Theoretical analysis of transient gain phenomena in a fast-axial flow type CO/sub 2/ laser amplifier

1989 ◽  
Vol 25 (1) ◽  
pp. 121-131 ◽  
Author(s):  
E. Tsuchida ◽  
H. Sato
Keyword(s):  
Theoretical Analysis ◽  
Axial Flow ◽  
Laser Amplifier ◽  
Flow Type

Compressibility Effects on the Two Generations of Unsteady Flow Types in Axial Flow Compressors

2005 ◽  
Author(s):  
Xinqian Zhen ◽  
Sheng Zhou ◽  
Anping Hou ◽  
Jinsong Xiong
Keyword(s):  
Unsteady Flow ◽  
Axial Flow ◽  
Separated Flows ◽  
Design System ◽  
Relative Reduction ◽  
Positive Effects ◽  
Flow Type ◽  
Wide Range ◽  
Two Generations ◽  
Axial Flow Compressors

There occurred unsteady separated flows inside axial flow compressors, which was however not taken into consideration in the present aerodynamic design system. This discrepancy indicates that the potential underlying unsteady separated flows is yet to be explored, hence the present research team proposes the concept of two generations of unsteady flow types, i.e. Unsteady Natural Flow Type (UNFT) and Unsteady Cooperative Flow Type (UCFT). Numerical simulations are carried out in the present paper to study the compressibility effect on the unsteady cooperative flow type in axial flow compressors. The studies show that aerodynamic performances are remarkably enhanced by means of transforming the flow type from UNFT into UCFT by imposing unsteady excitations. In the case of 2D subsonic cascade, performances are greatly improved in a wide range of Ma number (Ma < 0.8) and the maximum relative reduction of the loss coefficient reaches 40.2%. In the case of 2D trans-supersonic cascade, positive effects can’t be captured. However, in the case of a 3D trans-supersonic single rotor, the adiabatic efficiency is increased from 87.0% to 90.2%.

Effects of Inertia on Flow of Steam through Nozzles and Blading of Axial-flow Turbines

1952 ◽  
Vol 166 (1) ◽  
pp. 429-442
Author(s):  
W. J. Kearton
Keyword(s):  
Energy Balance ◽  
Theoretical Analysis ◽  
Steam Turbine ◽  
Radial Distribution ◽  
Axial Flow ◽  
Nozzle Outlet ◽  
Degree Of Reaction ◽  
Outlet Angle ◽  
Inner Radius ◽  
Blade Tip

A method is given for calculating the radial distribution of pressure in a steam turbine with long blades, the conditions for radial equilibrium, for continuity, and for energy balance being satisfied simultaneously. An example, illustrating the application of the method, shows that if there is pure impulse at the root of the blade, an appreciable degree of reaction may be reached at the outer end of the blade. It is shown that if the steam flow is to be parallel to the axis of the turbine then the variation of nozzle outlet angle with change of radius depends on the steam velocity at the inner radius. An alternative theoretical analysis of the problem is given which yields quickly the radial distribution of pressure where the nozzle outlet angle is uniform. This analysis is extended to give the degree of reaction at the blade tip in terms of that at the blade root. The paper concludes with a brief note showing that in geometrically similar turbines operating with the same blade speed, but different speeds of rotation, the radial distribution of pressure is the same.

The Development of an Axial Flow Gas Turbine for Jet Propulsion

1947 ◽  
Vol 157 (1) ◽  
pp. 471-482 ◽  
Author(s):  
D. M. Smith
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Axial Flow ◽  
Bench Test ◽  
Jet Propulsion ◽  
Flow Type ◽  
Company Limited ◽  
Flow Compressor ◽  
Main Component

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.

Blade Design of Axial-Flow Compressors by the Method of Optimal Control Theory—Physical Model and Mathematical Expression

1987 ◽  
Vol 109 (1) ◽  
pp. 99-102 ◽  
Author(s):  
Chuan-gang Gu ◽  
Yong-miao Miao
Keyword(s):  
Optimal Control ◽  
Control Theory ◽  
Physical Model ◽  
Optimal Control Theory ◽  
Initial Conditions ◽  
Axial Flow ◽  
Mathematical Expression ◽  
Type Problem ◽  
Or Efficiency ◽  
Flow Type

In the design of compressor blades we put forward an optimization flow-type problem which enables the designers to consider the optimization of specified performance index of the flow-type characteristics, such as that of work or efficiency of a compressor stage. The method of the diffusion factor flow-type design (DFFTD), presented by the authors [1], is taken here as a physical model. On the basis of optimal control theory a mathematical model of the optimal flow-type problem has been established and further recast into a typical form of optimal control problem with free initial conditions, terminal constraints, and state variable inequality constraints.

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