MAXIMUM SURFACE HEAT FLUX DURING JET IMPINGEMENT QUENCHING OF VERTICAL HOT SURFACE

The rapid quenching of a hot surface is desirable in several industrial applications, e.g., metal processing, nuclear power plants, electronics, etc. Therefore, an experimental investigation has been carried out on a hot vertical stainless steel surface of 0.25 mm thickness at 800 +/- 10 degrees C initial temperature. The surface has been quenched with the impingement of a round water jet in the range of 2.5-4.8 mm diameters. The maximum surface heat flux during quenching has been determined for jet Reynolds number in the range of Re = 5000-24,000. The observations are made from the stagnation point to the 24 mm downstream spatial locations, for both upside and downside directions of the test surface. It has been observed that the maximum surface heat flux increases with the rise in jet Reynolds number and jet diameter. The correlation proposed to determine the maximum surface heat flux predicts the experimental data within an error band of +/- 20%. The published correlation for the horizontal surface predicts the experimental data of maximum surface heat flux within the range of +40% to -20%.