Effect of Impinging Rotating Jets on Horizontal Cylinder Cooling

Abstract

Experimental investigations have been conducted on the effect of quenching of hot horizontal stainless-steel cylinder by sub-cooled liquid water jets. Many studies dealt with fixed circular jets, and few investigated the usage of rotating jets. Investigating quenching phenomena has important impact on some industries such as steel hardening. The cooling rates have been studied for changing different parameters, such as cylinder initial temperature (250,350 and 450°C), coolant temperature (degrees of sub-cooling between 20°C and 60°C), number of jets (No. of jets 1, 2 and 3 jets) and jets rotation speed (Nj = 0, 20, 40 and 60 rpm).The coolant was impinged from jet/jets with diameter Dj= 4 mm to the center of the cylinder. The jets were 5 cm above the cylinder in the vertical direction. These parameters will be discussed to achieve the optimum cooling rates and homogenous temperature distributions all over the cylinder surface, which enhances the cooling process and the heat treatment as a consequence. The study deduce that the cooling effect of the triple jets appears at angles 90° to 180° and shows that it achieves better cooling at near surface impinging points than double or single jet impinging. Using jet rotation speed Nj= 20 rpm, the surface temperature decreases faster than static or any jet rotation at angles 150-180°. Also using rotating triple jet achieves more homogenous distribution of temperature than using fixed jets.