Heat exchanger and method for manufacturing same

A method for manufacturing a heat exchanger including:

• a core portion,
• a first flow path which is provided in the core portion and through which a first fluid flows, and
• a second flow path which is provided in the core portion and through which a second fluid flows, wherein:
• the first fluid flowing through the first flow path and the second fluid flowing through the second flow path exchange heat through a partition in the core portion;
• the first flow path and the second flow path are tubular flow paths aligned in regular fashion;
• the first flow path includes:
• a plurality of main flow paths extending in a first direction and having a certain cross section of a flow path;
• an introducing chamber extending in the second direction and communicating with a plurality of the main flow paths, of the plurality of main flow paths, aligned in the second direction;
• and
• a discharge chamber extending in the second direction and communicating with a plurality of the main flow paths, of the plurality of main flow paths, aligned in the second direction;
• the main flow path includes:
• an introducing side shape changing section in which a certain flow path is gradually changed in a cross-sectional shape as approaching to the introducing chamber and connected in a straight shape to the main flow path adjacent thereto;
• and
• a discharge side shape changing section in which the certain flow path is gradually changed in a cross-sectional shape as approaching to the discharge chamber and connected in a straight shape to the main flow path adjacent thereto;
• and
• the method comprises integrally forming the core portion by additive manufacturing.