Experimental study of quenching process on a rotating hollow cylinder by one row of impinging jets

Quenching cooling rate of rotary hollow cylinder by one row of water impinging jets has been experimentally studied. Water jets (d = 8 mm) with sub-cooling 55 to 85 ◦C and Reynolds number 8,006 to 36,738 impinged over rotary hot hollow cylinder (rotation speed 10 to 70 rpm) with initial temperature 250 to 600 ◦C. Impingement impact angle of row of jets varied between 0 to 135 ◦ and jet-to-jet spacing in row patten was 2 to 8d. The results revealed more uniformity on cooling rate of quenching in smaller jet-to-jet spacing (2 and 4d) where wetting front regions are located closer to neighbor jet’s region. By increasing spacing, footprint of annular transition region was highlighted in quenching cooling rate contour. A distinct quenching characteristic was obtained for impingement impact angle of 0 ◦ compare to other angles. With initial temperature above the Leidenfrost temperature, low cooling rate was achieved in film and transition boiling compare to a steep increase of cooling rate at start of quenching with higher maximum heat transfer for experiments with initial temperatures less than Leidenfrost temperature. The effect of other parameters on quenching cooling rate was highlighted in film and transition boiling while no significant differences were observed in nucleate boiling.