| 主权项 |
1. A gas turbine engine comprising:
a fan section including less than 18 fan blades, with a low fan pressure ratio of less than about 1.45, the low fan pressure ratio measured across the fan blades alone; a bypass ratio greater than 10; a gear train having a gear ratio greater than about 2.3; a compressor section; a combustor in fluid communication with the compressor section; a turbine section in fluid communication with the combustor and including a fan drive turbine and a second turbine, the fan drive turbine driving a fan rotor through the gear train wherein:
the engine includes a power density greater than 1.5 lbf/in3 wherein power density is defined as Sea Level Takeoff Thrust in lbf produced divided by the volume of the turbine section in cubic inches;the fan drive turbine includes at least one rotor having a live rim radius (r) and a bore width (W), and a ratio of W/r is between 4.65 and 5.55;the fan drive turbine includes an inlet, an outlet, and a fan drive turbine pressure ratio greater than 5, wherein the fan drive turbine pressure ratio is a ratio of a pressure measured prior to the inlet as related to a pressure at the outlet prior to any exhaust nozzle;the fan drive turbine has a first exit area and is configured to rotate at a first speed, the second turbine has a second exit area and is configured to rotate at a second speed, which is faster than the first speed, said first and second speeds being redline speeds, wherein a first performance quantity is defined as the product of the first speed squared and the first area, a second performance quantity is defined as the product of the second speed squared and the second area, and a performance ratio of the first performance quantity to the second performance quantity is greater than or equal to 0.8, and less than 1.5; andthe fan drive turbine has a number of fan drive turbine stages, and a ratio between the number of fan blades and the number of fan drive turbine stages is between 2.5 and 8.5. |
