STUDYING THE EFFECTS OF THE PERCENTAGE OF DIFFERENT TYPES OF FUEL AND BINDER ON DECOY FLARE PERFORMANCE.

ABSTRACT
IR guided missiles pose the major threat to military aircrafts. Pyrotechnic decoy flares are still the most commonly used passive countermeasures for heat seeking missiles. Such flares require rapid burning rate and very high output radiant intensity values. Metal /Teflon compositions as Mg/Teflon are highly energetic materials sufficient to produce high flame temperature and high spectral radiant intensity that enables these compositions to protect aircrafts from threat of IR guided missiles. In this study, thermochemical calculations were carried out for certain decoy flare compositions to predict the thermal radiation characteristics and the over all performance of such compositions. The study focuses on investigation the flame temperature of number of selected types of metallic fuel (Mg, Al, B and Ti) of different metal percentage (10% – 80%). Different types of binders [(viton) as energetic binder and (polyurethane) as moderate energetic binder] were examined with different percentage (1% - 9%). In the study Equilibrium Specific Impulse (Isp) was used to calculate the flame temperature based on formula of the elements, density, and heat of formation. Metal/Teflon compositions gave the highest flame temperature which means high burning rater at metal percentages (30% Mg, 30% Al, 40% Ti and 10% B). The other results show that energetic binder (viton) is preferable to use in compositions rather than moderate energetic binder as polyurethane because it maintain the high flame temperature and burning rate as the percentage increase at pressure 1 atm. Two values of operating pressure (0.5 - 1atm) have been examined to study the effect of pressure at different altitudes during the aircraft flight on the decoy flares flame temperature.