What is the Difference between a turbine blade and a compressor blade?

Answer 1

A turbine is a machine that has a rotor of some sort that spins as a reaction to the flow of a fluid of some kind. A generator can be one of may things, but we often associate that term to a piece of equipment that converts mechanical energy into electromagnetic energy, or electricity. That said, the turbine could be connected to the generator to produce electricity from mechanical energy. The turbine is all about mechanical energy, and the generator converts mechanical energy into electric energy.

Answer 2

In a ram-jet the forward momentum of the engine allows the incoming mass of cold air to be both the firewall and self-charger. Fuel is burnt to create expansion of the charge gas, the escape of this hot gas from the jet nozzle is the thrust produced by the engine. If such an engine is started on the ground, it behaves like a large space heater, i.e. no thrust at all.

One solution to this low-forward speed / no thrust dilemma is the gas-turbine engine. This has an arrangement whereby some of the power generated by the combustion gasses is used to drive a rotary turbine shaft which, in turn, drives a rotary compressor. The compressor creates a flow of high-speed cold gas which is fed into the combustion chamber(s) of the engine. This air mimics the flow in a pure ramjet. Thus the blades in the turbine shaft act as a power takeoff (i.e. a windmill); the blades in the compressor act like a pump. The essential difference between the blade assemblies are:

The turbine section has two or three rows, the blades are relatively small and have to be made to withstand high temperatures without shattering, creep-distorting or melting. The blades have complex internal passages to allow cooling air to be fed internally during operation. Sealing arrangements between the blades and the engine casing have to cater both for the high temperatures and pressures during cruise opperation and the expansion of the turbine assembly between startup and cruise operation.

The compressor blades are much more variable in length, they deal with relatively cold air so they do not need such complex internal shapes, exotic Metallurgy or complex tip-sealing. An axial-flow gas turbine would have twenty plus rows of blades, largest towards the intake of the engine.

The airfoil sections of each blade type reflect their use, (suck or blow) but are essentially similar in actual shape and operation.

Answer 3

A 'turbine' is an example of a prime mover, the device which drives a generator. Turbines may be driven by steam, gas, or by water. A 'generator' is a device which converts kinetic energy into electrical energy.