Computational Study of Velocity Distribution for Designing some Gas Quench Chamber and Furnace Ducts
2005 (English)In: Journal of Materials Processing Technology, ISSN 0924-0136, Vol. 155, no Part 2 Sp. Iss. SI, 1727-1733 p.Article in journal (Refereed) Published
Gas cooled quenching and many other applications require high-speed uniform-velocity flows, with minimal pressure drop. The flow ducting geometry is often rather complex, with flow splitting, 90-180 degrees bends, and circular-to-rectangular cross-section transition ducts (the latter are used, for example, between the circular blower duct and the rectangular quenching baskets). Similar situations exist in forced convection furnaces. To provide design guidance in the choice of such ducts, and focusing primarily on circular-to-rectangular transition ducts. the flow was modelled and computed, and the results were successfully validated. Sensitivity of the velocity uniformity and pressure drop with respect to the primary geometric parameters, pressure, and Reynolds numbers was examined in the range (1.3) 10(5) # Re # (7.8)10(5), with an ultimate objective to produce optimal designs. For a length-to-diameter ratio AL = L/D < 1.0, flow nonuniformity at the exit plane and pressure drop are increased by 33 and 83%, respectively, as the aspect ratio (rectangular duct width-to-height) AR decreases from 4 to 1. Increasing AR beyond 1.5 leads to linearly increasing nonuniformity and pressure drops. A diverging-contracting duct has proven to lead to lesser nonuniformity, while it did not influence the pressure drop. Increasing the inlet pressure from 1 to 20 bar led to a decrease in flow distortion by 11% at the duct exit planes. At atmospheric pressure, increasing the Reynolds number from (1.3)10(5) to (7.8)10(5) increased distortion by 8%. Some preliminary design recommendations for circular-to-rectangular duct transitions are to try and keep AL > 1 and AR < 1.5.
Place, publisher, year, edition, pages
2005. Vol. 155, no Part 2 Sp. Iss. SI, 1727-1733 p.
circular-to-rectangular duct transitions, duct flow, duct bends, quench chamber design, velocity uniformity, furnace design
IdentifiersURN: urn:nbn:se:kth:diva-5203DOI: 10.1016/j.jmatprotec.2004.04.335ISI: 000225845800096ScopusID: 2-s2.0-10044221822OAI: oai:DiVA.org:kth-5203DiVA: diva2:8019
QC 20101019 QC 201109202005-05-312005-05-312011-09-20Bibliographically approved