Condensed-phase particles are frequently present in turbulent combustion systems and can have a profound influence on the thermochemical nature of their surroundings. Fuel droplets and soot particles are two examples of important condensed phase species in combustion. The evaporation of the former largely determines the distribution of the combustible gaseous fuel/air mixture, while the presence of the latter impacts strongly on the degree of radiant heat transfer from the system. It is thus desirable to be able to predict the evolution of these particles, in a turbulent combusting environment, in response to their local thermochemical conditions. A number of difficulties surround the modelling of the mean rate of particle phase and chemical reactions in turbulent combustion. Perhaps the most significant difficulty is associated with determining the mean influence of carrier fluid properties such as temperature and chemical species concentrations upon the particle population. Wherever the local properties of the carrier fluid fluctuate according to turbulent mixing action, these fluctuations couple with the non-linearity of the particle reactions to prevent a simple first order closure of the mean reaction rates using mean properties. This type of closure problem is the same as that experienced in modelling the mean rate of chemical reaction is purely gas phase combustion when using conventional averaging techniques. The Conditional Moment Closure (CMC) method (see Klimenko 1990, Bilger 1993) for modelling turbulent (ges phase) nonpremixed combustion makes use of averages which are conditional upon the local value of a conserved scalar (mixture fraction), which is indicative of the state of mixing between fuel and air masses. Conditional averaging on mixture fraction captures much of the turbulence-induced fluctuations and a first order closure is often possible. The success of the CMC model in gas phase combustion makes it of some interest in modelling particle reactions. The purpose of this study was to simulate the dynamics of reactive particle mass and motion in a turbulent combusting environment and attempt to model the observed mean thermodynamic behaviour of the reacting particles using a derivative of the CMC method. In this report, the simulation and modelling of pseudo-soot particles is described. A similar study conducted for pseudo-droplet particles is described by Smith (1998).
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