Laser Ignition of Various Pyrotechnic Mixtures – an Experimental Study

Abstract

[a] 1IntroductionLaser ignition of pyrotechnic mixtures offers at echnical method of physically separating ignition energy from the energetic material. This enables av iable solution to designing moderns afe-and-arm systems, which can meet higher safety standardsf or solid rocket igniters [1].Av ariety of pyrotechnic materials have beenu sed as ignition compositions in the past [2].O ft heseo nly as pecific mixture of boron and potassium nitrate( B/KNO 3 )c an be used without interruption of the pyrotechnic chain, according to MilStd1901. This is mainly due to the inherenti nsensitivity of the powder [3].H owever,n ew compositions are continually being investigated.S ome offer higher performance, and may in the future be foundt ob ea ss afe as, or even safer than B/KNO 3 .O ne example is am ixture of titanium sub hydride and potassium perchlorate with af lame temperature of about 3500 K[ 4] comparedt o 2800 Kp roducedb yB /KNO 3 .T he electro-static sensitivity of titanium sub-hydride composition has also been studied [5] and found to be less sensitivet han the NSI (NASA Standard Initiator)w hich employs ac omposition of zirconium and potassium perchlorate.Apart from ignition purposes pyrotechnic mixtures are used for several other applications, delay fuses for instance. Am ixture of borona nd barium chromate is often used for this purpose [4].I ns uch application ignitionb yl asera lso offers advantages, sucha shigher safety and reliability.In ap reviousw ork [6] an ovel experimentals etup used to characterizei gnition of ap yrotechnic pellet by laser was described. In that work only the ignition and combustion of B/KNO 3 was reported. Herewith ignition of several pyrotechnic mixtures is reported and compared in terms of ignition delay time and emission spectroscopy.T he goali st o identify any common trends which pertain to laser ignition of such pyrotechnics, and study the differences in ignition behavior.T his worki sp art of an endeavor to construct au nified modelt hat can be used to predict ignition of pyrotechnic mixtures. 2R esults and DiscussionIgnitiond elay times are af unction of laser intensity for the different mixtures are shown in Figure 1.Ignition delay times ( Figure 1) were measured using two methods. The first is by observing the pressure increase as af unction of time. The point in time at whicht he first derivative of pressure increase was higher thanathreshold of 1.5 of the noise level was considered as the ignition delay time by pressure measurement. The second method to measure ignition delay timew as by appearance of first light emission. For all mixtures both methodsy ielded similar results, apart from the B/BaCrO 4 pyrotechnic mixtures, for which no pressure increasew as detected duringc om- Abstract:I gnition of severalp yrotechnic mixtures by diode-laser was studied experimentally using an ovel combustion chamber.T he ignition delay times dependence on laser intensity could be fit by the expression t ign = aI Àn for all compositions, with I being the laser intensity at target an...

Study on the Ignition Process and Characteristics of the Nitrate Ester Plasticized Polyether Propellant

“…Demko et al [17] measured the ignition delay time at the pressure between 3.5 MPa and 15.5 MPa using a CO 2 laser igniter and studied the effect of novel nanoaddictive catalysts on the ignition delay time. Sivan et al [18] studied the diode-laser ignition of pyrotechnic mixtures and investigated the ignition delay time's dependence on laser intensity, combustion temperature, and composition. Feng et al [19] investigated the ignition and combustion of aluminum droplets using aluminum wires and a CO 2 laser igniter.…”

Dual-mode response behavior of a graphene oxide implanted energetic system under different thermal stimuli

“…GO was produced and used as an additive in boron/potassium nitrate mixtures (B/KNO 3 for short) which are used extensively as propellant igniters and gas generators. 23,24 Several different percentages of GO were appended to B/KNO 3 , and the thermal decomposition, critical ignition distance and pressure-time curves for each sample were used to analyse the changes achieved under diverse thermal stimuli.…”

High-Speed Visualization of Nanopowder Combustion in Air

“…Nowadays, a number of methods are used for producing new materials, which are associated with the interaction of powerful energy fluxes with a matter or high-temperature combustion processes [1][2][3][4][5][6][7][8][9]. One of these processes is manufacturing aluminum nitride (AlN) by combustion of aluminum nanopowder in air [1][2][3][4][5][6][7].…”