CN218764791U

CN218764791U - Heat exchange enhanced pipe based on spiral flow type structure

Info

Publication number: CN218764791U
Application number: CN202222518220.6U
Authority: CN
Inventors: 何赣鹏; 李娜; 李�瑞; 林士杰; 胡方帅; 田泽刚
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2022-09-22
Filing date: 2022-09-22
Publication date: 2023-03-28
Anticipated expiration: 2032-09-22

Abstract

The utility model provides a heat transfer enhancement pipe based on spiral flow type structure, be circular shape tubular metal resonator including a cross-section, be provided with a plurality of sunk structures that can make intraductal fluid produce spiral flow type on the tubular metal resonator internal surface. The single sunken structure is in a hemispherical crown shape formed by a spherical surface and a circular tube, and the plurality of sunken structures are spirally arranged on the metal tube. The discontinuous pipe internal thread rib surface constructed by utilizing the vertical surface of the sunken structure can effectively guide fluid in the pipe to generate spiral flow type flow, has obvious heat exchange strengthening effect, particularly can highlight the spiral flow effect under the circumferential non-uniform heating condition, can strengthen the mixing of the fluid with different circumferential temperatures, and improves the radial and circumferential heat transfer effects; secondly, the discontinuous area of the thread rib surface also plays a role of reducing resistance loss, and the back surface of the sunken vertical surface is curved surface transition, which generates smaller streaming vortex loss compared with the common thread rib.

Description

Heat exchange enhanced pipe based on spiral flow type structure

Technical Field

The utility model belongs to the technical field of heat-conduction, in particular to heat transfer enhanced tube based on spiral flow type structure uses in being applicable to the heat exchanger of all kinds of flow medium, is particularly useful for having the device of higher requirement to high-efficient heat transfer and low resistance.

Background

The energy is an important material basis of the modern society, and the improvement of the performance of the heat exchange equipment has important significance on the efficient utilization of the energy. The tubular heat exchanger has the advantages of good heat transfer performance, high efficiency, simple manufacturing process and the like, so that the tubular heat exchanger is widely applied to the industries of heating, ventilating and air conditioning, low temperature and refrigeration, power energy, petrochemical engineering, aerospace and the like. In the tube heat exchanger, the most widely used technology for enhancing heat transfer is to use a heat transfer enhancement tube with a rough surface or an expanded surface, so that various special-shaped heat transfer enhancement tubes are developed and widely used in actual industrial production, and mainly include: corrugated pipe, expansion pipe, pin fin pipe, heat transfer pipe for placing turbulence element, pin head pipe, cross-grooved pipe, zigzag finned pipe, petal-shaped finned pipe, screwed pipe, spiral twisted flat pipe, etc. The flow in the threaded pipe is guided by the thread structure, and part of the fluid close to the wall surface rotates along the direction of the thread rib, so that the fluid in the central area in the pipe flows along the axial direction, and the other part of the fluid flows downstream in a spiral flow mode. The spiral flow type plays a great role in thinning the fluid boundary layer on one hand, and simultaneously can cause the disturbance of particles in the fluid boundary layer, thereby accelerating the heat transfer; on the other hand, in practical engineering application, a plurality of non-uniform heating conditions exist, such as a boiler water-cooled wall, a solar heat collector and the like, particularly, the swirling effect can be more prominent under circumferential non-uniform heating conditions, so that fluid mixing with different temperatures can be obviously enhanced, and the radial and circumferential heat transfer effects are improved.

The design and optimization of the spiral flow type are effective methods for improving the heat transfer effect of the heat exchange structure. In the spiral flow type structure design process, the heat exchange performance of the heat exchange tube needs to be considered, and the problems of energy loss and flow resistance need to be paid attention to. The heat exchange performance of the common round pipe is relatively poor, and the internal thread pipe and the spiral groove pipe can form near-wall surface rotational flow to improve the heat exchange effect, but the flow resistance is also obviously increased. Therefore, it is necessary to establish a high-efficiency heat transfer and low-resistance pipeline configuration to optimize the flow form of the internal flow field, thereby effectively improving the comprehensive heat exchange efficiency.

Disclosure of Invention

To the demand of establishing the pipeline configuration of a high-efficient heat transfer and low resistance, the utility model provides a heat transfer enhanced pipe based on spiral flow type structure.

The utility model adopts the following technical scheme:

the utility model provides a heat transfer enhanced tube based on spiral flow type structure, includes that a cross-section is circular shape tubular metal resonator, be provided with a plurality of sunk structures that can make the intraductal fluid of tubular metal resonator produce spiral flow type on the tubular metal resonator internal surface.

The concave structure is in a semi-spherical crown shape formed by a spherical surface and the inner surface of the metal pipe.

The depth of the concave structure is h = (0.166-0.276) D, the radius of a concave circular surface is r = (0.213-0.316) D, and D is the diameter of the metal pipe.

The plurality of concave structures are spirally arranged on the inner surface of the metal pipe.

The centers of circles of the plurality of concave structures are sequentially connected to form a spiral line on the inner surface of the metal pipe.

The spiral line of the inner surface of the metal pipe is 2 or 4.

The pitch of the spiral line is p = (1.35-1.96) D, and the lead angle of the spiral line is alpha = (36-51 degrees).

The number of the concave structures on each spiral line is the same, and the axial distance L = (0.375-0.632) D between the adjacent concave structures is kept the same.

The straight side lines of the plurality of concave structures and the spiral line on the inner surface of the metal pipe are in the same direction, and the vertical surfaces of the plurality of concave structures discontinuously form a rib surface of the internal thread of the metal pipe.

Has the advantages that: the utility model discloses to the demand of establishing the pipeline configuration of high-efficient heat transfer and low resistance, provide a heat transfer enhanced tube based on spiral flow type structure. Firstly, the utility model reasonably designs the sunken structure on the surface of the round pipe, and utilizes the vertical surface of the sunken structure to construct the rib surface of the discontinuous internal thread of the pipe, so that the fluid in the pipe can be effectively guided to flow in a spiral flow type, and the pipe has obvious enhanced heat exchange effect, especially the spiral flow effect can be more prominent under circumferential non-uniform heating condition, so that the mixing of the fluid with different circumferential temperatures can be enhanced, and the radial and circumferential heat transfer effects are improved; secondly, the discontinuous area of the thread rib surface also plays a role of reducing resistance loss, and the back surface of the sunken vertical surface is curved surface transition, which generates smaller streaming vortex loss compared with the common thread rib. The utility model provides a pair of high-efficient pipeline configuration of conducting heat and low resistance can effectively improve comprehensive heat transfer efficiency.

Drawings

FIG. 1 is a schematic view of a recessed structure;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a schematic view of a heat exchange enhancement tube based on a spiral flow type configuration;

FIG. 4 is a left side view of FIG. 2;

in the figure, I is the inner wall surface of the metal tube; II, spherical surface; III, concave spherical surface; IV, a sunken vertical surface; v is the center of the circle of the concave circular surface; VI, passing a straight line of the circle center of the concave circular surface; d is the diameter of the metal tube; r is the radius of the sphere; r is the radius of the concave round surface; h is the depth of the recess; VII, a metal tube; VIII, a recessed structure; p is the pitch of the helix; alpha is the lead angle of the spiral line; l is the axial spacing of adjacent recesses.

Detailed Description

The invention is further explained below with reference to the drawings.

As shown in fig. 1 to 4, the utility model discloses a heat exchange strengthening tube based on spiral flow type structure, including a cross-section for circular shape tubular metal resonator VII, be provided with a plurality of sunk structure VIII that can make intraductal fluid produce spiral flow type on the tubular metal resonator VII internal surface. The concave structure VIII is in a hemispherical crown shape formed by a spherical surface and the inner wall of the metal pipe, and the three-dimensional hemispherical crown configuration and the geometric dimension of the concave structure VIII are mainly determined by the geometric parameters and the relative positions of the wall surface of the I round pipe and the spherical surface of the II round pipe. Preferably, the depth of the recessed structure VIII is h = (0.166 to 0.276) D, and the radius of the recessed circular surface r = (0.213 to 0.316) D, wherein D is the diameter of the metal tube VII.

The arrangement of the plurality of recessed structures VIII on the wall surface of the circular tube is reasonably designed, and as shown in fig. 3 to 4, the plurality of recessed structures VIII are spirally arranged on the inner surface of the metal tube VII as a whole. The centers of the circle of the plurality of concave structures VIII (i.e., as indicated by V in fig. 2) are sequentially connected to form a spiral line on the surface of the circular tube. The straight lines (i.e. VI in fig. 2) of the plurality of recessed structures VIII are in the same direction as the spiral line on the surface of the circular pipe, and the vertical surfaces (i.e. IV in fig. 1) of the plurality of recessed structures VIII intermittently form the rib surface of the thread in the circular pipe.

Preferably, the spiral line on the inner surface of the metal tube VII has 2 or 4 ends, the pitch of the spiral line is p = (1.35-1.96) D, and the helix angle is alpha = (36-51 degrees). The number of the recessed structures VIII on each spiral line is the same, and the axial distance L = (0.375 to 0.632) D between adjacent recessed structures remains the same.

The rib surface of the internal thread of the discontinuous pipe can effectively guide the fluid in the pipe to flow in a spiral flow type on one hand, and has remarkable heat exchange strengthening effect; on the other hand, the discontinuous region of the thread rib surface also plays a role of reducing resistance loss, and the back surface of the concave vertical surface is a curved surface transition, which generates smaller streaming vortex loss compared with the common thread rib.

Examples

First, for a metal pipe having a diameter D =0.38mm, a spherical radius R =0.09mm, a recess depth h = (0.237) D, and a recess circular radius R = (0.237) D are selected.

Secondly, the spiral line on the surface of the metal pipe is designed to be 2 heads, the pitch of the spiral line is p = (1.58) D, and the helix lead angle is alpha = (45 degrees). The number of depressions per helix is the same and the axial spacing L =0.394D of adjacent depressions remains the same.

Based on the above design, a heat transfer enhanced tube is obtained as shown in fig. 3 and 4.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The utility model provides a heat transfer enhanced tube based on spiral flow type structure which characterized in that: the spiral flow type metal pipe comprises a metal pipe with a circular cross section, wherein a plurality of spiral flow type sunken structures capable of enabling fluid in the metal pipe to generate spiral flow type are arranged on the inner surface of the metal pipe.

2. The spiral-flow-type-configuration-based heat exchange enhanced tube of claim 1, wherein: the concave structure is in a hemispherical crown shape formed by a spherical surface and the inner surface of the metal pipe.

3. The heat exchange enhanced tube based on the spiral flow type structure as claimed in claim 2, wherein: the depth of the concave structure is h = (0.166-0.276) D, the radius of a concave circular surface is r = (0.213-0.316) D, and D is the diameter of the metal pipe.

4. The spiral-flow-type-configuration-based heat exchange enhanced tube of claim 1, wherein: the plurality of concave structures are spirally arranged on the inner surface of the metal pipe.

5. The heat exchange enhancement tube based on the spiral flow type structure as claimed in claim 4, wherein: the centers of circles of the plurality of concave structures are sequentially connected to form a spiral line on the inner surface of the metal pipe.

6. The spiral-flow-type-configuration-based heat exchange enhanced tube of claim 5, wherein: the spiral line of the inner surface of the metal pipe is 2 or 4.

7. The heat exchange enhancement tube based on the spiral flow type configuration as claimed in claim 5 or 6, wherein: the pitch of the spiral line is p = (1.35-1.96) D, and the lead angle of the spiral line is alpha = (36-51 degrees).

8. The spiral-flow-type-configuration-based heat exchange enhanced pipe of claim 6, wherein: the number of the concave structures on each spiral line is the same, and the axial distance L = (0.375-0.632) D between the adjacent concave structures is kept the same.

9. The spiral-flow-type-configuration-based heat exchange enhanced tube of claim 6, wherein: the straight side lines of the plurality of concave structures and the spiral line on the inner surface of the metal pipe are in the same direction, and the vertical surfaces of the plurality of concave structures discontinuously form a rib surface of the internal thread of the metal pipe.