HEAT EXCHANGE SURFACE AND A HEAT EXCHANGER AND METHOD FOR THE MANUFACTURE THEREOF

摘要

A heat transfer surface for nucleate boiling of liquids is formed on the outer surface of a heat exchanger tube. Helical ridges having two fins each encase the tube. A fin at each ridge is angled toward the adjacent fin on the adjacent ridge forming a gapped cavity therebetween. The method of making the tube includes rolling alternating deep grooves and shallow grooves in the outside surface of the tube and then flaring the fins to form the gapped cavity.