The U.S. Navy is developing an Intercooled Recuperated (ICR) marine gas turbine, designated the WR-21, for propulsion of future surface ships. The objectives of this development program and the key technical requirements are summarized. The design of the WR-21 is described in considerable detail. Meeting all the design requirements for performance, space, weight, reliability, maintainability, and life has been challenging. Numerous design tradeoffs and iterations have been performed to optimize the design within the constraints imposed in the ICR technical specification. Integration of the WR-21 engine into the DDG51 Flight IIA ship, which is the U.S. Navy’s first application, has influenced the WR-21 design. This paper discusses the aspects of the DDG-51 application that were factored into the design of the ICR engine in order to reduce installation costs.

The U.S. Navy is developing an intercooled Recuperated (ICR) marine gas turbine, designated the WR-21, for propulsion of future surface ships. The objectives of this development program and the key technical requirements are summarized. The design of the WR-21 is described in considerable, detail. Meeting all of the design requirements for performance, space, weight, reliability, maintainability and life has been challenging. Numerous design tradeoffs and iterations have been performed to optimize the design within the constraints imposed in the ICR technical specification. Integration of the WR-21 engine into the DDG51 Flight IIA ship, which is the U.S. Navy’s first application, has influenced the WR-21 design. This paper discusses the aspects of the DDG-51 application that were factored into the design of the ICR engine in order to reduce installation costs.

Investigations are currently being conducted by the Navy and several contractors to determine the technical feasibility and cost effectiveness of advanced regenerative or intercooled‐regenerative gas turbines as a naval propulsion engine for future mid‐size surface combatants. A comparison of the performance characteristics of these engines indicates that significant increases in the thermal efficiency above current simple‐cycle engines will result by adding heat exchangers for regeneration alone or with intercooling. Design and performance characteristics of several advanced‐cycle gas turbines are described which utilize turbomachinery from various existing simple‐cycle gas turbines. Estimates of the weight and volume of recuperators and intercoolers for these conceptual engines are provided. The nominal part‐load fuel consumption trends of the simple‐cycle and the advanced‐cycle engines are used to compare annual fuel usage of typical ships with various combinations of propulsion engines. The relative impacts of the advanced‐cycle gas turbine on propulsion machinery spaces are compared with other energy efficient prime movers using the simple‐cycle gas turbine as the baseline. Commercial applications for an advanced‐cycle gas turbine are surveyed according to output power and market sector. This paper presents an overview of current results and discusses the technology areas which require additional investigation.

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.

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 is the second part of a two-part paper which 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 analyzed existing and next generation engines for performance improvement. Part II includes: definitions of performance parameters such as effectiveness and pressure drop, a discussion of regenerator types, and comments on regenerator materials, life, maintenance, and fouling. Tradeoffs between size, weight, and performance of plate-fin recuperators are examined using two of the hypothetical engines from Part I as examples. Results are compared for several different recuperator matrices to illustrate the effects of air-side and gas-side fin density and plate spacing on size, weight, and performance.