Demands for reduced maintenance, reduced manning and reduced cost are resulting in the need for new and alternative materials for introduction in the fleet. The new materials in many cases tend to be non-metallic and organic (combustible) materials. In order to maintain a minimum level of fire safety, the US Navy has set performance requirements for new materials in many applications. These include the use of composite materials in ships and submarines. Performance requirements for composites, in most cases, are based on full-scale fire tests. The use of composites for structural applications in submarines is covered by MIL-STD-2031. The use of composites aboard US Navy ships for topside applications is now covered by Fire Safety testing criteria. The recommended fire performance criteria contain requirements for fire growth, smoke toxicity, visibility (ISO 9705), fire resistance and structural integrity under fire (UL 1709). When developing new composite systems, it is expensive to repeatedly conduct these typical full-scale fire tests to determine the performance of the most recent design. Instead, more costeffective small-scale testing is preferable to evaluate performance. To facilitate the introduction of new and modified fire tolerant materials/systems/designs, and to reduce the financial burden on small business, the US Navy has developed a low cost composite system fire screening protocol which offers the potential of predicting the full-scale fire performance. Fire growth potential of new composite systems and designs can be screened by using small-scale test data from cone calorimeter (ASTM E-1354) and Lateral Ignition Flame spread Test (ASTM E-1321) in conjunction with the Composite Fire Hazard Analysis Tool (CFHAT). The small-scale burn-through test (2 Â 2 ft) was shown capable of screening fire resistance performance determined in furnace testing with a UL-1709 fire curve. These screening techniques provide cost-effective approaches for evaluating fire performance of new technologies, which in turn aids in the product development process. Full-scale fire testing is still required before inclusion of products onboard US Navy submarines and surface ships. Published in

Analytical studies are currently being conducted by the David Taylor Naval Ship R&D Center to assess the suitability of regenerative-cycle and intercooled, regenerative-cycle gas turbines for naval applications. This paper, which is presented in two parts, discusses results of initial investigations to identify attractive engine concepts based on existing turbomachinery and to consider the regenerator technology required to develop these engine concepts. Part I of the paper deals with the attractive engine concepts. A survey of simple-cycle engines rated from 2500 to 50,000 hp (2 to 37 MW) was conducted to determine the cycle conditions, performance characteristics, and mechanical configurations of current marine gas turbines. Comparative cycle studies were performed to establish the performance trends of the simple, regenerative, intercooled-simple, and intercooled-regenerative cycles. Hypothetical engine concepts are described which illustrate the improved performance obtained by adding heat exchangers for regeneration and intercooling to today’s simple-cycle marine engines.

Auxiliary power generation to satisfy demands for electricity and pressurized air onboard naval ships represents a significant impact on the ship's design and performance. These demands are continually growing as newer ships require improved capabilities and shipboard systems become more complex. This paper briefy examines options to the present use of multiple, simple-cycle, gasturbine-driven generator sets on U.S. Navy destroyers and cruisers. Improved engines for ship service generator drive applications are considered which are presently available from industry or are adapations of presently available engines. The feasibility of producing an auxiliary gas turbine from components taken from an intercooled-recuperative propulsion gas turbine is examined, as well as an integrated gas turbine plant which allows auxiliary power to be supplied as power takeoff from the propulsion gas turbine. The paper describes some of the design and performance aspects of these alternative approaches as well as some of their advantages and disadvantages.

During the phases of a U.S. Navy acquisition program for any new system, such as a gas turbine system, various analyses are conducted to evaluate the economic and technical benefits that can be gained by the new system. It is important that the economic analyses provide a good estimation of the nonrecurring and recurring costs. For the development of a new gas turbine system, a test program to prove the system’s technical and operational capability will have to be conducted and a support system will have to be developed to operate and maintain it during its life cycle. The costs of the engine development, the test program, and the support system development are considered nonrecurring or investment costs. The operation and maintenance costs over the life of the system are the recurring costs. This paper presents the life cycle cost scenario that should be used to evaluate the economics of a U.S. Navy marine gas turbine and the considerations that should be included in a Return on Investment analysis of the engine. The major cost categories discussed include engineering, logistics support, program management, and deployment support. Also, the unique considerations that would apply to marine gas turbines for Naval use are discussed along with how these considerations affect the economics of a gas turbine acquisition program. In addition, the paper identifies the funding responsibility of each cost item and provides discussion on ways to reduce the investment cost.

Analytical studies conducted by the U.S. Navy for the future marine gas turbine propulsion engines have concentrated in the mid-20,000 horsepower (HP) range. This power range meets the propulsion requirements of current surface ships, such as auxiliary and amphibious, frigate, destroyer, and light-cruiser ship types. In looking at future ship propulsion requirements, the possibility of developing a 50,000 HP marine gas turbine should be considered. This paper discusses the results of an initial investigation into the feasibility of a 50,000 HP marine gas turbine propulsion engine for surface ships. The current U.S. Navy 25,000 HP marine gas turbine and a theoretical 50,000 HP marine gas turbine propulsion engine performance characteristics are compared to establish performance trends of simple cycle marine engines. In addition, an advanced cycle 50,000 HP gas turbine with intercooling and recuperating is analyzed. This paper provides comparative results of engine performance for various ship operating profiles, engine size and weight and developmental cost.