Double pipe for heat exchanger

Abstract

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<d1 / d2.

Description

technical field [0001] The present invention relates to a double-layer tube for a heat exchanger that can be applied to, for example, a heat exchange cycle of an air conditioner for an automobile. Background technique [0002] A heat exchange cycle (also called a refrigeration cycle) of an automobile air conditioner, etc. is a system that includes a condenser, an evaporator, a compressor, and an expansion valve, and uses fluorocarbons, CO 2 Refrigerants such as ammonia and ammonia circulate in the circulation path connecting the above-mentioned components. In the above-mentioned heat exchange cycle, a structure is proposed in which double-layer pipes are arranged in the circulation path, and the high-temperature refrigerant discharged from the condenser and the low-temperature refrigerant discharged from the evaporator are separated in the double-layer space constituted by the double-layer pipes. The refrigerant convects and exchanges heat, thereby improving heat exchange p...

AI Technical Summary

Problems solved by technology

However, when the double-layer pipe with such a structure is applied to, for example, an automobile air conditioner and the like and is bent, the shape of the convex portion of the inner pipe is greatly deformed, and adjacent convex portions contact or approach each other, resulting in a part of the If the outer channel is clogged or the area of ​​the channel is narrowed, the fluidity of the channel will deteriorate, resulting in an increase in pressure loss and a decrease in the thermal efficiency of the channel.

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