Acoustic structure with internal thermal regulators

Abstract

Thermally insulating septums are located internally within the cells of an acoustic honeycomb to regulate heat flow into the acoustic structure. The internally located insulating septums protect the honeycomb and acoustic septums located within the honeycomb cells from heat damage that might otherwise be caused by a heat source, such as the hot section of a jet engine. The internal thermal regulators are useful in combination with heat blankets or other thermal insulating structures to provide a reduction in size and / or weight of the insulating structure while still providing the same overall degree of thermal insulation for the acoustic honeycomb.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates generally to acoustic structures that are used to attenuate or dampen noise that emanates from a particular source. More particularly, the present invention is directed to acoustic structures that are exposed to relatively high temperatures and the systems that are used to protect such acoustic structures from damage that might be caused by such heat exposure.[0003]2. Description of Related Art[0004]It is widely recognized that the best way of dealing with noise generated by a specific source is to treat the noise at the source. This is typically accomplished by adding acoustic damping structures to the structure of the noise source. One particularly problematic noise source is the jet engine used on most passenger aircraft. Acoustic structures are typically incorporated in the engine inlet, nacelle and combustion / exhaust structures. These acoustic structures include acoustic resonators tha...

AI Technical Summary

Benefits of technology

The present invention is about using internal thermally insulating septums in an acoustic honeycomb to regulate heat flow and protect against heat damage. This eliminates the need for an external heat blanket or other external thermal barrier, reducing the size and weight of the thermal protection system while still maintaining necessary thermal protection. The internalization of a portion of the heat protection system allows for efficient thermal regulation and design variables not possible with an external heat blanket. This invention is useful for protecting acoustic structures in the next generation of jet engines against higher operating temperatures while minimizing the size and weight of the thermal protection system.

Problems solved by technology

One particularly problematic noise source is the jet engine used on most passenger aircraft.

This is a particular problem for acoustic honeycomb made from composite materials which utilize matrix resins that have maximum operating temperatures on the order of 350° F. to 500° F. depending upon the type of resin.

The material used to make the acoustic septum may also be damaged when exposed directly to the heat generated by the hot section.

Although heat blankets provide adequate thermal insulation, they also take up valuable space and add weight to the engine.

In addition, the service life of a typical heat blanket is limited so that it must be replaced at specified time intervals.

This removal and reinstallation process is time consuming and many times results in the heat blanket being damaged.

Repairing and / or replacing a damaged heat blanket can involve significant added time and costs.

This is a time consuming process that also destroys the coating.

Application of a new silicone coating is a time consuming process that includes the additional cost of the new high temperature silicone coating material.

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