Simple Particle Separator for the Secondary Air System of Gas Turbines

2012 ◽  
Author(s):  
Natalia García Víllora ◽  
Klaus Dullenkopf ◽  
Hans-Jörg Bauer ◽  
Cyrille Bricaud ◽  
Thomas Zierer
Keyword(s):  
Turbulent Flows ◽  
Gas Turbines ◽  
Separation Efficiency ◽  
Cooling System ◽  
Material Selection ◽  
Solid Particles ◽  
Air System ◽  
Secondary Air ◽  
Institute Of Technology ◽  
Particle Separator

In heavy-duty gas turbines as well as in aero-engines, air is extracted from the compressor and led to the hot parts of the combustor and the turbine in order to cool them. Despite active design solutions such as material selection, and inclusion of compressor inlet filters, dust holes, and so on, the cooling air can be charged with solid particles, which can block the cooling holes. Therefore prediction of the particle behaviour within the secondary air system remains crucial for the design of a robust and efficient cooling system for the hot parts. For this study a particle separator prototype was designed by Alstom and its particle separation efficiency together with its total pressure losses were measured at the Institute of Thermal Turbomachinery (ITS) at the Karlsruher Institute of Technology (KIT) for two geometrical configurations and numerous flow conditions. The test rig design was optimized to provide accurate boundary conditions for the simulations. In addition, the influence of the particle shape, size, and density on the separation efficiency was studied. The experimental results were used to validate the predicted flow field and to evaluate standard methods available in a commercial CFD-solver, to simulate the interaction of solid particles with turbulent flows and the containing walls. Comparisons between the measured and calculated separation efficiencies were performed for spherical and flat particles with different Stokes numbers. In particular, the way in which a simple modelling approach used for the prediction of sphere trajectories can be transferred to flat particles was investigated. Finally this study delivers generic data for improved modelling of solid particles, like spheres and flat particles, in turbulent flows.

Separation of Particles in the Secondary Air System of Gas Turbines

2011 ◽  
Author(s):  
Natalia Garci´a Vi´llora ◽  
Klaus Dullenkopf ◽  
Hans-Jo¨rg Bauer
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Separation Efficiency ◽  
Cooling System ◽  
Turbine Blades ◽  
Spherical Particles ◽  
Experimental Investigations ◽  
Air System ◽  
Secondary Air ◽  
Aero Engines

Particles contaminating the secondary air system of land based gas turbines or aero-engines can cause serious problems in various engine components, particularly in the cooling system. The capability of the pre-swirl system in separating particles will be described in this paper. So far, only a few publications can be found on experimental investigations on this subject. The work presented in this paper attempts to give a contribution to fill this gap and thus represents a further step towards a better understanding of the behaviour of solid contaminants in the secondary air system. Due to the strong swirl in the pre-swirl cavity, the aero-dynamical forces can be used to separate particles, thus preventing depositions inside the turbine blades or even block-age of the film cooling holes. Numerous experiments in a pre-swirl system have been performed using spherical particles and non-spherical particles. As reference cases, three types of spheres, with two size ranges and different materials, were used to understand how size and density influence the separation efficiency. For further experiments, irregularly-shaped particles, more similar to the ones found in real aero-engines, were used too. The separation efficiency was investigated at different pre-swirl nozzle pressure ratios, rotational speeds and radial mass flows. The results are presented in relation to the particle Reynolds numbers, drag coefficients, Stokes numbers and swirl ratios in the pre-swirl cavity.

Heavy Duty Gas Turbine Simulation: Global Performances Estimation and Secondary Air System Modifications

2006 ◽  
Author(s):  
Carlo Carcasci ◽  
Bruno Facchini ◽  
Stefano Gori ◽  
Luca Bozzi ◽  
Stefano Traverso
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Energy System ◽  
Operating Conditions ◽  
Coupled Analysis ◽  
Ambient Conditions ◽  
Air System ◽  
Secondary Air ◽  
And Performance

This paper reviews a modular-structured program ESMS (Energy System Modular Simulation) for the simulation of air-cooled gas turbines cycles, including the calculation of the secondary air system. The program has been tested for the Ansaldo Energia gas turbine V94.3A, which is one of the more advanced models in the family Vx4.3A with a rated power of 270 MW. V94.3A cooling system has been modeled with SASAC (Secondary Air System Ansaldo Code), the Ansaldo code used to predict the structure of the flow through the internal air system. The objective of the work was to investigate the tuning of the analytical program on the basis of the data from design and performance codes in use at Ansaldo Energy Gas Turbine Department. The results, both at base load over different ambient conditions and in critical off-design operating points (full-speed-no-load and minimum-load), have been compared with APC (Ansaldo Performance Code) and confirmed by field data. The coupled analysis of cycle and cooling network shows interesting evaluations for components life estimation and reliability during off-design operating conditions.

An Efficient Procedure for the Analysis of Heavy Duty Gas Turbine Secondary Flows in Different Operating Conditions

2010 ◽  
Author(s):  
Matteo Cerutti ◽  
Luca Bozzi ◽  
Federico Bonzani ◽  
Carlo Carcasci
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Cooling System ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Efficient Procedure ◽  
Air System ◽  
Secondary Air ◽  
Flow Functions

Combined cycle and partial load operating of modern heavy-duty gas turbines require highly efficient secondary air systems to supply both cooling and sealing air. Accurate performance predictions are then a fundamental demand over a wide range of operability. The paper describes the development of an efficient procedure for the investigation of gas turbine secondary flows, based on an in-house made fluid network solver, written in Matlab® environment. Fast network generation and debugging are achieved thanks to Simulink® graphical interface and modular structure, allowing predictions of the whole secondary air system. A crucial aspect of such an analysis is the calculation of blade and vane cooling flows, taking into account the interaction between inner and outer extraction lines. The problem is closed thanks to ad-hoc calculated transfer functions: cooling system performances and flow functions are solved in a pre-processing phase and results correlated to influencing parameters using Response Surface Methodology (RSM) and Design of Experiments (DOE) techniques. The procedure has been proved on the secondary air system of the AE94.3A2 Ansaldo Energia gas turbine. Flow functions for the cooling system of the first stage blade, calculated by RSM and DOE techniques, are presented. Flow functions based calculation of film cooling, tip cooling and trailing edge cooling air flows is described in details.

A numerical study on combined baffles quick-separation device

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ehsan Dehdarinejad ◽  
Morteza Bayareh ◽  
Mahmud Ashrafizaadeh
Keyword(s):  
Turbulent Flows ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Turbulence Models ◽  
Complete Separation ◽  
Solid Particles ◽  
Flow Rates ◽  
Separation Device ◽  
Coupling Technique ◽  
Laminar And Turbulent Flows

Abstract The transfer of particles in laminar and turbulent flows has many applications in combustion systems, biological, environmental, nanotechnology. In the present study, a Combined Baffles Quick-Separation Device (CBQSD) is simulated numerically using the Eulerian-Lagrangian method and different turbulence models of RNG k-ε, k-ω, and RSM for 1–140 μm particles. A two-way coupling technique is employed to solve the particles’ flow. The effect of inlet flow velocity, the diameter of the splitter plane, and solid particles’ flow rate on the separation efficiency of the device is examined. The results demonstrate that the RSM turbulence model provides more appropriate results compared to RNG k-ε and k-ω models. Four thousand two hundred particles with the size distribution of 1–140 µm enter the device and 3820 particles are trapped and 380 particles leave the device. The efficiency for particles with a diameter greater than 28 µm is 100%. The complete separation of 22–28 μm particles occurs for flow rates of 10–23.5 g/s, respectively. The results reveal that the separation efficiency increases by increasing the inlet velocity, the device diameter, and the diameter of the particles.

scholarly journals Cooling and Sealing Air System in Industrial Gas Turbine Engines

1996 ◽  
Author(s):  
A. W. Reichert ◽  
M. Janssen
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Inlet Temperature ◽  
Turbine Inlet ◽  
Air System ◽  
Calculation System ◽  
Cooling Air

Siemens heavy duty Gas Turbines have been well known for their high power output combined with high efficiency and reliability for more than 3 decades. Offering state of the art technology at all times, the requirements concerning the cooling and sealing air system have increased with technological development over the years. In particular the increase of the turbine inlet temperature and reduced NOx requirements demand a highly efficient cooling and sealing air system. The new Vx4.3A family of Siemens gas turbines with ISO turbine inlet temperatures of 1190°C in the power range of 70 to 240 MW uses an effective film cooling technique for the turbine stages 1 and 2 to ensure the minimum cooling air requirement possible. In addition, the application of film cooling enables the cooling system to be simplified. For example, in the new gas turbine family no intercooler and no cooling air booster for the first turbine vane are needed. This paper deals with the internal air system of Siemens gas turbines which supplies cooling and sealing air. A general overview is given and some problems and their technical solutions are discussed. Furthermore a state of the art calculation system for the prediction of the thermodynamic states of the cooling and sealing air is introduced. The calculation system is based on the flow calculation package Flowmaster (Flowmaster International Ltd.), which has been modified for the requirements of the internal air system. The comparison of computational results with measurements give a good impression of the high accuracy of the calculation method used.

Exergy Analysis for the Performance Evaluation of Different Setups of the Secondary Air System of Aircraft Gas Turbines

2007 ◽  
Author(s):  
Philipp W. Zeller ◽  
Stephan Staudacher
Keyword(s):  
Performance Evaluation ◽  
Gas Turbines ◽  
Exergy Analysis ◽  
Entropy Increase ◽  
Engine Efficiency ◽  
Specific Entropy ◽  
Air System ◽  
Exergy Method ◽  
Secondary Air ◽  
Careful Design

Secondary Air System related losses in aircraft gas turbines cannot be directly assessed and quantified as possible for other sub-systems of the engine. If a particular setup is to be evaluated and compared to other, competing designs, it is required to have a distinct understanding of the loss mechanisms and the way these losses appear in the cycle. The relevant loss phenomena are therefore discussed in detail and are quantified with regard to the respective specific entropy increase. The exergy method is found to be the method of choice, since it holds some important advantages compared to other loss accounting methods like gas horsepower or thrust work potential. An exergy analysis is carried out for a high TET, two shaft engine of the medium thrust range. A comparison of setups with different compressor offtake positions is performed. It is found that the contribution of Air System related losses to overall engine efficiency deficits is significant, but may be reduced by careful design.

Analysis of Gas Turbine Rotating Cavities by an One-Dimensional Model

2009 ◽  
Author(s):  
Riccardo Da Soghe ◽  
Bruno Facchini ◽  
Luca Innocenti ◽  
Mirko Micio
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Design Tool ◽  
Operating Conditions ◽  
Outer Flow ◽  
One Dimensional ◽  
Wide Range ◽  
Air System ◽  
Secondary Air ◽  
Radial Outflow

Reliable design of secondary air system is one of the main tasks for the safety, unfailing and performance of gas turbine engines. To meet the increasing demands of gas turbines design, improved tools in prediction of the secondary air system behavior over a wide range of operating conditions are needed. A real gas turbine secondary air system includes several components, therefore its analysis is not carried out through a complete CFD approach. Usually, that predictions are performed using codes, based on simplified approach which allows to evaluate the flow characteristics in each branch of the air system requiring very poor computational resources and few calculation time. Generally the available simplified commercial packages allow to correctly solve only some of the components of a real air system and often the elements with a more complex flow structure cannot be studied; among such elements, the analysis of rotating cavities is very hard. This paper deals with a design-tool developed at the University of Florence for the simulation of rotating cavities. This simplified in-house code solves the governing equations for steady one-dimensional axysimmetric flow using experimental correlations both to incorporate flow phenomena caused by multidimensional effects, like heat transfer and flow field losses, and to evaluate the circumferential component of velocity. Although this calculation approach does not enable a correct modeling of the turbulent flow within a wheel space cavity, the authors tried to create an accurate model taking into account the effects of inner and outer flow extraction, rotor and stator drag, leakages, injection momentum and, finally, the shroud/rim seal effects on cavity ingestion. The simplified calculation tool was designed to simulate the flow in a rotating cavity with radial outflow both with a Batchelor and/or Stewartson flow structures. A primary 1D-code testing campaign is available in the literature [1]. In the present paper the authors develop, using CFD tools, reliable correlations for both stator and rotor friction coefficients and provide a full 1D-code validation comparing, due to lack of experimental data, the in house design-code predictions with those evaluated by CFD.

Finite Element Transient Modelling for Aero-Thermo-Mechanical Analysis of Whole Gas Turbine Engine

2019 ◽  
Author(s):  
Sabrina Giuntini ◽  
Antonio Andreini ◽  
Bruno Facchini
Keyword(s):  
Gas Turbines ◽  
Structural Integrity ◽  
Numerical Procedure ◽  
Mechanical Analysis ◽  
Operating Conditions ◽  
Test Case ◽  
Large Power ◽  
Turbine Engine ◽  
Air System ◽  
Secondary Air

Abstract It is here proposed a numerical procedure aimed to perform transient aero-thermo-mechanical calculations of large power generation gas turbines. Due to the frequent startups and shutdowns that nowadays these engines encounter, procedures for multi-physics simulations have to take into account the complex coupled interactions related to inertial and thermal loads, and seal running clearances. In order to develop suitable secondary air system configurations, guarantee structural integrity and maintain actual clearances and temperature peaks in pre-established ranges, the overall complexity of the structure has to be reproduced with a whole engine modelling approach, simulating the entire machine in the real operating conditions. In the proposed methodology the aerodynamic solution providing mass flows and pressures, and the thermo-mechanical analysis returning temperatures and material expansion, are performed separately. The procedure faces the aero-thermo-mechanical problem with an iterative process with the aim of taking into account the complex aero-thermo-mechanical interactions actually characterizing a real engine, in a robust and modular tool, combining secondary air system, thermal and mechanical analysis. The heat conduction in the solid and the fluid-solid heat transfer are computed by a customized version of the open source FEM solver CalculiX®. The secondary air system is modelled by a customized version of the embedded CalculiX® one-dimensional fluid network solver. In order to assess the physical coherence of the presented methodology the procedure has been applied to a test case representative of a portion of a real engine geometry, tested in a thermal transient cycle for the assessment of the interaction between secondary air system properties and geometry deformations.

Robust Design Optimization of a Low Pressure Turbine Rotor Discs Secondary Air System

2017 ◽  
Author(s):  
Giulia Antinori ◽  
Ilya Arsenyev ◽  
Andreas Fischersworring-Bunk
Keyword(s):  
Parameter Space ◽  
Cooling System ◽  
Optimization Methods ◽  
Low Pressure ◽  
Life Cycles ◽  
Robust Design Optimization ◽  
Design Parameters ◽  
Low Pressure Turbine ◽  
Air System ◽  
Secondary Air

Low pressure turbine (LPT) rotor discs undergo high thermal and mechanical loads during normal aircraft missions. Therefore, to meet the minimum requirement for life, temperatures and stresses in the disk need to be maintained within certain limits. This is achieved by carefully designing the disk shape and the cooling system. The complexity of this multi-physics problem together with a large number of design parameters require the use of numerical optimization methods for the Secondary Air System (SAS) design. Moreover, possible variations in the boundary conditions due to ambient parameters (e.g. temperatures, pressures) and manufacturing tolerances of the SAS components should be taken into account within the system design and optimization phase. In this paper an application of robust optimization methods for the design of a LPT secondary air system is proposed. The objective is to increase the engine efficiency by minimizing the amount of cooling flow, which is needed to guarantee a minimum required number of life cycles and to keep maximal temperatures within the limits. In order to predict the disks life accurately, transient thermal-structural analysis is used, which is computationally demanding. For this reason, optimization should be performed with a very limited amount of system evaluations. The dimension of the parameter space is reduced through the application of global sensitivity analysis methods by selecting the parameters that most affect the results. Optimization methods are sped up by the use of surrogate models, created over the reduced parameter space, which approximate the objective function and the constraints.

Particulate Monitor for Gas Turbine Cooling Air

2008 ◽  
Author(s):  
Richard H. Bunce ◽  
Francisco Dovali-Solis ◽  
Robert W. Baxter
Keyword(s):  
Gas Turbine ◽  
Monitoring System ◽  
Cooling System ◽  
Gas Turbine Engine ◽  
Minimum Size ◽  
Turbine Engine ◽  
Air System ◽  
Air Cooler ◽  
Secondary Air ◽  
Cooling Air

It is important to monitor the quality of the air used in the cooling system of a gas turbine engine. There can be many reasons that particulates smaller than the minimum size removed by typical engine air filters can enter the secondary air system piping in a gas turbine engine system. Siemens has developed a system that provide real time monitoring of particulate concentrations by adapting a commercial electrodynamic devise for use within the confines of the gas turbine secondary air system with provision for a grab sample option to collect samples for laboratory analysis. This on-line monitoring system is functional at typical engine cooling system piping operating pressure and temperature. The system is calibrated for detection of iron oxide particles in the 1 to 100 micrometer range at concentration of from 1 to 50 parts per million mass wet (ppmmw) The electro dynamic device is nominally operable at 800°C. The particulate monitoring system requires special mounting and antenna. This system may be adjusted for other materials, sizes and concentrations. The system and its developmental application are described. The system has been tested and test results are reviewed. The test application was the cooling air piping of a Siemens gas turbine engine. Multiple locations were monitored. The cooling system in this engine incorporates an air cooler and the particulate monitoring system was tested upstream and downstream of the air cooler for temperature contrast. The monitor itself is limited to the piping system and not the engine gas-path.

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