scholarly journals Not So Simple Machines

2013 ◽  
Vol 135 (01) ◽  
pp. 30-35
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbines ◽  
Jet Engines ◽  
Engineering Technology ◽  
Commercial Aviation ◽  
Jet Engine ◽  
Simple Machines ◽  
History Of ◽  
Extensive Program ◽  
Four Square ◽  
Bypass Ratio

This article talks about evolving technologies in making efficient gears for different auto engines. Gears are integral to a new engine that has the potential to change commercial aviation. Pratt & Whitney’s geared turbofan (GTF) jet engine will have significantly better fuel economy and much quieter operation. The P&W GTF combines existing jet engine technology with the well-established mechanical engineering technology of gears. Due to its high bypass ratio, the geared turbofan engine is 16% more efficient than standard jet engines. A key facility for developing the GTF gearbox has been a specially designed four-square gear test rig at P&W’s Middletown plant. The orientation of the GTF test gearboxes can be adjusted with respect to gravity to simulate different flight conditions. After an extensive program using a four-square rig and a long history of gearbox experience associated with their very popular turboprop gas turbines at Pratt & Whitney Canada, P&W engineers are convinced their new GTF engines will have a bright future.

scholarly journals Gears Galore!

2013 ◽  
Vol 135 (04) ◽  
pp. 51-54 ◽  
Author(s):  
Lee S. Langston
Keyword(s):  
Fuel Consumption ◽  
Gas Turbines ◽  
Historical Analysis ◽  
Jet Engines ◽  
Efficient Operation ◽  
Jet Engine ◽  
The Status ◽  
The 1960S ◽  
A Company ◽  
Bypass Ratio

This paper presents a review of gas turbines and Honeywell, a company based in Phoenix, history. The article through the review and historical analysis intends to provide perspective on the status of geared fan engines. The addition of a fan to a jet engine, first proposed by Frank Whittle, one of the inventors of the jet engine, increases thrust and reduces fuel consumption. Pratt & Whitney and Rolls Royce were the first to develop a dual spool engine for more efficient operation over a range of flight conditions. Work started on the geared fan TFE731 at the Garrett AiResearch Phoenix Division in 1968. The TFE731 gearbox resulted in a gear reduction of 1.8:1, to power the fan for a 2.5 bypass ratio, which was very high for the 1960s. Honeywell also has another geared turbofan engine, the ALF502. It was developed by AVCO Lycoming in Stratford, Connecticut, and has a 6000–7000 lbt thrust range. Honeywell’s successful 45-year record of producing geared fan small gas turbines gives promise of a bright future for geared fans on large commercial jet engines, providing lower fuel consumption and less noise.

Practical Bypass Mixing Systems for Fan Jet Aero Engines

1966 ◽  
Vol 17 (2) ◽  
pp. 141-160 ◽  
Author(s):  
T. H. Frost
Keyword(s):  
Gas Turbines ◽  
Minimum Weight ◽  
Jet Engines ◽  
Metal Interface ◽  
Combustion Chambers ◽  
Propulsion Systems ◽  
Jet Engine ◽  
Aero Engines ◽  
Corrugated Metal ◽  
Constant Static Pressure

SummaryMixing systems have many applications in gas turbines and aircraft jet propulsion, e.g. mixing zones in combustion chambers, ejectors for jet lift thrust augmentors and supersonic propulsion systems. A further application similar to that of combustion chamber mixing is that of mixing the cold and hot exhausts of a bypass jet engine. These are both characterised by mixing at constant static pressure and approximately constant total pressure as opposed to the more general case of unequal pressures in ejector systems (Fig. 1).The exhaust mixing process as used in Rolls-Royce bypass jet engines, e.g. Spey and Conway, enables the potential of the bypass principle, in terms of minimum weight and fuel consumption, to be exploited by a simple practical device.This is achieved by mixing the two streams in a common duct of fairly short dimensions with a corrugated metal interface on the inlet side. The consideration of these practical systems forms the main topic of this paper.

The United States Navy “Standard Day” for Marine Gas Turbines

2017 ◽  
Author(s):  
John Hartranft ◽  
Bruce Thompson ◽  
Dan Groghan
Keyword(s):  
United States ◽  
Gas Turbine ◽  
United States Navy ◽  
Gas Turbines ◽  
The United States ◽  
Industrial Applications ◽  
Jet Engines ◽  
Jet Engine ◽  
Advantages And Disadvantages ◽  
Power Capability

Following the successful development of aircraft jet engines during World War II (WWII), the United States Navy began exploring the advantages of gas turbine engines for ship and boat propulsion. Early development soon focused on aircraft derivative (aero derivative) gas turbines for use in the United States Navy (USN) Fleet rather than engines developed specifically for marine and industrial applications due to poor results from a few of the early marine and industrial developments. Some of the new commercial jet engine powered aircraft that had emerged at the time were the Boeing 707 and the Douglas DC-8. It was from these early aircraft engine successes (both commercial and military) that engine cores such as the JT4-FT4 and others became available for USN ship and boat programs. The task of adapting the jet engine to the marine environment turned out to be a substantial task because USN ships were operated in a completely different environment than that of aircraft which caused different forms of turbine corrosion than that seen in aircraft jet engines. Furthermore, shipboard engines were expected to perform tens of thousands of hours before overhaul compared with a few thousand hours mean time between overhaul usually experienced in aircraft applications. To address the concerns of shipboard applications, standards were created for marine gas turbine shipboard qualification and installation. One of those standards was the development of a USN Standard Day for gas turbines. This paper addresses the topic of a Navy Standard Day as it relates to the introduction of marine gas turbines into the United States Navy Fleet and why it differs from other rating approaches. Lastly, this paper will address examples of issues encountered with early requirements and whether current requirements for the Navy Standard Day should be changed. Concerning other rating approaches, the paper will also address the issue of using an International Organization for Standardization, that is, an International Standard Day. It is important to address an ISO STD DAY because many original equipment manufacturers and commercial operators prefer to rate their aero derivative gas turbines based on an ISO STD DAY with no losses. The argument is that the ISO approach fully utilizes the power capability of the engine. This paper will discuss the advantages and disadvantages of the ISO STD DAY approach and how the USN STD DAY approach has benefitted the USN. For the future, with the advance of engine controllers and electronics, utilizing some of the features of an ISO STD DAY approach may be possible while maintaining the advantages of the USN STD DAY.

Fatigue stress analysis of the DV-2 engine turbine disk

2019 ◽  
Vol 91 (4) ◽  
pp. 708-716 ◽  
Author(s):  
Jozef Čerňan ◽  
Karol Semrád ◽  
Katarína Draganová ◽  
Miroslava Cúttová
Keyword(s):  
Development Program ◽  
Software Tool ◽  
Aircraft Engine ◽  
Turbine Disk ◽  
Jet Engines ◽  
Jet Engine ◽  
Content Type ◽  
History Of ◽  
Residual Fatigue ◽  
Aviation Engines

Purpose The purpose of this study is to improve life prediction of certain components. Fatigue of the high-stressed structural elements is an essential parameter that affects the lifetime of such components. In particular, aviation engines are devices whose failure due to fatigue failure of one of the important components can lead to fatal consequences. Design/methodology/approach In this study, two analyses in the turbine disk of the jet engine during the simulated operating load were performed: The first one was the analysis of the heat-induced stresses using the finite element method. The goal of the second analysis was to determine the residual fatigue strength of a loaded disk by the software tool using the Palmgren - Miner Linear Damage Theory. Findings The results showed a high degree of similarity with the real tests performed on the aircraft engine and revealed the weak points in the design of the jet engine. Research limitations/implications It should be mentioned that without appropriate experiments, results of this analysis could not be verified. Practical implications These results are helpful in the re-designing of the jet engines to increase their technical feasibility. Originality/value Such analysis has been realized in the DV-2 jet engine research and development program for the first time in the history of jet engine manufacturing process in Slovakia and countries of Eastern Europe region.

scholarly journals Gears Steer New Engine Designs

2017 ◽  
Vol 139 (09) ◽  
pp. 54-55 ◽  
Author(s):  
Lee S. Langston
Keyword(s):  
General Public ◽  
Mechanical Engineering ◽  
First Generation ◽  
Reduction Ratio ◽  
Engineering Technology ◽  
Jet Engine ◽  
Gear Trains ◽  
Passenger Aircraft ◽  
Bypass Ratio

This article reviews the development of geared turbofan (GTF) engines. GTF engines have a hub-mounted epicyclic gearbox that drives the front-mounted fan at lower rotational speeds than the engine turbine section that powers the fan. The turbine driving the fan is most efficient at high-rotational speeds. The fan operates most efficiently and creates less noise at lower rpm. The operating gear reduction ratio also permits increasing the engine’s bypass ratio with larger fans. Gear trains are one of the oldest known machines, and none is more closely identified by the general public with the profession of mechanical engineering. Pratt & Whitney is in production of their first generation of GTF engines in the 18,000–30,000 lbt range, which power twin engine single-aisle, narrow body 70–200 passenger aircraft. The GTF combines existing jet engine technology with the well-established mechanical engineering technology of gears.

The History of the Siemens Gas Turbine

2008 ◽  
Author(s):  
Ihor Diakunchak ◽  
Hans Juergen Kiesow ◽  
Gerald McQuiggan
Keyword(s):  
Power Generation ◽  
World War Ii ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Joint Venture ◽  
Early Years ◽  
World War ◽  
Jet Engine ◽  
Industrial Gas Turbines ◽  
History Of

Siemens gas turbine history can be traced back to the early years of World War II. The Westinghouse aero jet engine (J 30) and the Junkers JUMO 004 jet engine were the basis for the industrial gas turbines designed and manufactured by Westinghouse and Siemens / Kraftwerk-Union since World War II. KWU was formed in 1969 as a joint venture of AEG and Siemens and became wholly owned by Siemens in 1977. AEG worked with Junkers on the development of the Jumo 004 jet engine during the War. Westinghouse Power Generation was purchased by Siemens in 1998. This paper examines the history of those early gas turbines and traces the evolution of the modern Siemens gas turbine from that time. Details are also given of the latest Siemens gas turbine to enter into operation, the 340MW SGT5-8000H.

scholarly journals Changing the Game

2008 ◽  
Vol 130 (05) ◽  
pp. 25-29
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbine ◽  
Airline Industry ◽  
Gas Turbines ◽  
Jet Engines ◽  
Commercial Aircraft ◽  
Commercial Aviation ◽  
Steady Growth ◽  
Military Aviation ◽  
Electrical Generation ◽  
Future Growth

This article reviews potentially radical advances in gas turbines that came in all shapes and sizes in 2007. Gas turbine production is now a $30 billion industry, one that has been dominated, except for a stretch in the late 1990s, by commercial and military aviation. In its 70-year history, the gas turbine has become one of society’s most important and versatile energy conversion, which is relatively inert. Fuel converted to power through a gas turbine is as kinetic a substance as you can find, and one that can create great wealth. In the $21.8 billion aviation market, nearly 80 percent is for commercial aircraft engines, while the dominance of electrical generation in the $10.5 billion non-aviation market is even greater. New aircraft represents advances for commercial aviation, but commercial jet engines are themselves the key to future growth of the airline industry. While the aviation market has seen steady growth over the past decade or so, the non-aviation market for gas turbines has a noticeable production spike.

Modified Jet Engine Application for Industrial Drives in the Libyan Desert

1973 ◽  
Author(s):  
D. A. Greenberg ◽  
W. R. Bohannan
Keyword(s):  
Gas Turbines ◽  
Gas Injection ◽  
Sahara Desert ◽  
Jet Engines ◽  
Jet Engine ◽  
Expansion Turbine ◽  
Shaft Power ◽  
Single Jet ◽  
Libyan Desert ◽  
Selection Of

Gas turbines utilizing modified aircraft jet engines are successfully providing shaft power for three vital services in oil production operations in the Libyan Sahara Desert. Each of three trains of high-pressure compressors in gas injection service is powered by twin jet engines exhausting to a double-flow double-ended expansion turbine. Packaged single jet engine/expander combinations are the drivers for two low-pressure gas compressor trains in the LPG plants and for three electric generators. The remote location placed heavy emphasis on reliability and ease of maintenance in the selection of this equipment. This machinery has demonstrated its ability to perform satisfactorily under the punishing conditions required by these operations.

scholarly journals Focus on Fans

2010 ◽  
Vol 132 (08) ◽  
pp. 51-51
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbines ◽  
Field Tests ◽  
Jet Fuel ◽  
Operating Costs ◽  
Jet Engines ◽  
Fuel Use ◽  
Ongoing Research ◽  
Fan Performance ◽  
Aircraft Flight ◽  
History Of

This article discusses ongoing research in the area of turbofans used in jet engines. P&W’s gear facilities in Middletown Connecticut have been developing the fan gearbox over a period of 20 years. The company has a long history of gearbox experience associated with their very popular turboprop gas turbines at Pratt & Whitney Canada. Field tests have shown that the geared turbofan has a much lower level of noise. Currently, some airlines have as much as 35–60% of their operating costs in jet fuel use. If the geared fan engine does indeed significantly reduce fuel use, this improvement in fan performance will be hard for the competition to beat. Another way to improve fan performance is to change the pitch of fan blades, during an aircraft flight cycle. Rotating Composite Technologies, a small firm in Kensington, Conn. has also come up with a unique patented design for the variable pitch fan that promises to overcome the deficiencies of those tested in the 1990s.

scholarly journals Ultrahigh-Temperature Materials for Jet Engines

MRS Bulletin ◽  
2003 ◽  
Vol 28 (9) ◽  
pp. 622-630 ◽  
Author(s):  
J.-C. Zhao ◽  
J. H. Westbrook
Keyword(s):  
Platinum Group Metal ◽  
Jet Engines ◽  
High Melting Point ◽  
Jet Engine ◽  
Thermal Barriers ◽  
Introductory Article ◽  
History Of ◽  
Ultrahigh Temperature ◽  
The Individual

AbstractThis introductory article provides the background for the September 2003 issue ofMRS Bulletinon Ultrahigh-Temperature Materials for Jet Engines. It covers the need for these materials, the history of their development, and current challenges driving continued research and development. The individual articles that follow review achievements in four different material classes (threein situcomposites—based on molybdenum silicide, niobium silicide, and silicon carbide, respectively—and high-melting-point platinum-group-metal alloys), as well as advances in coating systems developed both for oxidation protection and as thermal barriers. The articles serve as a benchmark to illustrate the progress made to date and the challenges ahead for ultrahigh-temperature jet-engine materials.

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