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. (C) 2012 Elsevier Ltd. All rights reserved.