Cut sine wave fin structure for heat exchanger

Abstract

The application relates to a slit sine wave fin structure for a heat exchanger, and specifically, a heat exchanger comprising a plurality of plate fins is described herein. The at least one plate fin includes a plurality of holes arranged in one or more rows, and a profile region formed proximate one of the plurality of holes and having a sinusoidal ripple. The contoured region includes a plurality of elongate adjustable willow leaf elements, where the sinusoidal ripple in each row includes three half-waves of a first wave size in a middle portion of the corresponding row, and two half-waves of a second wave size on a side end of the corresponding row, where the second wave size is smaller than the first wave size.

Description

Technical Field

[0001] The present invention relates to the field of fin-and-tube heat exchangers, and more particularly to a lanced sinusoidal fin for a heat exchanger. Background Art Summary of the invention

[0002] A heat exchanger including a plurality of plate fins is described herein. At least one plate fin includes a plurality of holes arranged in one or more rows, and a contour region formed near one of the plurality of holes and having a sinusoidal corrugation, the contour region including a plurality of elongated adjustable willow-leaf elements; wherein the sinusoidal corrugation in each row includes three half waves of a first wave size in a middle portion of the corresponding row, and two half waves of a second wave size on the side ends of the corresponding row, wherein the second wave size is smaller than the first wave size.

[0003] In one or more embodiments, the plurality of elongated adjustable willow elements are offset relative to a center plane disposed at a midpoint of the amplitude of the sinusoidal corrugations.

[0004] In one or more embodiments, the plurality of elongated adjustable willow elements have non-uniform willow widths.

[0005] In one or more embodiments, the plurality of elongated adjustable willow elements have a non-uniform willow offset.

[0006] In one or more embodiments, a width of a willow element associated with a wave having a first wave size is greater than a width of a willow element associated with a wave having a second wave size.

[0007] In one or more embodiments, an amplitude of the willow element associated with a wave having a first wave size is greater than an amplitude of the willow element associated with a wave having a second wave size.

[0008] In one or more embodiments, an inter-row region between adjacent half-waves associated with adjacent rows in the one or more rows has a planar profile.

[0009] In one or more embodiments, the sinusoidal corrugation includes at least one peak and at least one valley, wherein at least one elongated adjustable willow element of the plurality of elongated adjustable willow elements is formed at the at least one valley and / or at least one peak.

[0010] In one or more embodiments, the sinusoidal corrugation includes at least one peak and at least one valley, wherein at least one elongated adjustable willow element of the plurality of elongated adjustable willow elements is formed at the waveform between the at least one valley and the at least one peak.

[0011] In one or more embodiments, at least one of the multiple slender adjustable willow leaf elements is offset so that a first gap generated between a leading edge of the corresponding willow leaf element upstream in the airflow direction and the surface of the plate fin is larger than a second gap generated between a trailing edge of the corresponding willow leaf element opposite to the leading edge and the surface of the plate fin.

[0012] In one or more embodiments, at least one elongated adjustable willow element of the plurality of elongated adjustable willow elements has a curved profile.

[0013] In one or more embodiments, at least one elongated adjustable willow element of the plurality of elongated adjustable willow elements has a flat profile.

[0014] In one or more embodiments, at least one of the plurality of elongated adjustable willow elements is canted.

[0015] In one or more embodiments, at least one of the elongated adjustable willow elements is tilted such that there is an uneven gap between the leading edge and the trailing edge of the corresponding willow element.

[0016] In one or more embodiments, at least one adjusted willow element of the plurality of elongated adjustable willow elements is moved in a first direction beyond a lower surface of the plate fin.

[0017] In one or more embodiments, at least one adjusted willow element of the plurality of elongated adjustable willow elements is moved in the second direction beyond the lower surface of the plate fin.

[0018] Also described herein is a heat exchanger comprising a plurality of plate fins. At least one plate fin comprises a plurality of holes arranged in one or more rows, and a contour region formed near one of the plurality of holes and having a sinusoidal corrugation, the contour region comprising a plurality of elongated adjustable willow leaf elements; wherein the sinusoidal corrugations in each row comprise three half waves of a first wave size in a middle portion of the corresponding row, and two half waves of a second wave size on the side ends of the corresponding row, the second wave size being smaller than the first wave size, wherein the width and amplitude of the willow leaf elements associated with the waves having the first wave size are greater than the width and amplitude of the willow leaf elements associated with the waves having the second wave size.

[0019] In one or more embodiments, at least one of the multiple slender adjustable willow leaf elements is offset so that a first gap generated between a leading edge of the corresponding willow leaf element upstream in the airflow direction and the surface of the plate fin is larger than a second gap generated between a trailing edge of the corresponding willow leaf element opposite to the leading edge and the surface of the plate fin.

[0020] In one or more embodiments, an amplitude of the willow element associated with a wave having a first wave size is greater than an amplitude of the willow element associated with a wave having a second wave size.

[0021] Further described herein is a plate fin for a heat exchanger. The plate fin includes a sheet material, the sheet material includes a plurality of holes arranged in one or more rows, and a contour area formed near one of the plurality of holes on the sheet material and having a sinusoidal corrugation, the contour area including a plurality of elongated adjustable willow-leaf elements; wherein the sinusoidal corrugations in each row include three half waves of a first wave size in the middle portion of the corresponding row, and two half waves of a second wave size on the side ends of the corresponding row, wherein the second wave size is smaller than the first wave size.

[0022] The foregoing summary is illustrative only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, other aspects, embodiments, features, and techniques of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are included to provide a further understanding of the subject disclosure and are incorporated in and constitute a part of this specification. The accompanying drawings illustrate exemplary embodiments of the subject disclosure and together with the description serve to explain the principles of the subject disclosure.

[0024] In the drawings, similar components and / or features may have the same reference label. In addition, various components of the same type may be distinguished by following the reference label with a second label that distinguishes the similar components. If only the first reference label is used in the specification, the description applies to any one of the similar components having the same first reference label regardless of the second reference label.

[0025] Figure 1 A perspective view of an exemplary plate fin heat exchanger according to one or more embodiments of the subject disclosure is shown.

[0026] Figure 2 One or more embodiments of the present disclosure are shown. Figure 1 Top view of the plate fins of a heat exchanger.

[0027] Figure 3 A perspective cross-sectional view of an exemplary profile region of a plate fin is shown in accordance with one or more embodiments of the subject disclosure.

[0028] Figure 4 One or more embodiments of the present disclosure are shown. Figure 3 A cross-sectional view of an embodiment of a contour region.

[0029] Figure 5 A cross-sectional view of another embodiment of a profile region of a plate fin according to one or more embodiments of the subject disclosure is shown.

[0030] Figure 6 A cross-sectional view of yet another embodiment of a profile region of a plate fin according to one or more embodiments of the subject disclosure is shown.

[0031] Figure 7 A cross-sectional view of yet another embodiment of a profile area of ​​a plate fin having angled willow elements according to one or more embodiments of the subject disclosure is shown. DETAILED DESCRIPTION

[0032] The following is a detailed description of the embodiments of the subject disclosure depicted in the accompanying drawings. The embodiments are very detailed in order to clearly convey the subject disclosure. However, the number of details provided is not intended to limit the expected variations of the embodiments; on the contrary, it is intended to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the subject disclosure as defined by the appended claims.

[0033] Various terms are used herein. If a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0034] In the specification, reference may be made to the spatial relationship between various components and the spatial orientation of various aspects of the components when depicting the device in the accompanying drawings. However, as will be recognized by those skilled in the art after reading the subject disclosure in its entirety, the components of the present invention described herein may be positioned in any desired orientation. Therefore, the use of terms such as "above", "below", "upper", "lower", "first", "second" or other similar terms to describe the spatial relationship between various components or to describe the spatial orientation of various aspects of these components should be understood to describe the relative relationship between the components or the spatial orientation of various aspects of these components accordingly, because the plate fins, tubes, holes, waves, willow-leaf elements and corresponding components described herein can be oriented in any desired direction.

[0035] Slit fins have been used previously to provide surface variations that enhance the transfer of thermal energy between fluids flowing through tubular members and the surface of plate fins in heat exchangers. Although existing split fin designs, in which the willow leaf elements are moved upward or downward relative to the plate fins, have been used, there remains a need to further improve and optimize existing split fin geometries used in heat exchangers that would enhance the heat transfer process and overall performance of the heat exchanger while keeping overall manufacturing costs low.

[0036] refer to Figure 1, an exemplary plate fin heat exchanger coil 100 is shown. As shown, the heat exchanger coil 100 includes a plurality of plate fins 200. Each plate fin 200 includes a sheet 202 having one or more holes 204 (e.g., Figure 2 ) for receiving one or more tubes 102 of the heat exchanger coil 100. The plurality of plate fins 200 are held together by oppositely positioned tube sheets (not shown) having holes therethrough, the holes being axially aligned with the tube holes 204 of the plate fins 200. The plurality of tubes 102 may be laced through the holes 204 formed in the plate fins 200 and have their open ends joined together in fluid communication, the plate fins 200 being secured to the tubes 102 by welding, brazing, etc. In one or more embodiments, there may be no interference between the tubes 102 and the fin material 202, however, the tubes 102 may only be arranged to contact the plate fins 200.

[0037] In one embodiment, a first fluid to be cooled or heated may flow through the tubes 102, and then a second cooling or heating fluid may flow between the fin materials 202 and on the outer surface of the tubes 102 in the direction indicated by arrow A. Thermal energy may be transferred from the first fluid passing through the tubes 102 and the plate fins 200 to another fluid or from another fluid to the first fluid. The fluids may be of different types; for example, the fluid flowing through the tubes may be a refrigerant, while the fluid flowing between the plate fins 200 and on the tubes 102 may be air. However, embodiments in which the fluids are the same type of fluid are also contemplated herein.

[0038] In one or more embodiments, the plurality of plate fins 200 may be staggered in parallel such that the holes 204 associated with each plate fin 200 for receiving the tubes 102 are also staggered or aligned. In addition, each tube 102 associated with the heat exchanger coil 100 may extend through the aligned holes 204 of the plate fins 200. Figure 2 , a plurality of holes 204 may be arranged in one or more rows (202A, 202B) on the plate fin sheet 202, wherein all holes 204 in a given row (202A, 202B) have a common centerline (C-C')), which may be oriented parallel to the fin edges 202-1, 202-2. In addition, there may be an inter-row region 206 having a flat profile between the rows (202A, 202B) of tube holes 204, which may reduce the pressure drop of air flowing along the surface of the plate fin 200. In one or more embodiments, the fin collar 304 may surround each tube hole, such as Figure 3The fin collars 304 can be configured to extend outwardly from the surface of the plate fin 200 in a first direction. The plurality of fin collars 304 can be used to determine the spacing (also referred to as the fin pitch) between adjacent plate fins 200 in a given heat exchanger coil 100 by the length by which they extend from the fin surface. The plurality of fin collars 304 can also be used to ensure sufficient contact area and a tight mechanical fit between the plate fin 200 and the tube 102, and therefore good heat transfer.

[0039] refer to Figure 3 , showing Figure 2 A perspective view of a cross section of the plate fin 200 in the figure taken on a plane (B-B') oriented generally transverse to the plate fin 200. As shown, in one or more embodiments, the plate fin 200 may include a contour area 302 between adjacent holes 204 in the same row (202A or 202B) disposed on the fin material 202. The contour area 302 may include a sinusoidal corrugation or a sinusoidal waveform extending parallel to the direction of the airflow A and perpendicular to the edges 202-1, 202-2 of the plate fin 200. The sinusoidal corrugation 302 may have at least one peak and at least one valley. As used herein, the term "sinusoidal" is intended to encompass waveforms or patterns that may be true sine curves or approximate sine curves. In addition, it should be understood that the term "sinusoidal corrugation" may also include waveforms representing sine waves with phase shifts, such as producing cosine-shaped waveforms. The inherent design requirements and practical considerations in preparing for processing and manufacturing the fins mean that the waveform is not necessarily a mathematically precise sine curve.

[0040] In one or more embodiments, Figures 4 to 7 , the sinusoidal corrugation region 302 in each row (202A, 202B) of the plate fin 200 may include three half waves (W1 to W3) of the first wave size in the middle portion 302-1 (adjacent to the tube hole) of the corresponding row and two half waves (W4, W5) of the second wave size on the side end 302-2 of the corresponding row, with a total number of 2.5 waves per row. Therefore, the sinusoidal corrugation 302 may have two peaks and one valley in the middle portion 302-1 and two valleys in the side end 302-2. However, embodiments having a contour region 302 that includes sinusoidal corrugations extending for fewer wave numbers (such as a single wave number or 1.5 wave numbers, or more than 2.5 wave numbers) are also contemplated herein, and all such embodiments are within the scope of the subject disclosure.

[0041] The term “wave size” includes the wavelength and amplitude or height of the corresponding waves formed in the sinusoidal corrugations 302 .

[0042] In one or more embodiments, the second wave size of the two half waves (W4, W5) on the side end 302-2 of the row can be smaller than the first wave size of the three half waves (W1 to W3) in the middle portion 302-1 of the corresponding row. Therefore, the sinusoidal ripples 302 in each row can have two peaks and one valley (with larger wave size) in the middle portion 302-1, and two valleys (with smaller wave size) in the side end 302-2. However, it should be understood that the wave size of the two half waves (W4, W5) on the side end 302-2 can also be equal to or greater than the wave size of the three half waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the subject disclosure.

[0043] In one or more embodiments, the amplitude of the two half-waves (W1, W2) on the side ends 302-2 of the row can be smaller than the amplitude of the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row. Therefore, the sinusoidal ripples 302 in each row can have two peaks and one valley (with larger amplitude) in the middle portion 302-1, and two valleys (with smaller amplitude) in the side ends 302-2. However, it should be understood that the amplitude of the two half-waves (W4, W5) on the side ends 302-2 can also be equal to or greater than the amplitude of the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the subject disclosure.

[0044] In one or more embodiments, the sinusoidal corrugations 302 including at least one peak and at least one valley located at the contour area of ​​the plate fin 200 cannot have a continuous surface. Instead, the contour area of ​​the plate fin 200 may include at least one elongated willow leaf element 306A, 306B, 306C (collectively referred to herein as 306) generated and defined by a longitudinal slit 308 formed in the contour area 302. Figure 3 In a non-limiting embodiment, six longitudinal slits 308 in the contour region 302 of the plate fin 200 form a total of seven willow leaf elements 306. In other embodiments, such as Figures 4 to 7 , the contour region 302 may include eleven willow elements 306. Thus, it should be understood that contour regions 302 having any suitable number of willow elements 306, such as, for example, five willow elements, six willow elements, eight willow elements, nine willow elements, ten willow elements, twelve willow elements, or thirteen willow elements, are within the scope of the subject disclosure.

[0045] Although the slits 308 are shown as extending perpendicular to the direction of the airflow A, or parallel to the edges 202-1, 202-2 of the plate fin 200, embodiments in which one or more slits 308 can be arranged at a certain angle to the edges of the plate fin 200 also fall within the scope of the subject disclosure. In one or more embodiments, the willow leaf element 306 can be located only in the middle portion 302-1 of the sinusoidal corrugated area that is substantially aligned with a portion of the tube hole 204. Therefore, the waves or valleys on the side ends 302-2 of the corrugated area 302 and the inter-row area 206 formed between adjacent tube rows (202A, 202B) do not have any willow leaf elements formed therein. In addition, in one or more embodiments, the willow leaf element 306 can be located in the middle portion 302-1 and the side ends 302-2 of the sinusoidal corrugated area 302.

[0046] In one or more embodiments, the first portion of the willow element can be fixed in place along the curvature of the sinusoidal corrugation 302. These willow elements are also referred to herein as fixed willow "elements". The second portion of the willow element can be moved, e.g., translated, after it is formed, such as relative to the centerline of the sinusoidal corrugation, which is shown as the center plane P (see Figures 4 to 7 The willow elements (306A-306C) with adjusted positions may also be referred to herein as "adjusted willow elements". Figure 3 In the embodiment shown in FIG. 3 , the sinusoidal corrugation 302 may include four fixed willow leaf elements and three adjusted willow leaf elements. Figures 4 to 7 In a non-limiting embodiment, the sinusoidal corrugation 302 may include six fixed willow leaf elements and five adjustable willow leaf elements.

[0047] In one or more embodiments, the plurality of elongated adjustable willow elements 306 may be offset relative to a center plane P disposed at the midpoint of the amplitude of the sinusoidal corrugations 302. As shown, the center plane P may extend through the sinusoidal corrugations 302 substantially at the midpoint of the amplitude or height of the waveform. Thus, the distance between the plane P and the peaks of the sinusoidal corrugations is equal to the distance between the plane P and the valleys of the sinusoidal corrugations. In one embodiment, at least one of the adjustable willow elements may be offset from the sinusoidal corrugations by a distance (O), referred to as the willow offset, as shown. Figures 4 to 7 Example in.

[0048] In one or more embodiments, the plurality of willow elements 306 may have a curved profile such that the willow elements 306 may maintain the curvature of the sinusoidal corrugation 302. In other words, each of the plurality of elongated willow elements 306 has a cross-sectional shape that is a segment of the sinusoidal corrugation 302. The adjustable elongated willow elements 306 may be cut or slit such that the slits 308 defining the adjustable willow elements 306 are configured to have a generally curved profile. In such embodiments, the number of waves over which the sinusoidal corrugation 302 extends at least partially determines the total number of willow elements 306 included. Thus, the adjustable willow element 306A disposed at the peak of the sinusoidal corrugation 302 may have a generally concave curvature, and the adjustable willow elements 306B, 306C disposed at the valley of the sinusoidal corrugation may have a generally convex curvature.

[0049] Although the adjustable willow leaf elements 302 are shown as being disposed on opposite sides of the peaks and valleys of the sinusoidal corrugation, in one or more embodiments (not shown), at least one of the plurality of elongated adjustable willow leaf elements 306 may not be present at a peak or valley, but may instead be produced at a waveform between adjacent peaks and valleys of the sinusoidal corrugation region 302.

[0050] In one or more embodiments, the plurality of willow elements 306 can have a substantially flat profile such that the willow elements 306 can remain substantially tangential to the waveform of the sinusoidal corrugations 302. The adjustable elongated willow elements 306 can be cut or slit such that the slits 308 defining the adjustable willow elements 306 can have a generally planar profile.

[0051] refer to Figure 7 In one or more embodiments, the plurality of willow leaf elements 306 may be tilted such that an uneven gap is maintained between the leading and trailing edges of the corresponding willow leaf elements. In such embodiments, the willow leaf elements 306 may have a planar profile as shown and / or a curved profile (not shown) that may be tilted toward one of the edges. Additionally, in one or more embodiments, the tilted willow leaf elements 306 may be disposed on opposite sides of the peaks and valleys of the sinusoidal corrugations, however, the tilted willow leaf elements 306 may not be present at the peaks or valleys, but may be generated at the waveform between adjacent peaks and valleys of the sinusoidal corrugation region.

[0052] In one or more embodiments, at least one of the plurality of elongated adjustable willow blade elements 306A to 306C can be offset so that a first gap created between a leading edge (upstream in the airflow direction A) of the corresponding willow blade element and the surface of the plate fin 200 is larger than a second gap created between a trailing edge of the corresponding willow blade element 306 opposite to the leading edge and the surface of the plate fin 200. The profiles of these inclined willow blade elements 306 and the corrugated region 302 can form jets of airflow, thereby disrupting the boundary layer and reducing the thermal wake effect, thereby significantly enhancing heat transfer.

[0053] In one or more embodiments, the plurality of slender adjustable willow elements 306 in the corrugated area may have uneven willow widths. For example, the willow elements 306A associated with the waves W1 and W3 at two peaks in the middle portion 302-1 of each row and the willow elements 306B associated with the waves W2 at one valley may have the same or different willow widths. Similarly, the willow elements 306C associated with the two waves W4 and W5 at two valleys on the side ends 302-2 of each row may have the same or different willow widths. In addition, in one or more embodiments, the plurality of slender adjustable willow elements 306 in the corrugated area may have uneven willow offsets relative to the center plane. For example, the willow elements 306A and 306B at two peaks and one valley in the middle portion 302-1 of each row may have the same or different willow offsets relative to the center plane P. Similarly, the willow elements 306C at two valleys on the side ends 302-2 of each row may have the same or different willow offsets.

[0054] In one or more embodiments, the width of the willow elements 306C associated with the two half-waves (W4, W5) on the side ends 302-2 of the row (having the second wave size) can be less than the width of the willow elements 306B, 306C associated with the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row (having the first wave size). However, it should be understood that the width of the willow elements 306C associated with the two half-waves (W4, W5) on the side ends 302-2 can also be equal to or greater than the width of the willow elements 306B, 306C associated with the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the subject disclosure.

[0055] In one or more embodiments, the amplitude of the willow elements 306C associated with the two half-waves (W4, W5) on the side ends 302-2 of the row (having the second wave size) can be less than the amplitude of the willow elements 306B, 306C associated with the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row (having the first wave size). However, it should be understood that the amplitude of the willow elements 306C associated with the two half-waves (W4, W5) on the side ends 302-2 can also be equal to or greater than the amplitude of the willow elements 306B, 306C associated with the three half-waves (W1 to W3) in the middle portion 302-1 of the corresponding row, and all such embodiments are within the scope of the subject disclosure.

[0056] refer to Figure 4In one or more embodiments, at least one of the adjusted willow leaf elements 306A to 306C may be moved in a downward direction beyond the lower surface of the plate fin 200. The downward direction is a second direction opposite to the first direction in which the fin collar 304 extends from the plate fin 200. As shown, each of the adjusted willow leaf elements 306B, 306C originating from the valley of the sinusoidal corrugation 302 may be moved downward away from the plane P such that the upper surface of the willow leaf elements 306B, 306C is vertically below the lower surface of the plate fin 200. Due to this movement, the distance between the willow leaf elements 306B, 306C and the plane P increases. In addition, each of the willow leaf elements 306A originating from the peak of the sinusoidal corrugation 302 may similarly be moved in the same second downward direction such that the upper surface of the willow leaf element 306A is vertically below the lower surface of the plate fin 200. However, the downward movement may move the willow leaf element 306A toward the plane P such that the distance between the willow leaf element 306A and the plane P decreases. Thus, the distance between the plane P and the willow elements 306B, 306C may be different than the distance between the willow element 306A and the plane P. In one or more embodiments, the distance that adjacent willow elements 306A-306C are offset from the sinusoidal corrugation 302 in a direction perpendicular to the flow direction A (such as, for example, relative to the plane P, also referred to herein as a willow offset) may be uniform.

[0057] In one or more embodiments, Figure 5 , at least one willow-leaf element 306B, 306C disposed at the valley of the sinusoidal corrugations can be moved in a direction opposite to at least one willow-leaf element 306A disposed at the peak of the sinusoidal corrugations 302. As shown, each willow-leaf element 306B, 306C disposed at the valley of the sinusoidal corrugations 302 can be moved in a second direction, downwardly away from the plane P. Thus, the upper surface of the willow-leaf element 306B, 306C can be vertically located below the lower surface of the plate fin 200. Due to this movement, the distance between the willow-leaf element 306B, 306C and the plane P can be increased. Similarly, each willow-leaf element 306A formed at the peak of the sinusoidal corrugations can be moved in a first upward direction in which the fin 200 collar extends from the plate fin 200. By this movement away from the plane P, the lower surface of the willow-leaf element 306A can be vertically located above the upper surface of the plate fin 200. In one or more embodiments, the total distance that each willow element (306A-306C) may move in a direction perpendicular to the flow direction A (such as, for example, relative to the plane P) may be equal or may vary.

[0058] refer to Figure 6In one or more embodiments, a plurality of elongated adjustable willow elements (306A-306C) may be offset relative to a center plane P disposed at the midpoint of the amplitude of the sinusoidal corrugations 302. As shown, each of the adjusted willow elements 306B, 306C originating from the valleys of the sinusoidal corrugations may be moved upward toward the center plane P such that the bottom surface of the corresponding willow element 306B, 306C is vertically located above the lower surface of the plate fin 200. Additionally, each of the willow elements 306A originating from the peaks of the sinusoidal corrugations may similarly be moved in a downward direction such that the upper surface of the corresponding willow element 306A is vertically located below the lower surface of the plate fin 200. Due to this movement, the distance between the willow elements (306A-306C) and the plane P is reduced.

[0059] It will be appreciated that the contours of the corrugated areas and willow-leaf elements in the plate fins can form jets of airflow that disrupt the boundary layer and reduce the thermal wake effect, thereby significantly enhancing heat transfer. Thus, the present invention improves and optimizes the existing cut-fin geometry used in heat exchangers by enhancing the heat transfer process and the overall performance of the heat exchanger while keeping the overall manufacturing cost of the plate fins low.

[0060] Although the subject disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and elements thereof may be substituted with equivalents without departing from the scope of the subject disclosure as defined by the appended claims. Modifications may be made to adapt specific circumstances or materials to the teachings of implementing the subject disclosure without departing from its scope. Therefore, the subject disclosure is not limited to the specific embodiments disclosed, but rather the subject disclosure includes all embodiments within the scope of the subject disclosure as defined by the appended claims.

[0061] In interpreting this specification, all terms should be interpreted in the broadest manner consistent with the context. In particular, the terms "include" and "comprise" should be interpreted as referring to elements, parts or steps in a non-exclusive manner, indicating that the referenced elements, parts or steps may be present, used or combined with other elements, parts or steps not explicitly referenced. When the specification claims refer to at least one item selected from the group consisting of A, B, C... and N, the text should be interpreted as requiring only one element in the group, rather than A plus N, or B plus N, etc.

Claims

1. A heat exchanger comprising a plurality of plate fins, at least one of the plate fins comprising: a plurality of holes arranged in one or more rows; as well as a contoured region formed adjacent one of the plurality of apertures and having a sinusoidal corrugation, the contoured region including a plurality of elongated adjustable willow-leaf elements; Wherein, the sinusoidal ripples in each row include three half waves of a first wave size in the middle part of the corresponding row, and two half waves of a second wave size on the side ends of the corresponding row, wherein the second wave size is smaller than the first wave size.

2. The heat exchanger according to claim 1, wherein: The plurality of elongated adjustable willow elements are offset relative to a center plane disposed at a midpoint of the amplitude of the sinusoidal corrugations.

3. The heat exchanger according to any one of claims 1 and 2, wherein: The plurality of elongated adjustable willow elements have non-uniform willow widths.

4. The heat exchanger according to any one of claims 1 to 3, wherein: The plurality of elongated adjustable willow elements have a non-uniform willow offset.

5. The heat exchanger according to any one of claims 1 to 4, wherein: A width of the willow element associated with waves having the first wave size is greater than a width of the willow element associated with waves having the second wave size.

6. The heat exchanger according to any one of claims 1 to 5, wherein: An amplitude of the willow element associated with a wave having the first wave size is greater than an amplitude of the willow element associated with a wave having the second wave size.

7. The heat exchanger according to any one of claims 1 to 7, wherein: An inter-row region between adjacent half-waves associated with adjacent rows of the one or more rows has a planar profile.

8. The heat exchanger according to any one of claims 1 to 7, wherein: The sinusoidal corrugation includes at least one peak and at least one valley, wherein at least one elongated adjustable willow element of the plurality of elongated adjustable willow elements is formed at the at least one valley and / or the at least one peak.

9. The heat exchanger according to any one of claims 1 to 8, wherein: The sinusoidal corrugation includes at least one peak and at least one valley, wherein at least one elongated adjustable willow element of the plurality of elongated adjustable willow elements is formed at the waveform between the at least one valley and the at least one peak.

10. The heat exchanger according to any one of claims 1 to 9, wherein: At least one of the multiple slender adjustable willow leaf elements is offset so that a first gap generated between a leading edge of the corresponding willow leaf element upstream in the airflow direction and the surface of the plate fin is larger than a second gap generated between a trailing edge of the corresponding willow leaf element opposite to the leading edge and the surface of the plate fin.

11. The heat exchanger according to any one of claims 1 to 10, wherein: At least one elongated adjustable willow element of the plurality of elongated adjustable willow elements has a curved profile.

12. The heat exchanger according to any one of claims 1 to 11, wherein: At least one elongated adjustable willow element of the plurality of elongated adjustable willow elements has a flat profile.

13. The heat exchanger according to any one of claims 1 to 12, wherein: At least one of the plurality of elongated adjustable willow elements is canted.

14. The heat exchanger according to claim 13, wherein: The at least one elongated adjustable willow element is tilted such that there is an uneven gap between the leading edge and the trailing edge of the corresponding willow element.

15. The heat exchanger according to any one of claims 1 to 14, wherein: At least one of the plurality of elongated adjustable willow elements is moved in a first direction beyond a lower surface of the plate fin.

16. The heat exchanger according to any one of claims 1 to 15, wherein: At least one of the plurality of elongated adjustable willow elements is moved in a second direction beyond the lower surface of the plate fin.

17. A heat exchanger comprising a plurality of plate fins, at least one of the plate fins comprising: a plurality of holes arranged in one or more rows; as well as a contoured region formed adjacent one of the plurality of apertures and having a sinusoidal corrugation, the contoured region including a plurality of elongated adjustable willow-leaf elements; wherein the sinusoidal ripples in each row include three half waves of a first wave size in the middle portion of the corresponding row, and two half waves of a second wave size on the side ends of the corresponding row, the second wave size being smaller than the first wave size, Wherein a width and an amplitude of the willow leaf element associated with a wave having the first wave size are greater than a width and an amplitude of the willow leaf element associated with a wave having the second wave size.

18. The heat exchanger according to claim 17, wherein: At least one of the multiple slender adjustable willow leaf elements is offset so that a first gap generated between a leading edge of the corresponding willow leaf element upstream in the airflow direction and the surface of the plate fin is larger than a second gap generated between a trailing edge of the corresponding willow leaf element opposite to the leading edge and the surface of the plate fin.

19. The heat exchanger according to any one of claims 17 and 18, wherein: An amplitude of the willow element associated with a wave having the first wave size is greater than an amplitude of the willow element associated with a wave having the second wave size.

20. A plate fin for a heat exchanger, the plate fin comprising: a sheet comprising a plurality of holes arranged in one or more rows; as well as a contoured region formed in said sheet adjacent one of said plurality of apertures and having sinusoidal corrugations, said contoured region comprising a plurality of elongated adjustable willow-leaf elements; Wherein, the sinusoidal ripples in each row include three half waves of a first wave size in the middle part of the corresponding row, and two half waves of a second wave size on the side ends of the corresponding row, wherein the second wave size is smaller than the first wave size.

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