The cooling process in gas quenching

Gas quenching is a relatively new process with several important advantages, such as minimal environmental impact, clean products, and ability to control the cooling locally and temporally for best product properties. To meet the high cooling rates required for quenching, the cooling gas must flow at very high velocities, and such flows are highly turbulent and separated. Consequently, there is a need for good understanding of these flows and their consequences for the process. To that end, we researched the state of the art, and have conducted numerous numerical and experimental studies and developed CFD models on this subject, and show the results for flows inside quench chambers and their components, and for external flows, including multi-jet impingement, on cylindrical and prismatic single and multiple bodies (the quench charge). Velocity distributions and uniformity, pressure drop, and flow effects on heat transfer coefficients and product uniformity, as well as recommendation for improved processes, are shown. (C) 2004 Elsevier B.V. All rights reserved.