January 20th, 2020
Flight safety and security are of paramount importance in aviation. Aerospace and defense engineers must consider every detail to guarantee that components, operations, and protocols are all geared towards maintaining the safety of passengers and flight personnel. When it comes to prescribing the right materials for the job, this requires careful consideration of a multitude of parameters. The engine vicinity in particular must be handled with great care.
Quartz is routinely used in aircraft engine vicinities owing to its outstanding thermal properties. It can retain its integrity as an insulator up to temperatures of 1050°C (1922°F), with a low coefficient of thermal expansion (0.54x10-6 K-1) and remarkable thermal shock resistance. Most importantly, quartz boasts excellent resistance to fire and kerosene flame. Saint-Gobain Quartz consequently supplies Quartzel® Low-Density Felts and Quartzel® Needle Punched Felts for both high temperature and fireproof insulation in aircraft nacelles, auxiliary power units (APUs), and other critical structures.
In this article, Saint-Gobain Quartz will explore how insulating an aircraft engine and its surroundings is crucial to the safety and survivability of propulsion systems and providing a raft of peripheral benefits that significantly improve the overall flight quality.
Aircraft engines have been the driving force behind aerospace and aviation for almost a century, propelling aircraft forward using remarkably high thrust. Although there are several different engine formats (turbojet, turboprop/turbofan, etc.), all aircraft engines operate on the same principle: Cold air is drawn through an intake, compressed, mixed with liquid fuel, combusted, and exhausted. Central to this whole process is the ignition that occurs in the combustion chamber, where temperatures can routinely reach peaks of 2000°C (3632°F). The vicinity of the engine is then exposed to various temperatures and hazards, amongst which is the risk of a fire fuelled with kerosene.
To learn more about quartz solutions in aviation, read our previous blog post Using Quartz in Aerospace Radomes
The aircraft engine is housed in a protective nacelle; an aerodynamically-designed housing that links to the aircraft structure. This nacelle must also be able to sustain all constraints and hazards induced by the aircraft engine. Similarly, APUs – located in the tail – provide power for diverse functions in the aircraft, and share the same challenges with the added constraint of being even closer to the aircraft main fuselage.
Aircraft weight is another consistent issue that underpins the cost efficiency of the overall system. Aerospace engineers are regularly challenged to use insulating materials and protective components with low weight impacts. Quartz is one of the greatest materials for insulating aircraft engines, nacelles, and APUs with respect to weight-to-performance ratios.
Quartz has the advantage of providing both thermal insulation and fire protection, making it a versatile and reliable material for take-off, regular cruise flights, and emergency situations. It also come with a remarkable performance-to-weight ratio courtesy of a range of densities. This allows engineers to select a reference – depending on the part of the structure concerned – optimizing the impact on overall weight of the aircraft. Quartzel® Felts have a density of as low as 80 gsm and Quartzel® Needle Punched Felts have a density of up to 1000 gsm.
Quartzel Felts are also highly customizable and can be cut in shape, assembled, encapsulated, sawn, glued, packed etc. making it the ideal solution for protecting mission-critical components in the medium-temperature and fire-sensitive environs of aircraft engines and nacelles. Quartzel® material also provide benefits in the overall working conditions of aircraft engines and behaviour of nacelles during the flight. Manufacturers regularly use quartz insulation as part of blanket firewalls and to make fireproof cables, effectively eliminating the undesirable propagation of hazardous thermal energy into sensitive components. Quartz insulation can be used in multiple parts of the aircraft structure to maintain optimal cruise conditions and guarantee flight safety.
Saint-Gobain Quartz is an industry leader in the development of high-performance insulation products based on pure quartz fiber. The Quartzel® product family covers a wide range of formats, including yarns, rovings, low- and high-density felts, and more.