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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.

As part of the SP-100 Space Reactor Power System Program being undertaken for the U. S. Department of Energy, GE is developing a thermoelectric (T/E) power converter which utilizes reactor delivered heat and transforms it into usable electric power by purely static means. This converter is based to GE's product line of successful thermoelectric space power systems. The SP-100 power converter embodies the next generation improvement over the type of T/E converter successfully flown on the six U. S. space missions. That is, conduction coupling of T/E cell to both the heat source and the heat rejection elements. The current technology utilizes radiation coupling in these areas. The conduction coupling technique offers significant improvements in system specific power since it avoids the losses associated with parasitic ΔT's across the radiation gap between the heat source and the hot junction of the thermoelectric (T/E) cell.

System level design studies of space applications ranging in power from 77 kWt to 200 MWt have indicated no practical limit to the thermal power that can be reliably generated by a space reactor system based on the technologies being developed in the SP-100 program. These technologies include uranium nitride fuel, PWC-11/rhenium bonded fuel cladding, PWC-11 structural material for the lithium coolant boundary, electromagnetic coolant pumps, safety and reactivity control drive mechanisms, sensors, shielding materials, etc. at operating temperatures up to 1400K. The physical arrangements and characteristics of the nuclear reactor materials are described. The physical size of components and the arrangement of components change, but the basic technologies required are generally the same, irrespective of the total power output.

This paper describes how the SP-100 Space Reactor Power System (SRPS) can be tailored to meet the specific requirements for a lunar surface power system to meet the needs of the consolidation and utilization phases outlined in the 90-day NASA SEI study report. This same basic power system can also be configured to obtain the low specific masses needed to enable robotic interplanetary science missions employing Nuclear Electric Propulsion (NEP). In both cases it is shown that the SP-100 SRPS can meet the specific requirements. For interplanetary NEP missions, performance upgrades currently being developed in the area of light weight radiators and improved thermoelectric material are assumed to be technology ready in the year 2000 time frame. For lunar applications, some system rearrangement and enclosure of critical components are necessary modifications to the present baseline design.

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.

Alternative engine concepts to the advanced high bypass turbofan which have promise of reducing energy consumption including regenerative cycles and other engines with heat exchangers, unconventional engine arrangements such as geared fan engines, and high disc loading turboprops. After initial screening, several concepts were selected for a systematic evaluation of the merits of each relative to a high bypass turbofan based on advanced technology consistent with the mid 1980's time period. Both mission fuel and direct operating cost for typical long range transport missions were considered in the evaluation.

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.

The effects of transmission selection on the performance and fuel economy of a gas turbine powered automobile are analyzed. Both single-shaft and two-shaft turbines are considered. Examples are given of fuel economy for an urban cycle, and performance of these engines with an infinitely variable transmission and with a power shift automatic transmission. The primary conclusions are that the infinitely variable transmission is necessary for a single-shaft engine and highly desirable for a two-shaft engine, and the use of an infinitely variable transmission with the single-shaft turbine eliminates any need for the wider output speed range of a two-shaft engine.

The problems and choices in the design of an advanced subsonic transport turbofan for reduced noise and improved aircraft performance are examined in this paper. The effects of bypass ratio, fan pressure ratio, and fan tip speed on jet noise, fan noise, and acoustic treatment suppression are described. The results do not indicate a clear optimum bypass ratio considering the effects upon installed engine performance and weight as well as acoustic performance. Low fan tip speed designs with the associated high aerodynamic loading are compared to high tip speed low loading designs. Other factors affecting noise such as the installation and other noise sources are discussed. The long duct installation is indicated to have potential advantages over the short duct separate flow installation. The problem of assuring that growth models of an engine also have low noise is discussed.

THE problem of this study was: 1. Can a method of analysis be found which adequately predicts the heat-transfer and cyl-wall temperature phenomena in diesel engines? 2. Are there criteria for the design of diesel engine cyl that give the limits of reliable practice as found in typical diesels? Such a method of analysis is detailed in this paper. Design criteria were also found which appear applicable to broad classes of diesel engines. It was determined that the method was useful in prediction of the thermodynamic performance of a diesel insofar as the influence of cyl heat transfer on efficiency, power, and cooling load were predictable.