Abradable Stator Gas Turbine Labyrinth Seals: Part 2 Numerical Modelling of Differing Seal Geometries and the Construction of a Second Generation Design Tool

2002 ◽  
Author(s):  
David Allcock ◽  
Paul Ivey ◽  
John Turner
Keyword(s):  
Numerical Modelling ◽  
Gas Turbine ◽  
Second Generation ◽  
Design Tool ◽  
Labyrinth Seals

Towards Improved Prediction of Aero-Engine Combustor Performance Using Large Eddy Simulations

2008 ◽  
Author(s):  
S. James ◽  
M. S. Anand ◽  
B. Sekar
Keyword(s):  
Gas Turbine ◽  
Radial Profile ◽  
Design Tool ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Gas Turbine Combustor ◽  
Systematic Assessment ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Aero Engine

The paper presents an assessment of large eddy simulation (LES) and conventional Reynolds averaged methods (RANS) for predicting aero-engine gas turbine combustor performance. The performance characteristic that is examined in detail is the radial burner outlet temperature (BOT) or fuel-air ratio profile. Several different combustor configurations, with variations in airflows, geometries, hole patterns and operating conditions are analyzed with both LES and RANS methods. It is seen that LES consistently produces a better match to radial profile as compared to RANS. To assess the predictive capability of LES as a design tool, pretest predictions of radial profile for a combustor configuration are also presented. Overall, the work presented indicates that LES is a more accurate tool and can be used with confidence to guide combustor design. This work is the first systematic assessment of LES versus RANS on industry-relevant aero-engine gas turbine combustors.

scholarly journals Effect of Pressure on Second-Generation Pressurized Fluidized Bed Combustion Plants

1994 ◽  
Vol 116 (2) ◽  
pp. 345-351 ◽  
Author(s):  
A. Robertson ◽  
D. Bonk
Keyword(s):  
Gas Turbine ◽  
Fluidized Bed ◽  
Coal Gasification ◽  
Second Generation ◽  
Electrical Power ◽  
Fluidized Bed Combustion ◽  
Fuel Gas ◽  
Combustion Gas ◽  
New Type ◽  
Pressurized Fluidized Bed Combustion

In the search for a more efficient, less costly, and more environmentally responsible method for generating electrical power from coal, research and development has turned to advanced pressurized fluidized bed combustion (PFBC) and coal gasification technologies. A logical extension of this work is the second-generation PFBC plant, which incorporates key components of each of these technologies. In this new type of plant, coal is devolatilized/carbonized before it is injected into the PFB combustor bed, and the low-Btu fuel gas produced by this process is burned in a gas turbine topping combustor. By integrating coal carbonization with PFB coal/char combustion, gas turbine inlet temperatures higher than 1149°C (2100°F) can be achieved. The carbonizer, PFB combustor, and particulate-capturing hot gas cleanup systems operate at 871°C (1600°F), permitting sulfur capture by time-based sorbents and minimizing the release of coal contaminants to the gases. This paper presents the performance and economics of this new type of plant and provides a brief overview of the pilot plant test programs being conducted to support its development.

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.

scholarly journals Development of Parametric Mass and Volume Models for an Aerospace SOFC/Gas Turbine Hybrid System

2005 ◽  
Author(s):  
Robert Tornabene ◽  
Xiao-Yen Wang ◽  
Christopher J. Steffen ◽  
Joshua E. Freeh
Keyword(s):  
Power Systems ◽  
Gas Turbine ◽  
Hybrid System ◽  
Electrical Power ◽  
Thermodynamic System ◽  
Design Tool ◽  
Commercial Aircraft ◽  
Immediate Feedback ◽  
Component Sizing ◽  
Volume Models

In aerospace power systems, mass and volume are key considerations to produce a viable design. The utilization of fuel cells is being studied for a commercial aircraft electrical power unit. Based on preliminary analyses [1, 2], a SOFC/gas turbine system may be a potential solution. This paper describes the parametric mass and volume models that are used to assess an aerospace hybrid system design. The design tool utilizes input from the thermodynamic system model and produces component sizing, performance and mass estimates. The software is designed such that the thermodynamic model is linked to the mass and volume model to provide immediate feedback during the design process. It allows for automating an optimization process that accounts for mass and volume in its figure of merit. Each component in the system is modeled with a combination of theoretical and empirical approaches. A description of the assumptions and design analyses is presented.

Application of a Turbulent Jet Flame Flashback Propensity Model to a Commercial Gas Turbine Combustor

2016 ◽  
Author(s):  
Alireza Kalantari ◽  
Elliot Sullivan-Lewis ◽  
Vincent McDonell
Keyword(s):  
Gas Turbine ◽  
Equivalence Ratio ◽  
High Pressures ◽  
Design Tool ◽  
Test Rig ◽  
Preheat Temperature ◽  
High Hydrogen ◽  
Turbine Engine ◽  
Jet Flame ◽  
Micro Turbine

Because flashback is a key operability issue associated with low emission combustion of high hydrogen content fuels, design tools to predict flashback propensity are of interest. Such a design tool has been developed by the authors to predict boundary layer flashback using non-dimensional parameters. The tool accounts for the thermal coupling between the flame and burner rim and was derived using detailed studies carried out in a test rig at elevated temperature and pressure. The present work evaluates the applicability of the tool to a commercial 65 kW micro turbine generator (MTG). Two sets of data are evaluated. One set is obtained using the combustor, removed from the engine, which has been configured to operate like it does in the engine but at atmospheric pressure and various preheat temperatures. The second set of data is from a combustor operated as it normally would in the commercial engine. In both configurations, studies are carried out with various amounts of hydrogen added to either natural gas or carbon monoxide. The previously developed model is able to capture the measured flashback tendencies in both configurations. In addition, the model is used to interpret flashback phenomena at high pressures and temperatures in the context of the engine conditions. An increase in pressure for a given preheat temperature and velocity reduces the equivalence ratio at which flashback occurs and increases the tip temperature due to lower quenching distance. The dependency of the flashback propensity on the injector tip temperature is enhanced with an increase in pressure. The variation of critical velocity gradient with equivalence ratio for a constant preheat temperature is more pronounced at higher pressures. In summary, the model developed using the high pressure test rig is able to predict flashback tendencies for a commercial gas turbine engine and can thus serve as an effective design tool for identifying when flashback is likely to occur for a given geometry and condition.

Mixing Field Analysis of a Gas Turbine Burner

2002 ◽  
Author(s):  
Peter Flohr ◽  
Patrick Schmitt ◽  
Christian Oliver Paschereit
Keyword(s):  
Gas Turbine ◽  
Recirculation Zone ◽  
Numerical Study ◽  
Turbulence Models ◽  
Design Tool ◽  
Field Analysis ◽  
Mixing Process ◽  
Fuel Injector ◽  
Air Mixing ◽  
Gas Turbine Burner

An analytical and numerical study has been carried out with the view on the understanding of the physical mechanisms of the mixing process in a gas turbine burner. To this end, three methods at various levels of approximation have been used: At the simplest level an analytical model of the burner flow and the mixing process has been developed. It is demonstrated how this approach can be used to understand basic issues of the fuel-air mixing and how it can be applied as a design tool which guides the optimisation of a fuel injector device. At an intermediate level of approximation, steady-state CFD simulations, based on the k–ε- and RSM-turbulence models are used to describe the mixing process. All steady simulations fail to either predict the recirculation zone or the turbulence level correctly, and can therefore not be expected to capture the mixing correctly. At the most involved level of modelling time-accurate CFD based on unsteady RSM and LES-turbulence models are performed. The simulations show good agreement with experiments (and in the case of LES excellent agreement) for both, velocity and turbulence fields. Mixing predictions close to the fuel injectors suffer from a simplification used in the numerical setup, but the mixing field is predicted very well towards the exit of the burner. The contribution of the asymmetric coherent flow structure (which is associated with the internal recirculation zone) to the mixing process is quantified through a triple decomposition technique.

A New Approach to Evaluating the In-Service Performance of Marine Gas Turbine Air Filters

1988 ◽  
Vol 110 (4) ◽  
pp. 621-627
Author(s):  
J. S. Hobday ◽  
J. Havill
Keyword(s):  
Gas Turbine ◽  
Meteorological Data ◽  
Analytical Techniques ◽  
Design Tool ◽  
Operating Conditions ◽  
Marine Aerosol ◽  
Air Filter ◽  
New Approach ◽  
Aerosol Model ◽  
Naval Engineering

Early work by the Naval Engineering Department of NGTE Pyestock, now RAE Pyestock, sought to define the Marine Aerosol through simple relationships between wind speed and aerosol size and distribution. Experience has shown the resulting Standard Aerosols to be unrepresentative of the actual conditions found in service. This paper describes a new approach using available ship and meteorological data and proven analytical techniques to generate a multivariable mathematical model of the Marine Aerosol embracing a wide envelope of operating conditions. It further describes how a simple model of a gas turbine air filter can be used in conjunction with the Marine Aerosol model and a model describing a ship propulsion system to predict the performance of the filter in terms of probable salt ingestion by the ship’s engines. This versatile design tool can be used for direct or comparative assessments of separator applications for marine gas tubine propulsion engines and generating sets.

scholarly journals Exergy Analysis of Two Second-Generation SCGT Plant Proposals

1998 ◽  
Author(s):  
A. Corti ◽  
L. Failli ◽  
D. Fiaschi ◽  
G. Manfrida
Keyword(s):  
Gas Turbine ◽  
Second Generation ◽  
Combined Cycle ◽  
Point Of View ◽  
Specific Power ◽  
Co2 Removal ◽  
Good Efficiency ◽  
Specific Power Output ◽  
Combined Cycle Plant ◽  
Gas Turbine Exhaust

Two different power plant configurations based on a Semi-Closed Gas Turbine (SCGT) are analyzed and compared in terms of First and Second Law analysis. SCGT plant configurations allow the application of CO2 separation techniques to gas-turbine based plants and several further potential advantages with respect to present, open-cycle solutions. The first configuration is a second-generation SCGT/CC (Combined Cycle) plant, which includes inter-cooling (IC) between the two compression stages, achieved using spray injection of water condensed in a separation process removing vapor from the flue gases. The second configuration (SCGT/RE) combines compressor inter-cooling with the suppression of the heat recovery steam generator and of the whole bottoming cycle; the heat at gas turbine exhaust is directly used for gas turbine regeneration. The SCGT/CC-IC solution provides good efficiency (about 55%) and specific power output figures, on account of the spray inter-cooling; however, with this configuration the cycle is not able to self-sustain the CO2 removal reactions and amine regeneration process, and needs a substantial external heat input for this purpose. The SCGT/RE solution is mainly attractive from the environmental point of view: in fact, it combines the performance of an advanced gas turbine regenerative cycle (efficiency of about 49%) with the possibility of a self-sustained CO2 removal process. Moreover, the cycle configuration is simplified because the HRSG and the whole bottoming cycle are suppressed, and a potential is left for cogeneration of heat and power.

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