A rotor-stator assembly for a gas turbine engine, the assembly including a rotor having a layer of ceramic material forming an abrasive coating deposited on its tip, the layer being constituted mainly by zirconia and possessing a void ratio less than or equal to 15%, and a stator arranged around the rotor and provided facing the tip of the rotor with a layer of ceramic material forming an abradable coating, the layer being constituted mainly by zirconia possessing a void ratio lying in the range 20% to 50% with pores having size less than or equal to 50 m.

A Hybrid rolling bearing includes an inner raceway and an outer raceway and a plurality of rolling elements arranged therebetween. The outer raceway and the inner raceway are made from bearing steel, having a first surface RMS roughness R.sub.q1. The rolling elements are made from a ceramic material and have second surface RMS roughnesses R.sub.q2,i. At least one of the rolling elements has an increased surface RMS roughness R.sub.q2,N, which is significantly higher than the RMS roughnesses R.sub.q2,i, of the remaining rolling elements. The hybrid rolling bearing can be installed within a refrigerant compressor.

A thermal barrier coating (TBC) with depth-varying material properties is formed on a turbine component. Exemplary depth-varying material properties include physical ductility, strength and thermal resistivity that vary from the TBC layer inner to outer surface. Exemplary ways to modify physical properties include application of plural separate overlying layers of different material composition or by varying the applied material composition during the application of the TBC layer. Various embodiment described herein also apply a calcium-magnesium-aluminum-silicon (CMAS)-retardant material over the TBC layer to retard reaction with or adhesion of CMAS containing combustion particulates to the TBC layer. In other embodiments the CMAS retardant material is also applied within engineered groove features (EGFs) that are formed in the TBC surface.

Methods and systems for manipulating surface topology of additively manufactured fluid interacting structures, such as additively manufactured heat exchangers or airfoils, and associated additively manufactured articles, are disclosed. In one aspect, an article which interacts with a fluid is imparted with surface topology features which affect performance parameters related to the fluid flow. The topological features may be sequenced, combined, intermixed, and functionally varied in size and form to locally manipulate and co-optimize multiple performance parameters at each or selectable differential lengths along a flow path. The co-optimization method may uniquely prioritize selectable performance parameters at different points along the flow path to improve or enhance overall system performance. Topological features may include design features such as dimples, fins, boundary layer disruptors, and biomimicry surface textures, and manufacturing artefacts such as surface roughness and subsurface porosity distribution and morphology.

A method for producing an impeller, includes the following steps: a forming step of forming the impeller by fused deposition modeling; and a polishing step of polishing a wall that defines a channel of the impeller using particulate polishing materials. The particulate polishing materials are sprayed on the wall of the channel or the wall of the channel is rubbed with the particulate polishing materials in the polishing step.

A nacelle exhaust nozzle having a deployable noise-reducing component is described. The noise-reducing component includes an annular perforated sleeve coinciding with the inner nacelle loft line and circumscribing a mixed exhaust gas flow exiting the nacelle. The annular perforated sleeve is radially spaced apart from of a displaceable wall of an inflatable envelope that is displaceable between a deployed position, wherein noise-reduction is active, and a retracted position, wherein noise-reduction is inactive. When the inflatable envelope is pressurized, portions of the displaceable wall project through openings in the perforated sleeve and into the exhaust gas flow to form a rough surface at the loft line which causes a reduction in noise level. The portions of the displaceable wall that project through the openings in the perforated sleeve when the inflatable enveloped is pressurized include a plurality of dimples formed on the inner wall and forming the rough surface.

A method of manufacturing an integrated impeller has a first shroud forming a bottom portion, a second shroud forming a lid portion, a hub formed at the center portion of the first shroud, and blades that section a flow path which is formed between the first shroud and the second shroud and through which a fluid flows. This method has the steps of: forming a flow path on the inner circumferential side of the impeller; and forming a flow path on the outer circumferential side of the impeller. The step of forming the flow path on the outer circumferential side of the impeller has the steps of: while rotating the linear electrode having a tip-end part and a base-end part about a longitudinal direction axis thereof, applying electric discharge machining to the first shroud; applying electric discharge machining to the second shroud; and applying electric discharge machining to the blade.

A gas turbine engine component has an engine component body and at least one hole formed within the engine component body and extends between a hole inlet and a hole outlet. The hole has a first portion with a first roughness and a second portion having a second roughness that is less than the first roughness. The first portion is upstream of the second portion. A gas turbine engine and a method of forming a cooling hole are also disclosed.

An abradable seal comprises an organic matrix composite comprising an additive and an organic component, the additive is configured to prevent adhesion of the organic component onto an abrasive blade tip.

Engineered groove features (EGFs) are formed within thermal barrier coatings (TBCs) of turbine engine components. The EGFs are advantageously aligned with likely stress zones within the TBC or randomly aligned in a convenient two-dimensional or polygonal planform pattern on the TBC surface and into the TBC layer. The EGFs localize thermal stress- or foreign object damage (FOD)-induced crack propagation within the TBC that might otherwise allow excessive TBC spallation and subsequent thermal exposure damage to the turbine component underlying substrate. Propagation of a crack is arrested when it reaches an EGF, so that it does not cross over the groove to otherwise undamaged zones of the TBC layer. In some embodiments, the EGFs are combined with engineered surface features (ESFs) that are formed in the component substrate or within intermediate layers applied between the substrate and the TBC.