High-temperature corrosive damage to superalloys during operation of blades of gas-turbine engines and power plants

2013 ◽  
Vol 6 (3) ◽  
pp. 250-255
Author(s):  
M. R. Orlov
2018 ◽  
Vol 220 ◽  
pp. 03001
Author(s):  
Andrey Tkachenko ◽  
Ilia Krupenich ◽  
Evgeny Filinov ◽  
Yaroslav Ostapyuk

This article describes the multi-level approach to developing the virtual testing rig of gas turbine engines and power plants. The described virtual rig is developed on the basis of computer-aided system of thermogasdynamic calculations and analysis ASTRA, developed at Samara National Research University. Existing testing rig is widely used in educational process to supply the students’ research activities with the information on engine operation in a variety of ambient and flight conditions during transients. An approach to upgrading the virtual testing rig is proposed. The described modifications would provide the capabilities to solve more complex research tasks, including investigation of influence of geometry of engine elements on the engine characteristics, multidisciplinary investigations, identification of engine models using the results of experimental investigations and identification of sources of engine deficiencies during the development phase of engine designing.


2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Houman Hanachi ◽  
Jie Liu ◽  
Ping Ding ◽  
Il Yong Kim ◽  
Chris K. Mechefske

Gas turbine engines (GTEs) are widely used for power generation, ranging from stationary power plants to airplane propulsion systems. Compressor fouling is the dominant degradation mode in gas turbines that leads to economic losses due to power deficit and extra fuel consumption. Washing of the compressor removes the fouling matter and retrieves the performance, while causing a variety of costs including loss of production during service time. In this paper, the effect of fouling and washing on the revenue of the power plant is studied, and a general solution for the optimum time between washes of the compressor under variable fouling rates and demand power is presented and analyzed. The framework calculates the savings achievable with optimization of time between washes during a service period. The methodology is utilized to optimize total costs of fouling and washing and analyze the effects and sensitivities to different technical and economic factors. As a case study, it is applied to a sample set of cumulative gas turbine operating data for a time-between-overhauls and the potential saving has been estimated. The results show considerable saving potential through optimization of time between washes.


Author(s):  
David A. Shifler

High temperature applications demand materials that have a variety of properties such as high strength, toughness, creep resistance, fatigue resistance, as well as resistance to degradation by their interaction with the environment. All potential metallic materials are unstable in many high temperatures environments without the presence of a protective coating on the component surface. High temperature alloys derive their resistance to degradation by forming and maintaining a continuous protective oxide surface layer that is slow-growing, very stable, and adherent. In aggressive environments, the superalloy oxidation and corrosion resistance needs to be augmented by coatings. Propulsion materials for Naval shipboard gas turbine engines are subjected to the corrosive environment of the sea to differing degrees. Increasing fuel efficiency and platform capabilities require higher operating temperatures that may lead to new degradation modes of coatings and materials. Fuel contaminants or the lack of contaminants from alternative synthetic fuels may also strongly influence coating and/or materials performance which, in turn, can adversely affect the life in these propulsion or auxiliary gas turbine engines. This paper will dwell on some past results of materials testing and offer some views on future directions into materials research in high temperature materials in aggressive environments that will lead to new advanced propulsion materials for shipboard applications.


Author(s):  
Nanahisa Sugiyama

This paper describes a real-time or faster-than-real-time simulation of gas turbine engines, using an ultra high speed, multi-processor digital computer, designated the AD100. It is shown that the frame time is reduced significantly without any loss of fidelity of a simulation. The simulation program is aimed at a high degree of flexibility to allow changes in engine configuration. This makes it possible to simulate various types of gas turbine engines, including jet engines, gas turbines for vehicles and power plants, in real-time. Some simulation results for an intercooled-reheat type industrial gas turbine are shown.


Author(s):  
David A. Shifler ◽  
Dennis M. Russom ◽  
Bruce E. Rodman

501-K34 marine gas turbine engines serve as auxiliary power sources for the U.S. Navy’s DDG-51 Class. It is desired that 501-K34 marine gas turbine engines have a mean time between removal of 20K hours. While some engines have approached this goal, others have fallen significantly short. A primary reason for this shortfall is hot corrosion (Type I and Type II) damage in the turbine area (more specifically the first row turbine hardware) due to both intrusion of salts from the marine air and from sulfur in the gas turbine combustion fuel. The Navy’s technical community recognizes that engine corrosion problems are complex in nature and are often tied to the design of the overall system. For this reason, two working groups were formed. One group focuses on the overall ship system design and operation, including the inlet and fuel systems. The second, the corrosion issues working group, will review the design and performance of the turbine itself and develop sound, practical, economical, and executable changes to engine design that will make it more robust and durable in the shipboard operating environment. Metallographic examination of unfailed blades removed from a marine gas turbine engine with 18000 operating hours showed that the coating thickness under the platform and in the curved area of transition between the platform to the blade stem was either very thin, or in a few cases, non-existent on each unfailed blade. Type II hot corrosion was evident at these locations under the platform. It was also observed that this corrosion under the platform led to corrosion fatigue cracking of first stage turbine blades due to poor coating quality (high porosity and variable thickness). Corrosion fatigue cracks initiated at several hot corrosion sites and had advanced through the stems to varying degrees. Cracking in a few blades had advanced to the point that would have led to premature blade failure. Low velocity, atmospheric-pressure burner-rig (LVBR) tests were conducted for 1000 hours to evaluate several alternative high-temperature coatings in both Type I and Type II hot corrosion environments. The objectives of this paper are to: (1) report the results of the hot corrosion performance of alternative high temperature coating systems for under the platform of the 1st stage blade of 501-K34 gas turbine engine, (2) compare the performance of these alternative coating systems to the current baseline 1st stage blade coating, and (3) down select the best performing coating systems (in terms of their LVBR hot corrosion and thermal cycling resistance) to implement on future 501-K34 first stage blades for the Fleet.


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