Control System for and Sea Operation Experience With CODOG-Powered Frigates

The Royal Danish Navy frigate Peder Skram successfully passed her sea trials on March 15–19, 1966, and has been in operation for about nine months, with an accumulated gas turbine operation of 490 hr at the end of December 1966. The frigate has twin-screw CODOG propulsion machinery consisting of a 22,000-shp jet-engine-fed power turbine and a 2400-shp two-stroke diesel engine. These two alternative prime movers drive the propeller shafts with controllable-pitch propellers through a common reduction gear including freewheeling clutches. The control system is described, embracing the governor system, the maneuvering system, and the instrumentation and safety systems. Operational experience at sea, including parts of the trials, is described, as well as experience gained by the Royal Danish Navy, including the voyage made by the frigate to the United States in October–December 1966.

Design Aspects of Power Plants for V/STOL Aircraft

Thrust in execess of that required for cruise and flight maneuvering is necessary to provide an aircraft with a VTOL capability. The extra thrust may be obtained by enlarged cruise engines with thrust vectoring or by retaining the optimum-size cruise engine possibly with thrust vectoring and adding a lift power plant in the form of lift jets or lift fans. A brief outline of extensive experience with lift jets, thrust vectoring, and lift fans is given and the importance of this background in making it possible to design more advanced engines which will satisfactorily meet practical operational requirements is brought out. Experience in two generations of lift-jet flight testing has shown many important areas where specal features must be incorporated in the design from the beginning to achieve high thrust for a compact volume, light weight, and high integrity in the relatively severe environment in which the lift jet has to operate. Examples are cited. The relative importance of thrust/volume and thrust/weight ratio is shown with reference to VTOL strike and transport aircraft. An integrated concept, using compact lift jets for VTOL strike aircraft and compact low-efflux-velocity lift fans using the same engine as a gas generator, is briefly noted.

Operating Gas Turbines in a Gas Processing Plant

In their gas processing plant on the Texas Gulf Coast the authors’ company recently converted from their original power source to two gas turbine units. This paper describes the equipment and reviews its installation, inlet and exhaust systems, maintenance, operation, and comparative cost. Based on this experience, the authors propose several changes for future installations.

Gas Turbine Propulsion Machinery for the MSTS Roll-On/Roll-Off Ship

The history of the roll-on/roll-off type of cargo ship is reviewed to illustrate the development of the specific ship requirements for the Adm. Wm. M. Callaghan. The ship is unique in that it is the first large cargo ship to be built which has been initially designed to incorporate all advantages of gas turbine propulsion. The basic engineering problems and selections involved in the design of the machinery plant are briefly described. The service performance of this ship will have a significant influence on future applications of gas turbine machinery for commercial ships.

A Rapid Approximate Method of Determining Axial-Flow Turbine Disk and Blade Temperatures

A method of determining the temperature profile of a single-stage axial-flow turbine disk with uncooled blades is presented. The blade temperature is also estimated. Information required for the solution is: the gas properties and velocity entering the rotor, the blade and disk geometry, the blade fastening geometry, and the disk-to-shaft attachment geometry. Impingement disk cooling may be used. The temperature of the shaft at a point near the journal bearing mutt be assumed, but it is shown that this assumption is not critical. A stepwise numerical solution, suitable for either hand calculation or computer programming, is employed. The method may be extended to multi-stage turbines. A typical example is given and the effect of changing the radius of injection of the disk cooling air is shown.

Mechanisms of Gas Turbine Regenerator Fouling

Possible mechanisms of gas turbine regenerator fouling are examined and compared with extant experimental evidence. A theoretical model of fouling which encompasses a two-phase process is proposed. It is shown that the controlling mechanism is the condensation of heavy hydrocarbon isomers which form an adhesive coating in which particulate matter subsequently become entrapped. Typical overall heat transfer and pressure drop degradation data are presented which tend to support the proposed model.

Fuel Problems With Marine Gas Turbine Engines

This paper describes a test program undertaken by the Navy to determine the causes of two problems in the fuel-oil systems of gas turbine engines. The first problem concerns short filter life; the second, copper deposits that cause clogging of fuel-oil nozzles. Results are given for operating experience with va-ious filter units from both laboratory tests and fleet experience. The effect of copper deposits on thermal stability is discussed. The author concludes with a review of remedial actions being taken to solve these problems.

The Effects of Microstructural Variations on Stress-Corrosion Cracking Susceptibility of Ti-8Al-1Mo-1V Alloy on Marinized Gas Turbines

Salt can cause titanium alloys to crack, and if long-time operation of titanium hardwares in salt atmospheres is expected, effective means must be found to eliminate or control this tendency. The authors describe in detail their stress-corrosion testing of titanium alloys, and the results are plotted in a number of tables. Figures show stress-versus-temperature charts at different high temperatures, and the microstructure of the alloy after testing is illustrated. The results of the tests are evaluated and a brief summary is given.

Creole’s 50 Industrial Gas Turbines in Repressuring Service

This paper describes the application of gas turbines to crude-oil production in a Venezuelan underwater reservoir. Decreasing pressure caused a gradual slowing down of the natural flow, and Creole Corporation was faced with the problem of either artificial lifting of the crude or curtailment of operations with several years of ample supply remaining untapped. This challenge was met successfully through repressurization of the wells by gas turbines. The design of these turbine facilities, their operation, and some of the problems involved are described. The author summarizes with a review of the performance of the gas turbines at their various locations.

Gas Turbine Propulsion for High-Speed Railcars

Experimental tests of a turbine-powered, self-propelled, high-speed railcar are presently being conducted on a section of the Long Island Railroad. This paper describes the railcar, the unique gas turbine power plant and mechanical drive system, and the expected railcar performance. The objectives of the demonstration program, the merits of the selected turbomechanical drive system, and the market potential for production turbine-powered railcars are discussed. A summary of test experience to date and a preview of propulsion-system innovations that may be tested in follow-on programs are presented.