Optimisation of heat transfer enhancement devices in a bayonet tube heat exchanger

This paper considers the assessment and analysis of heat transfer enhanceme nt devices which can be considered for a bayonet tube heat exchanger. Due t o restraining conditions, such as material selection, manufacturing complex ity, etc., simple rib roughened surfaces in the form of rings were used on the air side flow, in the annulus. Analysis of the effect of the rings were studied, starting from cited geometries, using computational fluid dynamic s. Validation was carried out using laser diagnostics. For the range of Rey nolds numbers (Re-ave = 160,000) considered the optimal ring configuration was a ring to annulus height ratio of 0.37 with a pitch to ring height rati o of 10. This provided the optimal heat Aux to pressure drop for the given conditions. (C) 2000 Elsevier Science Ltd. All rights reserved.