A torsionally stiff heat exchange structure

Abstract

The application discloses a twisted heat exchange structure, which is arranged in a channel, is a twisted structure, is arranged transversely along the width direction of the channel, and has a middle slice directly facing a flow direction. Each transverse slice is a low-resistance airfoil along the height direction, and adjacent airfoils are twisted by a certain angle around a twist center line. The size and quantity of the structure in the channel are determined according to the channel size. Through the twisted structure, a longitudinal vortex can be formed in the channel, the thermal boundary layer of fluid in the channel is destroyed, and the fluid in the center is guided to the edge of the channel. The flow control structure can be applied to a heat exchange process, can significantly improve the heat exchange capacity of the channel under the condition that the flow resistance is slightly increased, and can greatly improve the temperature uniformity of the heat exchange surface of the channel, thereby reducing the equipment volume and improving the economy, safety and reliability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of heat exchange in the industries of energy power, petroleum chemical industry, transportation and aerospace, and particularly relates to a twisted heat exchange structure. BACKGROUND

[0002] Many industrial fields, such as energy, transportation, microelectronics, chemical industry, spacecraft thermal control and manufacturing industry, are related to energy transfer process, in which heat exchange equipment plays a very key role. With the rapid development of science and technology and the increasing energy problem, the load of heat exchange equipment gradually increases, and higher requirements are put forward for the system efficiency, so that the heat exchange enhancement technology is paid more and more attention by the academic and engineering circles.

[0003] The heat exchange enhancement using flow control structures, such as ball socket, ball convex, fin and the like, has been widely studied and applied, and is an effective heat exchange enhancement technology. The flow control structure is arranged on the inner side or outer side of the channel in a certain rule, which will destroy the flow boundary layer when the fluid flows through the channel, avoid the further thickening of the flow boundary layer, destroy the thermal boundary layer, promote the energy exchange between the main flow and the fluid near the wall, and then improve the coordination of velocity and temperature gradient in the heat flow field, so that the heat exchange process is enhanced.

[0004] However, on the other hand, due to the introduction of the flow control structure, the flow resistance in the channel will increase sharply during the heat exchange enhancement. How to improve the heat exchange performance while keeping the flow resistance increase small is the key to greatly improve the comprehensive heat exchange efficiency of the heat exchange process.

[0005] Further, uniformity is an important parameter for heat exchange equipment, and too large temperature difference will cause instability of the equipment and produce thermal stress to cause physical damage of the equipment, and the current heat exchange enhancement structure cannot well solve the problem of poor uniformity of the channel heat exchange surface. SUMMARY

[0006] The present application aims to overcome the above-mentioned shortcomings of the prior art, and provides a twisted heat exchange structure to solve the problem that high heat exchange performance and low resistance are difficult to be considered together and the temperature difference on the channel heat exchange wall is large in the prior art.

[0007] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0008] A twisted heat exchange structure,

[0009] The twisted structure is composed of a large number of slices stacked by rotating around a twist center line; the twist center line intersects with the camber line of each slice; the slice is a low-resistance airfoil; and the twist center line is perpendicular to the slice.

[0010] The angle between the camber line of each slice and the camber line of the upper adjacent slice is α, and the angle between the camber line of each slice and the camber line of the lower adjacent slice is -α along the height direction of the twisted structure;

[0011] The twisted structure is arranged in a channel.

[0012] The further improvement of the present application is that:

[0013] Preferably, the slice in the middle of the height direction of the twisted structure is a middle slice; the tangent line of the camber line of the middle slice at the leading edge of the middle slice is parallel to the outer normal line of the channel inlet slice.

[0014] Preferably, the twist center line of the twisted structure is composed of the center point of each slice, and the center point is the intersection of the camber line and the perpendicular bisector of the chord.

[0015] Preferably, the upper end surface of the twisted structure is a top slice, and the lower end surface is a bottom slice, and the angle between the top slice and the bottom slice is The angle The plane located at is perpendicular to the twist center line; the The value range of is

[0016] Preferably, the wing type size and type of the adjacent slices are the same.

[0017] Preferably, all the twisted structures arranged in a row along the channel transverse direction in the channel are a feature unit, and the feature units are arranged in an array along the flow direction of the channel.

[0018] Preferably, when the number of twisted structures in a feature unit is odd, a twisted structure is arranged at the middle position in the channel transverse direction, and the remaining twisted structures are symmetrically arranged relative to the middle twisted structure.

[0019] Preferably, when the number of twisted structures in a feature unit is even, all the twisted structures are symmetrically arranged relative to the middle position in the channel transverse direction.

[0020] Preferably, 0.4

[0021] Wherein, H is the height of the channel, L is the length of a feature unit of the channel, W is the width of a feature unit of the channel; h is the height of the twisted structure, l is the length of the twisted structure, w1 is the width of the twisted structure, w2 is the distance between adjacent twisted structures, and w3 is the distance between the edge twisted structure and its adjacent wall surface.

[0022] Preferably, the number of twist structures in the same feature unit is n, then nw1+2w3+(n-1)w2=W.

[0023] Compared with the prior art, the application has the following beneficial effects:

[0024] The application discloses a twist-strengthened heat exchange structure, which is arranged in a channel and is a twist structure. The twist structure is formed by stacking a large number of slices around a twist center line. In the height direction, each slice is a low-resistance airfoil, and adjacent airfoils are twisted by a certain angle. The twist center line intersects with a camber line of each slice and is perpendicular to each slice. The twist structure is arranged in the channel, and the size and number of the structure are determined according to the size of the channel. Through the twist structure, the thermal boundary layer of fluid in the channel can be destroyed, and the fluid in the center can be guided to the edge of the channel. The flow control structure can be applied to the process of strengthening heat exchange. When fluid flows through the flow control structure, the fluid is affected by the twist body, and two front and rear vortexes are formed around the structure, so that the fluid near the wall and the cooling fluid in the middle of the channel are fully mixed, and the fluid is guided to the side of the channel. The uniformity of the heat exchange surface of the whole channel is greatly improved, and the heat exchange performance is also greatly improved. In the case of small increase in flow resistance, the channel heat exchange capacity can be significantly improved, especially the uniformity of the channel heat exchange surface is greatly improved, so that the equipment volume is reduced, and the economy, safety and reliability are improved. The application first applies the low-resistance airfoil to the field of strengthening heat exchange, and first combines the airfoil and the twist feature and applies them to the field of strengthening heat exchange, thereby providing a new idea for the design of low-resistance heat exchange structure.

[0025] Further, the twist structure is arranged transversely along the incoming slice, and the middle slice faces the incoming direction. The arrangement can achieve the best disturbance effect and heat exchange effect.

[0026] Further, the whole twist structure is located at the center of the channel in the height direction, so that the heat exchange effect can be better strengthened.

[0027] Further, the included angle between the top slice and the bottom slice in the twist structure is limited, that is, the twist angle of the whole twist structure is limited. The twist structure in the twist angle range has better heat exchange effect, and the fluid resistance is not increased too much.

[0028] Further, the contour of each slice in the twist structure is a low-resistance airfoil, which has a streamline structure and smaller flow resistance compared with other flow control structures. The size and type of the low-resistance airfoil of each slice can be the same or different. Preferably, the type is the same, so that the twist structure is easier to manufacture.

[0029] Furthermore, the torsional structure of the present invention is applicable to channels of various sizes, and each characteristic unit in the channel can be arranged according to needs; more specifically, the characteristic units can be arranged in an array, or each characteristic unit can be arranged in a targeted manner according to the flow field conditions in the channel.

[0030] Furthermore, the torsional structures are symmetrically arranged in the characteristic units to achieve a uniform enhanced heat exchange effect.

[0031] Furthermore, in the present invention, due to the introduction of the torsion structure, the effective area of ​​heat exchange between the channel and the fluid is increased, further improving the heat exchange effect.

[0032] Furthermore, the present invention relies on mainstream energy for regulation and control, and does not require the introduction of additional energy input into the system, thereby not increasing the complexity of system control. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of a characteristic unit with an odd number of twisted structures arranged inside a rectangular channel;

[0034] Figure 2 are the xoy plane view and yoz plane view of the characteristic unit of the odd number of torsion structures;

[0035] Figure 3 are the xoy plane view and yoz plane view of the characteristic unit of the even number of torsion structures;

[0036] Figure 4 It is a schematic diagram of a single torsion structure;

[0037] Figure 5 It is a schematic diagram of the array of all characteristic units along the flow direction;

[0038] Figure 6 It is a schematic diagram of the personalized arrangement of characteristic units along the flow direction;

[0039] Figure 7 The temperature nephograms before and after the torsion structure is arranged in the embodiment are compared, wherein (a) is before the arrangement, and (b) is after the arrangement;

[0040] Figure numerals: 1, channel; 2, bottom slice; 3, torsion structure; 4, top slice; 5, middle slice; 6, slice; 7, leading edge; 8, trailing edge; 9, characteristic unit. DETAILED DESCRIPTION

[0041] The present invention is described in further detail below with reference to the accompanying drawings:

[0042] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application; the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance; in addition, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] One embodiment of the present application discloses a twist-strengthened heat exchange structure, the twist structure 3 is formed by stacking a plurality of slices 6 around a twist center line, each slice is a low-resistance airfoil (an airfoil with a smaller resistance coefficient when Re is less than 1800). Each slice 6 comprises a leading edge 7 and a trailing edge 8, and the corresponding twist structure 3 has a front end and a rear end, the upper end surface of the twist structure 3 is a top slice 4, and the lower end surface is a bottom slice 2. The twist center line of the twist structure intersects the camber line of the airfoil of each slice 6 and is perpendicular to each slice.

[0044] Specifically, the adjacent slices 6 in the twist structure 3 along the height direction are twisted by a certain angle, and the angle is α. Specifically, the included angle between the camber line of the airfoil of each slice 6 and the camber line of the airfoil of the adjacent upper slice 6 is α, the included angle between the camber line of the airfoil of each slice 6 and the camber line of the airfoil of the adjacent lower slice 6 is -α, and α tends to 0; therefore the twist structure 3 is a structure composed of a plurality of slices 6.

[0045] More specifically, the middle slice 5 of the twist structure 3 is located at the middle of the height of the twist structure 3, and all the slices 6 above the middle slice 5 of the twist structure 3 are twisted in the same direction in sequence; the slices 6 below the middle slice 5 of the twist structure 3 are twisted in the opposite direction of the upper slices 6 in sequence. All the slices 6 are twisted around the twist center line.

[0046] Preferably, the middle slice 5 is taken as a reference, and all the slices 6 above the middle slice 5 are twisted uniformly in the counterclockwise direction, a total of all the slices 6 below the middle slice 5 are twisted uniformly in the clockwise direction, a total of The twist angle between the bottom slice 2 of the twist structure and the top slice 4 of the twist structure is That is, the twist angle of the twist structure is The rotation angle a between all the slices 6 is based on the twist center line, which is perpendicular to the plane of the twist structure 3.

[0047] Further, the twist angle a or -a of the adjacent slices 6 in the same twist structure 3 can be changed according to the heat exchange requirement in the channel 1, in which case the upper part and the lower part of the same twist structure 3 can be asymmetric, and the twist angle a or -a of the adjacent slices 6 in the upper part or the lower part can also be different. Preferably, the twist angle in the same twist structure 3 is a constant value, i.e. the upper part and the lower part of the twist structure 3 divided by the middle slice 5 are symmetric. The range of a is 0° < a < 10°; preferably, the range of a is 0° < a < 1°, and more preferably, the range of a is 0° < a < 0.1°.

[0048] Further, the airfoil size and type of each slice 6 in the height direction of each twist structure can be different, and the airfoil size can be adjusted according to the heat exchange and resistance requirement of the channel 1. Preferably, the airfoil size and type are the same, which makes the processing and manufacturing process easier and more accurate.

[0049] One of the embodiments of the present application discloses the arrangement of the above twist structure in the channel 1, and the twist structure 3 is arranged in the channel 1, and the cross section of the channel 1 can be rectangular, trapezoidal, triangular or circular. Referring to Figure 1 The twist structure 3 is arranged on the heat exchange surface of the channel 1, which is perpendicular to the flow direction and arranged transversely, and the middle slice 5 is directly opposite to the flow direction, i.e. the camber line of the airfoil of the middle slice 5 is parallel to the tangent line of the leading edge point and the outer normal line of the inlet slice of the channel 1.

[0050] As one of the preferred schemes, the whole twist structure 3 is located at the middle position of the height direction (or the radial direction) of the channel 1, which is equal to the distance from the upper and lower walls.

[0051] One of the embodiments of the present application discloses the arrangement of the above twist structure in the channel 1, and the fluid flow direction of the channel 1 is set as the x direction, the width direction of the channel 1 is set as the y direction, and the height direction of the channel 1 is set as the z direction. Referring to Figure 2 and Figure 3 The height of the channel 1 is H, and the width of the channel 1 is W.

[0052] Referring to Figure 5 and Figure 6, the twisted structure 3 is arranged transversely along the width direction of the channel 1 in the channel 1 as a feature unit 9, the feature unit 9 is arranged along the flow direction of the channel 1 in the channel 1. The feature units 9 can be arrayed in the channel 1, the distance between adjacent feature units 9 can also be unequal, and different feature units can also be individually designed, and the specific arrangement is adjusted according to requirements. Further, in the same channel 1, the distance and arrangement of adjacent twisted structures 3 in different feature units 9, and the structure and size of the twisted structure 3 itself can be adjusted according to requirements. The above requirements are the flow and heat exchange of the fluid in the channel 1.

[0053] Further, the maximum length of the projection of a single structure of the twisted structure 3 in the x direction (water flow direction) in the xoy plane parallel to the main flow direction is the length l of the twisted structure 3; the maximum width of the projection of the twisted structure 3 in the y direction in the yoz plane perpendicular to the main flow direction is the width w1 of the twisted structure. The minimum distance between two twisted structures 3 in the y direction in the yoz plane perpendicular to the main flow direction is the distance w2 between the twisted structure 3 and the twisted structure 3. The minimum distance in the y direction between the projection of the twisted structure 3 close to the wall surface in the yoz plane perpendicular to the main flow direction and the wall surface is the distance w3 between the twisted structure 3 and the left and right wall surfaces.

[0054] Preferably, the size of the twisted structure 3 can be adjusted according to the size of the channel 1, and the specific relationship is: 0.4

[0055] Preferably, in the same twisted unit, the number of the twisted structures 3 is n, which satisfies the relationship n w1+2 w3+(n-1) w2=W.

[0056] Preferably, referring to Figure 2 , when the number n of the twisted structures 3 is odd, one twisted structure 3 is arranged at the transverse middle position of the channel 1, and the remaining twisted structures 3 are symmetrically arranged on both sides of the middle twisted structure 3, and the edge distance between any two adjacent twisted structures 3 is w2. For the two twisted structures close to the left and right side walls of the channel, the trailing edge of the top slice 4 of the twisted structure is biased to the left and right side walls of the channel with the worst heat exchange effect, and the trailing edge of the bottom slice 2 of the twisted structure is biased to the middle of the channel.

[0057] Preferably, referring to Figure 3When the number n of torsional structures 3 is even, all torsional structures 3 are symmetrically arranged along the transverse center of the channel. The distance between the two torsional structures 3 near the transverse center section of channel 1 and the transverse center section of channel 1 is w2 / 2. Unlike traditional torsional structures, which primarily focus on improving overall thermal performance, these torsional structures are designed with improving channel temperature uniformity as a key consideration, utilizing low-resistance torsional structures to enhance disturbance and flow diversion.

[0058] Each slice of the twisted structure has a low-drag airfoil profile, resulting in a streamlined structure and low drag. By twisting the structure at a certain angle, it enhances fluid turbulence and directs the fluid in the middle of the channel toward the wall, where heat transfer is less effective. This twisted structure not only controls flow but also dissipates heat, increasing the effective heat transfer area. The size and number of twisted structures can be adjusted to suit the channel dimensions.

[0059] The design method of the present invention comprises the following steps:

[0060] First, based on computational fluid dynamics simulations combined with experimental measurements, the flow structure of the unstructured flow field and its variation with boundary conditions are analyzed under boundary conditions comparable to those in actual applications. The focus is on capturing areas with weak heat transfer within the flow field, and a surface heat transfer coefficient distribution map is also obtained.

[0061] Next, based on the surface heat transfer coefficient distribution map, we preliminarily determined the layout, size, and number of torsional structures to enhance areas of weak heat transfer. Furthermore, we needed to utilize parameter optimization design methods to determine the optimal size, number, and location of the torsional structures, with the goal of ensuring heat transfer efficiency and improving temperature uniformity, reducing system flow resistance, and enhancing overall thermal performance.

[0062] The structure of the present invention is further described below with reference to specific embodiments.

[0063] Example 1

[0064] Will Figure 1 The structure is applied in a microchannel. The inlet section size of the microchannel is 200μm×50μm. The three-dimensional numerical simulation is performed with a characteristic unit length of 150μm in the flow direction. Water is used as the working fluid. The heat flux density of the channel wall and the torsional structure is 500,000W / m 2 The inlet temperature is 300K, the inlet flow rate is 8.79m / s, and three torsional structures are added. The following table compares the heat transfer enhancement effect of the torsional structure of the present invention with that of the structure described in a 2020 heat transfer journal article under the same number of structures, same operating conditions, and same boundary conditions:

[0065]

[0066] As attachedFigure 7 is the temperature cloud atlas comparison before and after adding the channel of the torsion structure of the present application.

[0067] As can be seen from the table and the figure, the torsion structure of the present application significantly reduces the channel temperature, improves the channel temperature uniformity, and the improvement in heat exchange performance is obviously superior to the existing structure, and the increase in resistance is less than most of the existing structures, verifying the feasibility of the present application.

[0068] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A torsional enhanced heat exchange structure, characterized in that: including the torsion structure (3), The twisted structure (3) is composed of a plurality of slices (6) stacked and rotated around a twist center line; the twist center line intersects with the airfoil mid-camber line of each slice, and the slice (6) is a low-drag airfoil; the twist center line is perpendicular to the slice (6); Along the height direction of the torsion structure (3), the angle between the mid-arc line of the airfoil of each slice (6) and the mid-arc line of the airfoil of the adjacent upper slice (6) is α, and the angle between the mid-arc line of the airfoil of each slice (6) and the mid-arc line of the airfoil of the adjacent lower slice (6) is -α; the range of α is 0°<0≤10°; The torsion structure (3) is arranged in the channel (1); The upper end surface of the torsion structure (3) is the top slice (4), the lower end surface is the bottom slice (2), and the angle between the top slice (4) and the bottom slice (2) is 2 , the angle 2 The plane located is perpendicular to the torsion centerline; the 2 The value range is 30°<2 <120°.

2. The torsional enhanced heat exchange structure according to claim 1, characterized in that: The slice (6) in the middle of the torsion structure (3) in the height direction is the middle slice (5); the tangent line of the middle slice (5) airfoil mid-arc line at the leading edge (7) of the middle slice (5) is parallel to the outer normal line of the inlet slice of the channel (1).

3. The torsional enhanced heat exchange structure according to claim 1, characterized in that: The twist centerline of the twist structure (3) is composed of the center point of each slice (6), and the center point is the intersection of the airfoil mid-camber line and the chord perpendicular bisector.

4. The torsional enhanced heat exchange structure according to claim 1, characterized in that: The airfoil size and type of adjacent slices (6) are the same.

5. The torsion-enhanced heat exchange structure according to any one of claims 1 to 4, characterized in that: All twisted structures (3) in a row arranged transversely along the channel (1) constitute a characteristic unit (9), and the characteristic units (9) are arranged in an array along the flow direction of the channel (1).

6. The torsional enhanced heat exchange structure according to claim 5, characterized in that: When the number of torsion structures (3) in a characteristic unit is an odd number, a torsion structure (3) is provided at a lateral middle position of the channel (1), and the remaining torsion structures (3) are arranged symmetrically with respect to the middle torsion structure (3).

7. The torsional enhanced heat exchange structure according to claim 5, characterized in that: When the number of the torsion structures (3) in a characteristic unit is an even number, all the torsion structures (3) are symmetrically arranged relative to the lateral middle position of the channel (1).

8. The torsional enhanced heat exchange structure according to claim 5, characterized in that: 0.4<h / H<0.8,1<w2 / w1<3,0.3<w3 / w1<1,6<W / w1<12,2<L / l <3; Wherein, H is the height of the channel (1), L is the length of a characteristic unit (9) of the channel (1), W is the width of a characteristic unit (9) of the channel (1); h is the height of the torsion structure (3), l is the length of the torsion structure (3), w1 is the width of the torsion structure (3), w2 is the distance between adjacent torsion structures (3), and w3 is the distance between the torsion structure (3) at the edge and its adjacent wall.

9. The torsional enhanced heat exchange structure according to claim 8, characterized in that: Assuming that the number of torsion structures (3) in the same characteristic unit (9) is n, then nw1+2w3 +(n-1) w2 =W.

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