On the Performance of Gas Turbine Secondary Air Systems

2001 ◽  
Author(s):  
Andrew Foley
Keyword(s):  
Gas Turbine ◽  
Air System ◽  
Secondary Air

The paper proposes a straightforward technique to quantify the performance of a gas turbine secondary air system. By recognising the air system as a component in its own right and performing the calculations suggested the systems engineer should be better able to develop and optimise a given air system. The effect of any requested compromise can also be better quantified to other component groups.

Virtual Gas Turbines Part II: an Automated Whole-Engine Secondary Air System Model Generation

2021 ◽  
Author(s):  
Davendu Y. Kulkarni ◽  
Luca di Mare
Keyword(s):  
Gas Turbine ◽  
Network Model ◽  
Design Analysis ◽  
Model Generation ◽  
Time Cost ◽  
Flow Network ◽  
Turbine Engine ◽  
Geometry Model ◽  
Air System ◽  
Secondary Air

Abstract The design and analysis of the secondary air system (SAS) of gas turbine engine is a complex and time-consuming process because of its complicated geometry topology. The conventional SAS design-analysis model generation process is quite tedious, time consuming. It is still heavily dependent on human expertise and thus incurs high time-cost. This paper presents an automated, whole-engine SAS flow network model generation methodology. During the SAS preprocessing step, the method accesses a pre-built whole-engine geometry model created using a novel, in-house, feature-based geometry modelling environment. It then transforms the engine geometry features into the features suitable for SAS flow network analysis. The proposed method not only extracts the geometric information from the computational geometry but also retrieves additional non-geometric attributes such as, rotational frames, boundary types, materials and boundary conditions etc. Apart from ensuring geometric consistency, this methodology also establishes a bi-directional information exchange protocol between engine geometry model and SAS flow network model, which enables making engine geometry modifications based on SAS analysis results. The application of this feature mapping methodology is demonstrated by generating the secondary air system (SAS) flow network model of a modern three-shaft gas turbine engine. This capability is particularly useful for the integration of geometry modeler with the simulation framework. The present SAS model is generated within a few minutes, without any human intervention, which significantly reduces the SAS design-analysis time-cost. The proposed method allows performing a large number of whole-engine SAS simulations, design optimisations and fast re-design activities.

An Integrated Approach to Simulate Gas Turbine Secondary Air System

2020 ◽  
Author(s):  
Ali Izadi ◽  
Seyed Hossein Madani ◽  
Seyed Vahid Hosseini ◽  
Mahmoud Chizari
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Great Influence ◽  
Integrated Approach ◽  
Cfd Modeling ◽  
Connectivity Matrix ◽  
Analysis Tool ◽  
Air System ◽  
Secondary Air

Abstract One of the most critical parts of a modern gas turbine that its reliability and performance has a great influence on cycle efficiency is the secondary air system (SAS). Modern systems functions to supply not only cooling air flow for turbine blades and vanes but sealing flow for bearing chambers and turbine segments as well as turbine disks’ purge flow in order to eliminate hot gas ingestion. Due to the various interactions between SAS and main gas, consideration of the former is substantially crucial in design and analysis of the whole engine. Geometrical complexities and centrifugal effects of rotating blades and disks, however, make the flow field and heat transfer of the problem so complicated AND too computationally costly to be simulated utilizing full 3-D CFD methods. Therefore, developing 1-D and 0-D tools applying network methods are of great interests. The present article describes a modular SAS analysis tool that is consisted of a network of elements and nodes. Each flow branch of a whole engine SAS network is substituted with an element and then, various branches (elements) intersect with each other just at their end nodes. These elements which might include some typical components such as labyrinth seals, orifices, stationary/rotating pipes, pre-swirls, and rim-seals, are generally articulated with characteristic curves that are extracted from high fidelity CFD modeling using commercial software such as Flowmaster or ANSYS-CFX. Having these curves, an algorithm is developed to calculate flow parameters at nodes with the aid of iterative methods. The procedure is based on three main innovative ideas. The first one is related to the network construction by defining a connectivity matrix which could be applied to any arbitrary network such as hydraulic or lubrication networks. In the second one, off-design SAS calculation will be proposed by introducing some SAS elements that their characteristic non-dimensional curves are influenced by their inlet total pressure. The last novelty is the integration of the blades coolant calculation process that incorporates external heat transfer calculation, structural conduction and coolant side modeling with SAS network simulation. Finally, SAS simulation of an industrial gas turbine is presented to illustrate capabilities of the presented tool in design point and off-design conditions.

An Integrated Approach to Simulate Gas Turbine Secondary Air System

2021 ◽  
Author(s):  
Ali Izadi ◽  
Seyed Vahid Hosseini ◽  
Seyed Hossein Madani ◽  
Mahmoud Chizari
Keyword(s):  
Gas Turbine ◽  
Integrated Approach ◽  
Air System ◽  
Secondary Air

scholarly journals Transient modelling and simulation of gas turbine secondary air system

2020 ◽  
Vol 170 ◽  
pp. 115038
Author(s):  
Theoklis Nikolaidis ◽  
Haonan Wang ◽  
Panagiotis Laskaridis
Keyword(s):  
Gas Turbine ◽  
Modelling And Simulation ◽  
Air System ◽  
Secondary Air

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.

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.

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.

ALGOR Gas Turbine Performance Modular Tool: Map Based Modules Development

2016 ◽  
Author(s):  
Roberto Canepa ◽  
Stefano Piola ◽  
Marco Pirotta ◽  
Andrea Silingardi ◽  
Federico Bonzani ◽  
...  
Keyword(s):  
Mass Balance ◽  
Gas Turbine ◽  
Reference Points ◽  
Performance Estimation ◽  
Modular Structure ◽  
Nonlinear Phenomena ◽  
Turbine Engine ◽  
Air System ◽  
Secondary Air ◽  
Flow Functions

Commercially available or in-house developed performance tools, mostly based on heat and mass balance, are nowadays widespread among Universities, consulting companies and utilities. Generally these software are based on main gas turbine measurable information and, yet accurate on global performance estimation, are limited in the level of insight on component performance they can provide and also in the range of analysis, generally limited to engine possible operating points. On the other hand, the tools adopted by OEMs generally differ for components (compressor, turbine and combustor) and secondary air system details. In ASEN experience ALGOR heat and mass balance software is used as a platform for system integrations between each disciplines by means of a modular structure in which a large number of modules, chosen from the available library, are freely connected allowing to potentially analyze any gas turbine engine configuration. This paper describes the structure and the implementation of latest ALGOR updates, developed by ASEN and University of Florence, aimed at creating new map based modules for compressor and secondary air system. With this approach, component performance coming from field data can be continuously adopted to refine the reliability of calculation. Furthermore, nonlinear phenomena occurring in stationary and rotating cooling passages can be evaluated only with devoted calculation tools, which output can be conveniently translated in flow functions maps. Thanks to ALGOR modular structure, with these newly available (map-interpolating) modules, additional levels of analysis are allowed, ranging from “cycle deck” map-matching level, to mixed modelling in which map based modules are linked with 1D mean line analysis modules. Moreover their use can be also foreseen in ASEN conceptual design approach in which just map reference points are adjusted to reflect expected technological leaps required by engine upgrade.

Numerical and Experimental Investigation of Secondary Flows and Influence of Air System Design on Heavy-Duty Gas Turbine Performance

2012 ◽  
Author(s):  
Luca Bozzi ◽  
Enrico D’angelo
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Engine Performance ◽  
Combined Cycle ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Heavy Duty ◽  
Turbine Performance ◽  
Air System ◽  
Secondary Air

High turn-down operating of heavy-duty gas turbines in modern Combined Cycle Plants requires a highly efficient secondary air system to ensure the proper supply of cooling and sealing air. Thus, accurate performance prediction of secondary flows in the complete range of operating conditions is crucial. The paper gives an overview of the secondary air system of Ansaldo F-class AEx4.3A gas turbines. Focus of the work is a procedure to calculate the cooling flows, which allows investigating both the interaction between cooled rows and additional secondary flows (sealing and leakage air) and the influence on gas turbine performance. The procedure is based on a fluid-network solver modelling the engine secondary air system. Parametric curves implemented into the network model give the consumption of cooling air of blades and vanes. Performances of blade cooling systems based on different cooling technology are presented. Variations of secondary air flows in function of load and/or ambient conditions are discussed and justified. The effect of secondary air reduction is investigated in details showing the relationship between the position, along the gas path, of the upgrade and the increasing of engine performance. In particular, a section of the paper describes the application of a consistent and straightforward technique, based on an exergy analysis, to estimate the effect of major modifications to the air system on overall engine performance. A set of models for the different factors of cooling loss is presented and sample calculations are used to illustrate the splitting and magnitude of losses. Field data, referred to AE64.3A gas turbine, are used to calibrate the correlation method and to enhance the structure of the lumped-parameters network models.

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