HEAT TRANSFER PIPE WITH INNER SURFACE GROOVE

摘要

PROBLEM TO BE SOLVED: To provide a heat transfer pipe with an inner surface groove to prevent the occurrence of a boundary layer different in a composition ratio even when a mixture refrigerant and R32 are used and high heat exchange efficiency is provided. SOLUTION: A number of fins 2 extending in an inclination state based on the axial direction of a metal pipe and a number of protrusions 4 crossing the fins 2 are formed in and on the inner peripheral surface of the metal pipe 1. The height of the fin 2 from the inner peripheral surface of the metal pipe is 0.1-0.3 mm and the height of the protrusion 4 from the inner peripheral surface of the metal pipe is 0.03-0.1 mm.