scholarly journals How to Get Component Maps for Aircraft Gas Turbine Performance Calculations

1996 ◽  
Author(s):  
Joachim Kurzke
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Measured Data ◽  
Turbine Performance ◽  
The Many ◽  
Map Data ◽  
Performance Calculation ◽  
Excellent Tool ◽  
Very High ◽  
Drawing Program

Precise simulations of gas turbine performance cannot be done without component maps. In the early days of a new project one often has to use scaled maps of similar machines. Alternatively one can calculate the component partload characteristics provided that the many details needed for such an exercise are available. In a later stage often rig tests will be done to get detailed information about the behavior of the compressors respectively turbines. Performance calculation programs usually require the map data in a specific format. To produce this format needs some preprocessing. Measured data cannot be used directly because they show a scatter and they are not evenly distributed over the range of interest. Due to limitations in the test equipment often there is lack of data for very low and very high speed. With the help of a specialized drawing program available on a PC one can easily eliminate the scatter in the data and also inter- and extrapolate additional lines of constant corrected speed. Many graphs showing both the measured data and the lines passing through the data as a function of physically meaningful parameters allow to check whether the result makes sense or not. The extrapolation of compressor maps toward very low speed, as required for the calculation of starting, idle and windmilling performance calculations, is discussed in some detail. Instead of true measured data one can use data read from maps published in open literature. The program is also an excellent tool for checking and extending component maps one has derived from sparse information about a gas turbine to be simulated.

scholarly journals Gas Turbine Train Development in France

1975 ◽  
Author(s):  
M. R. Garde
Keyword(s):  
Diesel Engine ◽  
Gas Turbine ◽  
High Speed ◽  
Rolling Stock ◽  
Lightweight Construction ◽  
The Future ◽  
Railway Traction ◽  
Aircraft Type ◽  
Very High

This paper presents a discussion on aircraft type gas-turbine train development. For railway traction purposes, the turbo-engines used on aircraft would improve the quality of the services provided in the electrified lines. The gas turbine should insure high speed and satisfactory acceleration. It would enable relatively lightweight construction to be carried out and run at a higher speed than trains on non-electrified lines. The gas turbine will not completely replace the diesel engine, but it will enable rolling stock to be constructed for which the diesel is unsuitable, especially in the case of high-speed, lightweight trainsets and, in the future, very high-powered units.

Development of Foil Bearings for Small Rotors

2013 ◽  
Author(s):  
Sadanand Kulkarni ◽  
Soniya D. Naik ◽  
K. Sarosh Kumar ◽  
M. Radhakrishna ◽  
Soumendu Jana
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Load Capacity ◽  
Capacity Design ◽  
Micro Gas Turbine ◽  
Foil Bearings ◽  
High Speeds ◽  
Lubricating Property ◽  
Very High

Lubricant free high speed turbo-machineries are one of the emerging fields in the gas turbine technology. Foil bearings are the major contenders in the lubricant free bearings due to their ability to support significant loads at very high speeds. The paper deals with the various stages in the development of discrete and continuous bump foil bearings and testing of the same for designed speeds and loads. Development of bumps involves determination of bump geometry for the desired load capacity, design of special purpose dies for the fabrication of corrugated sheets, identification of suitable bump material and evolution of heat treatment process. Here Beryllium–Copper (Be-Cu) is used as a bump material because of its self-lubricating property and good mechanical strength. The clearance between the shaft and top foil can be adjusted by providing the back-up foils between the encircling foil and bump foil. The rotor system simulating the weight of a typical micro gas turbine is designed and fabricated. The foil bearings developed are tested under this simulated load conditions at speeds above 50,000 rpm. The results obtained show that the rotor is completely airborne at speed slightly above 9000 rpm and at higher speeds the rotor is stable.

scholarly journals The Effect of Heat Transfer on Turbine Performance

2020 ◽  
Vol 142 (09) ◽  
pp. 56-57
Author(s):  
Lachlan J. Jardine ◽  
Robert J. Miller
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Large Temperature ◽  
Gas Turbine Blades ◽  
Turbine Performance ◽  
Very High

Abstract For over 50 years, high-pressure gas turbine blades have been cooled using air bled from the compressor. This cooling results in very high rates of heat transfer, both within the fluid and within the blade, shown in figure 1. The heat transfer often occurs across large temperature differences and is thus highly irreversible. It is therefore surprising that little is understood about the effect of this heat transfer on turbine performance.

Three-Dimensional Graphic Analysis of Absorption Cycles

1999 ◽  
Author(s):  
Sam V. Shelton ◽  
John P. Vodenicker ◽  
Laura A. Schaefer
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Computer Software ◽  
Internal Heat ◽  
Absorption Heat Pump ◽  
Fluid Mixtures ◽  
Graphic Analysis ◽  
The Many ◽  
Advanced Cycles ◽  
Excellent Tool

Abstract Due to new computer software tools and high speed personal computers, it is now possible to quickly analyze and optimize complex absorption heat pump cycles. These cycles utilize fluid mixtures and can have a large number of components. Absorption cycles are typically displayed on two-dimensional graphs, but these diagrams can cause confusion in understanding new cycle configurations and their potentials and limitations. This study uses three-dimensional graphs to create accurate representations of four cycles. In the advanced cycles, the many opportunities for internal heat recovery can be clearly seen. Additionally, the three-dimensional representations can justify the inclusion or removal of cycle components. They are an excellent tool for those new to the field to more quickly understand the cycles, and for those experienced with absorption to be innovative in developing new cycles.

Thermodynamic studies of a novel aeroengine concept

2000 ◽  
Vol 214 (2) ◽  
pp. 71-83 ◽  
Author(s):  
J R Panting ◽  
K R Pullen
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
New Technology ◽  
Weight Ratio ◽  
Transmission System ◽  
Specific Power ◽  
Electrical Transmission ◽  
Sophisticated Model ◽  
Very High ◽  
Engine Type

The purpose of the work described is to indicate the potential of a high-speed, spark ignition compound-turbocharged engine as an alternative to the gas turbine powered turboprop. Using relatively simple thermal cycle models, it is possible to show that such a compound-turbocharged engine should be capable of achieving very high thermal efficiency levels. A more sophisticated model of this engine type confirms these findings. It proves more difficult to estimate the power-weight ratio, but the specific power output of such an engine, measured in units of kW/1, is shown to be very high. In addition, such a thermally efficient engine type will permit a much reduced take-off fuel payload. As well as modelling the compound-turbocharged engine itself, comparisons are also made with the conventional gas turbine. The study focuses on propeller shaft input powers in the region of 1 MW. A suitable design strategy for the new engine type is discussed, including the requirement for a lightweight, continuously variable transmission system. At present, it is intended to employ a high-speed electrical transmission system for this purpose, and this relatively new technology is briefly highlighted.

A Simple Sub-Idle Component Map Extrapolation Method

2007 ◽  
Author(s):  
Shaun R. Gaudet ◽  
J. E. Donald Gauthier
Keyword(s):  
Gas Turbine ◽  
Extrapolation Method ◽  
Test Case ◽  
Performance Models ◽  
Idle Speed ◽  
Turbine Performance ◽  
Lack Of Information ◽  
Start Up ◽  
Map Data ◽  
Component Map

This paper describes a simple sub-idle component map extrapolation method. Used in conjunction with gas turbine performance models, it enables designers to estimate sub-idle gas turbine performance during engine start-up. The lack of information available regarding component maps in the sub-idle regime creates major challenges for starting system designers or control system designers as the numerical convergence of performance models decreases rapidly below idle speed. The proposed component map extrapolation method alleviates this problem by extrapolating given component map data well below idle speed. The underlying equations of the method are based on the principles of incompressible similarity laws. Also known as pump laws, these equations are modified to account for compressibility effects by varying the similarity law exponents. To estimate the integrity of the extrapolated component maps and to build confidence in the sub-idle extrapolation method, extrapolate speed lines were compared to speed lines found in the original component map. Even though the extrapolation method is yet to be experimentally validated, preliminary estimates showed that the extrapolation method did produce adequate component maps. To demonstrate the potential of the component extrapolation method when used in conjunction with gas turbine performance models, a virtual test case engine was modeled and used to produce start-up performance data.

A Realistic Method to Establish the Required Gearbox Rating for a Gas Turbine Application

1995 ◽  
Author(s):  
A. K. Rakhit
Keyword(s):  
Gas Turbine ◽  
Air Temperature ◽  
Gas Turbines ◽  
High Speed ◽  
Great Majority ◽  
Operating Conditions ◽  
Successful Operation ◽  
Turbine Performance ◽  
Transmission Equipment ◽  
Turbine Output

A reliable gearbox rating is essential for successful operation of high speed gas turbines. Presently, there is no dependable method to establish such a rating based on actual gas turbine performance under operating conditions. A great majority of manufacturers of this equipment use gas turbine output power at inlet air temperature of −20°F as the basis for this rating, while others assume an arbitrary inlet air temperature profile for turbine operation and use turbine output powers at various temperatures of the profile to derive an average rating for the gearbox. The major drawbacks of these methods are that they do not consider the effects of turbine performance characteristics and also do not include temperature profiles of actual installation sites. Thus, a vast majority of gear transmission equipment used in today’s high speed turbomachinery applications are either under- or over-rated. The procedure, as outlined in this paper, provides a reliable method to rate gearboxes for gas turbine driven equipment.

scholarly journals Modular Simulation of Coolant Internal Network and Rotating Cavity Analysis

1998 ◽  
Author(s):  
Carlo Carcasci ◽  
Ennio Carnevale ◽  
Bruno Facchini ◽  
Giovanni Ferrara
Keyword(s):  
Gas Turbine ◽  
Heavy Duty ◽  
Rotating Disks ◽  
Blade Cooling ◽  
Turbine Performance ◽  
Rotating Cavity ◽  
Accurate Design ◽  
Internal Network ◽  
Fast Procedure ◽  
Very High

The increase in gas turbine performance requires very high total inlet temperatures even in heavy-duty applications. Therefore, an accurate design of both the blade cooling and the cooling network from the compressor to the blade is very important. In previous works, the authors have studied the cooling blade problems for both the stator and the rotor case. The present paper presents a simple and fast procedure to study the cooling network: a modular code has been developed for this purpose and particular attention has been focused on the study o the rotating cavities between the stator and the rotating disks. The results we have obtained are good and the code developed is at present used in industry.

Structural changes in silicon-on-insulator material during post-implantation annealing

1986 ◽  
Vol 44 ◽  
pp. 736-737
Author(s):  
C. O. Jung ◽  
S. J. Krause ◽  
S.R. Wilson
Keyword(s):  
Integrated Circuits ◽  
Oxide Layer ◽  
High Speed ◽  
Structural Changes ◽  
Device Fabrication ◽  
Silicon On Insulator ◽  
High Quality ◽  
Radiation Hardened ◽  
Post Implantation ◽  
Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

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