scholarly journals Maintenance of Marine Gas Turbine Engines

1970 ◽  
Author(s):  
J. S. Siemietkowski

Marine gas turbines have been in the U.S. Navy since 1951. At present there are approximately 386 engines including both main propulsion and electric power generation in all types of craft. The maintenance of those engines is performed under a three-level concept, those being organizational, intermediate, overhaul. (Depot.) The lack of a large-scale commitment of gas turbines to the Fleet until mid-year 1969, prevented the establishment of a comprehensive maintenance program. For that reason, manufacturers recommendations rather than firm operating experience, are initially dictating the level of maintenance to be performed at specified intervals.

Author(s):  
M. A. Monroe ◽  
A. H. Epstein ◽  
H. Kumakura ◽  
K. Isomura

The performance of a regenerated gas turbine generator in the 3–5 kW power range has been analyzed to understand why its measured efficiency was on the order of 6% rather than the 20% suggested by consideration of its components’ efficiencies as measured on rigs. This research suggests that this discrepancy can be primarily attributed to heat and fluid leaks not normally considered in the analysis of large gas turbine engines because they are not as important at large scale. In particular, fluid leaks among the components and heat leakage from the hot section into the compressor flow path contributed the largest debits to the engine performance. Such factors can become more important as the engine size is reduced. Other non-ideal effects reducing engine performance include temperature flow distortion at the entrance to both the compressor and turbine. A cycle calculation including all of the above effects matched measured engine data. It suggests that relatively simple changes such as thermal isolation and leak sealing can increase both power output and efficiency of this engine, over 225% in the latter case. The validity of this analysis was demonstrated on an engine in which partial thermal isolation and improved sealing resulted in a more than 40% increase in engine output power.


Author(s):  
Meinhard T. Schobeiri ◽  
Seyed M. Ghoreyshi

The current article introduces a physics based revolutionary technology that enables energy efficiency and environmental compatibility goals of future generation aircraft and power generation gas turbines. An Ultra-High Efficiency Gas Turbine technology (UHEGT) is developed, where the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed in three stages and integrated within the first three HP-turbine stator rows. The proposed distributed combustion results in high thermal efficiencies, which cannot be achieved by conventional gas turbine engines. Particular fundamental issues of aero-thermodynamic design, combustion, and heat transfer are addressed in this study along with comprehensive CFD simulations. The aero-thermodynamic study shows that the UHEGT-concept improves the thermal efficiency of gas turbines 5–7% above the current most advanced high efficiency gas turbine engines, such as Alstom GT24. Multiple configurations are designed and simulated numerically to achieve the optimum configuration for UHEGT. CFD simulations include combustion process in conjunction with a rotating turbine row. Temperature and velocity distributions are investigated as well as power generation, pressure losses, and NOx emissions. Results show that the configuration in which fuel is injected into the domain through cylindrical tubes provides the best combustion process and the most uniform temperature distribution at the rotor inlet.


Author(s):  
Judith C. Gomez ◽  
Robert Tirawat ◽  
Edgar E. Vidal

Next-generation solar power conversion systems in concentrating solar power (CSP) applications require high-temperature advanced fluids in the range of 600° to 900°C. Molten salts are good candidates for CSP applications, but they are generally very corrosive to common alloys used in vessels, heat exchangers, and piping at these elevated temperatures. The majority of the molten-salt corrosion evaluations for sulfates with chlorides and some vanadium compounds have been performed for waste incinerators, gas turbine engines, and electric power generation (steam-generating equipment) applications for different materials and molten-salt systems. The majority of the molten-salt corrosion kinetic models under isothermal and thermal cyclic conditions have been established using the weight-loss method and metallographic cross-section analyses. Electrochemical techniques for molten salts have not been employed for CSP applications in the past. Recently, these techniques have been used for a better understanding of the fundamentals behind the hot corrosion mechanisms for thin-film molten salts in gas turbine engines and electric power generation. The chemical (or electrochemical) reactions and transport modes are complex for hot corrosion in systems involving multi-component alloys and salts; but some insight can be gained through thermochemical models to identify major reactions. Electrochemical evaluations were performed on 310SS and In800H in the molten eutectic NaCl-LiCl at 650°C using an open current potential followed by a potentiodynamic polarization sweep. Corrosion rates were determined using Tafel slopes and the Faraday law. The corrosion current density and the corrosion potentials using Pt wire as the reference electrode are reported.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4214
Author(s):  
Kranthi Kumar Maniam ◽  
Shiladitya Paul

The increased demand for high performance gas turbine engines has resulted in a continuous search for new base materials and coatings. With the significant developments in nickel-based superalloys, the quest for developments related to thermal barrier coating (TBC) systems is increasing rapidly and is considered a key area of research. Of key importance are the processing routes that can provide the required coating properties when applied on engine components with complex shapes, such as turbine vanes, blades, etc. Despite significant research and development in the coating systems, the scope of electrodeposition as a potential alternative to the conventional methods of producing bond coats has only been realised to a limited extent. Additionally, their effectiveness in prolonging the alloys’ lifetime is not well understood. This review summarises the work on electrodeposition as a coating development method for application in high temperature alloys for gas turbine engines and discusses the progress in the coatings that combine electrodeposition and other processes to achieve desired bond coats. The overall aim of this review is to emphasise the role of electrodeposition as a potential cost-effective alternative to produce bond coats. Besides, the developments in the electrodeposition of aluminium from ionic liquids for potential applications in gas turbines and the nuclear sector, as well as cost considerations and future challenges, are reviewed with the crucial raw materials’ current and future savings scenarios in mind.


Author(s):  
Edward M. House

Four Textron Lycoming TF40B marine gas turbine engines are used to power the U.S. Navy’s Landing Craft Air Cushion (LCAC) vehicle. This is the first hovercraft of this configuration to be put in service for the Navy as a landing craft. The TF40B has experienced compressor blade pitting, carbon erosion of the first turbine blade and hot corrosion of the hot section. Many of these problems were reduced by changing the maintenance and operation of the LCAC. A Component Improvement Program (CIP) is currently investigating compressor and hot section coatings better suited for operation in a harsh marine environment. This program will also improve the performance of some engine components such as the bleed manifold and bearing seals.


Author(s):  
P. A. Phillips ◽  
Peter Spear

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.


Author(s):  
Alex C. Greve ◽  
Nathaniel P. Miller ◽  
Jesse D. Shaw

There are various methods used to start marine gas turbine engines on large naval surface combatants. Methods include pneumatic, mechanical, hydraulic, and electric starting systems. This paper gives an overview of basic starting requirements, describes each method used on large surface combatants, and identifies which systems are used on many of the U.S. Navy surface combatants.


2021 ◽  
Author(s):  
Jeffrey S. Patterson ◽  
Kevin Fauvell ◽  
Dennis Russom ◽  
Willie A. Durosseau ◽  
Phyllis Petronello ◽  
...  

Abstract The United States Navy (USN) 501-K Series Radiological Controls (RADCON) Program was launched in late 2011, in response to the extensive damage caused by participation in Operation Tomodachi. The purpose of this operation was to provide humanitarian relief aid to Japan following a 9.0 magnitude earthquake that struck 231 miles northeast of Tokyo, on the afternoon of March 11, 2011. The earthquake caused a tsunami with 30 foot waves that damaged several nuclear reactors in the area. It was the fourth largest earthquake on record (since 1900) and the largest to hit Japan. On March 12, 2011, the United States Government launched Operation Tomodachi. In all, a total of 24,000 troops, 189 aircraft, 24 naval ships, supported this relief effort, at a cost in excess of $90.0 million. The U.S. Navy provided material support, personnel movement, search and rescue missions and damage surveys. During the operation, 11 gas turbine powered U.S. warships operated within the radioactive plume. As a result, numerous gas turbine engines ingested radiological contaminants and needed to be decontaminated, cleaned, repaired and returned to the Fleet. During the past eight years, the USN has been very proactive and vigilant with their RADCON efforts, and as of the end of calendar year 2019, have successfully completed the 501-K Series portion of the RADCON program. This paper will update an earlier ASME paper that was written on this subject (GT2015-42057) and will summarize the U.S. Navy’s 501-K Series RADCON effort. Included in this discussion will be a summary of the background of Operation Tomodachi, including a discussion of the affected hulls and related gas turbine equipment. In addition, a discussion of the radiological contamination caused by the disaster will be covered and the resultant effect to and the response by the Marine Gas Turbine Program. Furthermore, the authors will discuss what the USN did to remediate the RADCON situation, what means were employed to select a vendor and to set up a RADCON cleaning facility in the United States. And finally, the authors will discuss the dispensation of the 501-K Series RADCON assets that were not returned to service, which include the 501-K17 gas turbine engine, as well as the 250-KS4 gas turbine engine starter. The paper will conclude with a discussion of the results and lessons learned of the program and discuss how the USN was able to process all of their 501-K34 RADCON affected gas turbine engines and return them back to the Fleet in a timely manner.


Author(s):  
Yoshiharu Tsujikawa ◽  
Makoto Nagaoka

This paper is devoted to the analyses and optimization of simple and sophisticated cycles, particularly for various gas turbine engines and aero-engines (including scramjet engine) to achive the maximum performance. The optimization of such criteria as thermal efficiency, specific output and total performance for gas turbine engines, and overall efficiency, non-dimensional thrust and specific impulse for aero-engines have been performed by the optimization procedure with multiplier method. The comparisons of results with analytical solutions establishes the validity of the optimization procedure.


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