Insulating layered composite materials manufacturing and thermal diffusivity measurements

In the modern solid fuel rocket engines two or three layers of different materials are applied between fuel and combustion chamber body. The most significant is thermal insulation. Without this layer, solid fuel rocket engines would not have so wide range of operating. The other two layers are an inhibitor and a liner. The inhibitor protects the surface, on which it is applied, from combustion, what enables to control a pressure inside the combustion chamber, through changing combustion surface area. The liner connects fuel with thermal insulation. Most often liners have great thermal deformation capability. Due to features, such as compact and simple construction, relatively easy storage conditions and instantaneous ready-to-use ability, in different terrain and atmospheric conditions, solid fuel rocket engines are used as a propulsion for machine gun bullets, control engines of middleand long-range rockets. They are also used in takeoff and primary propulsion systems of ballistic missiles, meteorological and geophysical rockets and in spacecrafts. Propulsion charge and ignition systems are both placed in the combustion chamber. It has shape of light-wall, cylindrical tube and is designed for keeping possibly optimal fuel ignition and combustion conditions. Combustion chamber body is usually used as a base of rocket’s supporting structure. Basic load on the combustion chamber is usually a pressure force of gaseous combustion products, which vertically and horizontally affects internal surface of the combustion chamber. The engine is exposed to the strongest impact of forces during its initial operating moment Intensive heating up of combustion chamber walls by hot combustion products, causes appearance of addition thermal stress and deteriorates endurance of wall material [3, 4]. After short time, it can lead to an engine explosion, even if the pressure in the combustion chamber is lower than maximum, allowed, working pressure. A layer of thermal insulation is applied on the internal side of the supporting wall, to prevent extraordinary increase of the average temperature of combustion chamber walls [5]. Thermal insulation layer should have possibly low density of the cover material and good adherence, while its endurance is not so important. Epoxy and phenolic resins work well in these applications. One of the most important elements of the solid fuel rocket engines development are constantly improving mass characteristics. This development can be obtained thanks to implementation of new combustion chamber and nozzle construction materials. Metal is replaced, in constructions, by varied kinds of reinforced composites, which are durable and resistant to high temperature.