The present work is aimed at quantifying the effects of frequency in the heat transfer at multiple-intermittent impacts of a hollow cone spray in a way to contribute to the development of advanced heat transfer techniques. The flow configuration is that of a spray impacting perpendicularly onto an aluminium flat plate located at 55 mm. The experiments are conducted at prescribed temperatures ranging from local nucleate/boiling to local transition regimes of heat transfer and with frequencies of injection from 10 Hz to 30 Hz with durations of 5 ms. Analysis is based on spatial resolved measurements of the instantaneous surface temperature during the period of injection, processed in order to obtain estimates of the instantaneous heat flux. The results show that the local heat transfer is enhanced when the frequency of injection increases from 10 Hz to 20 Hz, but deteriorates with a further increase of frequency, as a clear indication of the interaction between successive intermittent injections. However, the total heat flux removed over the entire area of impact follows the behaviour of typical boiling curves with an Overall Nukiyama Temperature. In the overall nucleate boiling regime, the total heat transfer is dominated by a thin film boiling mechanism which lead to breakdown of the liquid at a nearly constant surface temperature, regardless of frequency or any other spray conditions. While at low frequencies this regime is not limited neither by the delivery of liquid to the surface, nor by the removal of vapour from the surface, at higher frequencies it is triggered by enhanced vaporization induced by piercing and mixing the liquid film. A correlation is found for the total heat flux removed from the surface within the nucleate regime which accounts for the combined non-linear effects of surface temperature and pulse frequency, [GRAPHICS] The critical heat flux is shown to be well predicted by correlations reported in the literature for continuous water and dielectric sprays. However, the present multiple-intermittent spray allows achieve higher specific heat fluxes with higher efficiencies. (c) 2006 Elsevier Ltd. All rights reserved.