Experimental result on rewetting of hot surfaces by droplet impingement

The rewetting velocity has been calculated from the response of the thermocouples placed on the heated wall and from a digital image system based on the video image registered during the runs. A comparison of the two methods is provided. Two different locations of the jet impingement on the heated surface are tested. The spray is impinging outside the heated length, just upstream the copper clamp in one series of tests, while in a second series of tests the spray impinges directly on the first wall thermocouple, 25 mm below the beginning of the heated length. Prediction of the rewetting velocity obtained using available correlations has shown a good agreement with experimental data.