Paper 7: Radial Gas Turbines

1968 ◽  
Vol 183 (14) ◽  
pp. 59-70 ◽  
Author(s):  
M. C. S. Barnard ◽  
R. S. Benson
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Future Trends ◽  
One Dimensional ◽  
Optimum Speed ◽  
Speed Range ◽  
Rotor Losses ◽  
Rotor Loss

The optimum speed range for radial gas turbines is given and the practical advantages of this type of turbine are discussed with reference to some current applications. One-dimensional flow considerations are briefly reviewed and the representation of nozzle and rotor loss data described. Two- and three-dimensional flows in the rotor turbine are examined in the light of recent numerical techniques. Comparison is made of the predictions in the rotor losses using these techniques and some experimental results. The design performance of a small radial gas turbine is given. The mechanical and thermal stresses of rotor life together with materials and methods of manufacture are examined. The results of service experience are reviewed with particular reference to rotor and nozzle life. Future trends in development of the radial gas turbine are indicated.

CTV: A New Method for Mapping a Full Scale Prototype of an Axial Compressor

1996 ◽  
Author(s):  
Vasco Mezzedimi ◽  
Pierluigi Nava ◽  
Dave Hamilla
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Theoretical Basis ◽  
Axial Compressor ◽  
Heavy Duty ◽  
Test Vehicle ◽  
Testing Method ◽  
Area Reduction ◽  
Speed Range ◽  
Compressor Inlet

The full mapping of a new gas turbine axial compressor at different speeds, IGV settings and pressure ratios (from choking to surge) has been performed utilizing a complete gas turbine with a suitable set of modifications. The main additions and modifications, necessary to transform the turbine into the Compressor Test Vehicle (CTV), are: - Compressor inlet throttling valve addition - Compressor discharge bleed valve addition - Turbine 1st stage nozzle area reduction - Starting engine change (increase in output and speed range). This method has been successfully employed on two different single shaft heavy-duty gas turbines (with a power rating of 11MW and 170 MW respectively). The paper describes the theoretical basis of this testing method and a specific application with the above mentioned 170 MW machine.

Three-Dimensional Time-Resolved Flow Field in the First and Last Turbine Stage of a Heavy Duty Gas Turbine: Part II — Interpretation of Blade Pressure Fluctuations

2000 ◽  
Author(s):  
Martin von Hoyningen-Huene ◽  
Wolfram Frank ◽  
Alexander R. Jung
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Potential Interaction ◽  
Heavy Duty ◽  
Turbine Stage ◽  
Count Ratio ◽  
Heavy Duty Gas Turbine

Unsteady stator-rotor interaction in gas turbines has been investigated experimentally and numerically for some years now. Most investigations determine the pressure fluctuations in the flow field as well as on the blades. So far, little attention has been paid to a detailed analysis of the blade pressure fluctuations. For further progress in turbine design, however, it is mandatory to better understand the underlying mechanisms. Therefore, computed space–time maps of static pressure are presented on both the stator vanes and the rotor blades for two test cases, viz the first and the last turbine stage of a modern heavy duty gas turbine. These pressure fluctuation charts are used to explain the interaction of potential interaction, wake-blade interaction, deterministic pressure fluctuations, and acoustic waveswith the instantaneous surface pressure on vanes and blades. Part I of this two-part paper refers to the same computations, focusing on the unsteady secondary now field in these stages. The investigations have been performed with the flow solver ITSM3D which allows for efficient simulations that simulate the real blade count ratio. Accounting for the true blade count ratio is essential to obtain the correct frequencies and amplitudes of the fluctuations.

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.

Ongoing Development and Recent Results of the Research in the Swedish Gas Turbine Centre (GTC)

2004 ◽  
Author(s):  
Sven Gunnar Sundkvist ◽  
Michael Andersson ◽  
Bogdan Gherman ◽  
Andreas Sveningsson ◽  
Damian Vogt
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Industrial Development ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Life Time ◽  
Research Areas ◽  
Verification Methods ◽  
Acoustic Instabilities ◽  
Research Students

This paper describes a way of co-operation between industries, universities and government that has proven to be very fruitful. The Swedish Gas Turbine Centre (GTC) is constituted as a research consortium between technical universities and gas turbine industry. The overall goal of the centre, that was founded in 1996 on a governmental initiative, is to build up a basis of knowledge at Swedish universities to support the industrial development in Sweden of gas turbines of the future with expected requirements on low emissions, high efficiencies, high availability, and low costs. Since the start the research has had a focus on high temperature components of gas turbines (combustion chamber and turbine). This is also reflected in the on-going development phase where the research program consists of four project areas: cooling technology, combustion technology, aeroelasticity, and life time prediction of hot components. The projects are aiming at developing design tools and calculation and verification methods within these fields. A total of eleven research students (among them one industrial PhD student) are active in the centre at present. Numerical analysis as well as experimental verification in test rigs are included. The program has so far produced eleven Licentiate of Engineering and five PhD. On-going activities and recent results of the research in the four research areas are presented: • A new test rig for investigation of time-dependent pressures of three-dimensional features on a vibrating turbine blade at realistic Mach, Reynolds and Strouhal numbers and first experimental results. • Results of numerical simulations of heat loads on turbine blades and vanes, especially platform cooling. • First results of numerical investigations of combustion and thermo-acoustic instabilities in gas turbine chambers. • Experimental investigation of crack propagation in gas turbine materials using the scanning electron microscope (SEM).

One-Dimensional Model to Quantify NOx Reduction in Gas Turbines Using EGR

1998 ◽  
Author(s):  
K. K. Botros ◽  
M. J. de Boer ◽  
G. Kibrya
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Nox Reduction ◽  
Simulation Software ◽  
Specific Work ◽  
Dimensional Model ◽  
Nox Formation ◽  
One Dimensional ◽  
Thermal Nox

A one dimensional model based on fundamental principles of gas turbine thermodynamics and combustion processes was constructed to quantify the principle of exhaust gas recirculation (EGR) for NOx reduction. The model utilizes the commercial process simulation software ASPEN PLUS®. Employing a set of 8 reactions including the Zeldovich mechanism, the model predicted thermal NOx formation as function of amount of recirculation and the degree of recirculate cooling. Results show that addition of sufficient quantities of uncooled recirculate to the inlet air (i.e. EGR>∼4%) could significantly decrease NOx emissions but at a cost of lower thermal efficiency and specific work. Cooling the recirculate also reduced NOx at lower quantities of recirculation. This has also the benefit of decreasing losses in the thermal efficiency and in the specific work output. Comparison of a ‘rubber’ and ‘non-rubber’ gas turbine confirmed that residence time is one important factor in NOx formation.

scholarly journals A Quasi-Three Dimensional Analysis of Choking Flow for Radial Gas Turbines

1978 ◽  
Author(s):  
Yoshiyuki Nakase ◽  
Junichiro Fukutomi ◽  
Masanobu Inubushi ◽  
Takashi Watanabe ◽  
Yoshiyasu Hama ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Recovery ◽  
Three Dimensional ◽  
Layer Growth ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Numerical Examples ◽  
Annular Cascade ◽  
Boundary Layer Growth

A quasi-three dimensional.flow analysis has previously been reported for a mixed flow impeller by one of the present authors. In the analysis, the velocity gradient method has been used in meridional plane and the rotating annular cascade theory has been used for blade-to-blade solution. In this report, the analysis is generalized to allow prediction and analysis of choking flow for a radial inflow gas turbine. Moreover, this analysis is corrected to include passage contraction effects and passage loss effects due to boundary-layer growth. The efficiency and choking flow rate of gas turbine may be obtained in a single computer run without the complicated throat area estimation. Some numerical examples for a burst furnace gas energy recovery turbine are presented.

A Model for the Simulation of Large-Size Single-Shaft Gas Turbine Start-Up Based on Operating Data Fitting

2007 ◽  
Author(s):  
Mirko Morini ◽  
Giovanni Cataldi ◽  
Michele Pinelli ◽  
Mauro Venturini
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Simulated Data ◽  
Data Fitting ◽  
Turbine Engine ◽  
Operating Data ◽  
Large Size ◽  
Start Up ◽  
Thermal Status

Start-up is an important aspect of gas turbine operation. In the last years plant operators have shown an ever increasing interest in this critical phase, with particular focus on start-up reliability and start-up time. Several issues should be considered in order to achieve optimal start-up behavior: operability issues (e.g. compressor aerodynamics, combustor light-off and light-around, shaft acceleration), impact of thermal stresses on cyclic life, proper sizing of external starting devices. Models for the simulation of gas turbine behavior during start-up are very useful both for the design of new gas turbines and for the analysis and improvement of engines already in operation. In this paper, a physics-based model for the simulation of the start-up phase of large-size single-shaft gas turbines is presented. The model is based on operating data fitting and covers machine operation from combustor light-off to compressor blow off valve closure. The model makes use of steady-state component characteristics, while dynamics is taken into account through shaft power balance. Special features are also included to properly model the effects of heat soakage, i.e. the dependence of the engine behavior on its thermal status before the start-up. The quality of the model has been proven by application to the gas turbine engine ALSTOM GT13E2 and by comparison between measured and simulated data.

Paper 21: Investigation of Flow in the Nozzle-Less Spiral Casing of a Radial Inward-Flow Gas Turbine

1969 ◽  
Vol 184 (7) ◽  
pp. 66-71 ◽  
Author(s):  
F. S. Bhinder
Keyword(s):  
Experimental Investigation ◽  
Angular Momentum ◽  
Theoretical Analysis ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cost ◽  
Performance Characteristics ◽  
Technical Literature ◽  
One Dimensional ◽  
Spiral Casing

Nozzle-less spiral casings are used frequently with radial inward-flow gas turbines of small turbochargers for automotive type diesel engines. The broad performance characteristics and low cost of this type of casing are two particularly attractive features for turbocharger applications. Considerable data on the performance of radial inward-flow gas turbines have appeared recently in the technical literature, but in contrast very little has been published on the performance of volute casings. The paper presents the results of a theoretical and experimental investigation in which three nozzle-less volute casings of a 2·85-in diameter turbine were studied. The theoretical analysis, based on the assumptions of steady isentropic one-dimensional flow and the conservation of mass and of angular momentum, is essentially design orientated.

The Effect of Turbulence on the Heat Transfer in Closed Gas-Filled Rotating Annuli

1998 ◽  
Vol 120 (4) ◽  
pp. 824-830 ◽  
Author(s):  
D. Bohn ◽  
J. Gier
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Navier Stokes ◽  
Turbine Blade Cooling ◽  
Blade Cooling ◽  
Correction Scheme

Higher turbine inlet temperatures are a common measure for increasing the thermal efficiency of modern gas turbines. This development leads not only to the need for more efficient turbine blade cooling but also to the requirement for a more profound knowledge of the mechanically and thermally stressed parts of the rotor. For determining thermal stresses from the temperature distribution in the rotor of a gas turbine, one has to encounter the convective transfer in rotor cavities. In the special case of an entirely closed gas-filled rotating annulus, the convective flow is governed by a strong natural convection. Owen and other researchers have found that the presence of turbulence and its inclusion in the modeling of the flow causes significant differences in the flow development in rotating annuli with throughflow, e.g., different vortex structures. However, in closed rotating annuli there is still a lack of knowledge concerning the influence of turbulence. Based on previous work, in this paper the influence of turbulence on the flow structure and on the heat transfer is investigated. The flow is investigated numerically with a three-dimensional Navier–Stokes solver, based on a pressure correction scheme. To account for the turbulence, a low-Reynolds-number k–ε model is employed. The results are compared with experiments performed at the Institute of Steam and Gas Turbines. The computations demonstrate that turbulence has a considerable influence on the overall heat transfer as well as on the local heat transfer distribution. Three-dimensional effects are discussed by comparing the three-dimensional calculation with a two-dimensional calculation of the same configuration and are found to have some impact.

scholarly journals Effects of Damaged Rotor Blades on the Aerodynamic Behavior and Heat-Transfer Characteristics of High-Pressure Gas Turbines

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 627
Author(s):  
Thanh Dam Mai ◽  
Jaiyoung Ryu
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Rotor Blade ◽  
High Speed ◽  
Power Plants ◽  
Thermal Stresses ◽  
Turbine Blades ◽  
Combined Cycle

Gas turbines are critical components of combined-cycle power plants because they influence the power output and overall efficiency. However, gas-turbine blades are susceptible to damage when operated under high-pressure, high-temperature conditions. This reduces gas-turbine performance and increases the probability of power-plant failure. This study compares the effects of rotor-blade damage at different locations on their aerodynamic behavior and heat-transfer properties. To this end, we considered five cases: a reference case involving a normal rotor blade and one case each of damage occurring on the pressure and suction sides of the blades’ near-tip and midspan sections. We used the Reynolds-averaged Navier-Stokes equation coupled with the k − ω SST γ turbulence model to solve the problem of high-speed, high-pressure compressible flow through the GE-E3 gas-turbine model. The results reveal that the rotor-blade damage increases the heat-transfer coefficients of the blade and vane surfaces by approximately 1% and 0.5%, respectively. This, in turn, increases their thermal stresses, especially near the rotor-blade tip and around damaged locations. The four damaged-blade cases reveal an increase in the aerodynamic force acting on the blade/vane surfaces. This increases the mechanical stress on and reduces the fatigue life of the blade/vane components.

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