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.

Testing of Ceramic Stator Vanes to 2500 F (1371 C)

Ceramic inlet vanes were tested in a full-size, eight-vane cascade rig to simulate power generation operation at 2200 and 2500 F (1204 and 1371 C). The 2200 F (1204 C) test, using only Si3N2 vanes, successfully completed over 100 start/stop cycles, except for some out-of-tolerance parts that caused edge loading. Initial 2500 F (1371 C) tests resulted in complete failure of the four carbide parts, while the four nitride parts remained funtional. Ramps up and down were somewhat more severe than for normal turbine operation, and all parts received debris impaction from an imploded combustor. Minor cracking occurred in only one nitride airfoil and two different nitride end caps. All LAS CERVIT C-140 insulator material was badly cracked after both test conditions. New insulator materials are being evaluated and cyclic tests are continuing.

The History and Use of Fire Resistant Fluids in Gas Turbines

This paper examines the three important developments of the trend toward increased use of phosphate esters, and provides a look at what can be expected in the next several years. Phosphate ester fire-resistant fluids offer three significant improvements in fire safety, when compared to petroleum products: (a) increased auto ignition and hot manifold ignition temperatures, (b) non-propagation of a flame, and (c) higher compression/ignition ratio. The use of fire-resistant phosphate ester fluids has increased significantly during the last ten years as a direct result of experience generated and problems being solved.

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.

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.

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.

Introduction of Aircraft-Derived Gas Turbines in Railroad Service

In 1963, the Deutsche Bundesbahn (German Federal Railways), together with KHD, studied the situation concerning a successful way of introducing gas turbines in rail-borne traffic. As a result, the Booster Locomotive V 169 (DL 219) was developed and introduced into service in 1965. This application, the first full service locomotive powered by a lightweight gas turbine, was presented to the public in 1965 at the World Traffic Exhibition in Munich and in 1966 at the International Gas Turbine Conference in Zurich, and gave an impulse to various other successful gas turbine applications in railroad traffic. The experience gained with the DL 219 led to the introduction of the DL 210 and VT 602 in 1971–1973. In the meantime, 25,000 hr of experience have been accumulated. Some highlights are presented and discussed in this paper.

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 ST6 Gas Turbine in Trains Operating Experience

This paper outlines the operating experience of the ST6 gas turbine installed in trains. Some of the problems encountered and the solutions used are discussed. The duty is compared to other more widely known duties. Some thoughts are offered for future applications of gas turbines to rail vehicles.