The heat transfer characteristics and rewetting behavior of hot horizontal downward facing surface by round water jet impingement

Abstract

Present paper reports the heat transfer characteristics and rewetting behavior of 0.15 mm thick hot horizontal stainless steel foil (SS-304) by circular impinging jet from bottom side through experimental investigation. The transient temperature of the hot foil is recorded by using thermal imaging camera (A655sc, FLIR system). Tests are performed for a varied range of Reynolds number (Re = 2500–10,000), nozzle to plate distance (z/d = 4–10) and initial surface temperature 500 ± 10 °C. Transient temperature obtained from thermal imaging camera is used to evaluate various parameters such as surface heat flux distribution, rewetting time, rewetting temperature and rewetting velocity. Surface heat flux is found to attain maximum value at the stagnation point and gradually decreases in the radial direction away from the stagnation point. Based on the experimental investigation correlations have been proposed to predict various parameters such as surface heat flux, rewetting temperature and non-dimensional rewetting velocity as a function of various parameters, namely, Reynolds number, non-dimensional radial distance and non-dimensional nozzle to plate distance.