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Poor performance in the condensers in power plants and chemical plants is due to the fact that condensed water is deposited on the heat transfer pipes. The dynamics of condensed water droplets forming on the surface of heat transfer pipes have a significant effect on the heat transfer efficiency of heat exchangers. In the present study, a numerical approach using a coupled level-set and volume of fluid (CLSVOF) method was adopted to investigate the impact of water droplets on cylindrical pipes. The numerical model was verified by an experiment, and both sets of results showed qualitative and quantitative agreements. The effects of the surface wettability, impact velocity and relative size of the droplet to the pipe on the droplet impact dynamics are systematically investigated. Moreover, the regularities of the contact area between the liquid and the pipe during the impacting process as well as the volume of residual liquid remaining on the pipe post-impact are also analyzed; these two parameters are the key factors which affect the heat transfer efficiency of heat transfer pipes, and they cannot be acquired very accurately using experiments.