Experimental study of heat transfer in a water film exposed to a radiant flux. Application to thermal protection of composite walls

The following work is dedicated to assessing the performance of a falling water film as a thermal protection for composite walls exposed to a radiant flux. For this purpose, an experimental set-up was designed. The water film is created by spray nozzles and flow rates lie between 120 and 880 kg/hmwall. Different radiant flux steps from 1 to 5 kW/m2 are tested. Temperature is measured at different locations inside the composite panel and at the water inlet and outlet. Three different experiments are considered: one without water film, to serve as a reference, another where the composite and the film are exposed to the radiant flux without initial heating, and finally a wall at 100 °C before the film is triggered. The film shows a good capacity to cool and to protect the wall in the range of this study.