Aircraft Turbomachinery Aarohi Palkar COSMOS 2015 Cluster 3

What is a Turbomachine? Why do we need them? A turbomachine is a device that exchanges mechanical energy with a continuously flowing fluid with the help of rotating blades. Why do we need them?

What is a Turbomachine? Two types: -Turbine: Fluid loses energy -Compressor: Fluid gains energy

History of Turbomachines Hero of Alexandria developed the first jet engine in 100 BC, called the Aeolipile Steam exiting the holes on the disk generated thrust to spin the disk

Aircraft Turbomachinery Turbojet Turbofan Turboprop Ramjet and Scramjet

Turbojet

Turbojet History -Sir Frank Whittle from Britain and Hans von Ohain from Germany invented the turbojet in the 1930’s -The first turbojet airplane was the Heinkel He 178 Pros: Relatively simple design Capable of very high speeds Takes up little space Cons: High fuel consumption Loud Poor performance at slow speeds

Turbofan

Turbofan Pros: Fuel efficient History Quieter than turbojets Cons: Heavier than turbojets Larger frontal area than turbojets Inefficient at very high altitudes History The Daimler-Benz DB 670 was the first turbofan, which was operated on April 1, 1943.

Turboprop

Turboprop Pros: History Very fuel efficient Most efficient at mid-range speed between 250-400 knots Most efficient at mid-range altitudes of 18,000-30,000 feet Cons: Limited forward airspeed Gearing systems are heavy and can break down History The first turboprop engine was designed by the Hungarian mechanical engineer György Jendrassik

Ramjet

Scramjet

Brayton cycle Isentropic in the compressor, and the turbine + nozzle Pressure is constant in the combustor Generates thrust

Scientists: Mach and Magnus

Ernst Mach Born on February 18th 1838 in Chirlitz-Turas, near Brno, in what today is the Czech Republic Began with the difference between geometric space and physiological space Contributions to philosophy, physics and physiological psychology. studied gas dynamics Mach numbers named after him

Mach Numbers Mach Number = Object Speed Speed of Sound Subsonic: < Mach 1 Transonic: Mach 1 Supersonic: > Mach 1 Hypersonic: > Mach 5 However, Mach numbers are relativistic, since the speed of sound depends on the given medium.

Heinrich Gustav Magnus German chemist and physicist, who did research under Gay-Lussac and Thénard. Born in Berlin, Germany, on 2 May 1802 Discovered Magnus’s Green Salt Dealt with thermoelectricity, electrolysis, electromagnetic induction,  absorption and conduction of heat in gases, polarization of heat, and the deflection of projectiles from firearms Magnus effect

Magnus Effect https://youtu.be/QtP_bh2lMXc?t=52s Bernoulli Effect: Velocity is inversely proportional to Pressure Lower pressure where the ball spins in the direction of the velocity, higher pressure where it spins against the direction of velocity. Force directed to the region of low pressure.

Thank You!

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