A geared turbofan engine is a special type of turbofan engine that includes a reduction gearbox. This gearbox sits between the fan and the low pressure turbine, allowing for improved efficiency. In traditional turbojet engines, the fan, low pressure compressor, and turbine are connected by a single shaft. This setup limits the rotational speed of the entire system based on the fan blade tip speed. Since high bypass ratios require lower fan speeds, this can lead to suboptimal speeds for the compressor and turbine. As a result, more stages in the compressor and turbine are necessary to keep efficiency levels acceptable.
With a geared turbofan design, the addition of the reduction gearbox means the fan can operate at a different speed compared to the turbine and compressor. This innovation helps optimize the performance of all components. The outcome is a design that needs fewer compressor and turbine stages, which ultimately leads to a smaller and lighter engine core. This makes geared turbofan engines not only more efficient but also lighter and more compact than their conventional counterparts.
