In some aspects, the techniques described herein relate to a refrigerant compressor, including: a stator; a rotor configured to rotate with respect to the stator; and at least one step seal between the rotor and the stator, wherein the step seal includes a first tooth and a second tooth extending from the rotor toward the stator, wherein a downstream surface of the first tooth and an upstream surface of the second tooth are arranged at an angle relative to one another, wherein the angle is less than 90°.

A bladed disc system for a turbine engine having a disk portion and a plurality of blade portions which are associated with a stator section and an intercavity sealing portion, disc portion shaped such that blade portions are able to fit within firtree slot in disc portion, blade portion having aerofoil section and root section, aerofoil section having portion shaped such that they extend proximate to intercavity sealing portion, disc portion extending from portion that connects with drum to outer edge at which blade portions are connected with disc portion having width transition region in which thickness of disc increases from point at which disc connects to drum to outer edge at which it holds blade portions, and wherein width transition region has curved width transition region with radius r, and an overhanging portion which extends into the intercavity spacing between the width transition region and the intercavity sealing portion.

A tubular ventilation sleeve for a turbomachine distributor, in particular for an aircraft, the sleeve having a generally elongate shape along an axis (A-A) and including a perforated tubular wall around said axis, one of the axial ends of the sleeve being open and the other being closed by a bottom wall, wherein it further includes support beams when the sleeve is made by additive manufacturing, the beams extending inside the sleeve between the tubular wall and the bottom wall and having a longitudinal cross-section with a generally triangular shape, two sides of which are respectively connected to the tubular wall and the bottom wall and the last side of which is free and extends inside the sleeve, perforations in the tubular wall being provided between the support beams.

An aircraft comprises a machine body. The machine body encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, a combustor module, and an exhaust module.

The machine body comprises either one or two fluid inlet apertures. The or each fluid inlet aperture is configured to allow a fluid flow to enter the machine body and to pass through the heat exchanger module. The heat exchanger module is configured to transfer a waste heat load from the gas turbine engine and the ancillary systems to the fluid flow prior to an entry of the fluid flow into the fan module, and thence into the compressor module, the turbine module, the combustor module, and the exhaust module.

A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a turbine module, and an exhaust module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D). The heat exchanger module is in fluid communication with the fan assembly by an inlet duct, and the heat exchanger module comprises a plurality of radially-extending hollow vanes arranged in a circumferential array with a channel extending axially between each pair of adjacent hollow vanes. The heat exchanger module has a square axial cross-sectional profile, where a side length of the square cross-section is D.

In some aspects, the techniques described herein relate to a refrigerant compressor, including: a stator; a rotor configured to rotate with respect to the stator; and at least one step seal between the rotor and the stator, wherein the step seal includes a first tooth and a second tooth extending from the rotor toward the stator, wherein a downstream surface of the first tooth and an upstream surface of the second tooth are arranged at an angle relative to one another, wherein the angle is less than 90°.

A construction system for mechanical metamaterials based on discrete assembly of a finite set of modular, mass-produced parts. A modular construction scheme enables a range of mechanical metamaterial properties to be achieved, including rigid, compliant, auxetic and chiral, all of which are assembled with a consistent process across part types, thereby expanding the functionality and accessibility of this approach. The incremental nature of discrete assembly enables mechanical metamaterials to be produced efficiently and at low cost, beyond the scale of the 3D printer. Additionally, a lattice structure constructed of two or more rigid, compliant, auxetic and chiral part types enable the creation of heterogenous macroscopic metamaterial structures.

An aircraft comprises a machine body. The machine body encloses a turbofan gas turbine engine and a plurality of ancillary systems. The turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, a combustor module, a turbine module, and an exhaust module. The machine body comprises a single fluid inlet aperture, with the fluid inlet aperture being configured to allow a fluid cooling flow to enter the machine body and to pass through the heat exchanger module. The heat exchanger module is configured to transfer a waste heat load from the gas turbine engine and the ancillary systems to the fluid cooling flow prior to an entry of the entire fluid cooling flow into the fan module.

A turbofan gas turbine engine comprises, in axial flow sequence, a heat exchanger module, a fan assembly, a compressor module, and a turbine module. The fan assembly comprises a plurality of fan blades defining a fan diameter (D). The heat exchanger module comprises a plurality of heat transfer elements.

The heat exchanger module is in fluid communication with the fan assembly by an inlet duct. The inlet duct has a fluid path length along a central axis of the inlet duct between a downstream-most face of the heat transfer elements and an upstream-most face of the fan assembly. The fluid path length is less than 10.0*D.

An aircraft comprises a machine body which encloses a turbofan gas turbine engine. The turbofan gas turbine engine includes a heat exchanger module, fan assembly, compressor module, turbine module, and exhaust module. The heat exchanger module communicates with the fan assembly by an inlet duct. The heat exchanger module includes first heat transfer elements that transfer heat energy from a first fluid within the transfer elements to an airflow passing over a surface of the transfer elements before entry of the airflow into a fan assembly inlet. The first fluid contained within transfer elements has a temperature, and the airflow passing over the transfer element surface has a temperature. The turbofan gas turbine engine further includes at least one second heat transfer element, with the or each second heat transfer element transfers heat energy from the first fluid to a second fluid.