Heat exchanger

A heat exchanger comprising:

• a plurality of flow channels, wherein
• the heat exchanger is configured to exchange heat between fluid flowing through the plurality of flow channels,
• the plurality of flow channels include:
• a first flow channel through which first fluid flows;
• and
• a second flow channel through which second fluid having a temperature different from a temperature of the first fluid flows,
• the first flow channel and the second flow channel are provided in such a manner as to be alternately stacked in a stacking direction perpendicular to a direction in which the flow channels extend,
• each of the first flow channel and the second flow channel includes:
• upstream parts disposed parallel to one another in a direction perpendicular to the stacking direction and to a direction in which the flow channels extend;
• downstream parts disposed parallel to one another in a direction perpendicular to the stacking direction and to a direction in which the flow channels extend;
• branching parts configured to branch the flow channels immediately upstream of the branching parts into two divergent channels;
• and
• merging parts configured to merge divergent channels adjacent to one another to form next flow channels, between the upstream parts and the downstream parts, wherein
• the branching parts and merging parts are provided in a plurality of stages between the upstream parts and the downstream parts,
• the second fluid is coolant having a lower temperature than the first fluid, the first fluid is fluid having a higher temperature than the second fluid, and
• the divergent channels in the first flow channels are formed more narrowly than the divergent channels in the second flow channels,
• wherein the next flow channels between the upstream parts and the downstream parts are linear flow channels, the linear flow channels being provided between an upstream merging part and a downstream branching part in the direction in which the flow channels extend,
• wherein the linear flow channels are parallel to the direction in which the flow channels extend, and
• wherein a width of the linear flow channels of the first flow channels and a width of the linear flow channels of the second flow channels are the same.