METHODOLOGY FOR DESIGNING IMPINGEMENT AIR-JET COOLERS FOR CONTINUOUS ANNEALING OF STEEL STRIP

This paper describes a methodology which may be used to design impinge ment air jet coolers for the continuous annealing of steel strip. The method is based on a one-dimensional thermal model which describes the strip temperature variation as it passes through the cooler. Although the model is valid for any coolant, the use of air impingement jets a s the cooling method is treated in detail. Providing that the thermal duty required can be obtained with air convective heat transfer coeffi cients up to about 200-250 VV m(-2) K-1, then the use of this air cool ing technique offers a compact and easily controlled solution for the cooling system. The design is based on a modular construction with eac h module having an independent fan. Control of the cooling line therma l performance may be achieved by varying the impingement jet hole latt ice or by direct fan control for a given lattice arrangement.