Heterogeneous condensation of submicron particles in a growth tube

This paper reports a study on the enlargement of particles, produced by a model ethylene/air flame, by heterogeneous condensation of water vapour. This was carried out in an instrumented lab-scale facility based on the use of a growth tube. Tests were performed by varying the temperature of the condensing vapour and the gas residence time in the growth tube. Particle enlargement was favoured by increasing the vapour temperature and the residence time. Experiments can be proficiently described using consolidated models for heterogeneous condensation, provided that the contact angle between the liquid embryo of condensing vapour and the particle surface is considered as an adjustable parameter, variable with temperature.

► Heterogeneous condensation of C2H4/air flame particles was studied in a growth tube.
► Tests at different temperatures, T, C/O ratios and residence times were performed.
► Particle nucleation and growth models were successfully used to describe experiments.
► The water–particle contact angle, θ, was effectively used as model parameter.
► The variation of θ with T mirrors the complex nature of combustion particulate.