NC-NG double-base propellant

Fig.4.n Rocket flight trajectories assisted by (a) an NC-NG double-base propellant and (b) an aluminized AP composite propellant. 

TMETN is a liquid at room temperature and the production process of NG-TMETN propellants is the same as that described for NG-NG propellants. The shock sensitivity of TM ETN is sufficiently lower than that of NG that no desensitizers are needed for NC-TMETN propellants. Instead of the DEP or TA used as low energy density plasticizers and stabilizers of NC-NG propellants, TMETN is mixed with TEGDN, which is a dinitrate ester and hence a relatively high energy density material. Thus, the overall energy density of double-base propellants composed of NC-TMETN is equivalent to or even higher than that of NC-NG double-base propellants. 

Figure 4.25 shows the adiabatic flame temperatures of mixtures of HMX with an NC-NG double-base propellant as a function of the mass fraction of HMX,... 

Fig. 6.1 Burning rate increases with increasing energy density of NC-NG double-base propellants at constant pressure the pressure exponent remains unchanged when the energy density is changed.

Fig. 6.2 The burning rates of NC-NG double-base propellants increase as the heat of explosion increases at constant pressure.

Fig. 6.4 Typical flame photographs of an NC-NG double-base propellant.

Fig. 6.22 shows a typical set of burning rates for catalyzed and non-catalyzed NC-NG double-base propellants. The burning rate of the non-catalyzed propellant composed of 53 % NC, 40% NG, and 7 % DEP is seen to increase linearly with increasing pres sure in an In r versus In p plot. When the propellant is catalyzed with a com-... 

Table 6.8 Chemical compositions of catalyzed NC-TMETN and NC-NG double-base propellants (% by mass).

Super-rate burning occurs when lithium fluoride (LiF) is incorporated into NC-NG or NC-TMETN double-base propellants. As shown in Fig. 6.27, the burning rate of a propellant catalyzed with 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 the pressure is increased above 0.5 MPa. The non-cata-lyzed 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. 

Fig. 4.12 Specific impulse and adiabatic flame temperature of NC-NG double-base propellants as a function of (NG).

Figure 4-6 shows the adiabatic flame temperature of the mixture of an NC-NG double-base propellant as a function of the mass fraction of HMX, (HMX). The base matrix of double-base propellant is composed of NC/NG in the ratio = 0.2/0.8. Since HMX is a stoichiometrically energetic material, HMX acts as an energetic material, not an oxidizer. Accordingly, the flame temperature increases monotonously as (HMX) increases. 

The combustion wave of NC-NG-GAP propellant consists of successive two-stage reaction zones1161. The first gas phase reaction occurs at the burning surface and the temperature increases rapidly in the fizz zone. The second zone is the dark zone which separates the luminous flame zone from the burning surface. Thus, the luminous flame stands some distance above the burning surface. This structure is equivalent to that of the NC-NG double-base propellants described in this section. The temperature in the dark zone is increased from 1400 K to 1550 K at 3 MPa... 

Typical gas-generating propellants are (1) AP-PB composite propellant composed of 50% AP and 50% HTPB that is cured with isophorone diisocyanate (IPDI), (2) NC-NG double-base propellant composed of 70% NC and 30% NG that is plasticized with diethyl phthalate (DEP), and (3) GAP propellant composed of GAP copolymer that is cured with 12.0% hexamethylene diisocyanate (HMDI) and cross-linked with 3.2 % trimethylolpropane (TM P). 

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