Quenching of High Temperature Cylindrical Surface with an Impinging Jet (Resident Time and Wetting Temperature)

An experiment study has been conducted to elucidate characteristics of transient heat transfer during quenching a hot cylindrical block with an impinging water jet. The experiment was done at atmospheric pressure for the following condition : an initial block temperature of 250 to 400 deg C, a subcooling of 5-80 K, a jet velocity of 3-15 m/s, and a nozzle diameter of 2 mm. It is observed that in a certain case the hot surface is hardly wetted immediately after the water jet impinges on it. After some times named resident time, the wetting of the surface starts and the position of wetting moves forwards. The quench of the hot block also starts with the movement of the wetting position. The resident time when the wetting location starts spreading after the jet impingement is one of the most importance and can be predicted by a proposed correlation. In addition, a correlation to predict the surface temperature at the resident time is proposed.