a Heavy Duty Gas Turbine: Part I — Secondary Flow Field

2000 ◽  
Author(s):  
Martin von Hoyningen-Huene ◽  
Wolfram Frank ◽  
Alexander R. Jung
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Companion Paper ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Time Resolved ◽  
Heavy Duty Gas Turbine ◽  
Secondary Flow Field

Unsteady stator-rotor interaction in gas turbines has been investigated both experimentally and numerically for some years now. Even though the numerical methods are still in development, today they have reached a certain degree of maturity allowing industry to focus on the results of the computations and their impact on turbine design, rather than on a further improvement of the methods themselves. The key to increase efficiency in modern gas turbines is a better understanding and subsequent optimization of the loss-generation mechanisms. A major part of these are the secondary losses. To this end, this paper presents the time-resolved secondary flow field for the two test cases computed, viz the first and the last turbine stage of a modern heavy duty gas turbine. A companion paper referring to the same computations focuses on the unsteady pressure fluctuations on vanes and blades. The investigations have been performed with the flow solver ITSM3D which allows for efficient calculations that simulate the real blade count ratio. This is a prerequisite to simulate the unsteady phenomena in frequency and amplitude properly.

Effect of Stage Reaction and Shaft Labyrinth Seal in a Stage of an Axial Steam Turbine

2020 ◽  
Author(s):  
Martin Nemec ◽  
Tomas Jelinek ◽  
Jan Uher ◽  
Petr Milcak
Keyword(s):  
Flow Field ◽  
Steam Turbine ◽  
Mass Flow ◽  
Labyrinth Seal ◽  
Measured Data ◽  
Total Loss ◽  
Relative Mass ◽  
Turbine Stage ◽  
Wide Range ◽  
Stage Performance

Abstract This paper focuses on the influence of shaft labyrinth seal flow on full stage performance. Experimental data are studied, expected design conditions and experimental results are compared and discussed and a losses breakdown for the design procedure is presented. The experimental investigation was performed in VZLU’s air test turbine which is a part of a closed-loop system equipped with a radial compressor. The test turbine configuration simulated the real drum-stage geometry of an axial steam turbine. The geometry of the turbine represents a typical mid-pressure stage of a steam turbine. The configuration of the test rig was adapted in order to easily change the shaft labyrinth seal geometry. The study covered a wide range of seal clearances from very small to extremely large clearances, reaching a maximum relative mass flow approximately 10% of the stator blade flow. Different types of seal feed were also tested to compare internal feed (the flow obtained from the stator flow by the hub-gap just in front of the stator) and external feed realized by additional piping with external regulation. Three stage reactions were tested in this work — Low Reaction, Mid Reaction and Full Reaction. The stator of the stages was the same in all cases, thus the reaction was changed by implementing three different rotor geometries. The influence of the labyrinth seal clearance was investigated by overall performance measurement and by detailed investigation of the flow field. The turbine stage was loaded by a hydraulic dynamometer used for regulating the rotational speed and a flange torquemeter was used to determine the stage efficiency. The total mass flow was measured using an orifice plate. Each seal geometry configuration was calibrated to compute the seal mass flow. The turbine stage and seal were equipped with a number of static pressure taps, and miniature pressure probes were used for measuring the flow field parameters in detail. The discussion of the results is divided into two areas. Firstly, the influence of the degree of reaction on axial steam turbine stage performance in the configuration without the seal flow is presented. Then, a combination of various degrees of reaction is studied as a function of mass flow through the shaft labyrinth seal. The measured data are evaluated by a breakdown of loss sources. The decomposition of the total loss into row losses, leakage losses and mixing losses is highly advantageous. This total loss analysis is carried out for all three stages and both off-design performance and ratios of the shaft seal flow to nozzle blade flow are measured. The post-processing of measured data through this loss breakdown and the comparison with the design is used to validate the design process.

Design and Numerical Analysis of a Forepart Rotation Vane for a Variable Nozzle Turbine

2019 ◽  
Vol 36 (3) ◽  
pp. 233-244 ◽  
Author(s):  
Dengfeng Yang ◽  
Dazhong Lao ◽  
Ce Yang ◽  
Leon Hu ◽  
Harold Sun
Keyword(s):  
Numerical Analysis ◽  
Shock Waves ◽  
Flow Field ◽  
Rotor Blades ◽  
Leakage Flow ◽  
Exhaust Gas ◽  
Turbine Stage ◽  
And Shock Waves ◽  
Stage Performance ◽  
Stage Efficiency

AbstractThe influence of nozzle clearance on the flow field for a variable nozzle turbine, and moreover on the turbine stage performance was numerically investigated. Meanwhile, unsteady calculations were also performed to capture the shock waves which were induced by excessive acceleration of the exhaust gas. Aiming at improving the turbine stage performance and mitigating the shock waves, a forepart rotation vane was proposed and investigated in this work. The results indicated that by using the forepart rotation vane, the stage efficiency is increased by 6 % and the shock waves were eliminated successfully at small nozzle openings. Additionally, the intensity of pressure fluctuation that acts on the rotor blades was reduced by mitigation of clearance leakage flow and shock waves, which is beneficial for the reliability of rotor blades.

Numerical investigation of non-uniform flow in twin-silo combustors and impact on axial turbine stage performance

2021 ◽  
pp. 095765092199394
Author(s):  
Hafiz M Hassan ◽  
Adeel Javed ◽  
Asif H Khoja ◽  
Majid Ali ◽  
Muhammad B Sajid
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Internal Flow ◽  
Large Temperature ◽  
Clear Understanding ◽  
Gas Temperature ◽  
Turbine Stage ◽  
Flow Angle ◽  
Axial Turbine ◽  
Stage Performance

A clear understanding of the flow characteristics in the older generation of industrial gas turbines operating with silo combustors is important for potential upgrades. Non-uniformities in the form of circumferential and radial variations in internal flow properties can have a significant impact on the gas turbine stage performance and durability. This paper presents a comprehensive study of the underlying internal flow features involved in the advent of non-uniformities from twin-silo combustors and their propagation through a single axial turbine stage of the Siemens v94.2 industrial gas turbine. Results indicate the formation of strong vortical structures alongside large temperature, pressure, velocity, and flow angle deviations that are mostly located in the top and bottom sections of the turbine stage caused by the excessive flow turning in the upstream tandem silo combustors. A favorable validation of the simulated exhaust gas temperature (EGT) profile is also achieved via comparison with the measured data. A drop in isentropic efficiency and power output equivalent to 2.28% points and 2.1 MW, respectively is observed at baseload compared to an ideal straight hot gas path reference case. Furthermore, the analysis of internal flow topography identifies the underperforming turbine blading due to the upstream non-uniformities. The findings not only have implications for the turbine aerothermodynamic design, but also the combustor layout from a repowering perspective.

The Time-Resolved Internal and External Flow Field Properties of a Fluidic Oscillator

2014 ◽  
Author(s):  
Sarah Gaertlein ◽  
Rene Woszidlo ◽  
Florian Ostermann ◽  
C. Nayeri ◽  
Christian O. Paschereit
Keyword(s):  
Flow Field ◽  
External Flow ◽  
Time Resolved ◽  
Fluidic Oscillator
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