Patent Application
20190153876
The present invention relates generally to polymer matrix composite parts and, more specifically, to nanostructures such as nanotubes in polymer matrix composites.
Polymer matrix composites incorporating carbon nanostructure, such as nanotubes, are known and have been suggested for use in machines such as gas turbine engines. United States Patent Application 2017/0234160 discloses a facing sheet for a fan casing comprising a support layer that includes a set of partitioned cavities with open faces and a facing sheet comprising a polymer matrix composite having a nanostructure. The fan casing is in a cold section of the engine. Hotter engine sections provide more difficult environments for parts or articles to operate in. Parts or articles operating in hot environments are subject to long term thermal exposure which can reduce durability and performance.
Polymer matrix composite parts operating in hot environments are subject to resin cracking due to thermal and thermal-oxidative resin degradation due to thermal cycling. High temperature polymer matrix composites for operating in a temperature range of 400-800 degrees fahrenheit are highly desirable. Composite resins, such as bismaleimide and polyamide, are particularly useful in this temperature operating range.
It is desirable to impede crack propagation and reduce the difference in coefficient of thermal expansion (CTE) between the composite resin and fiber in the polymer matrix composite (PMC) parts to minimize the cracking and/or damage due to thermal cycling. It is desirable to mitigate formation of resin microcracks and slow or stop the thermal degradation of the PMC material.
A high temperature polymer composite includes nanocomposite material dispersed in a polymer matrix composite resin interlayer region between fiber containing layers or plies. The nanocomposite material may be carbon nanotube. The resin interlayer region may include bismaleimide resin or polyamide resin. The nanocomposite material may be in an operating temperature in a range between 400-800 degrees Fahrenheit.
A gas turbine engine includes at least one part or component made of the high temperature polymer composite. The part or component may be an airfoil, a stator vane, a casing, or a duct. The part or component may having an operating temperature in a range between 400-800 degrees Fahrenheit.
The invention, in accordance with preferred and exemplary embodiments, is more particularly described in the following detailed description taken in conjunction with the accompanying drawings in which:
Illustrated in
This polymer composite 60 operates to mitigate the formation of resin microcracks and slow or stop the thermal degradation of the PMC material. The carbon nanotube and/or carbon nanofiber materials 62 in the PMC resin interlayer regions 64 create a tortuous path that prevents or slows the formation and propagation of resin cracks and provides the additional advantages that they can increase the interlaminar strength of the composite and reduce the difference in coefficient of thermal expansion (CTE) between the fiber and matrix materials.
The exemplary polymer composite 60 material disclosed herein is made up of at least 3 discrete materials resin, fiber, and nanotubes. The construction of the composite is a traditional combination of resin and fiber reinforcement, with the addition of the nanotubes within the resin layer. The resin can be a variety of chemistries with a particular interest being bismaleimide and polyamide for the high temperature operating conditions. The fiber can be glass or carbon and in the form of uni-directional fibers or woven into any number of fabric or braid styles. The nanotubes can be introduced into the composite by a variety of methods including but not limited to the following:
The nanotubes can also be aligned in a number of directions such as parallel to a plane 68 of the ply 66 as illustrated in
Illustrated in
The engine 10 is circumscribed about a longitudinal centerline or axis 12. The engine 10 includes, in downstream serial flow relationship, a fan section 14, booster section 16, high pressure compressor section 18, combustor section 20, high pressure turbine section 22, and low pressure turbine section 24. An outer shaft 26 drivingly connects a high pressure turbine 23 to a high pressure compressor 19. An inner shaft 28 drivingly connects the low pressure turbine 25 to a fan 15 and booster 17. The inner and outer shafts 28, 26 are rotatably mounted in bearings 30 which are mounted in a fan frame 32 and a turbine rear frame 34.
A flow splitter 35 surrounding the booster section 16 downstream of the fan section 14 includes a sharp leading edge 33 which splits the fan air 27 pressurized by the fan section 14 into a radially inner stream (core airflow 11) channeled through the booster section 16 and a radially outer stream or bypass airflow 13 is channeled through a bypass duct 36 spaced radially outwardly from the booster section 16. A fan casing 31 surrounding the fan section 14 and the bypass duct 36 is supported by an annular fan frame 32 circumscribed about the centerline 12.
The booster section 16 includes alternating annular row of booster blades and vanes 38, 42 extending radially outwardly and inwardly across a booster flowpath 39 in a booster duct 40. The annular row of booster blades 38 are suitably joined to the fan 15. The high pressure compressor 19 includes alternating annular row of compressor blades and vanes 43, 44 extending radially outwardly and inwardly across a compressor flowpath 48 in a compressor duct 50 surrounded by a compressor casing 51.
The high temperature polymer composites 60 may be used in the booster section 16 and the high pressure compressor 19 particularly in commercial engines and in the fan section 14 and the bypass duct 36 of military engines. Exemplary parts or components in these sections of the engine include airfoils 70, stator vanes 72, casings 74, ducts 76, and other parts of these engine sections or stages.
While there have been described herein what are considered to be preferred and exemplary embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein and, it is therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention.
Accordingly, what is desired to be secured by Letters Patent of the United States is the invention as defined and differentiated in the following claims:
