THRUST EFFICIENT TURBOFAN ENGINE
A disclosed turbofan engine includes a gas generator section for generating a gas stream flow. A speed reduction device is driven by the power turbine. A propulsor section includes a fan driven by the power turbine through the speed reduction device at a second speed lower than the first speed for generating propulsive thrust as a mass flow rate of air through a bypass flow path. The fan includes a tip diameter greater than about fifty (50) inches and an Engine Unit Thrust Parameter (“EUTP”) defined as net engine thrust divided by a product of the mass flow rate of air through the bypass flow path, a tip diameter of the fan and the first rotational speed of the power turbine is less than about 0.30 at a take-off condition.
1 . A turbofan engine comprising:
a gas generator section for generating a gas stream flow with higher energy per unit mass flow than that contained in ambient air;
a power turbine for converting the gas stream flow into shaft power, the power turbine configured for rotating at a first rotational speed and operating at a temperature less than about 1800° F. at a sea level take-off power condition;
a speed reduction device configured to be driven by the power turbine; and
a propulsor section including a fan configured to be driven by the power turbine through the speed reduction device at a second speed lower than the first speed for generating propulsive thrust as a mass flow rate of air through a bypass flow path,
wherein the engine is configured such that when operating at the sea level take-off power condition:
a bypass ratio of a first volume of air through the bypass flow path divided by a second volume of air directed into the gas generator is greater than about 10.0, and
a pressure ratio across the fan is less than about 1.50.
2 . The turbofan engine as recited in claim 1 , wherein the fan includes a tip diameter greater than about fifty (50) inches and an Engine Unit Thrust Parameter (“EUTP”) defined as net engine thrust divided by a product of the mass flow rate of air through the bypass flow path, a tip diameter of the fan and the first rotational speed of the power turbine is less than about 0.30 at the seal level take-off power condition.
3 . The turbofan engine as recited in claim 2 , wherein the EUTP is less than about 0.25 at the take-take off condition.
4 . The turbofan engine as recited in claim 2 , wherein the EUTP is less than about 0.20 at the take-off condition.
5 . The turbofan engine as recited in claim 2 , wherein the EUTP at one of a climb condition and a cruise condition is less than about 0.10.
6 . The turbofan engine as recited in claim 2 , wherein the EUTP at one of a climb condition and a cruise condition is less than about 0.08.
7 . The turbofan engine as recited in claim 2 , wherein the tip diameter of the fan is greater than about 50 inches and less than about 160 inches.
8 . The turbofan engine as recited in claim 1 , wherein the mass flow generated by the propulsor section is between about 625 lbm/hour and about 80,000 lbm/hour.
9 . The turbofan engine as recited in claim 1 , wherein the first speed of the power turbine is between about 6200 rpm and about 12,500 rpm.
10 . The turbofan engine as recited in claim 1 , wherein the propulsive thrust generated by the turbofan engine is between about 16,000 lbf and about 120,000 lbf.
11 . The turbofan engine as recited in claim 1 , wherein the gas generator defines an overall pressure ratio of between about 40 and about 80.
12 . A turbofan engine comprising:
a gas generator section for generating a gas stream flow with higher energy per unit mass flow than that contained in ambient air;
a power turbine for converting the gas stream flow into shaft power, the power turbine rotatable at a first rotational speed, wherein the power turbine operates at a temperature less than about 1800° F. at a sea level take-off power condition;
a speed reduction device configured to be driven by the power turbine; and
a propulsor section including a fan configured to be driven by the power turbine through the speed reduction device at a second speed lower than the first speed for generating propulsive thrust as a mass flow rate of air through a bypass flow path, wherein the fan includes a fan tip diameter greater than about fifty (50) inches and an Engine Unit Thrust Parameter (“EUTP”) defined as net engine thrust divided by a product of the mass flow rate of air through the bypass flow path, a tip diameter of the fan and the first rotational speed of the power turbine is less than:
about 0.30 at the seal level take-off power condition; and/or
about 0.15 at one of a climb condition and a cruise condition.
13 . The turbofan engine as recited in claim 12 , wherein the EUTP is less than about 0.125 for at least one of the climb condition and the cruise condition.
14 . The turbofan engine as recited in claim 12 , wherein the EUTP at one of the climb condition and the cruise condition is less than about 0.08.
15 . The turbofan engine as recited in claim 12 , wherein the EUTP at a take-off condition is less than about 0.15.
16 . The turbofan engine as recited in claim 12 , wherein the tip diameter of the fan is between about 50 inches and about 160 inches.
17 . The turbofan engine as recited in claim 12 , wherein the mass flow generated by the propulsor section is between about 625 lbm/hour and about 80,000 lbm/hour.
18 . The turbofan engine as recited in claim 12 , wherein the first speed of the power turbine is between about 6200 rpm and about 12,500 rpm.
19 . The turbofan engine as recited in claim 12 , wherein the propulsive thrust generated by the turbofan engine is between about 16,000 lbf and about 120,000 lbf.
20 . The turbofan engine as recited in claim 12 , wherein the gas generator defines an overall pressure ratio of between about 40 and about 80.
21 . A turbofan engine comprising:
a gas generator section for generating a high energy gas stream, the gas generating section including a compressor section, combustor section and a first turbine;
a second turbine converting the high energy gas stream flow into shaft power, the second turbine rotating at a first speed and including less than or equal to about six (6) stages;
a geared architecture driven by the second turbine; and
a propulsor section driven by the second turbine through the geared architecture at a second speed lower than the first speed, the propulsor section including a fan with a pressure ratio across the fan section less than about 1.50, the propulsor section generating propulsive thrust as a mass flow rate of air through a bypass flow path from the shaft power, wherein the fan includes a tip diameter greater than about fifty (50) inches and an Engine Unit Thrust Parameter (“EUTP”) defined as net engine thrust divided by a product of a mass flow rate of air through the bypass flow path, a tip diameter of the fan and the first rotational speed of the second turbine is less than about 0.30 at a take-off condition.
22 . The turbofan engine as recited in claim 21 , wherein the EUTP is less than about 0.25 at the take-off condition.
23 . The turbofan engine as recited in claim 21 , wherein the EUTP is less than about 0.20 at the take-off condition.
24 . The turbofan engine as recited in claim 21 , wherein the EUTP at one of a climb condition and a cruise condition is less than about 0.10.
25 . The turbofan engine as recited in claim 21 , wherein the EUTP at the take-off condition is less than about 0.08.
26 . The gas turbofan engine as recited in claim 21 , wherein the fan section defines a bypass airflow having a bypass ratio greater than about ten (10).
27 . The turbofan engine as recited in claim 21 , wherein the tip diameter of the fan is between about 50 inches and about 160 inches.
28 . The turbofan engine as recited in claim 21 , wherein the mass flow generated by the propulsor section is between about 625 lbm/hour and about 80,000 lbm/hour.
29 . The turbofan engine as recited in claim 21 , wherein the first speed of the second turbine is between about 6200 rpm and about 12,500 rpm.
30 . The turbofan engine as recited in claim 21 , wherein the second turbine comprises a low pressure turbine with 3 to 6 stages.