Characteristics of CMDB Propellants

Since the energy contained within double-base propellants is limited because of the limited energies of nitrocellulose (NC) and nitroglycerin (NG), the addition of ammonium perchlorate or energetic nitramine particles such as HMX and RDX increases the combustion temperature and specific impulse. Extensive experimental studies have been carried out on the combustion characteristics of composite-modified double-base (CMDB) propellants containing AP, RDX or HMX parhclesli- l and several models have been proposed to describe the burning rates of these pro- 

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Kubota, N., and Masamoto, T., Flame Structures and Burning Rate Characteristics of CMDB Propellants, 16th Symposium (International) on Combustion, The Combustion Instimte, Pittsburgh, PA, 1976, pp. 1201-1209. 

Aoki, I., Burning Rate Characteristics of Double-Base and CMDB Propellants, Ph.D. Thesis, Department of Aeronautics, University of Tokyo, Tokyo, 1998. 

Important results are that the dark zone temperature (Tf) decreases even though the flame temperature (Tg) is increased by the increase of Sj(N02) at constant pressure as shown in Fig. 7-38. Furthermore, (f> decreases also as Sj(N02) increases, and thus the burning rate decreases as Sj(N02) increases, i.e., the burning rate of HMX-CMDB propellants decreases as Ij(HMX) increases at a constant pressure. The observed burning rate characteristics of HMX-CMDB propellants are understood without consideration of the diffusional process and the chemical reaction between the decomposed gases of the base-matrix and the HMX particles. This is a significant difference from the burning rate characteristics of AP-CMDB propellants. 

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