Outer curved V-shaped air-cooled finned tube heat exchanger structure

Abstract

The invention discloses an outwards-bent V-shaped air-cooled finned tube heat exchanger structure which comprises outwards-bent V-shaped air-cooled finned tubes symmetrically arranged on the two sides, fans are arranged at upper air openings of the symmetrically-arranged outwards-bent V-shaped air-cooled finned tubes, and an internal air space and an external air space are formed; according to the outwards-bent V-shaped air cooling finned tube structure, the connecting lines of the upper side fixing points and the lower side fixing points of the heat exchangers are bent outwards to form circumscribed circular arc lines, and the included angle theta between the connecting lines of the upper side fixing points and the lower side fixing points of the two heat exchangers is larger than 49 degrees and smaller than 90 degrees. And the curvature radius of the circumcircle is 0.71-1.2 times of the length of the connecting line of the fixed points on the upper side and the lower side. The heat exchange area of the heat exchanger is increased, heat transfer uniformity of the air side of the heat exchanger is facilitated, and the overall heat exchange uniformity of the heat exchanger is greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of refrigeration, air conditioning, heat pump and special environment control system, and particularly relates to an outward curved V-shaped air-cooled fin tube heat exchanger structure. Background Art

[0002] V-shaped air-cooled fin-tube heat exchangers are widely used in environmental control applications such as refrigeration, air conditioning, and heat pumps. Due to its compact structure and small footprint, it has great advantages in limited space applications; at the same time, by optimizing the fin arrangement and pipeline layout, the maximum heat exchange effect can be achieved in a limited space. In particular, the V-shaped air-cooled fin-tube heat exchanger can be set to be mobile, which greatly facilitates the installation and operability of the equipment.

[0003] At present, V-shaped air-cooled fin-tube heat exchangers are mainly designed as outdoor condensers, and all of them are straight V-shaped structures. For example, patents "A V-shaped condenser" (CN202321420373.5), (CN202321420373.5) and (CN201921671410.3), "Air conditioning unit" (CN202410531951.5), "A compact V-shaped condenser" (CN202222902568.5), "V-shaped condenser with fixed condensing pressure control" (CN202221966466.3), "A V-shaped arrangement structure of an aircraft ground air conditioning unit condenser" (CN202221506052.2), "Condenser group and temperature control device" (CN202221309017.1), "A V-shaped condenser with adjustable air volume" (CN202221309017.1), "A V-shaped condenser with adjustable air volume" (CN202221309017.1). Condenser" (CN202022369446.5), "A new box-type compression condensing unit" (CN202021951372.X), "A new V-type box-type compression condensing machine" (CN202021951371.5), patent "A chiller with a V-type condenser" (CN202021842939.X), "A parallel V-type condensing unit" (CN201720227130.8), "Cabinet V-type condenser" (CN201621082365.4), "A wind-cooled machine room air conditioner outdoor unit" (CN201620062218.4), "A new type of cold dryer" (CN201020126971.8).

[0004] The core indicator for evaluating V-type air-cooled fin-tube heat exchangers is their comprehensive heat exchange performance, which mainly includes heat exchange efficiency and air flow loss. The current V-type air-cooled fin-tube heat exchanger structures are all arranged in a straight V shape. The disadvantage of this arrangement is that the air flow trace direction between the fins forms a certain angle with the vertical air flow trace direction of the fan (this angle is exactly the angle between the V-type heat exchanger and the horizontal plane). This air flow with an angle increases the flow resistance on the air side of the heat exchanger. At the same time, the wind speed between the fins close to the fan is higher, and the wind speed between the fins far from the fan is lower, resulting in uneven air volume in the heat exchanger; at the same time, since the heat exchange efficiency on the air side is generally low, increasing the heat exchange area on the air side is one of the effective ways to improve the heat exchanger.

[0005] Based on the above analysis of the heat transfer efficiency and air flow resistance of the V-shaped air-cooled fin-tube heat exchanger structure, the currently common straight V-shaped air-cooled fin-tube heat exchanger structures all have the above two problems.

[0006] Therefore, increasing the heat exchanger area, reducing air flow resistance and improving the uniformity of air flow velocity between fins are the design focuses of the V-type air-cooled fin-tube heat exchanger structure. Summary of the invention

[0007] In order to solve the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide an outward curved V-shaped air-cooled fin tube heat exchanger structure, which has the characteristics of compact system, increased heat exchanger area, reduced air flow resistance and improved heat exchanger wind speed uniformity.

[0008] The present invention is achieved through the following technical solutions.

[0009] In one aspect of the present invention, there is provided an outwardly curved V-shaped air-cooled fin tube heat exchanger structure, characterized in that it comprises outwardly curved V-shaped air-cooled fin tubes symmetrically arranged on both sides, and a fan is arranged at the upper air outlet of the symmetrically arranged outwardly curved V-shaped air-cooled fin tubes to form an internal air space and an external air space;

[0010] The outward curved V-shaped air-cooled fin tube structure is bent outwardly to form an arc line of a circumscribed circle by connecting the upper fixed point and the lower fixed point of the heat exchanger. The length L' of the arc line satisfies:

[0011]

[0012] Where R is the radius of the circumscribed circle, L is the length of the straight section of the V-shaped air-cooled fin tube, and θ is the corresponding angle between the lines connecting the upper and lower fixed points of the two heat exchangers.

[0013] Preferably, the angle θ between the lines connecting the upper fixing points and the lower fixing points of the two heat exchangers satisfies: 49°<θ<90°.

[0014] Preferably, the radius of curvature of the circumscribed circle is 0.71 to 1.2 times the length of the line connecting the upper and lower fixed points.

[0015] Preferably, the outwardly curved V-shaped air-cooled finned tube is provided with fins, which are arranged in the middle of the tube and are evenly arranged perpendicular to the tube.

[0016] Preferably, the tubes and fins of the air-cooled finned tubes are made of carbon steel, copper, aluminum metal or stainless steel alloy material.

[0017] The present invention adopts the above technical solution, which has the following beneficial effects:

[0018] Compared with the prior art, the present invention proposes an outward-curved V-shaped air-cooled fin-tube heat exchanger structure from the perspective of system compactness, increasing the heat exchanger area, reducing the air flow resistance on the air side of the heat exchanger, and improving the uniformity of the wind speed of the heat exchanger. Compared with the traditional straight V-shaped heat exchanger, first, the longitudinal length of the heat exchanger is increased, the number of fins is increased, and the heat exchange area of ​​the heat exchanger is increased; second, the air volume space surrounded by the V-shaped heat exchanger is increased, which is conducive to the uniformity of heat transfer on the air side of the heat exchanger; third, the outward-curved design adjusts the angle between the air flow traces between the fins at the near and far ends of the fan and the vertical air flow traces of the fan, so that the wind speed on the air side of the entire heat exchanger is more uniform, and the overall heat exchange uniformity of the heat exchanger is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 It is a straight V-shaped air-cooled fin tube heat exchanger structure;

[0022] FIG3(a) is a schematic longitudinal cross-sectional view of an outward curved V-shaped air-cooled fin-tube heat exchanger, and FIG3(b) is a geometric relationship diagram of the design and calculation of the curvature radius of the outward curved shape;

[0023] Figure 4 It is a schematic diagram of the angle between the air flow trace between the fins of the outward curved V-shaped air-cooled fin-tube heat exchanger and the vertical direction;

[0024] FIG5(a) is a three-dimensional schematic diagram of a straight V-shaped air-cooled fin-tube heat exchanger structure, and FIG5(b) is a three-dimensional schematic diagram of an outward curved V-shaped air-cooled fin-tube heat exchanger structure (θ=90°);

[0025] Figure 6 (a) and (b) show the increase in the number of fins and the increase in heat exchange area when 49°<θ<90°;

[0026] Figure 7 It is the increase in the air volume space enclosed by the outer curved V-shaped heat exchanger when 49°<θ<90°.

[0027] In the figure: 1. fan; 2. outward curved V-shaped air-cooled fin tube; 3. external air space; 4. internal air space. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0029] Reference Figure 1 As shown, the present invention shows an outward-curved V-shaped air-cooled fin tube heat exchanger structure, including outward-curved V-shaped air-cooled fin tubes 2 symmetrically arranged on both sides, the outward-curved V-shaped air-cooled fin tubes are outwardly curved along the line connecting the upper and lower fixed points, and the fan 1 is arranged at the upper air outlet of the symmetrically arranged outward-curved V-shaped air-cooled fin tubes 2, forming an internal air space 4 and an external air space 3.

[0030] The outward curved V-shaped air-cooled finned tube is in the vertical section of the V-shaped heat exchanger. The arc line of the circumscribed circle is based on the line connecting the upper fixed point and the lower fixed point of the heat exchanger. The curvature radius of the arc line is the radius of the circumscribed circle.

[0031] The fins arranged on the outward curved V-shaped air-cooled fin tube are arranged in the middle along the direction of the tube, the fins are perpendicular to the tube, and the fins are evenly arranged along the direction of the tube.

[0032] The tubes and fins of the air-cooled finned tubes are made of carbon steel, copper, aluminum metal or stainless steel alloy materials.

[0033] The fan 1 can adopt an upward suction or downward sweep operation mode.

[0034] by Figure 2 The straight V-shaped air-cooled fin tube heat exchanger structure shown is used as a basis and reference, and the straight line segment AB of the upper fixed point A and the lower fixed point B of the heat exchanger is used as a benchmark to design and construct a circumscribed circle of the straight line segment AB, whose radius of curvature is 0.71 to 1.2 times the length of the line connecting the upper and lower fixed points.

[0035] The angle θ between the circumscribed circle radii OA and OB satisfies: 49°<θ<90°. The arc segments A'B' are determined accordingly, and the outward curved V-shaped air-cooled fin tube heat exchanger structure can be designed based on them. The outward curved V-shaped air-cooled fin tube heat exchanger structure that meets the above design conditions can be easily installed on the upper and lower sides, and can also avoid interference with the side in the vertical direction.

[0036] Figure 3(a) is a schematic longitudinal cross-section of an outward-curved V-shaped air-cooled fin-tube heat exchanger, and Figure 3(b) is a geometric relationship diagram of the design and calculation of the curvature radius of the outward curvature. Among them, the straight line segment AB refers to the line connecting the upper and lower fixed points of the heat exchanger, and its length is L. The length of the arc segment A'B' is L', which is the circumscribed arc of the straight line segment AB, and its curvature radius is the radius R of the circumscribed circle. In the figure, O is the center of the circumscribed circle, and θ is the angle between the circumscribed circle radii OA and OB.

[0037] Specifically, the length L of the straight line segment AB is taken as a reference, and θ is taken as an independent variable to determine the curvature radius R of the outer curved line. The curvature radius of the outer curved line meets the requirements of formula (1):

[0038]

[0039] The length of arc segment A'B' is L', and the calculation formula (2) is as follows:

[0040]

[0041] The length L' of the arc segment A'B' is increased by ΔL compared to the length L of the straight line segment AB as shown in formula (3), where θ is radians:

[0042]

[0043] To ensure that the installation of the externally curved heat exchanger formed by the arc segment A'B' does not interfere with the upper and lower sides and the vertical side, the tangent direction of the arc segment A' end is vertical, and the tangent direction of the B' end is horizontal. At this time, θ = 90°, which is the maximum curvature of the external curve. In other words, the design angle of θ must satisfy: θ < 90°.

[0044] In addition, if the curvature of the arc segment A'B' is too small, the aforementioned advantage of increasing the heat exchanger area will be lost. Therefore, the design angle of θ must also satisfy: θ>49°.

[0045] The area F of a traditional air-cooled fin-tube heat exchanger consists of two parts: the heat exchange area of ​​the exposed tube part and the expanded area of ​​the fin part, which is calculated according to formula (4).

[0046] Heat exchange area F = (H × S + n × D × L) × N (4)

[0047] Where: H is the fin height, S is the fin spacing, n is the number of tube rows, D is the tube outer diameter, L is the tube length (L' for external curvature), and N is the number of fins (N = L / S).

[0048] When the angle θ satisfies 49°<θ<90°, the arc segment length L' is calculated according to formula (2), and the increase in tube length ΔL is calculated according to formula (3). Based on this, under the same fin spacing, the number of fins of the outward curved V-shaped N'=L' / S, and the number of fins that can be increased is ΔL / S.

[0049] The increased heat exchange area ΔF of the outer curved V-shape is calculated according to formula (5).

[0050] ΔF=F(external curved type)-F(straight type)(5)

[0051] According to formula (2) and formula (4), when the angle θ satisfies 49°<θ<90°, the area increase rate of the external curved V-shaped air-cooled fin tube heat exchanger is calculated according to formula (6):

[0052] ΔF / F(linear) = [F(external curvature) - F(linear)] / F(linear) (6)

[0053] The present invention is further illustrated by means of specific examples below.

[0054] Based on the traditional 35.9kW×2 straight V-shaped air-cooled fin-tube heat exchanger, due to the bilateral symmetrical arrangement, the structural dimensions of the single-sided air-cooled fin-tube heat exchanger are: fin spacing S = 2.5mm, fin height H = 121.2mm, tube row number n = 4, tube outer diameter D = 16mm. Assuming that the tube length L is unit length 1, when the angle θ satisfies 49°<θ<90°, according to formula (3), the increase in the arc segment length L' compared to the straight segment length L is ΔL = (0.031L~0.11L), where 0.031L corresponds to θ = 49° and 0.11L corresponds to θ = 90°. At the same fin spacing S = 2.5mm, the number of fins that can be increased is ΔL / (2.5 / 1000) = (0.031 ~ 0.11) × L / (2.5 / 1000) = (12 ~ 44) fins, and (24 ~ 88) fins can be added on both sides. The area increase rate of the external curved V-shaped air-cooled fin tube heat exchanger is 3.7% ~ 13.2% (where 3.7% corresponds to θ = 49°, and 13.2% corresponds to θ = 90°). Due to the symmetrical arrangement on both sides, the total area increase rate is 7.4% ~ 26.4%. Therefore, due to the increase in the longitudinal length of the heat exchanger and the increase in the number of fins, the heat exchange area of ​​the heat exchanger is greatly improved. As shown in Figures 6(a) and (b).

[0055] Secondly, it can be seen from Figure 3(a) and Figure 3(b) that the air volume space enclosed by the outer curved V-shaped heat exchanger increases. From the longitudinal cross-sectional diagram of Figure 3(a), the increased cross-sectional area is the area enclosed by the arc length L' and the straight line L, and its area is calculated by formula (7):

[0056]

[0057] When 49°<θ<90°, the range of cross-sectional area increase is (0.146×L 2 ~0.285×L 2 ), therefore, the increase in the cross-sectional area of ​​the air surrounded by the outer curved V-shaped heat exchanger increases, and accordingly, the volume of the air surrounded by it increases, which is beneficial to the uniformity of heat transfer on the air side of the heat exchanger. Figure 7 shown.

[0058] Finally, if Figure 4 As shown in the figure, the angle between the air flow trace between the fins of the traditional straight V-shaped air-cooled fin-tube heat exchanger and the vertical direction is the same, which is α. At this time, the wind speed between the fins close to the fan is larger, and the wind speed between the fins far from the fan is smaller, resulting in uneven air volume of the heat exchanger; while the angle between the air flow trace between the fins of the outward curved V-shaped air-cooled fin-tube heat exchanger and the vertical direction is β1<α below the center point of the arc L', which is conducive to increasing the air flow rate at the far end of the fan, and the angle β2>α above the center point of the arc L', which suppresses the air flow rate at the near end of the fan, thus greatly improving the heat exchange uniformity of the air side of the entire heat exchanger from a structural perspective.

[0059] The outward-curved V-shaped air-cooled fin-tube heat exchanger structure designed in the present invention increases the heat exchange area of ​​the heat exchanger, reduces the angle between the air flow trajectory between the fins at the far end of the fan and the vertical air flow trajectory of the fan, reduces the air flow resistance at the far end of the fan, and greatly improves the heat exchange uniformity on the air side of the entire heat exchanger.

[0060] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solution disclosed in the present invention, technicians in this field can make some substitutions and deformations to some technical features therein according to the disclosed technical content without creative labor, and these substitutions and deformations are all within the protection scope of the present invention.

Claims

1. An outward curved V-shaped air-cooled fin tube heat exchanger structure, characterized in that: It includes outward-curved V-shaped air-cooling fin tubes symmetrically arranged on both sides, and fans are arranged at the upper air ports of the symmetrically arranged outward-curved V-shaped air-cooling fin tubes, thereby forming an internal air space and an external air space; The outward curved V-shaped air-cooled fin tube structure is bent outwardly to form an arc line of a circumscribed circle by connecting the upper fixed point and the lower fixed point of the heat exchanger. The length of the arc line L' satisfies: Where R is the radius of the circumscribed circle, L is the length of the straight section of the V-shaped air-cooled fin tube, and θ is the angle corresponding to the line connecting the upper and lower fixed points of the two heat exchangers.

2. The outward curved V-shaped air-cooled fin tube heat exchanger structure according to claim 1, characterized in that: The angle θ corresponding to the line connecting the upper fixed point and the lower fixed point of the two heat exchangers satisfies: 49°<θ<90°.

3. The outward curved V-shaped air-cooled fin tube heat exchanger structure according to claim 1, characterized in that: The radius of curvature of the circumscribed circle is 0.71 to 1.2 times the length of the line connecting the upper and lower fixed points.

4. The outward curved V-shaped air-cooled fin tube heat exchanger structure according to claim 1, characterized in that: The length of the arc segment L' is greater than the length of the straight line segment L by an amount ΔL that satisfies: Wherein, θ is the angle corresponding to the line connecting the upper fixed point and the lower fixed point of the two heat exchangers.

5. The outward curved V-shaped air-cooled fin tube heat exchanger structure according to claim 1, characterized in that: The area of ​​the internal air space is calculated by the following formula: Among them, R is the radius of the circumscribed circle, ΔS is the area of ​​the internal air space, θ is the angle corresponding to the line connecting the upper fixed point and the lower fixed point of the two heat exchangers, and L is the length of the straight section of the V-shaped air-cooled fin tube.

6. The outward curved V-shaped air-cooled fin tube heat exchanger structure according to claim 1, characterized in that: The outward-curved V-shaped air-cooled finned tube is provided with fins, which are arranged in the middle along the direction of the tube, and the fins are evenly arranged vertically to the tube.

7. The outward curved V-shaped air-cooled fin tube heat exchanger structure according to claim 1, characterized in that: The tubes and fins of the air-cooled finned tubes are made of carbon steel, copper, aluminum metal or stainless steel alloy material.

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