DOUBLE PIPE FOR HEAT EXCHANGER

摘要

A double pipe for a heat exchanger includes an inner pipe having a plurality of spiral projections extending radially outward from an outer peripheral surface of the inner pipe. An outer pipe is disposed around the inner pipe. At least an inner peripheral surface of the outer pipe is at least substantially smooth and has an at least substantially circular cross section. The inner peripheral surface of the outer pipe contacts all of the projections of the inner pipe so as to define a plurality of peripherally-separated, outer flow paths between the inner pipe and the outer pipe. Fluid flowing within an inner flow path defined by the inner pipe exchanges heat with fluid flowing through the outer flow paths. Furthermore, an inscribed circle of the inner pipe has a first diameter (d1), an inscribed circle of the outer pipe has a second diameter (d2), and 0.6