| In this thesis, constant volume combustion of dust mixtures of varying particle size was investigated. A reduced gravity environment assisted in the generation of a quiescent, uniform dust suspension of known concentration, by allowing time for the decay of dispersion turbulence in the absence of gravity sedimentation. The difference between the theoretical and experimental maximum explosion pressures was systematically studied. Heat loss mechanisms, conduction and radiation, were evaluated in order to determine their contribution to the experimental pressure deficit. Gaseous explosions were also studied to validate the method of analysis and to provide a basis for comparison. It was found that conduction plays a negligible role in reducing the maximum explosion pressure in both gaseous and dust combustion until the flame is within one flame thickness from the vessel wall, causing flame quenching. The most significant factor in reducing the maximum explosion pressure was found to be flame quenching by the chamber wall in both the dust and gas flames, however radiative heat loss was found to contribute up to 10% of the experimental pressure deficit in the highly luminous aluminum dust flames. |
