| 摘要 |
A turbofan jet engine design that utilizes aerodynamic coupling to transmit power from a high-speed engine core to a lower speed fan, thereby simplifying the design and improving the thrust-to-weight ratio compared to previous turbofan designs. The engine uses a low speed co-rotating power turbine located upstream of the engine core to drive the fan. The high-speed core uses a centrifugal impeller to pressurize the inlet flow, the flow exits the high-speed impeller without diffusing its high-speed angular momentum and enters directly into the low speed co-rotating power turbine impeller. The incoming flow is then turned by the low speed co-rotating turbine impeller and exits the turbine opposing its direction of rotation, thereby extracting power from the flow to drive the fan. The exit flow from the low speed power turbine then enters the combustor inlet. This engine configuration enables the power turbine to be constructed from high strength, low-density materials (that are not suitable for use in higher temperature power turbines) thereby reducing the weight of the engine. This engine configuration also eliminates the need for the core compressor diffuser, the power turbine nozzle guide varies, and the low speed shaft that connects the fan to the power turbine in conventional turbofans.
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