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Ursprungligen postat av
KlokOchSnygg
Turbofläkt är en blandning mellan propellerplan och jetmotor. En Jetmotor komprimerar luft, antänder den och "kastar" luften bakåt med hög hastighet. Det finns en hel del begränsningar med hur mycket luft man kan komprimera om man står stilla eller kör långsamt.
En turbofläkt är enkelt beskrivet som man kopplat på en stor propeller. Desto högre förhållande mellan hur mycket luft som förs in från propellern i jämförelse med hur mycket av den luften som komprimeras och fungerar för jetmotorn desto mer likt ett propellerplan blir det.
Fördelen med propellern är att den kan flytta större mängd luft vid låg hastighet. Nackdelen är att propellern fungerar sämre och sämre desto snabbare planet går. Propellern har i sig ett luftmotstånd med dess mycket större diameter. Jetmotorn däremot behöver inte jobba lika hårt för att ta in luft när planet går snabbare, den klarar då att komprimera luft, antända och kasta bak luften mer effektivt
Hur fan kan du få till allt så fel och vinklat varje gång....? Fast vänta nu.... Du gör ju allt för att slippa erkänna att du har fel och för att det ska passa din fanatiska tro på konspirationer...
Kolla här i citatet...
Citat:
Turbofan
A turbofan is a type of jet engine, similar to a turbojet. It essentially consists of a large ducted fan with a smaller diameter turbojet engine mounted behind it that provides propulsion and also powers the fan. Part of the airstream from the ducted fan passes through the turbojet, providing oxygen to burn fuel to power the turbojet. But part, usually most, of the flow bypasses the turbojet, and is accelerated by turbine blades acting like a propeller. The combination of these two processes produces thrust more efficiently than other jet designs.[1]
A few designs work slightly differently and have the fan blades as a radial extension of an aft-mounted low-pressure turbine unit.
Turbofans have a net exhaust speed that is much lower than a turbojet. This makes them much more efficient at subsonic speeds than turbojets, and somewhat more efficient at supersonic speeds up to roughly Mach 1.6.
All of the jet engines used in currently manufactured commercial jet aircraft are turbofans. They are used commercially mainly because they are highly efficient and relatively quiet in operation. Turbofans are also used in many military jet aircraft.
Low-bypass Turbofan
Description
One- or two-stage fan added in front bypasses a proportion of the air through a bypass chamber surrounding the core. Compared with its turbojet ancestor, this allows for more efficient operation with somewhat less noise. This is the engine of high-speed military aircraft, some smaller private jets, and older civilian airliners such as the Boeing 707, the McDonnell Douglas DC-8, and their derivatives
Advantages
As with the turbojet, the design is aerodynamic, with only a modest increase in diameter over the turbojet required to accommodate the bypass fan and chamber. It is capable of supersonic speeds with minimal thrust drop-off at high speeds and altitudes yet still more efficient than the turbojet at subsonic operation
Disadvantages
Noisier and less efficient than high-bypass turbofan, with less static (Mach 0) thrust. Added complexity to accommodate dual shaft designs. More inefficient than a turbojet around M2 due to higher cross-sectional area
High-bypass Turbofan
Description
First stage compressor drastically enlarged to provide bypass airflow around engine core, and it provides significant amounts of thrust. Compared to the low-bypass turbofan and no-bypass turbojet, the high-bypass turbofan works on the principle of moving a great deal of air somewhat faster, rather than a small amount extremely fast. Most common form of jet engine in civilian use today- used in airliners like the Boeing 747, most 737s, and all Airbus aircraft
Advantages
Quieter due to greater mass flow and lower total exhaust speed, more efficient for a useful range of subsonic airspeeds for same reason, cooler exhaust temperature. Less noisy and exhibit much better efficiency than low bypass turbofans
Disadvantages
Greater complexity (additional ducting, usually multiple shafts) and the need to contain heavy blades. Fan diameter can be extremely large, especially in high bypass turbofans such as the GE90. More subject to FOD and ice damage. Top speed is limited due to the potential for shockwaves to damage engine. Thrust lapse at higher speeds, which necessitates huge diameters and introduces additional drag
KÄLLA:
http://horizons-2000.org/0.%20Professional/Engineering/jet%20engine%20types.doc
Som du ser så håller de inte med dig i dina påståenden, utan säger att Turbofan är effektivare än vanlig jetmotor upp till mach 1.6
Och som vanligt så visar det sig att dina påståenden är felaktiga när man synar dem....
