U.S. Navy Experience With SSS (Synchro-Self-Shifting) Clutches

Author(s):  
Morgan L. Hendry ◽  
B. Michael Zekas

The U.S. Navy has nearly forty years of experience using SSS (Synchro-Self-Shifting) Clutches in main reduction gears of gas-turbine-driven ships and propulsion systems with combinations of gas turbines and diesel engines or electric motors, and in steam-turbine propulsion plants for use with electric motor drives. Over 900 SSS Clutches have been installed in fourteen different classes of U.S. Navy ships, some in service for over thirty years. This paper presents a brief overview of the principle SSS Clutch design features and the operating experience in naval propulsion systems worldwide, including operation in various propulsion plants such as controllable reversible pitch (CRP) propellers, fixed-pitch propellers (FPP), etc. The paper will also focus on SSS Clutch designs for specific U.S. Navy applications and installations, U.S. Navy experience, and design changes and improvements that have been implemented since the initial U.S. Navy use of SSS Clutches. Detailed metric (statistical) data, used by the U.S. Navy to evaluate equipment performance and life cycle costs, such as mean time between failure (MTBF), mean time to repair (MTTR), mean logistics delay time (MLDT), and operational availability (Ao) will be used to support experience. In-service experience and failure modes will also be explained as well as findings from the evaluation of clutches that have been subjected to extreme operation/incidents such as overspeed, overtorque, high shock blast, and flood damage. The final part of the paper will discuss current/future applications on U.S. Navy vessels such as the LHD-8, LCS and others; and how the design/features of those SSS Clutch designs will satisfy the operational, reliability, and maintainability requirements established for each ship platform. The metrics and lessons learned will be shown to be equally applicable to clutches for critical auxiliary drive applications such as naval gas turbine generator starting and naval steam turbine generator turning gear systems and how these metrics and lessons learned are being applied for current and future U.S. Navy ship systems.

Author(s):  
Dennis M. Russom ◽  
Ivan Pin˜eiro

This paper looks back at the evolution of the Gas Turbine Generator sets (GTGs) in the U.S. Navy’s DDG 51 Class, reviewing lessons learned, successes and areas where work is still required. Topics are discussed in the context of Mean Time Between Failure (MTBF) Total Ownership Cost (TOC) and maintainability. It reviews changes that resulted in MTBF increasing by a factor of five and TOC dropping by a factor of four. It also looks to the future, identifying potential areas of further improvement.


Author(s):  
Roger Yee ◽  
Alan Oswald

A new generation of auxiliary ships to enter the U.S. Navy (USN) fleet is the AOE-6 SUPPLY CLASS. These fast combat support ships conduct operations at sea as part of a Carrier Battle group to provide oil, aviation fuel, and ammunition to the carrier and her escorts. The SUPPLY CLASS is the first ship in the entire USN fleet to use a combined gas turbine and diesel generator cooling air intake system to cool its respective engine modules. The cooling air intake was designed this way to save on costs. As the ships in this class continued with operations and problems of insufficient supply of cooling air for the gas turbines modules started surfacing, the entire intake system required investigation and analysis. Since the gas turbines and diesel generators share a common cooling air trunk, they were competing for air. This paper will outline the tests that were performed to determine the problems, the recommended solutions, and the lessons learned from the investigations.


1979 ◽  
Author(s):  
L. F. Fougere ◽  
H. G. Stewart ◽  
J. Bell

Citizens Utilities Company’s Kauai Electric Division is the electric utility on the Island of Kauai, fourth largest and westernmost as well as northernmost of the Hawaiian Islands. As a result of growing load requirements, additional generating capacity was required that would afford a high level of reliability and operating flexibility and good fuel economy at reasonable capital investment. To meet these requirements, a combined cycle arrangement was completed in 1978 utilizing one existing gas turbine-generator and one new gas turbine-generator, both exhausting to a new heat recovery steam generator which supplies steam to an existing steam turbine-generator. Damper controlled ducting directs exhaust gas from either gas turbine, one at a time, through the heat recovery steam generator. The existing oil-fired steam boiler remains available to power the steam turbine-generator independently or in parallel with the heat recovery steam generator. The gas turbines can operate either in simple cycle as peaking units or in combined cycle, one at a time, as base load units. This arrangement provides excellent operating reliability and flexibility, and the most favorable economics of all generating arrangements for the service required.


Author(s):  
Louis Ellington ◽  
Glenn McAndrews ◽  
Alexander Harsema-Mensonides ◽  
Ravi Tanwar

GE aero-derivative gas turbines were first introduced into marine operations during the late 1960’s and early 1970’s. GE is now leveraging its many years of proven marine experience and offshore dual-fuel experience to offer dual-fuel gas turbines for LNG Carrier (LNGC) propulsion and electric power. With building of new larger LNGC’s now beginning, the industry is seriously considering a change to gas turbine based systems in order to capitalize on their many advantages. CoGES (combined gas turbine — steam generator electric) plants for LNGC’s consist of dual-fueled gas-turbine-generator (GTG) set(s) and auxiliaries, heatrecovery steam generator (HSRG), a steam-turbine-generator set, feed-water, steam and condensate systems. Leveraging cruise-ship reliability programs, the GTG instrumentation and control systems are single-point fault tolerant. Gas turbine power plants offer many additional advantages, including but not limited to: Use of boil-off gas as a cost-effective and environmentally friendly fuel (slow speed diesel ships require complex on-board reliquifaction of boil-off gas). When installed on deck, CoGES plants provide high power-volume density that translates into increased cargo revenue and deferred capital cost. Gas turbines ease of maintenance and quick changeout. Developed to meet the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC) and classification society standards for marine applications, GE’s 2 X LM2500 CoGES plant is a very simple and reliable solution. Dry-run capable HRSG’s are used in lieu of exhaust damper and by-pass systems. Outage of any one prime mover leaves the plant with nominally 50% power remaining. Common spares are inherent. Established as having an equivalent level of safety as traditional LNGC propulsion systems via FMECA type studies, the 2 x dual-fueled LM2500 CoGES plant has been “Approved in Principle” by Class for use on LNG Carriers. Alternatively, GE’s 1 X dual-fueled LM6000 or 1 X LM2500+/G4 CoGES plant addresses capital & operating cost pressures via reduced equipment costs and improved fuel economy. Redundancy and simplicity are achieved via a dry-run capable HRSG and an STG, combined with auxiliary diesel generator sets. Both the LM2500 family and LM6000 CoGES plants offer viable alternatives to traditional steam turbine and slow-speed-diesel propulsion. Gas-fuel, liquid-fuel, and bi-fuel operation provide flexibility and redundancy to ship owners who must safely and reliably deliver cargo at the lowest possible cost per MMBTU throughout a fleet life cycle.


Author(s):  
Richard S. Carleton ◽  
Eugene P. Weinert

This paper is a brief review of the U.S. Navy involvement in shipboard gas turbines starting with studies in the 1930’s and proceeding to the point where gas turbine propulsion has been chosen for all recent cruiser, destroyer and frigate class construction programs. It tells some of the false starts and lessons learned and accentuates the decision of the Navy to take advantage of the major developments in aircraft jet engines by using these same engines, marinized for use in a shipboard environment, to power many of our new combatants.


Author(s):  
Charles T. Vincent ◽  
Rolf Weber

This paper reviews the highlights of the first two seasons of commercial operation of GE LM2500 gas turbines installed in the Aquastrada class of fast ferries. The ships’ total propulsion systems were supplied and packaged by MTU-Friedrichshafen for this first commercial marine application of the LM2500 gas turbine. Problems encountered and lessons learned are presented as part of the paper.


Author(s):  
Daniel E. Caguiat

Currently, the U.S. Navy DDG-51 class ships employ a system of piping, tanks, and nozzles for washing the four Gas Turbine Main (GTM) engines and three Ship Service Gas Turbine Generator (SSGTG) engines. The wash system employed, referred to as the crankwash system, allows the user to wash the compressor section of a gas turbine only when the turbine in question is not operating. On a DDG-51 class ship, it is possible to utilize the existing crankwash piping, tank, and overall architecture to supply water to an online water wash system. An online water wash system allows the compressor section to be cleaned while the gas turbine is in operation. This is intended to reduce the periodicity of crankwashing and associated starter cycling costs. Online water wash is also intended to maintain compressor cleanliness in the interval between crankwashes. NAVSEA Philadelphia researched appropriate online water wash system designs, methods for collecting data to address fuel savings and engine performance issues, and installation methods. GTM and SSGTG Online Water Wash Systems were then installed on USS PREBLE (DDG-88) in late 2008. USS PREBLE subsequently deployed for a period of six months beginning January 2009. During the deployment, data was collected as the systems were operated. This paper will discuss the system design, provide data analysis results, and discuss lessons learned.


2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Emmanuel O. Osigwe ◽  
Arnold Gad-Briggs ◽  
Theoklis Nikolaidis

When selecting a design for an unmanned aerial vehicle, the choice of the propulsion system is vital in terms of mission requirements, sustainability, usability, noise, controllability, reliability and technology readiness level (TRL). This study analyses the various propulsion systems used in unmanned aerial vehicles (UAVs), paying particular focus on the closed-cycle propulsion systems. The study also investigates the feasibility of using helium closed-cycle gas turbines for UAV propulsion, highlighting the merits and demerits of helium closed-cycle gas turbines. Some of the advantages mentioned include high payload, low noise and high altitude mission ability; while the major drawbacks include a heat sink, nuclear hazard radiation and the shield weight. A preliminary assessment of the cycle showed that a pressure ratio of 4, turbine entry temperature (TET) of 800 °C and mass flow of 50 kg/s could be used to achieve a lightweight helium closed-cycle gas turbine design for UAV mission considering component design constraints.


Author(s):  
J R Bolter

Sir Charles Parsons died some three years after the author was born. In this paper the author looks back at the pioneering work of Parsons in the field of power generation. It shows how he was able to increase output of the steam turbine generator from 7.5 kW in 1884 to 50000 kW in 1930 while increasing efficiency from 1.6 to 36 per cent, and relates these achievements to the current state of the art. Blading design, rotor construction and other aspects of turbine engineering are considered. The conclusion is that Parsons and his associates charted the course which manufacturers and utilities throughout the world have continued to follow, although increasingly sophisticated design and analytical methods have succeeded the intuitive approach of Parsons. His constant search for improved efficiency was and is highly relevant to today's concern for the environment. Finally, although it did not become a practical proposition in his lifetime, the paper reviews Parsons' vision of, and continuing interest in, the gas turbine, first mentioned in his 1884 patents.


Author(s):  
C. Rodgers

By the new millennia gas turbine technology standards the size of the first gas turbines of Von Ohain and Whittle would be considered small. Since those first pioneer achievements the sizes of gas turbines have diverged to unbelievable extremes. Large aircraft turbofans delivering the equivalent of 150 megawatts, and research micro engines designed for 20 watts. Microturbine generator sets rated from 2 to 200kW are penetrating the market to satisfy a rapid expansion use of electronic equipment. Tiny turbojets the size of a coca cola can are being flown in model aircraft applications. Shirt button sized gas turbines are now being researched intended to develop output powers below 0.5kW at rotational speeds in excess of 200 Krpm, where it is discussed that parasitic frictional drag and component heat transfer effects can significantly impact cycle performance. The demarcation zone between small and large gas turbines arbitrarily chosen in this treatise is rotational speeds of the order 100 Krpm, and above. This resurgence of impetus in the small gas turbine, beyond that witnessed some forty years ago for potential automobile applications, fostered this timely review of the small gas turbine, and a re-address of the question, what are the effects of size and clearances gaps on the performances of small gas turbines?. The possible resolution of this question lies in autopsy of the many small gas turbine component design constraints, aided by lessons learned in small engine performance development, which are the major topics of this paper.


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