Abstract

This thesis examines an industry-related problem in the field of solid granular propellant combustion. Through a literature review, it has been found that the safety aspects of propellants installations have not been well defined and studied. Such lack of standard could potentially lead to industrial accidents of varying magnitudes. The present project studies the flame propagation, heat output and pressure generated by the combustion of a range of propellants configurations. An experimental approach is first used to obtain a reliable set of data. Models are then obtained through the comparison of the empirical data with theoretical considerations, scaling and numerical simulations. Using the generated models, it shall eventually be possible to apply the findings in conceiving a set of guidelines for the safe design of propellant installations.

Flame propagation is central to the study of propellant combustion. Through the examination of video recordings from an array of propellant fire tests, it is possible to observe three main flame propagation modes: radiation heat transfer (ideal case), contact with burning projections and engulfment by a fireball. The maximum event dimensions depend on the dominant mode. A decision tree scheme is used to breakdown the possible events in the various propagation modes and assign conditions for their occurrence. Application of the methodology on a small scale flame propagation test shows that it is possible to scale the results to larger scale cases and obtain propagation rate estimates.

In both the radiant heat flux and pressure generation cases, theoretical forms are derived based on previous work and theoretical principles. Statistical analyses of the experimental results show good agreement with general theoretical forms. It is shown that one must, however, be attentive to possible collinearities and variable factors when interpreting statistical results. By taking into account the theoretical expectations, it is possible to estimate these additional factors and obtain models that are more generally applicable. It is also shown that the general models rely heavily on the combustion rate of the propellant configuration. This shows that the flame propagation analysis is an important part of estimating the various fire safety parameters of granular propellants.