Patent ID: 7866305

Claim:
A flow channel for a heat exchanger, an exhaust gas heat exchanger or charge air heat exchanger for heat transfer between a first fluid, an exhaust gas, exhaust gas/air mixture, or charge air and a second fluid, a coolant, a liquid, or a gaseous or mixed liquid-gas coolant, the flow channel comprising: a channel casing having an interior space surrounded by a channel casing inner surface; and a plurality of partitions arranged in the interior space on the channel casing inner surface, wherein the flow channel has a flow-through cross section, transverse to a flow channel axis, for guiding the first fluid in the interior space, and wherein a hydraulic diameter is four times the ratio of an area of the flow-through cross section to a periphery wettable by the first fluid, which is within a range between 2.8 mm and 3.8 mm.