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Technical Paper

Initial Testing of a 250 KW Starter/Generator for Aircraft Applications

The work reported in this paper has been conducted by a team from GE-Aircraft Engines, GE-CR&D, and Sundstrand under a contract sponsored by the USAF, Wright Laboratories, WPAFB, Contract No. F33615-90-C-2052. The objective of this contract is to prove the feasibility of an Integral Starter/Generator (IS/G) through the preliminary design stage and demonstrate the starter/ generator technology in the externally mounted version utilizing switched reluctance machine technology. This paper will report on the progress for the EIS/G-system through the initial testing stage. Comparison of the finished hardware with the design results presented earlier will lead of the paper. This is followed by the discussion of the early testing results for the system testing. Recommendation on additional testing will be presented at the end of the paper.
Technical Paper

Development Testing of High Temperature Bearings for SP-100 Control Drive Assemblies

Initial preliminary development phases of two distinct SP-100 control drive assembly bearing test programs were successfully completed at elevated temperature in vacuum. The first was for the reflector drive line spherical self-aligning bearings. Each bearing consisted of a carbon-graphite ball mounted on an aluminum oxide-coated Ta-10%W shaft, captured by an aluminum oxide-coated Ta-10%W socket. One set of these bearings was exposed to temperatures up to 1180K (1665°F) at 1.33x10-6 Pa (1x10-8 torr) and subjected to 38000 cycles of motion. Friction coefficients were found to be between 0.11 and 0.25 over the full range of operation. Overall performance of the bearings was excellent, with only slight wear observed. The second test program was for the safety rod slider bearing. Zirconium carbide coated Nb-1%Zr bearing pads were stroked inside a molybdenum tube at temperatures up to 1422K (2100°F) at ∼1.33x10-6 Pa with a normal load of 1.02 Kg between each sliding surface.
Technical Paper

Progress in SP-100 Tribological Coatings

The SP-100 reactor will operate at temperatures up to 1500K in high vacuum. Development of bearing coatings is necessary to avoid self welding and/or galling of moving components. No experience base exists for these conditions-the early SNAP (Space Nuclear Auxiliary Power) program requirements were over 400K lower with shorter lifetime requirements. To address the SP-100 needs, a tribology development program has been established at GE to investigate candidate coating materials. Materials were selected based on their high thermodynamic stability, high melting point, compatibility with the substrate, and coefficients of thermal expansion similar to niobium-1% zirconium - the candidate structural material for SP-100. An additional requirement was that the deposition processes should be commercially available to coat large components.
Technical Paper

SP-100 Position Multiplexer and Analog Input Processor

This paper describes the design, implementation, and performance test results of an engineering model of the Position Multiplexer (MUX)-Analog Input Processor (AIP) System for the transmission and continuous measurements of Reflector Control Drive position in SP-100. The specially tailored MUX-AIP combination multiplexes the sensor signals and provides an increase in immunity from low frequency interference by translating the signals up to a higher frequency band. The modulated multiplexed signals are transmitted over a single twisted shielded cable pair from the reflector drives located near reactor to the AIP located at the power conditioning/system controller end of the space craft boom. There the signals are demultiplexed and processed by the AIP, eliminating the need for individual cables for each of the twelve position sensors across the boom.
Technical Paper

SP-100 Initial Startup and Restart Control Strategy

Recent Generic Flight System (GFS) updates have necessitated revisions in the initial startup and restart control strategies. The design changes that have had the most impact on the control strategies are the addition of the Auxiliary Cooling and Thaw (ACT) system for preheating the lithium filled components, changes in the reactivity worths of the reflectors and safety-rods such that initial cold criticality is achieved with only a small amount of reflector movement following the withdrawal of the safety-rods, and the removal of the scram function from the reflectors. Revised control and operating strategies have been developed and tested using the SP-100 dynamic simulation model, ARIES-GFS. The change in the total reactivity worths of the reflectors and safety-rods has eliminated the need for the use of fast and slow reflector drive speeds during the initial on-orbit approach to criticality.
Technical Paper

The Marine Gas Turbine for the 1990's and Beyond

This paper discusses the technology, components and systems incorporated in the design of the LM1600 I/CR marine gas turbine propulsion system as well as describing some of the novel and imaginative ways that the highly acclaimed F404 fighter aircraft engine has been modified and adapted to provide the nucleus for this sophisticated marine propulsion system. Specifically, the modifications to the compressors, the high and low pressure turbines and the power turbine design characteristics are described. The proven materials technology from the highly successful LM2500 marine gas turbine has been applied to this engine as well.
Technical Paper

ORION A Gas-Generator Turbocompound Engine

THE “Orion” gas-generator turbocompound engine consists of a supercharged, regenerative aircooled, 2-stroke-cycle opposed-piston diesel engine driving two centrifugal compressors. One of these compressors is for combustion air with fine air filtration, while the other is for cylinder cooling with much less filtration. The gas-generator engine has a bore of 4¼-in. diameter and a stroke of 5⅞ in. × 2. The engine turns at 2340 rpm, and the combustion air compressor turns at 37,000 rpm while the cooling air compressor turns 17,000 rpm. The cylinder is cooled with air at nearly the supercharge level and at an equivalent temperature because this air later does work on the turbine. The cooling airflow is about 3½ times the combustion airflow. These two airstreams join in a plenum chamber downstream from the engine, and the mixture temperature is about 500 F. This hot gas stream then goes to the power turbine, which is mechanically free of the gas generator.
Technical Paper

ELECTRIC DRIVE for Off-Highway Vehicles

THE CONCEPT of an electric motor mounted inside the rim of a large wheel provides several advantages: flexibility, weight and cost reductions, and adaptability to established operating and maintenance patterns. A heavy-duty traction motor drive has been designed that eliminates the need for mechanical drive lines, differentials, and hydraulic torque converters. This paper describes the gear train, lubrication system, brakes, and ventilation of such a drive. Also discussed is the engine-generator set for an electric wheel motor.*
Technical Paper

Labyrinth Seal Designs Have Benefitted from Development and Service Experience

If the labyrinth seal designer can first determine the nature, cause, and resolution of previous problems, he can then better judge what to do and how to do it for today's engines. The designer of long-life labyrinth seals is primarily interested in those design features and design criteria which have been substantiated by actual service experience. If the design features or criteria are too recent to have had significant service experience, component or factory engine tests may provide valuable substantiation.
Technical Paper

Development of Hot-Isostatically Pressed and Forged P/M Rene 95 for Turbine Disc Application

Previous studies had demonstrated the economic and technical feasibility of producing high-quality forgings for aircraft turbine engine parts from hot-isostatically pressed (HIP) Rene 95 powder billets. The present program was aimed at developing a production practice for making HIP + forged turbine discs. The major goal was improved product fabricability and reliability with minimum cost. The program was conducted using argon atomized Rene 95 powder. Experimental studies were conducted to evaluate the effect of powder characteristics, HIP parameters, preform design, and forging conditions on forgeability, microstructure, and mechanical properties. The results of these studies were incorporated into a pilot production run in which 10 disc forgings were made and evaluated. The selected process involved the consolidation of -60 mesh powder to full density by hot-isostatic pressing at a temperature above the γ' solvus temperature.
Technical Paper

Quiet Clean Short-Haul Experimental Engine (QCSEE) Design Rationale

The principal design features of the NASA QCSEE UnderThe-Wing and Over-The-Wing powered lift propulsion systems are given. In the UTW engine, these include noise reduction features, a variable pitch low pressure ratio fan, a fan drive reduction gear, an advanced core and low pressure turbine with a low pollution combustor, a digital control, and advanced composite construction for the inlet, fan frame, fan exhaust duct, and variable area fan exhaust nozzle. The OTW engine is similar but has higher fan pressure and a fixed pitch fan. Both engines are scheduled to be fabricated and tested starting in 1976.
Technical Paper

Inspection of Turbine Blades Using Computer Aided Laser Technology

Measurement of dimensional characteristics of airfoil parts is primarily a manual, labor intensive operation. It employs a wide variety of gages that vary from very expensive optical comparitors to inexpensive pin gages. An automatic non-contacting inspection gage capable of measuring most dimensional characteristics would be cost effective, simplify inspection operations, consolidate a number of gages into one, and improve overall inspection reliability by minimizing human involvement. This paper presents the results of the design and development of a demonstrator semi-automatic laser gage dimensional inspection system that addresses this problem.
Technical Paper

Silicone Rubber Oil Seals for Diesel Engines

Standard laboratory immersion tests show silicone rubber to be stable in ASTM #1, #3 oils and in unused engine lube oils. However, new test data have shown that silicone rubber will degrade when exposed to engine lube oil which has functioned in lubricating a diesel engine for many hours of service. Special silicone rubber compounds have greatly improved the resistance to degradation as shown by laboratory tests and diesel engine tests of cylinder liner seals. These silicone rubber materials should also better the seal performance in other engine applications requiring low temperature flex, high temperature and petroleum base oil resistance.
Technical Paper

A Multi-Vane Expander, by Adding Power, Can Improve The Fuel Economy Of Long-Haul Diesel Trucks

An organic Rankine Bottoming cycle added to Diesel engines used for long-haul trucks has the potential of improving their peak fuel economy by up to 15% over a typical duty cycle. General Electric has developed a multi-vane rotary expander which has a measured isentropic brake efficiency of 80+% over a wide range of speed and power levels with organic working fluids. High cycle efficiency for design and off-design conditions is achieved with the multi-vane expander. The potential advantages of the multi-vane expander for the Diesel engine bottoming cycle include the elimination of a high speed gear box and the potential for over 80% isentropic engine efficiency. The multi-vane expander is a ruggedly built component running at Diesel engine speed. This paper describes the design and evaluation of a nominal 40 HP multi-vane expander for this application.
Technical Paper

SP-100 Nuclear Subsystem Hardware and Testing

The term “SP-100” is synonymous with a set of technologies that can be utilized to provide long lifetime, reliable, safe space power over the range of kilowatts to megawatts [1] using a nuclear reactor as the heat source. This paper describes recent development progress in a number of technology areas such as fuel, materials, reactivity control mechanisms and sensors. Without exception, excellent technical progress is being accomplished in all areas under development to optimize spacecraft performance characteristics.
Technical Paper

SP-100 Space Reactor Power System Readiness

The SP-100 Space Reactor Power System is being developed by GE, under contract to the U.S. Department of Energy, to provide electrical power in the range of 10's to 100's of kW. The system represents an enabling technology for a wide variety of earth orbital and interplanetary science missions, nuclear electric propulsion (NEP) stages, and lunar/Mars surface power for the Space Exploration Initiative (SEI). An effective infrastructure of Industry, National Laboratories and Government agencies has made substantial progress since the 1988 System Design Review. Hardware development and testing has progressed to the point of resolving all key technical feasibility issues. The technology and design is now at a state of readiness to support the definition of early flight demonstration missions. Of particular importance is that SP-100 meets the demanding U.S. safety, performance, reliability and life requirements.