摘要:
Devices, systems and methods for fabricating improved ceramic composite turbine shrouds with abradable seals are disclosed. A high temperature seal with an abradable coating is provided. The seal comprises a three-dimensional, high-density woven composite base structure recessed below the abradable coating, with loops incorporated in and protruding from the base structure. The abradable coating is integrally attached to the base structure via the loops. Additionally, a graded density seal is provided with a three-dimensional, low-density woven composite structure. The low-density structure is abradable. A three-dimensional, high-density woven composite base structure is recessed below the low-density structure, with the low-density structure integrally attached to the base structure via weaving.
摘要:
Devices, systems and methods for fabricating improved ceramic composite turbine shrouds with abradable seals are disclosed. A high temperature seal with an abradable coating is provided. The seal comprises a three-dimensional, high-density woven composite base structure recessed below the abradable coating, with loops incorporated in and protruding from the base structure. The abradable coating is integrally attached to the base structure via the loops. Additionally, a graded density seal is provided with a three-dimensional, low-density woven composite structure. The low-density structure is abradable. A three-dimensional, high-density woven composite base structure is recessed below the low-density structure, with the low-density structure integrally attached to the base structure via weaving.
摘要:
An exemplary morphable ceramic composite structure includes a flexible ceramic composite skin and a truss structure attached to the skin. The truss structure can morph shape of the skin from a first shape to a second shape that is different than the first shape. The flexible ceramic composite skin may include a single-layer of three-dimensional woven fabric fibers and a ceramic matrix composite. The truss structure may include at least one actuatable element or an actuator may move a portion of the truss structure from a first position to a second position. A cooling component may be disposed in thermal communication with the skin. The cooling component may include thermal insulation or a cooling system that circulates cooling fluid in thermal communication with the skin. The morphable ceramic composite structure may be incorporated into any of an air inlet, combustor, exhaust nozzle, or control surfaces of a hypersonic aircraft.
摘要:
The present method of manufacturing a ceramic composite material, composed of matrix and reinforcing materials and an intermediate weak interfice material, creates a composite material particuarly intended for use at temperatures above 1400° C. and in an oxidizing environment. The matrix and reinforcing materials consist of the same or different ceramic oxides having a melting point above 1600° C. The interface material provides in combination with the matrix and reinforcing materials a stress field liable to micro aciding. The reinforcing material is immersed into a powder slurry containing carbon (C) and ZrO2 so as to be coated thereby and then dried. After which, the thus created composite material is subjected to green forming and densifying steps. Finally, the composite material undergoes a heat-treatment in air leaving a porous structure of the interface material.
摘要:
A self-transpiring hot skin for a hypersonic or reusable space vehicle that can provide protection to the vehicle during short periods of abnormally high heat flux (either planned in the flight profile or an off-nominal event). The hot skin includes a ceramic composite structure having an internal cavity that is coupled either to the insulating layer or directly to the support structure of the hypersonic vehicle. The internal cavity includes a material system that vaporizes, sublimes or decomposes into a gas when the temperature exceeds the upper temperature capability of the composite material. The gas transpires through the outer layer of the composite material to provide cooling to the outer layer below the upper temperature capability. Cooling may occur both by conduction of heat from the composite material to the transpiring gas and by the interaction of the transpiring gas with the boundary layer of hypersonic flow over the outer surface, leading to a reduction of the heat flux entering the surface.
摘要:
A temperature tolerant hook and loop attachment, a method of forming a sheet of the hooks and, a method of insulating the skin of a flight vehicle. Temporary loops are formed in a fabric containing temperature tolerant fiber tows, e.g., the tows may be carbon, a metal, a carbide such as carbon silicide, a nitride, or an oxide. The temporary loops are stiffened (e.g., with resin, metal or ceramic), and severed to form temperature tolerant fiber composite hooks. The sheet may be cut and permanently applied, for example, to the skin of a spacecraft or aircraft. A fibrous material, e.g., fibrous insulation or batting, may be pressed in place or formed into the hooks, or the fibrous material may be attached to another structure and pressed in place for a temperature tolerant hook and loop attachment.