A turbofan engine is provided. The turbofan engine includes a low pressure spool; a fan mechanically coupled with the low pressure spool; a high pressure spool; an accessory gearbox mechanically coupled with the high pressure spool; a hydraulic pump mechanically coupled with the accessory gearbox; and one or more heat exchangers tied to the accessory gearbox, the one or more heat exchangers having a heat exchanger capacity defined by a product raised to a half power, the product being determined by multiplying an average heat exchanger effectiveness of the one or more heat exchangers by a heat conductance factor that relates an accessory gearbox heat load, a hydraulic pump power of the hydraulic pump, a fan diameter of the fan, an engine length of the turbofan engine, and an overall pressure ratio of the turbofan engine.

A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 2.0-4.0.

A gas turbine engine has a fan section including a fan, a compressor section including a low pressure compressor and a high pressure compressor, a turbine section including a low pressure turbine and a high pressure turbine, and a gear reduction. The low pressure compressor and the low pressure turbine have a number of blades in each of at least one of a plurality of blade rows. The blades are rotatable at least some of the time at a rotational speed in operation. The number of blades in at least one row and the rotational speed are such that the following formula holds true for at least one row of the compressor rotor turbine: 5500(number of bladesrotational speed)/6010000, the rotational speed being in revolutions per minute.

A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 2.0-4.0.

A turbomachine engine can include a fan assembly, a vane assembly, a core engine, a gearbox, and an overall engine efficiency rating. The fan assembly can include a plurality of fan blades. The vane assembly can include a plurality of vanes, and the vanes can, in some instances, be disposed aft of the fan blades. The core engine can include a low-pressure turbine. The gearbox includes an input and an output. The input of the gearbox is coupled to the low-pressure turbine of the core engine and comprises a first rotational speed, the output of the gearbox is coupled to the fan assembly and has a second rotational speed, and a gear ratio of the first rotational speed to the second rotational speed is within a range of 2.0-4.0.

A gas turbine engine has a fan, a turbine section having a first turbine including a first turbine rotor, a compressor rotor, and a gear reduction that effects a reduction in a speed of the fan relative to an input speed from the first turbine rotor. Each of the compressor rotor and the first turbine rotor includes a number of blades in each of a plurality of blade rows, the number of blades configured to operate at least some of the time at a rotational speed, and the number of blades and the rotational speed being such that the following formula holds true for at least a plurality of the blade rows of the first turbine rotor: (number of bladesrotational speed)/605500, and the rotational speed being an approach speed in revolutions per minute, and the following formula holds true for at least a plurality of the blade rows of the compressor rotor: (number of bladesrotational speed)/6010000, the rotational speed being an approach speed in revolutions per minute.

A gas turbine engine has a fan, a turbine section having a first turbine including a first turbine rotor, a compressor rotor, and a gear reduction configured to effect a reduction in a speed of the fan relative to an input speed from the first turbine rotor. Each of the compressor rotor and the first turbine rotor includes a number of blades in each of a plurality of blade rows, the number of blades configured to operate at least some of the time at a rotational speed, and the number of blades and the rotational speed being such that the following formula holds true for at least a majority of the blade rows of the first turbine rotor, but does not hold true for any of the blade rows of the compressor rotor: (number of bladesrotational speed)/605500, and the rotational speed being an approach speed in revolutions per minute.

A gas turbine engine according to an example of the present disclosure includes, among other things, a fan, a turbine section that has a fan drive turbine rotor, and a compressor rotor. A gear reduction effects a reduction in a speed of the fan relative to an input speed from the fan drive turbine rotor. The compressor rotor has a number of compressor blades in at least one of a plurality of blade rows of the compressor rotor, and the blades are configured to operate at least some of the time at a rotational speed. The number of compressor blades in at least one of the blade rows and the rotational speed are such that the following formula holds true for the at least one of the plurality of blade rows of the compressor rotor: (the number of bladesthe rotational speed)/60 secabout 5500 Hz. A method of designing a gas turbine engine is also disclosed.

A gas turbine engine has a fan, a turbine section having a first turbine including a first turbine rotor, a compressor rotor, and a gear reduction configured to effect a reduction in a speed of the fan relative to an input speed from the first turbine rotor. Each of the compressor rotor and the first turbine rotor includes a number of blades in each of a plurality of blade rows, the number of blades configured to operate at least some of the time at a rotational speed, and the number of blades and the rotational speed being such that the following formula holds true for at least a majority of the blade rows of the first turbine rotor, but does not hold true for any of the blade rows of the compressor rotor: (number of bladesrotational speed)/605500, and the rotational speed being an approach speed in revolutions per minute.

A gas turbine engine according to an example of the present disclosure includes, among other things, a fan, a turbine section that has a fan drive turbine rotor, and a compressor rotor. A gear reduction effects a reduction in a speed of the fan relative to an input speed from the fan drive turbine rotor. The compressor rotor has a number of compressor blades in at least one of a plurality of blade rows of the compressor rotor, and the blades are configured to operate at least some of the time at a rotational speed. The number of compressor blades in at least one of the blade rows and the rotational speed are such that the following formula holds true for the at least one of the plurality of blade rows of the compressor rotor: (the number of bladesthe rotational speed)/60 secabout 5500 Hz. A method of designing a gas turbine engine is also disclosed.