OPTIMIZED OFFSET STRIP FIN FOR USE IN COMPACT HEAT EXCHANGERS

摘要

An offset strip fin for use in compact automotiveheat exchangers is disclosed. The offset strip fin hasmultiple transverse rows of corrugations extending in theaxial direction wherein the corrugations in adjacent rowsoverlap in order that the oil boundary layer is continuallyre-started. The fin dimensions have been optimized inorder to achieve superior ratio of heat transfer topressure drop along the axial direction. In one aspect, ancompact concentric tube heat exchanger has an offset stripfin located in an annular fluid flow passageway locatedbetween a pair of concentric tubes. The preferred range oflanced lengths is determined to be between 0.035" to 0.075"for periodically developed flow. Maintaining the lancedlength in the regime of periodically developed flow isadvantageous in that it gives a higher heat transfercoefficient than is achievable with fully developed flow.This also provides the added advantage that variations inthe shape of the flow passages from the rectangular do notimpact negatively on the heat transfer.