Burn rate (chemistry)

About: Burn rate (chemistry) is a research topic. Over the lifetime, 847 publications have been published within this topic receiving 8908 citations. The topic is also known as: Burning rate.

Continuous Measurement of Solid Propellant Burning Rates

Abstract: An experimental system is presented for the direct and continuous measurement of the burning rates of solid rocket propellants under conditions closely approximating those of a solid rocket motor. The system involves a positioning type servomechanism which moves a sample of solid propellant within a two dimensional rocket motor such that the receding burning surface of the sample is maintained at a fixed position with respect to the motor. Since the burning surface remains fixed, the direct measurement of the velocity of the propellant feed mechanism for adjusting the position of the propellant sample yields the burning rate. The servomechanism incorporated a 50 m Ci 137Cs source of gamma rays coupled with a scintillation probe for detecting the position of the burning propellant surface. The output of the probe was converted into a voltage by a ratemeter. It was then amplified and compared to a standard voltage which was proportional to a desired propellant surface position. The resulting difference was amplified for the purpose of driving a 0.6 hp servomotor which positioned the burning surface of the propellant sample. The size of the sample was approximately 2.5 cm square by 10 cm long. The experimental data were obtained with the above servomechanism for two composite propellant formulations. The data were obtained for a range of pressures from 8.8 to 35.5 kg/cm2, and for burning rates ranging from 0.40 to 0.8 cm/sec. The data correlated well with previously published data. A theoretical analysis of the servomechanism was performed to determine system stability and performance. An optimization analysis of the servomechanism system yielded optimum operating parameters.

A Theoretical Study of the Combustion of Magnesium/Teflon/Viton Pyrotechnic Compositions

Abstract: : A theoretical study has been conducted using the NASA-Lewis CEC 76 computer code to model the combustion of pyrotechnic compositions based on magnesium/Teflon/Viton. The study examines the effect of formulation changes on the distribution of reaction products, the reaction temperature and the heat of reaction. The maximum temperature and heat are produced in the stoichiometric fuel concentration whilst the reaction products change significantly with the concentration of magnesium. The Teflon and Viton oxidizers generally have only a minor effect on the system thermodynamics. The major reaction products are magnesium fluoride, magnesium and solid carbon. The proportion of carbon as a combustion product remains relatively constant over a large range of fuel or oxidant concentration. The choice of the optimal MTV composition for IR decoy applications appears to be based more on burn rate and ignitability requirements than on temperature, heat output or optimization of reaction products.

Combustion control requirements in high loading density, solid propellant ETC gun firings

Abstract: This report investigates and quantifies the requirements for increasing performance (muzzle kinetic energy) in existing high performance (tank) gun systems utilizing solid propellants. Factors studied include propelling charge mass or loading density, propellant specific energy, grain geometry, and the use of electrothermal-chemical concepts. Results indicate that significant increases in performance require not only increased system energy but, more importantly, propellant combustion control In terms of the mass generation rate to operate near ideal gun performance. Specific requirements and approaches (e.g., burn rate modification by plasma interaction) to obtain the "ideal" gun performance are discussed. Plasma-propellant interaction study results are also discussed.

Chlorine-free composite rocket propellant

Abstract: A stable chlorine-free solid rocket propellant composition containing a low energy binder component having a heat of explosion value not exceeding about 350 cal/g which comprises a polyether or polyester-based polymer and at least one energetic plasticizer and further comprising, a nitrate salt and/or phase-stabilized nitrate salt as oxidizer component, a Mg/Al alloy of limited Mg content as a fuel component, and a burn rate catalyst.