Structural Response of Fiber Composite Fan Blades

A fiber composite airfoil, typical for high-tip speed compressor applications, is subjected to load conditions anticipated to be encountered in such applications, and its structural response is theoretically investigated. The analysis method used consists of composite mechanics embedded in pre- and post-processors and coupled with NASTRAN. The load conditions examined include thermal due to aerodynamic heating, pressure due to aerodynamic forces, centrifugal, and combinations of these. The various responses investigated include root reactions due to various load conditions, average composite and ply stresses, ply delaminations, and the fundamental modes and the corresponding reactions. The results show that the thermal and pressure stresses are negligible compared to those caused by the centrifugal forces. Also, the core-shell concept for composite blades is an inefficient design (core plies not highly stressed) and appears to be sensitive to interply delaminations. The results are presented in graphical and tabular forms to illustrate the types and amount of data required for such an analysis, and to provide quantitative data of the various responses which can be helpful in designing such composite blades.

Gas Turbine Train Development in France

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.

NASTRAN Analysis of a Turbine Blade and Comparison With Test and Field Data

A NASTRAN finite element analysis of a free standing gas turbine blade is presented. The analysis entails calculation of the first four natural frequencies, mode shapes, and relative vibratory stresses, as well as deflections and stresses due to centrifugal loading. The stiffening effect of the centrifugal force field was accounted for by using NASTRAN’s differential stiffness option. Natural frequencies measured in a rotating test correlated well with computed results. Areas of maximum vibratory stress (fundamental mode) coincided with the three zones of crack initiation observed in a metallographic examination of a fatigue failure. Airfoil stress distributions were found to be significantly different from that predicted by generalized beam theory, especially near the airfoil-platform junction.

Development of Real Time High Energy X-Ray Imaging System for Use in Dynamic Fluoroscopy of Aero Gas Turbines

This paper discusses the development of a real-time high energy x-ray imaging system for use in dynamic fluoroscopy of aero gas turbines. In order to cover the range of subjects on gas turbines, over ten combinations of film and screen types are used. Three different types of x-ray imaging systems were considered for use: direct type intensifiers (cesium iodide phosphors), and indirect type intensifiers — Marconi “Marionette” and the Oude Delft “Delcalix.”

Digital Fuel Control of Industrial Gas Turbines

This paper shows how the significant developments available today can bring digital controls within the price range of all but the very simplest control systems and at the same time provide very significant flexibility not possible hitherto, except in the most complicated installations. New development in the form of the microprocessor chip has made it possible to design digital fuel controls at a cost equivalent to current analog systems. These developments free the control system designer from many of his previous limitations, but they also impose new constraints.

Component Design Considerations for Gas Turbine HTGR Power Plant

The gas turbine high-temperature gas-cooled reactor (HTGR) power plant combines the existing design HTGR core with a closed-cycle helium gas turbine power conversion system directly in the reactor primary circuit. The high density helium working fluid results in a very compact power conversion system. While the geometries of the helium turbomachinery, heat exchangers, and internal gas flow paths differ from air breathing gas turbines because of the nature of the working fluid and the high degree of pressurization, many of the aerodynamic, heat transfer and dynamic analytical procedures used in the design are identical to conventional open-cycle industrial gas turbine practice. This paper outlines some of the preliminary design considerations for the rotating machinery, heat exchangers, and other major primary system components for an integrated type of plant embodying multiple gas turbine loops. The high potential for further improvement in plant efficiency and capacity, for both advanced dry-cooled and waste heat power cycle versions of the direct-cycle nuclear gas turbine, is also discussed.

Maintenance of Industrial Gas Turbines

This paper describes the maintenance requirements of the heavy-duty gas turbine. The various inspections and factors affecting maintenance are defined, and basic guidelines are presented for a planned maintenance program.

A Design Study of a Fan Augmented Ramjet

The characteristics of a hybrid propulsion system, which fills the gap between turbojets and ramjets, are presented. The hybrid system is a fan augmented ramjet and consists of a ramburner fed by an externally driven low pressure ratio fan. Cycle analyses, performance estimates and, scaling relationships for subsonic and supersonic operation, and a preliminary design of a subsonic version are presented. A 50 to 100 percent improvement in cruise performance above that of a ramjet can be expected in the subsonic regime.

The American Turboliner

The background for selection of turbine trains for corridor service is examined and characteristics of the RTG Turbine Train power units described. Design criteria for future performance requirements are also developed.

Gas Turbine Drive for New High Speed Trains

After numerous tests over the last 40 years, the aircraft gas turbine of two-shaft design has emerged as the most promising power unit for high-powered, fast and lightweight rail vehicles of the future. The performance characteristics, superior to those of the diesel engine, are complemented either by an electrical transmission system or a hydraulic transmission unit. The advantage of the gas turbine lies in its compactness and lightness in weight, allowing a doubling of power and savings in space. Viewed from a commercial standpoint, this means a covering of fuel costs. In respect of noise development and exhaust gas emission, the gas turbine is also more favorable than the diesel engine. The most successful series-built vehicles powered by gas turbines are the turbotrains of the SNCF which have also been imported into the USA where they are to be built under license.