EXPERIMENTAL INVESTIGATION OF WETTED ZONE DUE AN IMPINGING CIRCULAR WATER JET ON A MOVING SURFACE

Cooling liquid jet impingement has many industrial applications such as metal manufacturing where the shape and the size of wetting area around impingement point is important in heat transfer analysis. A series of experiments on a moving surface with an impinging industrial-scale circular water jet is conducted to explore experimentally the wetting region and the hydraulic jump as the front of wetted zone. The effects of surface motion on the wetting zone and the formation and location of hydraulic jump upstream the impingement point is examined by changing systematically the surface velocity and the jet flow rates. The surface motion impacted the radial evolution of wetted zone in all direction and decreased the radius of non-circular hydraulic jump. However, higher jet flow rate suppressed its effect. Both surface velocity and jet velocity or their velocity ratio has to be considered in adjusting jet space along a jet- line in industrial cooling application.