Darchem Insulation Systems High temperature lightweight engineered insulation

Darchem Insulation Systems provides a design and manufacturing source to solve today’s heat management problems.

We provide the best engineered solution for our customers needs. Solutions utilise metallic, composite and advanced hybrid materials.

For further information please contact
Mike Poole on +44 (0)1740 630461
and at mikepoole@darchem.co.uk

Darchem Insulation Systems is a world leader in the design and manufacture of lightweight engineered thermal insulation systems for the aerospace and high performance vehicle markets.

Insulation Systems provides products for the majority of commercial aircraft including the new Airbus A380. Programmes include the high volume single aisle European and North American aircraft series. In addition the majority of aero engine manufacturers have selected Darchem systems for their civil and

military engine programmes.

Typical aerospace applications include thrust reverser, jet pipe, ducting and braking insulation systems.

Insulation Systems provides optimised solutions for today’s heat

management problems and, with over 50 years experience, provide the best solution for each application to our customers.

A typical commercial aircraft gas turbine engine includes a thrust reverser cowling nacelle. The nacelle structure consists of an inner and outer cowl joined with bifurcations. The engine fan airstream runs through the annular cavity betweenthe two cowls. The inner cowl or wall covers the engine case, accessories, and ducting installed therein. Because the engine case is very hot, up to 1100 degrees F., the inside surface of the inner cowl, referred to as the thrust reverser inner wall,is exposed to high radiative energy.

Thrust reverser inner wall structures have generally been made with aluminum skin, an aluminum honeycomb core, and a layer of applied insulation on the hot surface adjacent to the engine case. This metallic thrust reverser inner wall has been effective in conducting heat away from the engine to the surface adjacent to the fan airstream. A metallic structure is heavy, resulting in a significant weight penalty. In addition, the aluminum is susceptible to corrosion damage.

To reduce the weight penalties and improve acoustic characteristics, the thrust reverser inner wall has been built with an aluminum honeycomb core sandwiched between carbon fiber layers. As a result of the carbon fibers adjacent to the aluminum core, the wall structure has been susceptible to galvanic corrosion, particularly in the presence of moisture. Such corrosion creates a potential for subsequent structural failure of the aluminum core that is not acceptable.

Accordingly, the aim is to provide a thrust reverser inner wall structure that substantially reduces the weight penalty realized, avoids susceptibility to corrosion, maintains the strength of the wall, and maintains adequate thermal conductivity, thereby reducing the need for insulation.

A thrust reverser wall is a sandwich structure with a top layer of epoxy impregnated perforated carbon fiber fabric, a non-metallic, composite honeycomb core, and a bottom layer of epoxy impregnated carbon fiber fabric without perforations.

The non-metallic honeycomb core is made with pitch (based) carbon fibers to achieve the necessary thermal conductivity. The wall's high level of thermal conductivity is such that the engine heat is conveyed to the perforated carbon fiber toplayer. Engine fan air passing over the top layer acts as a heat sink wherein enough heat is carried away from the engine to minimize the need for insulation on the engine side of the wall.