| 摘要 |
PROBLEM TO BE SOLVED: To increase a by-pass ratio and improve engine performance by extending a low speed fan having an outside diameter larger than that of a fan on an outer periphery side of a windmill, decelerating and revolving the windmill by air flow generated by revolution of the fan and generating main by-pass thrust by revolution of the low speed fan. SOLUTION: A turbo fan engine 20 is provided with a windmill 22 and a low speed fan 23 across a duct 21 on a front side. A fan 38 connected with a low pressure turbine 33 via a rotary shaft 34 and the windmill 22 which is freely rotatably located at the rear side constitute a torque converter, and air flow from the fan 38 imparts rotational torque to the windmill 22. Revolving air flow from the low speed fan 23 is straightened in a shaft direction by a straightening vane 44b, becomes by-pass flow and imparts main engine thrust. After air flow by the fan 38 imparts rotational torque to the windmill 22, a part becomes by-pass flow and contributes to engine thrust, and a part is compressed by low pressure and high pressure compressors 46, 47 and becomes air flowing into a combustion chamber 25.
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