FLAT HEAT TRANSFER TUBE FOR EGR COOLER, AND EGR COOLER USING THE FLAT HEAT TRANSFER TUBE

摘要

PROBLEM TO BE SOLVED: To provide a flat heat transfer tube for an EGR cooler as large as the conventional one, having high heat transfer performance, and securing high EGR rate in a broad flow rate region from low flow rate to high flow rate. SOLUTION: The flat heat transfer tube for an EGR cooler is composed of a flat tube with a flat-shaped cross section and a waveform fin structure inserted into the flat tube. The waveform fin structure is composed of a single waveform fin structure having a channel-like waveform with an approximately rectangular cross section (rectangular channel waveform). Inner height and inner width of the single waveform fin structure, an aspect ratio of the rectangular channel, and the corresponding diameter are set to be proper values. Further, the waveform fin structure is composed of a multi-stage type waveform fin structure comprising two or a plurality of stages of the single waveform fin structures overlapped and mutually joined at the contacting parts. COPYRIGHT: (C)2011,JPO&INPIT