Numerical Investigation of Heterogeneous Nucleation of Supersaturated Water Vapour on Coal-fired PM10
2020
Ju Gao, Ting-fang Yu, Run-guo Chen, Hao-jie Zhang and Lin Wang
The kinetic model is adopted to describe heterogeneous nucleation of supersaturated water vapour on coal-fired PM10. To verify the accuracy of the kinetic model, it is compared with the Fletcher model and experimental data. Additionally, the comparison for condensation and evaporation coefficients and the relative importance of two diffusion condensation mechanisms are systematically analysed during embryo growth process. Furthermore, the influence of vapour temperature on nucleation rate and critical supersaturation for coal-fired PM10 are researched. The results show that the predicted critical supersaturation for Kinetic model is far closer to the experimental data compared with the Fletcher model. What is more, once the embryo radius rn reaches the critical embryo radius r*, it can grow spontaneously, and the indirect surface diffusion mechanism is more important than the direct addition mechanism to embryo growth, the value of RTO is always above 100. It is also found that increase in the vapour temperature is conductive to nucleation process, which can increase the nucleation rate and decrease the barrier of nucleation free energy.
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