Twisted tube with internal spiral groove and heat exchanger

摘要

PROBLEM TO BE SOLVED: To provide a tube with a spiral grooved inner surface excellent in both a refrigerant evaporation performance and a refrigerant condensation performance, and a manufacturing method therefor.SOLUTION: The present invention provides a tube with a spiral grooved inner surface 11R, manufactured by directly applying twisting to an aluminum alloy extruded stock tube with a plurality of straight grooves along a length direction formed on an inner surface at a distance in a circumferential direction, thereby changing the straight grooves to spiral grooves and forming a fin into a spiral fin. A thickness of a bottom of the tube with the spiral grooved inner surface in the spiral grooves is equal to or greater than 0.55 mm, a height of the fin from the spiral grooves is equal to or greater than 0.24 mm, a fin apex angle represented by relative angles of two sidewall surfaces of the fin in a cross-section of the fin is equal to or less than 25°, and a mean crystal grain size is equal to or less than 120 m in a crystal grain structure.