This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this paper, condensation flows in a cross-flow air-cooled micro-condenser were investigated for
mass velocities (representing the mass flow rates over the micro-condenser cross-section area) lower than 12
kg.m (−2).s(−1), with n-pentane used as the working fluid. This micro-condenser consisted of a transparent square
cross-section micro-channel placed horizontally, having inner and outer edges of 553 and 675 μm,
respectively, and a real length exposed to the coolant of 196 mm. One of the specificities of the experimental
bench was the choice of the air as a coolant so that the external heat transfer is limiting. Three main flow
zones were identified: annular zone, intermittent (i.e. elongated bubbles or slug) zone and spherical bubbles
zone. A specific experimental procedure based on bubbles tracking was developed in order to determine the
hydraulic and thermal parameters in the intermittent zone. The mean displacement and condensation
velocities of the elongated bubbles were determined according to their mean length for different mass
velocities of the n-pentane. Besides, the mean latent heat flux density released by the condensation of the
elongated bubbles was determined according to their mean surface for different mass velocities of the n-pentane, and compared to the imposed heat flux density
