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What is contra-rotating turbine?
The contra-rotating turbine under consideration is an axial flow stage comprising two wheels rotating at the same speed and equal torque but in opposite direc tions (Fig. 1). Under these conditions, the swirl entering the first wheel has to be equal to the swirl leaving the second wheel.
What is the purpose of contra-rotating propellers?
Use of contra-rotating propellers recovers energy lost due to the motion of the air in the slipstream of the forward propeller and allows for an increase in power without a corresponding increase in propeller diameter. It will also help counter the torque effects of a high power piston engine.
What is counter rotating turbofan?
The counter rotating turbine is an axial turbine with a first stator followed by a first rotor, an optional second stator, and a second rotor, which rotates in opposite direction of the first stage.
How do contra-rotating propellers work?
In a counter-rotating installation, the propellers on the right wing turn counter-clockwise while those on the left wing turn clockwise. The principle advantage of counter-rotation is to balance propeller torque effects thus eliminating any problems associated with a Critical Engine.
Are contra-rotating propellers more efficient?
Contra-rotating propellers have been found to be between 6% and 16% more efficient than normal propellers. However they can be very noisy, with increases in noise in the axial (forward and aft) direction of up to 30 dB, and tangentially 10 dB. Most of this extra noise can be found in the higher frequencies.
What is contra-rotating propeller in ship?
The concept of contra-rotating propeller consists out of placing a pod behind the main propeller. The pod is rotating in the opposite direction of the main propeller. This way of propelling the vessel comes along with a number of advantages and disadvantages.
Are contra-rotating propellers efficient?
Contra-rotating propellers have been found to be between 6% and 16% more efficient than normal propellers. However they can be very noisy, with increases in noise in the axial (forward and aft) direction of up to 30 dB, and tangentially 10 dB.
How efficient are contra-rotating propellers?
How is the TU 95 so fast?
925 km/h
Tupolev Tu-95/Top speed
What is the disadvantage of contra-rotating propellers?
Advantages and disadvantages However they can be very noisy, with increases in noise in the axial (forward and aft) direction of up to 30 dB, and tangentially 10 dB. These substantial noise problems limit commercial applications. One possibility is to enclose the contra-rotating propellers in a shroud.
How does a counter rotating outboard work?
Counter rotating props means that the prop walk created by either engine are cancelled out, and the boat will track better. With two props rotating the same way the boat will always be turning one way or the other (depends on prop direction which way).
What is contra rotating propeller in ship?
How is a contra rotating turbine turbine designed?
The contra-rotating turbine is designed by retaining the existing flow path and HP turbine, and redesigning the LP turbine for fixed radial distributions of inlet total temperature, pressure and swirl. A comparative study between performance of the co-rotating and contra-rotating turbines is carried out for different speeds.
Why are contra rotating jet engines so effective?
For example the GE genx. The real benefits of the counter rotating spool jet engines are the following: Increase the efficiency by the increased compression ratio of the compressor, due to the counter rotation at intersection between the low and the high pressure stages. And just there.
What kind of engine has contra rotating spools?
Please try again later. The Trent XWB engine family follow on from the Trent 900 and also use contra rotating spools – the high pressure compressor is driven clockwise, while the low pressure and intermediate pressure compressors are driven counterclockwise.
What does counter rotation do to a turbofan?
Torque reduction DOES NOT MATTER and is NOT a factor either way. What counter rotation does for a turbofan (in the present non-geared designs) is Increase the efficiency of the compressor by switching the ‘swirl direction’ between the fan & the first compressor stage.