Axial-Flow Gas Turbines

2013 ◽  
pp. 195-224
Keyword(s):  
1970 ◽  
Vol 185 (1) ◽  
pp. 407-424 ◽  
Author(s):  
H. R. M. Craig ◽  
H. J. A. Cox

A comprehensive method of estimating the performance of axial flow steam and gas turbines is presented, based on analysis of linear cascade tests on blading, on a number of turbine test results, and on air tests of model casings. The validity of the use of such data is briefly considered. Data are presented to allow performance estimation of actual machines over a wide range of Reynolds number, Mach number, aspect ratio and other relevant variables. The use of the method in connection with three-dimensional methods of flow estimation is considered, and data presented showing encouraging agreement between estimates and available test results. Finally ‘carpets’ are presented showing the trends in efficiencies that are attainable in turbines designed over a wide range of loading, axial velocity/blade speed ratio, Reynolds number and aspect ratio.


2019 ◽  
pp. 167-188
Author(s):  
Bijay K. Sultanian
Keyword(s):  

Author(s):  
K V J Rao ◽  
S Kolla ◽  
Ch Penchalayya ◽  
M Ananda Rao ◽  
J Srinivas

This paper proposes the formulation and solution procedures in the stage optimization of the effective dimensions of an axial-flow gas turbine. Increasing the stage efficiency and minimizing the overall mass of components per stage are the common objectives in gas turbine design. This multiple objective function, with important constraints like natural frequency limits, root stress values, and tip deflection in blades, constitutes the overall optimization problem. The problem is solved by using a modified nonlinear simplex method with a built-in user interactive program that helps in on-line modifications of parameters other than variables in the problem. Results are presented with single objective and multiple objective criteria, including sensitivity analyses about the optimum point.


1979 ◽  
Author(s):  
N. R. L. Maccallum

During transients of axial-flow gas turbines, the characteristics of the compressor are altered. The changes in these characteristics (excluding surge line changes) have been related to transient heat transfer parameters, and these relations have been incorporated in a program for predicting the transient response of a single-shaft aero gas turbine. The effect of the change in compressor characteristics has been examined in accelerations using two alternative acceleration fuel schedules. When the fuel is scheduled on compressor delivery pressure alone. there is no increase in predicted acceleration times. When the fuel is scheduled on shaft speed alone, the predicted acceleration times are increased by about 5 to 6 percent.


Author(s):  
T. L. Bowen

The feasibility of an isolated reverse turbine concept for marine propulsion was examined with emphasis on (1) the reverse turbine size needed to meet the stopping distance requirement of a particular ship during a crashback maneuver, and (2) the ahead turbine performance penalty due to reverse turbine windage losses. This particular reverse turbine system was made adaptable to the exhaust elbow and output shaft of an existing free-power-turbine gas turbine. The analysis was based on the application of this reverse turbine concept to a notational single-shaft frigate. The study-ship’s propulsion system includes two General Electric LM2500 gas turbines with reversing capability, a reduction gear, and a fixed-pitch propeller. A ship propulsion simulation was developed for the purpose of calculating steady-state ahead and backing performance data, as well as transient behavior of the ship during crashback maneuvers. The reverse turbine’s speed and torque required to stop the ship in five ship-lengths and 3.5 ship-lengths were determined from these calculations. Four reverse turbine designs were generated using a computer program for preliminary design of axial-flow turbines. The designs included a single-stage and a two-stage impulse turbine for both stopping distances. The penalty on ahead performance due to reverse turbine windage was estimated for each design, using existing experimental data found in the literature. The results obtained thus far tend to support the feasibility of this reverse turbine concept.


1965 ◽  
Vol 87 (2) ◽  
pp. 193-196
Author(s):  
R. A. Strub ◽  
P. Suter

The character of different surge cycles is described, and the corresponding influence on the dynamic loading of the blades of axial flow compressors is discussed. It is shown that essentially fatigue is governed by the rapidity of loading or unloading of the blading. Test results from an experimental 4-stage axial flow compressor showed that the induced dynamic stresses in the blades, which reach about three times the steady gas bending stresses, can lead to fatigue failure. Reference is also made to previous surge tests carried out on a gas turbine installation, which indicate that a good correlation can be expected between the calculated and the measured pressure distribution. Mention is made of the fatigue failure of the rotor blades of an industrial compressor submitted to a long period of intense surging.


1981 ◽  
Vol 103 (4) ◽  
pp. 772-775 ◽  
Author(s):  
Akifumi Hori ◽  
Kazuo Takeya

A new reheat gas turbine system is being developed as a national project by the “Engineering Research Association for Advanced Gas Turbines” of Japan. The machine consists of two axial flow compressors, three turbines, intercooler, combustor and reheater. The pilot plant is expected to go into operation in 1982, and a prototype plant will be set up in 1984. The major objective of this reheat gas turbine is application to a combined cycle power plant, with LNG burning, and the final target of combined cycle thermal efficiency is to be 55 percent (LHV).


1947 ◽  
Vol 157 (1) ◽  
pp. 471-482 ◽  
Author(s):  
D. M. Smith

The paper reviews the technical development of the F2 jet propulsion engine, an axial flow gas turbine designed and manufactured by the Metropolitan-Vickers Electrical Company, Limited, under contract from the Ministry of Aircraft Production. An account is given of the preliminary work in 1938–9, in collaboration with the Royal Aircraft Establishment, on gas turbines for aircraft propulsion. The development of a simple jet engine of the axial flow type was started in July 1940. The first engine ran on bench test in December 1941. The first flights took place in June 1943 on a flying testbed, and in November 1943 on a jet-propelled aircraft. The evolution of engines of this type, leading up to the current F2/4 jet propulsion engine, is described. Each main component of the engine—the axial flow compressor, the annular combustion chamber and the high temperature turbine—necessitated extensive development work in fields previously unexplored; the methods used in the development of these and other components are explained. The F2 engine was the first British jet propulsion engine of axial flow type, and it is also unique amongst British engines in the straight-through design and annular combustion chamber that gives an exceptionally low frontal area.


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