CN110207530B - High-strength heat exchange fin adopting bidirectional discrete protrusions - Google Patents

Abstract

A high-strength heat exchange fin using bidirectional discrete protrusions, the heat exchange fin includes a fin base, a folded edge structure, a discrete protrusion structure and a heat exchange tube; the fin base is arranged with bidirectional discrete protrusions structure; the convex structure one and the convex structure four are in the same convex direction, which is opposite to the convex direction of the convex structure two and the convex structure three. For the high-strength heat exchange fins with bidirectional discrete protrusions, by setting multiple groups of discrete protrusions, the fluid can be violently disturbed, and heat exchange can be significantly enhanced; It can also reduce the flow resistance by acting on the fluid in the entire fin flow channel.

Description

A high-strength heat exchange fin with two-way discrete protrusions

technical field

The invention belongs to the technical field of heat exchangers, and relates to a tube-fin heat exchanger fin suitable for various industries such as heating, ventilation, air conditioning, refrigeration, chemical industry, automobile, etc., in particular to a high-strength heat exchange using bidirectional discrete protrusions fins.

Background technique

The heat exchanger is one of the important components in the air conditioner, and its performance directly affects the overall efficiency of the air conditioner. With the increasing demand for energy efficiency of household air conditioners in my country, how to improve the performance of heat exchangers at low cost is the focus of analysis and research. At present, tube-fin heat exchangers are mainly used in air conditioners. Due to the poor heat transfer performance on the air side, the thermal resistance of this heat exchanger is mainly concentrated on the air side outside the tubes, and the thermal resistance outside the tubes can account for 80% of the total thermal resistance. % to 90%, therefore, optimizing the fin structure outside the tube will effectively improve the heat transfer performance of the heat exchanger. There are various forms of heat exchanger fins, from the initial flat fins and corrugated fins to the later developed louver fins and slotted fins. These fins increase the heat exchange area on the air side of the heat exchanger, and at the same time increase the disturbance to the fluid, greatly enhancing the heat exchange performance of the heat exchanger. However, traditional slotted or louvered fins are usually suitable for heat transfer enhancement in non-frost conditions, because traditional slotted or louvered fin reinforcement structures are often easily blocked by frost in frosted conditions, thereby reducing the Heat transfer performance of fins.

However, slotted fins can effectively strengthen heat exchange. Therefore, in the present invention, the fins are improved as far as possible without opening windows and slots, and to meet the requirements of fin symmetry and high strength in the processing technology. The idea of two-way slits is proposed, and the two-way discrete convex structure fins are proposed, which can effectively reduce the effect of frosting on the heat transfer capacity of the fins.

SUMMARY OF THE INVENTION

In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a high-strength heat exchange fin using two-way discrete protrusions,

In order to achieve the above object, the technical scheme adopted in the present invention is:

A high-strength heat exchange fin using two-way discrete protrusions, including a fin base 1, and a heat exchange tube hole 7 for the heat exchange tube to pass through on the fin base 1, characterized in that the fin base 1 The upper periphery of the heat exchange tube hole 7 is provided with a bidirectional discrete convex structure. The fins achieve violent disturbance of the fluid through the bidirectional discrete convex structure, destroy the flow boundary layer, and have a drainage effect to reduce the flow stagnation area behind the tube.

The two-way discrete convex structures include several sections of convex structures one 3 and two convex structures 4 symmetrical about the center of the heat exchange tube hole 7, and convex structures three 5 and two convex structures located between adjacent heat exchange tube holes 7. A structure four 6 is formed, wherein the convex structure one 3, the convex structure two 4, the convex structure three 5, and the convex structure four 6 are all located on the fin base 1 and are not connected to each other.

The protruding structure 1 3 and the protruding structure 4 6 have the same protruding direction, and are opposite to the protruding direction of the protruding structure 2 4 and the protruding structure 3 5 .

Among them, each section of raised structure 1 3 and raised structure 2 4 that are symmetrical with respect to the center of the same heat exchange tube hole 7 are located on the same circumference, and the raised structure 4 6 is arranged on the connecting line of the adjacent heat exchange tube holes 7 There are multiple protruding structures 5 , which are symmetrically arranged along the connecting line of the adjacent heat exchange tube holes 7 , and the protruding structures 3 5 and the protruding structures 4 6 are both located outside the circumference.

The height of the raised structure one 3 is 0.5-1.0 mm, the bottom surface is a right-angled trapezoid, the length of the bottom side is 1.5-2.5 mm, the height of the bottom surface is 1.5-3.0 mm, and the bottom angle is 60-70°; The height of the structure 24 is 0.5-1.0mm, the inner radius of the bottom surface is 5.6mm, and the outer radius is 7.0-8.0mm. The angle between each side and the surface of the fin is 30-45°; the height of the raised structure 5 is 0.5-1.0mm, the bottom surface is an isosceles trapezoid, the length of the top side is 1.5-3.0mm, and the length of the bottom side is 2.5mm ～4.0mm, the height of the bottom surface is 2.5～3.5mm, the angle between the two sides near and far from the edge of the fin and the surface of the fin is 30～45°, and the angle between the other two sides and the surface of the fin is 45～ 60°; the height of the raised structure 6 is 0.5-1.0mm, the angle between the two arc surfaces and the surface of the fin is 45-60°, and the angle between the other two sides and the surface of the fin is 30- 45°, the length of the bottom surface along the sheet width direction is 2.5 to 4.0 mm, and the radius of the arc of the bottom surface is 8.5 to 9.5 mm.

The fin base 1 has a straight structure, the heat exchange tube holes 7 are located on a symmetrical line in the width direction of the fin base 1, and the bidirectionally discrete raised high-strength heat exchange fins are symmetrical fins.

The thickness of the fin base body 1 is 0.09-0.11mm, and the width is 18.19-21.65mm; the distance between the adjacent fin base bodies 1 is 1.3-1.6mm; the diameter of the heat exchange tube is 7mm or 7.94mm; The hole spacing of the heat exchange tube holes 7 is 21-23 mm.

Folding structures 2 are provided on both sides of the long side of the fin base 1 .

Compared with the prior art, the beneficial effects of the present invention are:

1) Discrete convex structures are arranged on the circumference of the heat exchange tube, which can enhance the disturbance of the fluid, increase the heat exchange intensity between the fluid and the heat exchange tube and the surface of the fins, and reduce the flow stagnation area of the fluid behind the heat exchange tube. Moreover, the use of bidirectional protrusions can disturb the fluid in the entire fin flow channel, which can significantly enhance heat exchange.

2) In the direction of the symmetry axis of the adjacent heat exchange tubes, three alternately reversed convex structures are arranged, which can effectively enhance the disturbance of the fluid in the main flow direction and further strengthen the heat exchange.

3) A certain inclination angle is adopted on the side surface of each protrusion, which can enhance the fluid heat exchange without generating large fluid resistance.

4) The folding structure is arranged on the leading edge and the trailing edge of the fin, which can effectively enhance the strength of the fin.

Description of drawings

The present invention will be further described below with reference to the embodiments described in the accompanying drawings.

FIG. 1 is a top view of an embodiment of the present invention.

Figure 2 is an A-A cross-sectional view of an embodiment of the present invention.

3 is a B-B cross-sectional view of an embodiment of the present invention.

4 is a C-C cross-sectional view of an embodiment of the present invention.

Figure 5 is an isometric view of an embodiment of the present invention.

Detailed ways

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples.

1 to 5, it is an embodiment of the bidirectional discrete convex high-strength heat exchange fin of the present invention. The main features of the fin include: a fin base 1, a folded edge structure 2, a convex structure one 3, a convex structure Lifting structure two 4 , raised structure three 5 , raised structure four 6 and heat exchange tube hole 7 .

The fin base 1 is a straight fin, and the two sides of the long side are provided with a folding structure 2 , and the heat exchange tube holes 7 for the heat exchange tubes to pass through are located on the symmetry line in the width direction of the fin base 1 . The fin base 1 is provided with a bidirectional discrete convex structure surrounding the heat exchange tube hole 7 , and the bidirectional discrete convex structure is mainly composed of several sections of the above-mentioned convex structure 1 3 and the convex structure 2 4 that are symmetrical about the center of the heat exchange tube hole 7 . , and the above-mentioned raised structures three 5 and four raised structures 6 between the adjacent heat exchange tube holes 7 are composed of raised structures one 3, raised structures two 4, raised structures three 5, raised structures four 6 are all located on the fin base 1 and are not connected to each other. Moreover, the protruding direction of the protruding structure 1 3 and the protruding structure 4 6 is the same, and both are opposite to the protruding direction of the protruding structure 2 4 and the protruding structure 3 5 .

The entire bidirectional discrete raised high-strength heat exchange fins are symmetrical fins. The fins achieve violent disturbance of the fluid through the bidirectional discrete raised structure, destroy the flow boundary layer, and have a drainage effect to reduce the flow stagnation area behind the tube.

In this embodiment, each segment of raised structure 1 3 and raised structure 2 4 that are symmetrical with respect to the center of the same heat exchange tube hole 7 are located on the same circumference, and the raised structure 4 6 is arranged on the connecting line of adjacent heat exchange tube holes 7 Above, there are a plurality of raised structures 5 , which are symmetrically arranged along the connecting line of the adjacent heat exchange tube holes 7 , and the raised structures 3 5 and the raised structures 4 6 are both located outside the above-mentioned circumference.

The specific structural parameters of the embodiment are described below. In the introduction, the width direction of the fins is the longitudinal direction, the length direction of the fins is the transverse direction, the direction close to the heat exchange tube hole 7 is the inner side, and the direction away from the heat exchange tube hole 7 is the outer side.

The width of the fins (that is, the width of the fin base 1) is 21.65 mm, the distance between the adjacent heat exchange tube holes 7 is 21 mm, and the thickness of the fins (that is, the thickness of the fin base 1) is 0.1 mm. The pipe diameter is 7mm. The height of all raised structures is 0.7mm. The bottom surface of the raised structure 1 3 is a right-angled trapezoid, the length of the bottom side is 2.0mm, the height of the bottom surface is 3.0mm, and the bottom angle is 70°. The inner radius of the bottom surface of the convex structure 24 is 5.6mm, the outer radius is 7.4mm, the angle between the two convex arc surfaces and the surface of the fin is 60°, and the angle between the other two sides and the surface of the fin is 45°. The bottom surface of the raised structure 35 is an isosceles trapezoid, the length of the top side is 2.5mm, the length of the bottom side is 4.0mm, the height of the bottom surface is 2.5mm, and the angles between the two sides near and far from the edge of the fin and the surface of the fin are equal. is 45°, and the angle between the remaining two sides and the surface of the fin is 60°. The angle between the two arc surfaces of the raised structure 46 and the surface of the fin is 60°, the angle between the other two side surfaces and the surface of the fin is 45°, the length of the bottom surface along the width direction of the fin is 4.0mm, and the arc of the bottom surface is 4.0 mm. The radius of the wire is 9.0mm. The vertical height of the folding structure 2 is 0.3mm, the slope is 20°, and the distance between the lower edge of the slope and the edge of the fin is 1.0mm.

ANSYS FLUENT software is used to numerically calculate the flow heat transfer performance of this embodiment and the folded straight fins that have been used in the industry. The calculation conditions are as follows: the air velocity is 1.597m/s, the inlet temperature is 308K, and the wall temperature of the heat exchange tube is 318.5K. The SST kw model of steady state and constant physical properties is adopted. The governing equations are discretized by the finite volume method, and the SIMPLE algorithm is used for the coupling of pressure and velocity. The simulation considers the influence of the thickness of the fin, the wall of the heat exchange fin is a velocity-free solid boundary, and the surface temperature of the fin is calculated by the fluid-solid heat transfer coupling. For the momentum and energy equations, the diffusion term uses the central difference format, and the convection term uses the second-order upwind difference format. The numerical results are considered convergent when the residuals of the continuity equation, momentum equation and energy equation are all below 10 ^-6 .

By extracting the pressure and temperature at the inlet and outlet of the calculation area, the heat exchange and pressure drop of different fins can be calculated, and the change of heat exchange under the same power can be obtained by considering the pressure drop lost by the fan itself. The data calculation results show that compared with the folded and straight fins that have been used in the industry, the heat transfer coefficient of this embodiment is greatly improved, and the heat transfer is increased by 9.3% under the same power condition, which can ensure that the window is not opened and In the case of slitting, the overall performance is significantly improved.

Claims (2)

1. A high-strength heat exchange fin using two-way discrete protrusions, comprising a fin base (1), and a heat exchange tube hole (7) for the heat exchange tube to pass through on the fin base (1). The fin base (1) is provided with a bidirectional discrete convex structure surrounding the heat exchange tube hole (7), characterized in that: the bidirectional discrete convex structure includes several sections of protrusions symmetrical about the center of the heat exchange tube hole (7). Structure one (3) and convex structure two (4), as well as convex structure three (5) and convex structure four (6) located between adjacent heat exchange tube holes (7), wherein convex structure one (3) The second raised structure (4), the third raised structure (5), and the fourth raised structure (6) are all located on the fin base (1) and are not connected to each other, and the fin base (1) is Straight structure, the heat exchange tube holes (7) are located on a symmetrical line in the width direction of the fin base (1), the bidirectionally discrete raised high-strength heat exchange fins are symmetrical fins, and the fin base (1) A folding structure (2) is arranged on both sides of the long side, the height of the raised structure one (3) is 0.5-1.0mm, the bottom is a right-angled trapezoid, the length of the bottom is 1.5-2.5mm, and the height of the bottom is 1.5 mm. ～3.0mm, the bottom angle is 60～70°; the height of the second raised structure (4) is 0.5～1.0mm, the inner radius of the bottom surface is 5.6mm, the outer radius is 7.0～8.0mm, the two raised The angle between the arc surface and the surface of the fin is 45-60°, and the angle between the other two side surfaces and the surface of the fin is 30-45°; the height of the raised structure three (5) is 0.5-1.0mm, The bottom surface is an isosceles trapezoid, the length of the top side is 1.5~3.0mm, the length of the bottom side is 2.5~4.0mm, and the height of the bottom surface is 2.5~3.5mm. The angle between the other two sides and the surface of the fin is 45-60°; the height of the raised structure four (6) is 0.5-1.0mm, and the two arc surfaces and the surface of the fin are clamped. The angle is 45-60°, the angle between the other two sides and the surface of the fin is 30-45°, the length of the bottom surface along the width direction of the fin is 2.5-4.0mm, and the radius of the arc of the bottom surface is 8.5-9.5mm. The convex structure one (3) and the convex structure four (6) have the same convex direction, and are opposite to the convex structure two (4) and the convex structure three (5) in the opposite direction. For the same heat exchange tube The convex structure one (3) and convex structure two (4) of each section with symmetrical center of the hole (7) are located on the same circumference, and the convex structure four (6) are arranged on the adjacent heat exchange tube holes (7). On the connection line, there are a plurality of raised structures three (5), which are symmetrically arranged along the connection line of the adjacent heat exchange tube holes (7), and the raised structures three (5) and the raised structures four (6) are both located in the connecting line. outside the circumference. 2 . The high-strength heat exchange fin using bidirectional discrete protrusions according to claim 1 , wherein the fin base body ( 1 ) has a thickness of 0.09-0.11 mm and a width of 18.19-21.65 mm; adjacent fins The spacing between the sheet bases (1) is 1.3-1.6 mm; the diameter of the heat exchange tubes is 7 mm or 7.94 mm; the hole spacing between adjacent heat-exchanging tube holes (7) is 21-23 mm.

Images