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Rocket Engines
Published in Ahmed F. El-Sayed, Aircraft Propulsion and Gas Turbine Engines, 2017
The liquid oxidizer is injected into the solid, whose fuel case also serves as the combustion chamber. An igniter starts the combustion process, which develops heat to vaporize the surface layer of solid fuel. The expanding hot fuel gas expands away from the solid surface and meets the spray of liquid oxidizer; the combustion process continues in a self-sustaining manner. The hot fuel gas layer and the combustion layer grow downstream in a boundary layer pattern until they merge at the centerline at nearly five diameters from the initial station. At some point, on the order of several tens of diameters in the downstream direction, the oxidizer supply has been fully used and no further combustion can be maintained. Figure 19.27 illustrates the combustion process in a hybrid motor.
Electrical systems
Published in Tom Denton, Advanced Automotive Fault Diagnosis, 2020
The pyrotechnic inflater and the igniter can be considered together. The inflater in the case of the driver is located in the centre of the steering wheel. It contains a number of fuel tablets in a combustion chamber. The igniter consists of charged capacitors, which produce the ignition spark. The fuel tablets burn very rapidly and produce a given quantity of nitrogen gas at a given pressure. This gas is forced into the airbag through a filter and the bag inflates breaking through the padding in the wheel centre. After deployment, a small amount of sodium hydroxide will be present in the airbag and vehicle interior. Personal protection equipment must be used when removing the old system and cleaning the vehicle interior.
Burning Rate Characterization of Guanidine Nitrate and Basic Copper Nitrate Gas Generants with Metal Oxide Additives
Published in Combustion Science and Technology, 2022
Andrew J. Tykol, F. A. Rodriguez, J. C. Thomas, E. L. Petersen
Once a pellet was pressed, its outer surface and one end face were coated with an inhibitor. This inhibitor forces the pellet to burn in a linear manner and was applied to avoid sidewall burning during the combustion process and corresponding artificially increased burning rates. Krylon spray paint and epoxy resin have been utilized as inhibitors in previous studies (Nakashima et al. 2018; Zeuner et al. 2003), and Krylon spray paint was utilized herein. Lastly, an ignitor powder was used to ensure rapid and reproducible pellet ignition. The igniter powder was composed of a stoichiometric boron and potassium nitrate mixture (B:KNO3) that was ignited via a nichrome wire and a corresponding electrical current, which is a standard technique for such propellants (Engelen, Lefebvre, De Ruyck 2001; Khandhadia and Burns 2001; Lundstrom and Shaw 1983; Mei et al. 2013; Mendenhall and Barnes 2004; Nakashima et al. 2018; Poole and Wilson 1990).
Transition Metal Catalysts for Boron Combustion
Published in Combustion Science and Technology, 2021
Kerri-Lee Chintersingh, Mirko Schoenitz, Edward L. Dreizin
Combustion of aerosolized powders was studied using a constant volume explosion (CVE) experiment (Mursalat, Schoenitz, Dreizin 2019). Two grams of each boron composite powder was loaded into a reservoir under a 9.2 L, nearly spherical vessel. The vessel was evacuated to approximately 0.3 atm. The powder was aerosolized with an air blast delivered from a high-pressure reservoir and bringing the initial pressure to 1 atm. This resulted in an effective equivalence ratio close to 1.7. After a 200 ms delay, a thermite igniter placed at the center of the vessel and operated as an electric match was initiated. Each igniter contained 0.8 g of fuel-rich aluminum copper oxide thermite (4Al-3CuO) filled in a 2 cm long, 0.5 cm diameter paper tube capped with Viton. The thermite was ignited by an electrically heated, 20-cm long, coiled tungsten wire. Using the thermite igniter without powders loaded accounts for a maximum pressure of 1.9 ± 0.05 atm. The igniter is expected to provide thermal energy for ignition and to aid in dispersion of the boron particles. Pressure traces were recorded using a PX2AN1XX500PSA Honeywell pressure transducer. The experiments were repeated at least three times for reproducibility.
Development and Parametric Study of B/BaCrO4/FG Pyrotechnic Delay Composition
Published in Combustion Science and Technology, 2018
Azizullah Khan, Abdul Qadeer Malik, Zulfiqar Hameed Lodhi, Syed Ammar Hussain
The configuration of the delay device used in this research work is shown in Figure 1. This delay device consists of a stainless steel delay body, pyrotechnic composition, igniter assembly, and O-ring. The igniter assembly is further divided into an igniter body with an anvil and percussion primer. A free volume of about 3.5 cm3 was kept empty between igniter and delay composition to provide an obturation effect to accumulate the gases produced during the burning of the delay composition. The O-ring is used to hermetically seal the delay composition from environmental effects and to allow the excess high pressure gases to escape from the delay devices. The front of the delay devices was sealed with aluminum foil.