Bor Potasyum Nitrat Piroteknik Üretimi ve Lazer ile Ateşlenme Karakteristiğinin Belirlenmesi
Özet
PRODUCTION OF BORON POTASSIUM NITRATE PYROTECHNIC AND DETERMINATION OF IGNITION CHARACTERISTICS BY LASER
İsmet KIZILIRMAK
Master of Science, Department of Chemical Engineering
Supervisor: Prof. Dr. Zümriye AKSU
May 2019, 115 pages
In this thesis, the production of boron potassium nitrate (BPN) pyrotechnic powder used in igniter of solid propellant rocket engines was realized, the pyrotechnic powder was made to pellet, the pellet was determined with the newly designed laser ignition test system and the firing characteristic of the pellet was determined by the closed bomb test system.
In the scope of the thesis, firstly, BPN pyrotechnic powder was produced in accordance with MIL-P-46994B military standard by using boron, potassium nitrate and Viton fluoroelastomer. DSC analysis indicated that the BPN pyrotechnic powder had a ignition temperature of 500-510°C. The calorific value of BPN pyrotechnic powder was determined as 1675 cal/g. As a result of the density determination of BPN pyrotechnic powder, the highest theoretical density was found to be 2.16 g/cm3.
BPN pyrotechnic powder has been turned into pellets to prolong the shelf life of pyrotechnic powder and to use the maximum amount of pyrotechnic in small volume. The BPN pyrotechnic powder was converted into pellet forms with a diameter of 10 mm, 9 mm, 8 mm and 3.27 mm by pressing under load and the average densities of the pellets produced were measured. The density of the pellets with different diameters was found to vary between 1.64-1.69 g/cm3. It has been observed that this density range meets the requirements specified in the MIL-P-46994B standard. The pellet porosity was calculated as 24% by the ratio of the pellet density to the density of the powder.
In the next phase of the thesis study, a new laser ignition test system was designed and the BPN pellets were ignited by laser in this system. Pellets with a diameter of 3.27 mm and a density of 1.69 g/cm3 were fired by laser according to the Bruceton Test Method, using the SenTest program software, the laser power required to fire BPN pellets at a 95% confidence level and 99.9% reliability level was found to be 550 mW and the duration of laser firing was 5.50 ms. When the level of reliability was 99.0%, laser power was found to be 470 mW and laser firing time was found as 10.45 ms. The power density required to fire the pellets using 550 mW power and 5.50 ms ignition time was 5682 W/cm2 and the energy density was 31.3 J/cm2.
Finally, the pellets of 3.27 mm diameter and 4.60 mm in length were fired at a 550 mW laser power in the closed bomb test apparatus and the average burning rate of the pellets was determined as 39.5 mm/s. This value corresponds to a minimum of 31.75 mm/s specified in the MIL-P-46994B standard.
As a result of the thesis, BPN pyrotechnic powder and pellet were produced according to MIL-P-46994B military standard, powder and pellet products have been shown to meet the calorific value, density and burning rate requirements thanks to a newly designed laser ignition test system.
Key Words: Pyrotechnics, Boron Potassium Nitrate, calorific value, average density, pellet, laser, ignition, closed bomb, burning rate
