Advanced‐cycle Gas Turbines for Naval Ship Propulsion

Abstract

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.

Improved Thermal Cycle Offers Significant Improvements in Naval Gas Turbine Efficiency

“…Scavenging of waste heat from the exhaust of a gas turbine is not a new goal. Several articles have been published in this journal (Rains 1984;Baskerville, Quandt, and Donovan 1984;Levedahl 1993;Bowen and Grogham 1984), most of which dealt with a concept called Racer (Rankine cycle energy recovery system (Figure 1), where the waste heat would be used to generate steam to be used in a peripheral conven-NAVAL ENGINEERS JOURNAL FALL 2001 9 3…”

Integrated Ship Machinery Systems Revisited

“…A variable-speed, constantfrequency alternator with feedback from a variablefrequency solid-state control system into a wound rotor was used in the 1980 design. Thanks to improvements in available high-power solid-state devices, in current studies a small, high-speed, high-frequency alternator feeds a cycloconverter or a rectifier-inverter which provides power of the appropriate voltage, frequency and harmonic content to the loads [4].…”

Gas Turbine Systems for World Navy Ships

“…The Intercooled-regenerative Cycle using one or more recuperators, is now being developed for U.S. Navy applications in the 10,000-20,000 HP range. Typical units were considered by Bowen and Ness(9)(10) and by Bowen and Groghan (11). These papers discussed the advantages of using a recuperator in the gas turbine exhaust stream and an intercooler to reduce the work of compression.…”