What does a free power turbine do?
Free turbines are used to drive the reduction gears for the propeller in a turboprop engine or the transmission and rotor of a helicopter. Also known as a power turbine or a free turbine. In a turbine engine, a turbine wheel drives the output shaft and is not connected to the shaft driving the compressor.
What is the function of power turbine?
Power turbines are a component that transfers enthalpy of exhaust gas into kinetic energy.
What is meant by a free turbine?
[¦frē ′tər·bən] (mechanical engineering) In a turbine engine, a turbine wheel that drives the output shaft and is not connected to the shaft driving the compressor.
What are the advantages of a turboprop engine with a free turbine?
The chief advantage of the free turbine is that it reduces torque loads during engine start, since the start mechanism does not have to rotate the propeller and reduction gear, but only the compressor and its turbine.
What is the difference between a free power turbine and a direct drive turbine?
Direct drive engines can only be pulled back about 4% in flight, while most free turbine engines can reduce prop rpm 10-15%. Free turbines are typically more efficient at low altitudes than direct drives. But direct drives perform better at high altitudes, and become more efficient than free turbines.
How does PT6 engine work?
PT6 engine, a lightweight free turbine engine incorporating a reverse flow combustion path, is designed for aircraft propulsion use. It utilizes two counter-rotating turbines; one driving the compressor and the other driving the propeller through a reduction gearbox.
What is the function of a turbine in a generator?
The role of the turbine is to transform the energy of water, steam or wind into mechanical energy that will make the generator spin. The generator transforms the mechanical energy into electricity. In hydropower plants, this combination of generator and turbine is called a generating unit.
What are the functions of the turbine stage?
The shape of nozzle vanes and rotating blades is determined by the function of the turbine stage, that is, to turn the flow with the least losses and to extract the required work at the prescribed circumferential velocity.
What are the two different sections in a free turbine engine?
What are the two basic sections of a turbine engine? The hot section and the cold section.
What is the purpose of a exhaust cone?
An assembly behind the turbine wheel of a gas turbine engine, consisting of an inner cone surrounded by an outer cone or casing, the open end of which forms the exhaust nozzle. The function of the exhaust cone is to collect and direct discharge gases from the turbine wheel.
What type of engine is a PT6?
The PT6A is a two-shaft engine with a multi-stage compressor driven by a single-stage compressor turbine and an independent shaft coupling the power turbine to the propeller through an epicyclic concentric reduction gearbox.
How does a PT6 turboprop engine work?
These power turbines spin just like the compressor turbine, with airfoil shaped blades. This forward engine shaft is directly connected to the propeller, providing the power for it to spin. About 30% of total engine power is dedicated to spinning the propeller in a PT6.
What is a free-turbine turboshaft?
A free-turbine turboshaft is a form of turboshaft or turboprop gas turbine engine where the power is extracted from the exhaust stream of a gas turbine by an independent turbine, downstream of the gas turbine.
What is the color of the free power turbine?
The free power turbine is in purple. A free-turbine turboshaft is a form of turboshaft or turboprop gas turbine engine where the power is extracted from the exhaust stream of a gas turbine by an independent turbine, downstream of the gas turbine.
What are the advantages and disadvantages of a free turbine?
The advantage of the free turbine is that the two turbines can operate at different speeds, and that these speeds can vary relative to each other. This is particularly advantageous for varying loads, such as turboprop engines. Austin 250hp gas turbine, sectioned.
What is the purpose of drawing the power turbine curves?
This shows the variation of power output with power turbine speed for a range of gas generator speeds and is normally drawn for ISO conditions. For a three-shaft engine operating with a free power turbine, the curves is drawn for a series of LP spool speeds.