Sensitivity of Burning Rate to Initial Temperature for a Binary Magnesium-Sodium Nitrate Mix

The temperature sensitivity of the burning rate of a mixture of magnesium and sodium nitrate (60/40 by weight) was determined at 0.1 and 1.0 MPa. The temperature sensitivity was 0.0021/K and 0.0028/K at 0.1 MPa and 1.0 MPa, respectively. A standard JANNAF composite propellant illustrated the same trend in temperature sensitivity with increasing pressure leading one to suggest the models used for composite propellant combustion are the starting point for modeling pyrotechnic combustion. Analysis of various combustion models suggests the dependence of temperature sensitivity with initial temperature as an additional tool to determine the capability of various models to describe combustion. At present the temperature sensitivity is assumed to be independent of initial temperature; experiments need to be performed over large temperature intervals in order to test this hypothesis. Pyrotechnics offer an attractive test case, since the initial temperature of a pyrotechnic can be raised to nearly 1000K before decomposition of the oxidizer or phase changes take place. (Author)