HEAT TRANSFER TUBE WITH INTERNAL GROOVES AND METHOD AND DEVICE FOR MANUFACTURING THE TUBE

摘要

A pressure loss is reduced by providing a plurality of rows of grooves (3) arranged in V-shaped patterns on an inner surface of a pipe body (1a) so as for the rows of grooves to be symmetric with respect to the pipe axis direction and by forming secondary grooves (6), (7) in a prescribed depth in part of projected portions (5) formed therebetween. Also, even when a refrigerant flow rate is low, the refrigerant flow in the pipe can be appropriately controlled by making widths of the plurality of rows of the grooves (3) arranged in the V-shaped patterns unequal in the circumferential direction to generate swirl in the spiral direction and thereby a heat transfer performance is improved as much as possible. <IMAGE>