Heat exchanger

A heat exchanger comprising:

• a pipe main body forming a flow path to which a first fluid is supplied;
• a pair of partition plates that are spaced apart in an extension direction of the pipe main body, that block part of the flow path in the extension direction, and that define an enclosed space in part of the flow path;
• a plurality of heat transfer tubes that each have a tubular shape with both ends open, that extend in the extension direction to penetrate the pair of partition plates, and that are disposed side by side and spaced from each other;
• a supply portion configured to supply a second fluid from outside of the pipe main body into the enclosed space;
• a discharge portion that is spaced apart from the supply portion in the extension direction and that is configured to discharge the second fluid in the enclosed space to the outside of the pipe main body;
• and
• a flow path forming portion that forms a plurality of small flow path portions between any two immediately adjacent heat transfer tubes out of the plurality of heat transfer tubes,
• wherein
• the second fluid flows between the plurality of heat transfer tubes in the enclosed space in a direction opposite to a flow direction of the first fluid,
• the plurality of small flow path portions are disposed at positions different from each other when viewed from the position where the discharge portion is disposed in the extension direction, and
• wherein the flow path forming portion includes:
• a plurality of first protrusion portions that protrude from an outer surface of one of the any two immediately adjacent heat transfer tubes toward the other of the any two immediately adjacent heat transfer tubes to extend in the extension direction and that are spaced from each other in a circumferential direction of the plurality of heat transfer tubes,
• a plurality of second protrusion portions that protrude from an outer surface of the other of the any two immediately adjacent heat transfer tubes toward the one of the any two immediately adjacent heat transfer tubes to extend in the extension direction and are disposed at intervals in the circumferential direction, and
• wherein each of the plurality of first protrusion portions and each of the plurality of second protrusion portions are disposed so as to be shifted relative to each other in the circumferential direction when viewed from the extension direction.