Full Authority Digital Electronic Control: Highlights of Next Generation Propulsion Control Technology

This paper describes the results of Pratt & Whitney Aircraft preliminary design studies for a full authority digital electronic control (FADED) system with capability for controlling an advanced variable cycle gas turbine engine in an advanced supersonic Navy fighter-type aircraft application. The FADEC system concept which resulted from these studies features essentially fail-operational fault tolerance capability for non-augmented operation through the use of redundant sensing, computation, and command paths; parameter synthesis; and self-test techniques. Incorporation of advanced electronic circuit technology and minimization of complex hydromechanical hardware projected to result in over 43 percent reduction in life cycle cost, 41 percent reduction in acquisition cost, 26 percent reduction in weight, and 130 percent improvement in piece part reliability, relative to a system configuration with latest current production control technology.

Telemetry for Rotating Measurements on Turbomachinery

In the past decade, the use of shaft-mounted radio telemetry systems, for measurements on the rotating components of turbomachines, has grown to maturity. This applications-oriented paper covers the following topics: What is telemetry? • Advantages and limitations • Choosing between telemetry and slip-rings • Designing a telemetry installation • Conducting the engine test • Forthcoming developments in telemetry.

A Quasi-Three Dimensional Analysis of Choking Flow for Radial Gas Turbines

A quasi-three dimensional.flow analysis has previously been reported for a mixed flow impeller by one of the present authors. In the analysis, the velocity gradient method has been used in meridional plane and the rotating annular cascade theory has been used for blade-to-blade solution. In this report, the analysis is generalized to allow prediction and analysis of choking flow for a radial inflow gas turbine. Moreover, this analysis is corrected to include passage contraction effects and passage loss effects due to boundary-layer growth. The efficiency and choking flow rate of gas turbine may be obtained in a single computer run without the complicated throat area estimation. Some numerical examples for a burst furnace gas energy recovery turbine are presented.

A Combined System of Fuel Washing Involving Both Centrifuges and Electrostatic Separators: A Hybrid

In the gas turbine business, heavy fuels have traditionally been treated by plants using either centrifuges or electrostatic precipitators as water/fuel separators. These systems individually have certain disadvantages when applied to treating difficult heavy fuels, which can be overcome by combining the two systems whereby in the first-stage centrifuges are used followed by electrostatic precipitators in the second and subsequent stages of the treatment. The first part of the paper will deal with the Hybrid system itself, outlining its advantages, to be followed by a second part which will provide a description of the world’s first Hybrid plant which will have been built for Qatar. This plant has two stages, the first with seven centrifuges and the second with an electrostatic precipitator. Extraction of the salt in the oil to the wash water is brought about in both stages by a multi-stage rotary paddle type extractor which will also be described.

Advanced Industrial Turbine Gear Calculation Methods

Calculation of industrial turbine gears is more than calculation of load capacity concerning Hertzian pressure, bending stress, and scoring phenomena. It also includes, for example, a complete vibration analysis of the gear, shaft, and bearing systems. Some newer methods used in the German practice for these calculations and also for determining exact tooth width corrections and some aspects of the new ISO calculation methods are discussed.

Design Considerations for Future Heat Recovery Boilers Aboard Naval Vessels

The DD963 Spruance Class Destroyers were the first Naval vessels to be outfitted with auxiliary type heat recovery boilers. After a combined total operating time of approximately 30,000 hr, various conclusions relative to future design considerations can be observed. The objective of this paper is threefold: (a) to identify existing problem areas that need further imporvement, (b) to develop new design criteria for future heat recovery boilers, and (c) to consolidate the above findings into an optimum design.

Investigation of an Axial Flow Compressor With Variable Reynolds Number and Inlet Casing Geometry

In the course of developing the compressor of a 100-MW gas turbine, extensive measurements took place on a test compressor provided with the four front stages scaled down to 1:4.63. The performance investigations have been supplemented by measurements of flow distribution down- and upstream of the blading, as well as at various intermediate axial positions. The test stand, operating in a closed circuit, allowed for the variation of the Reynolds number by changing the pressure level. The geometry of the inlet casing was variable as well, thus enabling the comparison of results with axial, two- and one-sided inlet flows. In this connection, the vibrational behavior of the rotating blades, besides the aerodynamics of the compressor, have been investigated. In case of the inlet casing with a two-sided inflow, additional flow field analyses have been performed using a model without compressor blading. The theoretical results calculated under the assumption of a rotational-symmetric flow, as well as the measurements at the gas turbine compressor itself, are used for comparison. The gas turbine compressor operating with a mass flow of 483 kg/s at ISO-conditions and a pressure ratio of 10 is running in the highest performance range of single-shaft compressors in operation today.

Advanced Turbofan Engines for Low Fuel Consumption

The anticipated commercial aircraft fuel usage through the year 2000 is divided into three categories: that which will be consumed by existing engines, new production of current type engines, and new turbofan engines with advanced technology. Means of improving fuel consumption of each of these engine categories will be reviewed and the potential fuel savings identified. The cycle selection and design characteristics of an advanced turbofan engine configuration will be discussed and the potential improvements in fuel consumption and economics identified.

The Prospects for Lightweight Ship Propulsion Systems

A comprehensive systems study was made to evaluate the technological and economic feasibility of utilizing open- and closed-cycle gas turbines for providing advanced lightweight propulsion power for future Navy ship applications. Extensive parametric analyses were made of the performance and weight characteristics for the propulsion engine cycles selected, and applicable turbomachinery technologies were reviewed to estimate their future advances expected. The payload capabilities and endurance limitations resulting from utilization of different propulsion systems in the 40,000 -to 300,000-shp range for selected ship types were identified.

Test Results of a New Distillate Fuels Purification System

Seven hundred gallons of jet fuel, stored at the Hartford Electric Light Company’s South Meadow station, had been contaminated with living organisms, water, loose solids, and foreign material. The fuel was treated with the Electrocoalescer Fuels Purification System, and all but traces of the contaminants were removed. The gas turbines, fed by this purified fuel, performed faultlessly during the recent cold-snap crisis. The operating cost of this purification process was estimated to be not more than 0.6¢ per gallon.