A stator vane including a vane root, a vane tip, a leading edge extending between the root and the tip, the leading edge having a serrated profile having a succession of teeth and of troughs each having an amplitude and a thickness, wherein a series of at least three teeth and three consecutive troughs starting from the vane root and/or from the vane tip have a growing amplitude and/or thickness.

A gas turbine engine defining a centerline and a circumferential direction, the gas turbine engine including: a turbomachine comprising a compressor section, a combustion section, and a turbine section arranged in serial flow order, the turbomachine defining a working gas flowpath and a fan duct flowpath; a primary fan driven by the turbomachine defining a primary fan tip radius R.sub.1 and a primary fan hub radius R.sub.2; a secondary fan located downstream of the primary fan and driven by the turbomachine, at least a portion of an airflow from the primary fan configured to bypass the secondary fan, the secondary fan defining a secondary fan tip radius R.sub.3 and a secondary fan hub radius R.sub.4, wherein the secondary fan is configured to provide a fan duct airflow through the fan duct flowpath during operation to generate a fan duct thrust, wherein the fan duct thrust is equal to % Fn.sub.3S of a total engine thrust during operation of the gas turbine engine at a rated speed during standard day operating conditions; wherein a ratio of R.sub.1 to R.sub.3 equals $\sqrt{\left(\mathrm{EFP}\right)\frac{\left(1-Rq{R}_{\mathrm{Sec}.-{\mathrm{Fan}}^2}\right)}{\left(1-Rq{R}_{\mathrm{Prim}.-\mathrm{Fa}{n}^2}\right)}\left(\frac{1}{\%{\mathrm{Fn}}_{3S}}-1\right)};$

A geared turbofan engine with a sun shaft driving a sun gear of planetary gearbox. The sun shaft having a front section proximal to the gearbox and a rear section distal from the gearbox. The outer diameter of the front section of the sun shaft is smaller than the outer diameter of the rear section of the sun shaft. The front section of the sun shaft having between two and four undulant sections, wherein each undulant section having at least one axial part extending in axial direction of the sun shaft and two diaphragm parts on either side of the at least one axial part extending in radial direction outward, the at least one axial part of the undulant section having an inner diameter smaller than the outer diameter of the front section of the sun shaft.

A turbomachinery engine comprises a ducted fan, a high-pressure compressor, a low-pressure turbine, a gearbox, and a ducted engine correlation parameter (DECP). The DECP is within a range of 0.10-0.25 and is defined as 10*D/GR/N.sub.LPT/N.sub.HPC, where D is a fan blade tip diameter at a leading edge of the ducted fan measured in feet, GR is a gear ratio of the gearbox, N.sub.LPT is a stage count of the low-pressure turbine, and N.sub.HPC is a stage count of the high-pressure compressor.

Systems and methods for improved gas turbine engine performance are disclosed. The method can include receiving an error function for a wide range of fuels. The error function can provide lower heating value (LHV) corrections over the wide range of fuels. The method can include receiving gas turbine engine operation data for a first period of run time on the gas turbine from one or more sensors of the gas turbine engine. The engine operation data can include a performance data points. The method can include determining an optimum LHV based on the engine operation data for the first period of run time and the error function. The method can then include adjusting fuel consumption of the gas turbine engine based on the optimum LHV.

A stator vane including a vane root, a vane tip, a leading edge extending between the root and the tip, the leading edge having a serrated profile having a succession of teeth and of troughs each having an amplitude and a thickness, wherein a series of at least three teeth and three consecutive troughs starting from the vane root and/or from the vane tip have a growing amplitude and/or thickness.

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. The overall engine efficiency rating is greater than or equal to 0.35GR.sup.1.5 and less than or equal to 0.7GR.sup.1.5.

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 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.