The double-tube heat exchanger has an outer tube and an inner tube inserted into the outer tube, is provided with an inside channel within the inner tube and an outside channel between the inner tube and the outer tube, and is configured to exchange heat between the fluid flowing in the inside channel and the fluid flowing in the outside channel. The inner tube has an uneven portion having unevenness on the outer peripheral surface. A large-diameter sealing portion is interposed between one axial end of the outer tube and the inner tube. A small-diameter sealing portion, which has a smaller diameter than the large-diameter sealing portion, is interposed between the other axial end of the outer tube and the inner tube. The outside channel and the uneven portion are arranged using the difference in axial position and diameter between the large-diameter sealing portion and the small-diameter sealing portion.

A fluid cooler for a gas turbine engine comprises an outer tube having an outer tube inlet at a first end of the fluid cooler and an outer tube outlet at a second end of the fluid cooler. A primary axis of the fluid cooler is defined within the outer tube between the first and second ends of the fluid cooler. A plurality of inner tubes extend within the outer tube between the first second ends of the fluid cooler. The inner tubes have a common inner tube inlet and a common inner tube outlet. The inner tubes extend helically about the primary axis. A first group of the inner tubes are disposed at a first radius from the primary axis and a second group of the inner tubes are disposed at a second radius from the primary axis, the second radius different from the first radius.

An inner pipe (2) is designed for a heat-transferring double pipe that exchanges heat between a fluid that flows through the interior of the inner pipe and a fluid that flows between the inner pipe and an outer pipe (10) that surrounds the inner pipe. The inner pipe has a first region (21) and a second region (22), which have transverse cross-sectional shapes that differ. The first region has a plurality of first protruding parts (211) that protrude outward and form a first recess-protrusion shape in which locations of the first protruding parts are offset helically in a longitudinal direction. The second region has a plurality of second protruding parts (221) that protrude outward and form a second recess-protrusion shape, in which locations of the second protruding parts are offset helically in the longitudinal direction. The number of second protruding parts is greater than the number of first protruding parts.

A fluid cooler for a gas turbine engine comprises an outer tube having an outer tube inlet at a first end of the fluid cooler and an outer tube outlet at a second end of the fluid cooler. A primary axis of the fluid cooler is defined within the outer tube between the first and second ends of the fluid cooler. A plurality of inner tubes extend within the outer tube between the first second ends of the fluid cooler. The inner tubes have a common inner tube inlet and a common inner tube outlet. The inner tubes extend helically about the primary axis. A first group of the inner tubes are disposed at a first radius from the primary axis and a second group of the inner tubes are disposed at a second radius from the primary axis, the second radius different from the first radius.

A heat exchanger includes a distributor, and a first heat transfer tube and a second heat transfer tube connected in parallel with each other with respect to the distributor. The first heat transfer tube is disposed above the second heat transfer tube. The first heat transfer tube has a first inner circumferential surface, and at least one first groove recessed relative to the first inner circumferential surface and arranged side by side in a circumferential direction of the heat transfer tube. The second heat transfer tube has a second inner circumferential surface, and at least one second groove recessed relative to the second inner circumferential surface and arranged side by side in a circumferential direction. An internal pressure loss of the first heat transfer tube is smaller than an internal pressure loss of the second heat transfer tube.

The present invention relates to an internal heat exchanger double-tube structure of an air conditioning system having an alternative refrigerant applied thereto for heat exchange between a low-temperature low-pressure refrigerant discharged from an evaporator and a high-temperature high-pressure refrigerant discharged from an condenser, the double-tube structure including: an inner pipe having a channel through which the low-temperature low-pressure refrigerant discharged from the evaporator flows; and an outer pipe surrounding the inner pipe and having a channel through which high-temperature high-pressure refrigerant flows, wherein the inner pipe has a spiral groove forming a channel on an outer side thereof, and the spiral groove is a recessed groove for generating a vortex that increase a channel volume where high-temperature high-pressure liquid flows inward and reduces a vortex of flowing fluid.

A heat-exchange apparatus comprising a plurality of tubes bundled together, each having segmented twisted segments is disclosed. Each of the plurality of tubes provides a tube body defining an interior passageway for carrying a first fluid and a plurality of segments along its length comprising a straight section and a twisted section that are in fluid communication with each other. Each of the plurality of tubes provides a central longitudinal axis along its length. The tube body along the twisted section exhibits rotation about the central longitudinal axis and the tube body along the straight section exhibits no rotation. An exterior surface of the tube body of a tube can come into contact with an exterior surface of the tube body of another tube along the twisted section, whereas the exterior surfaces of such tubes avoid contact along the straight section.

A duct for a turbine engine, such as a gas turbine engine, can be utilized to carry a fluid from one portion of the engine to another. The duct can include a metallic tubular element having one of a varying wall thickness, a varying cross section, or a tight bend. Such a duct can be formed utilizing additive manufacturing or metal deposition on an additively manufactured mandrel.

The double tube for heat exchange includes: a spiral pipe having ridges and valleys alternately formed on a circumferential surface along a spiral track thereof and guiding a first fluid therethrough; an outer pipe receiving the spiral pipe axially inserted thereinto and guiding a second fluid along the circumferential surface such that the second fluid exchanges heat with the first fluid; a resistance member protruding from the spiral pipe or valleys to increase time of the second fluid in the valleys and to support the ridges adjacent thereto. Unlike typical double tubes, this double tube can: improve heat exchange efficiency by virtue of the spiral pipe; improve flow directionality of the second fluid; reduce noise through expansion of a space between an end joint of the outer and inner pipe to reduce the pressure of the second fluid; and improve efficiency through resistance members protruding from the valleys.

The double tube for heat exchange includes: a spiral pipe having ridges and valleys alternately formed on a circumferential surface along a spiral track thereof and guiding a first fluid therethrough; an outer pipe receiving the spiral pipe axially inserted thereinto and guiding a second fluid along the circumferential surface such that the second fluid exchanges heat with the first fluid; a resistance member protruding from the spiral pipe or valleys to increase time of the second fluid in the valleys and to support the ridges adjacent thereto. Unlike typical double tubes, this double tube can: improve heat exchange efficiency by virtue of the spiral pipe; improve flow directionality of the second fluid; reduce noise through expansion of a space between an end joint of the outer and inner pipe to reduce the pressure of the second fluid; and improve efficiency through resistance members protruding from the valleys.