Burning stable

Andreev Chuiko (Ref 35) observed stable burning in PETN of 5 micron particle size and relative density 6 = 1.17, up to 60 atm pressure. At higher pressures (up to 100 atm) burning rate increased rapidly. The pressure at which transition from stable to accelerating... 

When a metallized energetic material is burned as a propellant igniter in a rocket chamber, a consequence of the aforementioned production of metal oxides as hot condensed particles is that there is very tittle associated pressure increase. However, the surface of the propellant grain in the chamber is ignited by the hot particles and a stable burning pressure is established. Typical metallized pyrolants used as igniters are shown in Table 11.1. 

Fig. 14.9 Mass balance principle and stable burning point in a rocket motor.

As shown in Fig. 15.5, when a pyrolant of high pressure exponent is used, the variable flow range is increased. However, it is evident from Fig. 14.6 that the pressure exponent is required to be n < 1 for stable burning. It must also be noted that the temperature sensitivity of the pressure in the gas generator becomes high when a pyrolant of high pressure exponent is used. 

In the open air, HN supports combustion, but the flame was extinguished upon removal of the ignition source. To achieve stable burning Shidlovskii (Ref 14) found that addition of 10 wt—% of K2Cr207 was necessary. 

Explosive silicon burning occurs in supernova explosions when the silicon is suddenly heated to temperatures well in excess of its quiescent burning temperature and therefore burns quite rapidly (in seconds). In Type la supernovae this happens when a runaway nuclear burning causes the temperature to overshoot stable burning, leading to a quasiequilibrium that is quite close to thermal equilibrium in Type II supernovae it occurs when the rebounding shock wave blasts the silicon shell of the presupernova star and heats it suddenly, so that the silicon undergoes rapid photodestruction and quasiequilibrium transmutation. 

Figure 9-21. A set of pressure versus time in stable burning region 4.5 MPa) and (b) the...

Hsu et al. [9] studied the two-section burner through experiments and computations. As the upstream extinction coefficient increased, the amount of preheating was reduced, resulting in lower peak flame temperatures. Their computational results predicted a smaller range of stable burning velocities than observed in the laboratory, and the sensitivity to various other porous medium properties was not investigated. 

Calculation of the Typical Combustion Noise Spectrum of a Stable Burning Flare from the Overall Sound Pressure Level OASPL... 

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