Role of Surface Roughness in Water Spray Cooling Heat Transfer of Hot Steel Plate

A water spray cooling has been widely used in a variety of engineering applications. The current study focuses on making quantitative measurements of heat transfer by water spray as it impinges on the rough surface of hot steel plate at higher temperature nominally up to 900 degrees C. The local heat flux measurements are introduced by a novel experimental technique in which test block assemblies with cartridge heaters, thermocouples are used to measure the heat flux distribution on the surface of hot steel plate as a function of heat flux gauge. The roles of surface roughness on heat transfer are presented for well-characterized four rough surfaces with average rms roughness heights ranging from 40 to 80 mu m. The results show that the local heat transfer for the rough surface is compared with that for a smooth surface. Finally the heat transfer enhancement mechanism on rough surface can be investigated by the different boiling phenomena.