Noncatalyzed propellant

The effect of the addition of metallic lead and copper powders on super-rate burning is shown in Fig. 6-24. Pb powder is more effective than Cu powder in increasing the burning rate. When these powders are mixed into the noncatalyzed propellant, there is no drastic burning rate increase, i.e., no super-rate burning is observed. However, when PbO powder (1 %) is added, the burning rate is increased approximately 250 %, i.e., there is super-rate burning. 

Figure6-26. The luminous flame front ofthe patonized propellant approaches more rapidly than that ofthe noncatalyzed propellant when pressure is increased in the plateau pressure region.

Super-rate burning occurs when lithium fluoride (LiF) is mixed with NC-NG or NC-TMETN double-base propellants. As shown in Fig. 6-29, the burning rate of the propellant catalyzed by 2.4% LiF and 0.1% C increases drastically in the pressure region between 0.3 MPa and 0.5 MPa. This super-rate burning effect diminishes gradually as pressure increases above 0.5 MPa. The noncatalyzed propellant is a conventional NC-NG double-base propellant composed of 55 % NC, 35 % NG, and 10% DEP. The maximum burning rate increase is about 230% at 0.5 MPa. 

Figure 7-28 shows a set of flame photographs of the HMX-GAP propellants with and without catalysts. The luminous flame front of the noncatalyzed propellant is... 

The combustion tests conducted using a rocket motor show that the combustion becomes unstable below 1.7 MPa and the burning becomes a chuffing mode for the noncatalyzed propellant. However, the combustion is stable, as expected, even below 0.5 MPa for the nickel-catalyzed NC-NG propellant. The propellants for which the flame temperature decreases with decreasing pressure tend to give T combustion instability. 

The propellants composed of NC-NG and HMX show super-rate and plateau burning rate characteristics as shown in Fig. 6-25 201. The chemical compositions on noncatalyzed and catalyzed propellants are shown in Table 6-6. 

The flame structures of the noncatalyzed and catalyzed propellants shown in Fig. 6-25 are similar except for the flame standoff distance, i.e., dark zone length, as shown in Fig. 6-26. The dark zone lengths of both propellants decrease with increas-... 

Table 6-7. Dark zone length and reaction time in the dark zone for noncatalyzed and catalyzed propellants.

Figure 7-14. Temperature gradient in the gas phase just above the burning surface of noncatalyzed and 0.5% LiF catalyzed AP composite propellants.

The super-rate burning rates of HMX-HTPE and HMX-HTPS propellants are shown in Figs. 7-23 and 7-24, respectively. The basic chemical compositions and physicochemical properties of the noncatalyzed HMX-HTPE and HMX-HTPS propellants are the HMX-HTPE and HMX-HTPS propellants shown in Fig. 7-16, respectively. The catalysts, 2.4% PbSt and 0.4% carbon, are mixed with each noncatalyzed... 

Figure 7-28. Flame photographs of catalyzed and noncatalyzed HMX-GAPcomposite propellants ...

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