SEMINAR ON ROLLS-ROYCE GAS TURBINE ENGINES BY A.KARTHIK
Rolls-Royce Limited was founded in 1906 by Henry Royce and The Honourable C.S. Rolls and produced its first aircraft engine in 1914. Around half the aircraft engines used by the Allies in World War I were made by Rolls-Royce.
International Aero Engines is a group of four aero-engine manufacturers, formed in 1983 to produce the engine. The companies and their responsibilities are:
- Pratt & Whitney - Combustor and high pressure turbine
- Rolls-Royce - high pressure compressor
- Japanese Aero Engines Corporation - Fan and low pressure compressor
- MTU Aero Engines - Low pressure turbine
Rolls-Royce’s civil aerospace business turned in a 4% increase in underlying profit, to £272 million ($543 million), over the first half of the year as increased deliveries of Airbus A320 engines and higher aftermarket sales pushed up revenues.
Airbreathing jet engines are gas turbines optimized to produce thrust from the exhaust gases, or from ducted fans connected to the gas turbines. Jet engines that produce thrust primarily from the direct impulse of exhaust gases are often called turbojets, whereas those that generate most of their thrust from the action of a ducted fan are often called turbofans or (rarely) fanjets.
Gas turbines are also used in many liquid propellant rockets, the gas turbines are used to power a turbopump to permit the use of lightweight, low pressure tanks to be used, which saves considerable dry mass.
Advantages of gas turbine engines
- Very high power-to-weight ratio, compared to reciprocating engines (ie. most road vehicle engines);
- Smaller than most reciprocating engines of the same power rating.
- Moves in one direction only, with far less vibration than a reciprocating engine.
- Simpler design.
- Low operating pressures.
- High operation speeds.
- Low lubricating oil cost and consumption.
Disadvantages of gas turbine engines
- Cost is much greater than for a similar-sized reciprocating engine (very high-performance, strong, heat-resistant materials needed);
- Use more fuel when idling compared to reciprocating engines.
- Slow response to changes in power settings.
As a member of the RB211 family, the RB211-524 is built on sound fundamentals:
The Rolls-Royce RB211 is a family of high-bypass turbofan engines made by Rolls-Royce plc and capable of generating 37,400 to 60,600 pounds-force (166 to 270 kilonewtons) thrust. Originally developed for the Lockheed L-1011 (TriStar), it entered service in 1972 and was the only engine to power this aircraft type.
Notable airline customers included Qantas, Cathay Pacific and South African Airways. When Boeing launched the larger 747-400 still more thrust was required, and Rolls responded with the -524G rated at 58,000 lbf thrust and then the -524H with 60,600; these were the first versions to feature FADEC.[11] (The term FADEC is an acronym for either Full Authority Digital Engine Control or Full Authority Digital Electronics Control. FADECs have been produced for both piston engines and jet engines, their primary difference due to the different ways of controlling the engines.)The -524H was also offered as a third engine choice on the Boeing 767, and the first of these entered service with British Airways in February 1990.
· Triple-spool high-bypass-ratio 4.3 - 4.1(By pass ratio:It is defined as the ratio between the mass flow rate of air drawn in by the fan but bypassing the engine core to the mass flow rate passing through the engine core.)
- Single-stage wide-chord fan
- Seven-stage IP compressor
- Six-stage HP compressor
- Single annular combustor with 18 fuel burners (24 on the G/H-T)
- Single-stage HP turbine
- Single-stage IP turbine
- Three-stage LP turbine
- After burner technology (Rolls-Royce/Turbomeca Adour)
Three-shaft architecture
The three-shaft architecture, first introduced on the RB211-22B, allows an engine to have fewer stages giving a shorter, stiffer structure. This ambitious and innovative technology allows the rotors to run to their optimum speeds thereby reducing the need for compressor variable guide vanes.
Wide-chord fan
The innovative wide-chord fan blades, well known across the Trent family originated on the RB211-524G/H engine in the 1980s. This technology allows a reduction in the number of fan blades, increasing efficiency, reducing noise and gives unrivalled protection against foreign object damage.
Incorporating Trent technology
Through the Rolls-Royce concept of family designs, the RB211-524G/H was upgraded with 04 module HP (high pressure) technology developed on the Trent 700 engine family in 1997.
In the RB211-524G/H-T the HP turbine system is designed to operate at Trent 700 temperatures that are significantly higher than the RB211-524. As a result of this, the engine is able to better retain its performance characteristics throughout its service life.
