WO2024157091A1

WO2024157091A1 - Partially finned tube for a heat exchanger

Info

Publication number: WO2024157091A1
Application number: PCT/IB2024/050125
Authority: WO
Inventors: Majid SAFFAR-AVVAL; Amirreza Mehdizadeh; Negar ALVANDIFAR
Original assignee: Saffar Avval Majid; Amirreza Mehdizadeh; Alvandifar Negar
Priority date: 2023-01-29
Filing date: 2024-01-06
Publication date: 2024-08-02

Abstract

Disclosed herein is a partially finned tube for a heat exchanger. The disclosed partially finned tube includes a base tube and a plurality of finned sections attached to an outer surface of the base tube. A finned section from the plurality of finned section includes a main fin and a secondary fin. The main fin includes an inner curved edge, an outer curved edge, a first straight edge, and a second straight edge. The secondary fin includes a secondary inner curved edge, a secondary outer curved edge, a third straight edge, and a fourth straight edge.

Description

PARTIALLY FINNED TUBE FOR A HEAT EXCHANGER

TECHNICAL FIELD

[0001] The present disclosure, generally, relates to heat exchangers, and particularly relates to tubes used in heat exchangers. The present disclosure, more particularly, relates to a partially finned tube for a heat exchanger.

BACKGROUND ART

[0002] Heat transfer plays an essential role in our life. In various industries such as power plants, oil and gas industries, petrochemical, food, and numerous other sectors, heat transfer is one of the most fundamental processes for cooling and heating. Due to the wide range of thermodynamic states of hot and cold flows, as well as the type and phase of each flow, heat exchangers may be used with various designs and arrangements. Choosing the type of heat exchanger plays an important role in the efficiency of the energy transfer process and manufacturing costs.

[0003] The heat transfer surface is one of the parameters affecting the performance of heat exchangers. The primary and essential purpose of finning may be to create a wider area for enhancing heat transfer. The finned tubes may provide an increase in surface area about 20-30 times compared to the bare tubes (tubes without fin). The fins may be placed on the pipes in various shapes and arrangements, for example, annular fins, serrated fins, and plate fins. Researchers have always tried to provide a heat exchanger that simultaneously has higher heat transfer and lower pressure drop. [0004] Various methods may be used to increase heat transfer, such as creating protrusions with different shapes, vortex generators, or wavy fins, which may increase flow mixing. These methods may enhance the pressure drop compared to the simple fin because protrusions have the dimensions of the scale of the pipe diameter, which may intensify the pumping power needed to drive the external airflow. In addition, using protrusions, vortex generators, and wavy fins may enhance the weight and cost of the heat exchanger due to increase in the fins area.

[0005] Researchers have proposed a plate fin tube heat exchanger, in which plate fins are placed parallel, with equal distances on the tube bundles, while pyramidal protrusions are created on the fins. In this heat exchanger, the internal flow inside the tubes exchanges the heat with the external flow and the pyramidal protrusions direct the external flow toward each of other protrusions. Fins with conical and elliptical protrusions are other types of fins. A plate fin tube heat exchanger was disclosed and a group of five rows of cooling slits are formed on the fins to guide the flow of air.

[0006] In other designs of it, the number of slots on the fin and their arrangement have been changed. A wavy fin heat exchanger has been disclosed, with multiple laminated fins. Each fin has multiple tops and bottoms. These fins prevent flow separation and produce the secondary flow of air that improves the heat transfer rate. The secondary flow is produced due to the wavy fins. A plate fin tube heat exchanger has been disclosed, which has some vortex generators. The vortex generators are arc-shaped protrusions and are placed around the tubes which have different designs. For example, four vortex generators are embedded around the heat exchanger tubes symmetrically. Two vortex generators are placed at the front and two vortex generators at the back of the tube to guide the airflow. When the external flow passes through the vortex generators, eddies are formed. These vortices increase the flow mixing and turbulence, which increases the rate of heat transfer, consequently. [0007] As mentioned above, increasing the amount of heat transfer may be the primary goal of putting and/or wrapping the find on tubes. On the other hand, finning may increase the weight of heat exchangers due to the increment in the consumption of materials and as a result, the cost of heat exchangers may be increased. Pressure drop augmentation may be another loss caused by finning. A higher pressure drop in a heat exchanger may mean that more power is needed to drive fluid through the heat exchanger, which may result in higher electricity consumption in pumps, fans, and/or blowers.

[0008] The heat transfer mechanism from fin tubes is usually in the form of convective heat transfer. Numerical modelling of the heat flux from the annular fins shows that the heat transfer from the surface of the fin to the external flow is not uniform. In other words, when the flow passes through the fin tube, the velocity of the external flow in the downstream (wake region) is lower than the upstream, and at the separation points, the velocity equals zero. Since the convection heat transfer depends on the flow velocity, the heat transfer rate reduces at downstream.

[0009] There is, therefore, a need for fin tubes in which pressure drop and the weight of the heat exchanger are reduced without a noticeable decrease in thermal performance or the heat transfer rate from the fin surface

SUMMARY OF THE DISCLOSURE

[0010] This summary is intended to provide an overview of the subject matter of the present disclosure, and is not intended to identify essential elements or key elements of the subject matter, nor is it intended to be used to determine the scope of the claimed implementations. The proper scope of the present disclosure may be ascertained from the claims set forth below in view of the detailed description below and the drawings. [0011] According to one or more exemplary embodiments of the present disclosure, a partially finned tube for a heat exchanger is disclosed. In an exemplary embodiment, the disclosed partially finned tube may include a base tube and a plurality of finned sections. In an exemplary embodiment, the plurality of finned sections may be attached to an outer surface of the base tube and along a main longitudinal axis of the base tube.

[0012] In an exemplary embodiment, a finned section from the plurality of finned sections may include a main fin and a secondary fin. In an exemplary embodiment, the main fin may include an inner curved edge, an outer curved edge, a first straight edge, and a second straight edge. In an exemplary embodiment, the inner curved edge may be attached to an outer surface of the base tube. In an exemplary embodiment, a radius of the inner curved edge may correspond to an outer radius of the base tube. In an exemplary embodiment, a center of the inner curved edge may coincide with a center of the base tube. In an exemplary embodiment, a center of the outer curved edge may coincide with the center of the base tube

[0013] In an exemplary embodiment, the first straight edge may be at a first side of the fin. In an exemplary embodiment, a first end of the first straight edge may be attached to a first end of the inner curved edge. In an exemplary embodiment, a second end of the first straight edge may be attached to a first end of the outer curved edge. In an exemplary embodiment, the first straight edge may be extended along a first axis. In an exemplary embodiment, the first axis may pass through the center of the base tube.

[0014] In an exemplary embodiment, the second straight edge may be at a second side of the fin. In an exemplary embodiment, a first end of the second straight edge may be attached to a second end of the inner curved edge. In an exemplary embodiment, a second end of the second straight edge may be attached to a second end of the outer curved edge. In an exemplary embodiment, the second straight edge may be extended along a second axis. In an exemplary embodiment, the second axis may pass through the center of the base tube.

[0015] In an exemplary embodiment, the secondary fin may include a secondary inner curved edge, a secondary outer curved edge, a third straight edge, and a fourth straight edge. In an exemplary embodiment, the secondary inner curved edge may be attached to the outer surface of the base tube. In an exemplary embodiment, a radius of the secondary inner curved edge may correspond to the outer radius of the base tube. In an exemplary embodiment, a center of the secondary inner curved edge may coincide with the center of the base tube. In an exemplary embodiment, a center of the secondary outer curved edge may coincide with the center of the base tube.

[0016] In an exemplary embodiment, a third straight edge may be at a first side of the secondary fin. In an exemplary embodiment, a first end of the third straight edge may be attached to a first end of the secondary inner curved edge. In an exemplary embodiment, a second end of the third straight edge may be attached to a first end of the secondary outer curved edge. In an exemplary embodiment, the third straight edge may be extended along a third axis. In an exemplary embodiment, the third axis may pass through the center of the base tube.

[0017] In an exemplary embodiment, the fourth straight edge may be at a second side of the secondary fin. In an exemplary embodiment, a first end of the fourth straight edge may be attached to a second end of the secondary inner curved edge. In an exemplary embodiment, a second end of the fourth straight edge may be attached to a second end of the secondary outer curved edge. In an exemplary embodiment, the fourth straight edge may be extended along a fourth axis. In an exemplary embodiment, the fourth axis may pass through the center of the base tube. [0018] In an exemplary embodiment, the first axis and the second axis may define an exterior angle between the first axis and the second axis. In an exemplary embodiment, the exterior angle may be between 40° and 180°. In an exemplary embodiment, the first axis and the third axis may define a first recess angle between the first axis and the third axis. In an exemplary embodiment, the first recess angle may be between 20° and 80°. In an exemplary embodiment, the second axis and the fourth axis may define a second recess angle between the second axis and the fourth axis. In an exemplary embodiment, the second recess angle may be between 20° and 80°.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawing figures depict one or more implementations in accord with the present teachings, by way of example only, not by way of limitation. In the figures, like reference numerals refer to the same or similar elements.

[0020] FIG. 1A illustrates a perspective view of a partially finned tube, consistent with one or more exemplary embodiments of the present disclosure.

[0021] FIG. IB illustrates a top view of a partially finned tube, consistent with one or more exemplary embodiments of the present disclosure.

[0022] FIG. 1C illustrates a front view of a partially finned tube, consistent with one or more exemplary embodiments of the present disclosure.

[0023] FIG. 2 illustrates a finned section from a plurality of finned sections, consistent with one or more exemplary embodiments of the present disclosure.

[0024] FIG. 3A illustrates a main fin, consistent with one or more exemplary embodiments of the present disclosure.

[0025] FIG. 3B illustrates a main fin, consistent with one or more exemplary embodiments of the present disclosure.

[0026] FIG. 4A illustrates a perspective view of a partially finned tube in a scenario in which an exterior angle is 180°, consistent with one or more exemplary embodiments of the present disclosure.

[0027] FIG. 4B illustrates a top view of a partially finned tube in a scenario in which an exterior angle is 180°, consistent with one or more exemplary embodiments of the present disclosure. [0028] FIG. 4C illustrates a front view of a partially finned tube in a scenario in which an exterior angle is 180°, consistent with one or more exemplary embodiments of the present disclosure.

[0029] FIG. 5 illustrates a front view of a finned section, consistent with one or more exemplary embodiments of the present disclosure.

[0030] FIG. 6A illustrates a front view of a secondary fin, consistent with one or more exemplary embodiments of the present disclosure.

[0031] FIG. 6B illustrates a front view of a secondary fin, consistent with one or more exemplary embodiments of the present disclosure.

[0032] FIG. 7 A illustrates a perspective view of a partially finned tube in a scenario in which an exterior angle is 180° and a first recess angle and a second recess angle are both 45°, consistent with one or more exemplary embodiments of the present disclosure.

[0033] FIG. 7B illustrates a top view of a partially finned tube in a scenario in which an exterior angle is 180° and a first recess angle and a second recess angle are both 45°, consistent with one or more exemplary embodiments of the present disclosure.

[0034] FIG. 7C illustrates a front view of a partially finned tube in a scenario in which an exterior angle is 180° and a first recess angle and a second recess angle are both 45°, consistent with one or more exemplary embodiments of the present disclosure.

[0035] FIG. 8A illustrates Nusselt Number VS Reynolds Number for some embodiments of a partially finned tube and a typical finned tube, consistent with one or more exemplary embodiments of the present disclosure.

[0036] FIG. 8B illustrates heat transfer rate in different Reynolds Number for some embodiments of a partially finned tube and a typical finned tube, consistent with one or more exemplary embodiments of the present disclosure. [0037] FIG. 8C illustrates thermal performance in different Reynolds Number for some embodiments of a partially finned tube and a typical finned tube, consistent with one or more exemplary embodiments of the present disclosure.

[0038] FIG. 9A illustrates a schematic representation of an in-line arrangement of B-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure.

[0039] FIG. 9B illustrates a schematic representation of a staggered arrangement of B-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure.

[0040] FIG. 10A illustrates a schematic representation of an in-line arrangement of C-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. [0041] FIG. 10B illustrates a schematic representation of a staggered arrangement of C-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. [0042] FIG. 11A illustrates a schematic representation of an in-line arrangement of D-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. [0043] FIG. 11B illustrates a schematic representation of a staggered arrangement of D-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure.

DESCRIPTION OF EMBODIMENTS

[0044] In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings.

[0045] The following detailed description is presented to enable a person skilled in the art to make and use the methods and devices disclosed in exemplary embodiments of the present disclosure. For purposes of explanation, specific nomenclature is set forth to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that these specific details are not required to practice the disclosed exemplary embodiments. Descriptions of specific exemplary embodiments are provided only as representative examples. [0046] Various modifications to the exemplary implementations will be readily apparent to one skilled in the art, and the general principles defined herein may be applied to other implementations and applications without departing from the scope of the present disclosure. The present disclosure is not intended to be limited to the implementations shown, but is to be accorded the widest possible scope consistent with the principles and features disclosed herein. [0047] Disclosed herein is a partially finned tube for a heat exchanger. FIG. 1A shows a perspective view of a partially finned tube 100, consistent with one or more exemplary embodiments of the present disclosure. FIG. IB shows a top view of partially finned tube 100, consistent with one or more exemplary embodiments of the present disclosure. FIG. 1C shows a front view of partially finned tube 100, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 1A, FIG. IB, and FIG. 1C, in an exemplary embodiment, partially finned tube 100 may include a base tube 102 and a plurality of finned sections 104. In an exemplary embodiment, plurality of finned sections 104 may be attached to an outer surface of base tube 102. In an exemplary embodiment, plurality of finned sections 104 may be arranged along a main longitudinal axis 122 of base tube 102. For purpose of reference, it may be understood that an internal flow may be driven inside base tube 102 and an external flow may pass over plurality of finned sections 104. In an exemplary embodiment, due to the temperature difference between the internal flow inside base tube 102 and the external flow over plurality of finned sections 104, the heat may exchange between these two streams through the fins and the surface of base tube 102.

[0048] FIG. 2 shows a finned section 200 from plurality of finned sections 104, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 2, in an exemplary embodiment, finned section 200 may include a main fin 202. FIG. 3A shows main fin 202, consistent with one or more exemplary embodiments of the present disclosure. FIG. 3B shows main fin 202, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 3A and FIG. 3B, in an exemplary embodiment, main fin 202 may include an inner curved edge 222, an outer curved edge 224, a first straight edge 226, and a second straight edge 228.

[0049] In an exemplary embodiment, inner curved edge 222 may be attached to the outer surface of base tube 102. In an exemplary embodiment, a center of inner curved edge 222 may coincide with a center of base tube 102. In an exemplary embodiment, a radius of inner curved edge 222 may correspond to an outer radius of base tube 102. In an exemplary embodiment, a center of outer curved edge 224 may also correspond to the center of base tube 102. In other words, in an exemplary embodiment, inner curved edge 222, outer curved edge 224, and base tube 102 may be concentric. [0050] In an exemplary embodiment, first straight edge 226 may be at a first side 221 of main fin 202 and second straight edge 228 may be at a second side 223 of main fin 202. In an exemplary embodiment, a first end 2262 of first straight edge 226 may be attached to a first end 2222 of inner curved edge 222. In an exemplary embodiment, a second end 2264 of first straight edge 226 may be attached to a first end 2242 of outer curved edge 224. In an exemplary embodiment, first straight edge 226 may be extended along a first axis 2265. In an exemplary embodiment, first axis 2265 may pass through center 125 of base tube 102.

[0051] In an exemplary embodiment, a first end 2282 of second straight edge 228 may be attached to a second end 2224 of inner curved edge 222. In an exemplary embodiment, a second end 2284 of second straight edge 228 may be attached to a second end 2244 of outer curved edge 224. In an exemplary embodiment, second straight edge 228 may be extended along a second axis 2285. In an exemplary embodiment, second axis 2285 may pass through center 125 of base tube 102. In an exemplary embodiment, first axis 2265 and second axis 2285 may define an exterior angle 2255 between first axis 2265 and second axis 2285. In an exemplary embodiment, exterior angle 2255 may be between 40° and 180°.

[0052] In an exemplary embodiment, exterior angle 2255 may be 180°. FIG. 4A shows a perspective view of partially finned tube 100 in a scenario in which exterior angle 2255 is 180°, consistent with one or more exemplary embodiments of the present disclosure. FIG. 4B shows a top view of partially finned tube 100 in a scenario in which exterior angle 2255 is 180°, consistent with one or more exemplary embodiments of the present disclosure. FIG. 4C shows a front view of partially finned tube 100 in a scenario in which exterior angle 2255 is 180°, consistent with one or more exemplary embodiments of the present disclosure.

[0053] FIG. 5 shows a front view of finned section 200, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 5, in an exemplary embodiment, finned section 200 may further include a secondary fin 502. FIG. 6A shows a front view of secondary fin 502, consistent with one or more exemplary embodiments of the present disclosure. FIG. 6B shows a front view of secondary fin 502, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 6A and FIG. 6B, in an exemplary embodiment, secondary fin 502 may include a secondary inner curved edge 601, a secondary outer curved edge 602, a third straight edge 603, and a fourth straight edge 604.

[0054] In an exemplary embodiment, secondary inner curved edge 601 may be attached to the outer surface of base tube 102. In an exemplary embodiment, a center of secondary inner curved edge 601 may coincide with center 125 of base tube 102. In an exemplary embodiment, a radius of secondary inner curved edge 601 may correspond to the outer radius of base tube 102. In an exemplary embodiment, a center of secondary outer curved edge 602 may coincide with center 125 of base tube 102. In other words, in an exemplary embodiment, secondary inner curved edge 601, secondary outer curved edge 602, and base tube 102 may be concentric. In an exemplary embodiment, third straight edge 603 may be at a first side 605 of secondary fin 502 and fourth straight edge 604 may be at a second side 606 of secondary fin 502.

[0055] In an exemplary embodiment, a first end 632 of third straight edge 603 may be attached to a first end 612 of secondary inner curved edge 601. In an exemplary embodiment, a second end 634 of third straight edge 603 may be attached to a first end 622 of secondary outer curved edge 602. In an exemplary embodiment, third straight edge 603 may be extended along a third axis 635. In an exemplary embodiment, third axis 635 may pass through center 125 of base tube 102.

[0056] In an exemplary embodiment, a first end 642 of fourth straight edge 604 may be attached to a second end 614 of secondary inner curved edge 601. In an exemplary embodiment, second end 644 of fourth straight edge 604 may be attached to second end 624 of secondary outer curved edge 602. In an exemplary embodiment, fourth straight edge 604 may be extended along a fourth axis 645. In an exemplary embodiment, fourth axis 645 may pass through center 125 of base tube 102.

[0057] As further shown in FIG. 5, in an exemplary embodiment, first axis 2265 and third axis 635 may define a first recess angle 505 between first axis 2265 and third axis 635. Also, in an exemplary embodiment, second axis 2285 and fourth axis 645 may define a second recess angle 506 between second axis 2285 and fourth axis 645. In an exemplary embodiment, first recess angle 505 and second recess angle 506 may be between 20° and 80°. In an exemplary embodiment, first recess angle 505 and second recess angle 506 may be equal. In an exemplary embodiment, first recess angle 505 and second recess angle 506 may be 45°. FIG. 7A shows a perspective view of partially finned tube 100 in a scenario in which exterior angle 2255 is 180° and first recess angle 505 and second recess angle 506 are both 45°, consistent with one or more exemplary embodiments of the present disclosure. FIG. 7B shows a top view of partially finned tube 100 in a scenario in which exterior angle 2255 is 180° and first recess angle 505 and second recess angle 506 are both 45°, consistent with one or more exemplary embodiments of the present disclosure. FIG. 7C shows a front view of partially finned tube 100 in a scenario in which exterior angle 2255 is 180° and first recess angle 505 and second recess angle 506 are both 45°, consistent with one or more exemplary embodiments of the present disclosure. In an exemplary embodiment, exterior angle, first recess angle 505, and second recess angle 506 may be determined based on the Reynolds number, the arrangement of finned tubes bundle, and the orientation and situation of partially finned tube 100 in the finned tubes bundle.

[0058] In order to investigate the hydrodynamic and thermal efficiency of different embodiments of disclosed partially finned tube 100, the external flow of the air on different embodiments of disclosed partially finned tube 100 and also on a typical finned tube have been simulated by using an open-source software for computational fluid dynamics (CFD) simulations such as OpenFOAM. In an exemplary embodiment, a typical finned tube may refer to a finned tube with fully annular fin tubes. FIG. 8A shows Nusselt Number VS Reynolds Number for some embodiments of partially finned tube 100 and a typical finned tube, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 8A, for a given Reynolds number, using different embodiments of partially finned tube 100 may increase the Nusselt number compared to the typical fully wrapped annular finned tube. FIG. 8B shows heat transfer rate in different Reynolds Number for some embodiments of partially finned tube 100 and a typical finned tube, consistent with one or more exemplary embodiments of the present disclosure. As shown in FIG. 8B, by using different embodiments of partially finned tube 100, the heat transfer may be reduced by a maximum of 21.2% while the material needed for finning the tube may be reduced by almost 50% (and at least 25%) in comparison with the typical fully wrapped annular finned tube. FIG. 8C shows thermal performance in different Reynolds Number for some embodiments of partially finned tube 100 and a typical finned tube, consistent with one or more exemplary embodiments of the present disclosure. For purpose of reference, it may be understood that in FIG. 8A, FIG. 8B, and FIG. 8C, “fully annular” may refer to a typical finned tube, “B-type” may refer to an embodiment of partially finned tube 100 in which exterior angle 2255 is 180° and first recess angle 505 and second recess angle 506 are both 45°, as shown in FIG. 7A, FIG. 7B, and FIG. 7C. “C-type” may refer to an embodiment of partially finned tube 100 in which secondary fin 502 does not exist and exterior angle 2255 is 90° and “D-type” may refer to an embodiment of partially finned tube 100 in which secondary fin 502 does not exist and exterior angle 2255 is 180°, as shown in FIG. 4A, FIG. 4B, and FIG. 4C [0059] In an exemplary embodiment, the term “thermal performance” for an embodiment of finned tube 100 may be defined as the ratio of Nusselt Number to the friction factor in a typical finned tube divided to the same ratio for the intended embodiment of finned tube 100. In an exemplary embodiment, it may be understood that the friction factor may have a direct relationship with the pressure drop and, therefore, lower friction factor may result in lower pressure drop. As shown in FIG. 8C, different embodiments of partially finned tube 100 may have higher thermal performance in comparison with the typical fully wrapped annular finned tube.

[0060] In an exemplary embodiment, different embodiments of partially finned tube 100 may be used as fin tube bundles with, for example, linear and staggered arrangements. FIG. 9A shows a schematic representation of an in-line arrangement of B-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. FIG. 9B shows a schematic representation of a staggered arrangement of B-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. FIG. 10A shows a schematic representation of an in-line arrangement of C-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. FIG. 10B shows a schematic representation of a staggered arrangement of C-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. FIG. 11A shows a schematic representation of an in-line arrangement of D-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. FIG. 11B shows a schematic representation of a staggered arrangement of D-type fin tubes bundle, consistent with one or more exemplary embodiments of the present disclosure. In FIG. 9A, FIG. 9B, FIG. 10A, FIG.

10B, FIG. 11A, and FIG. 11B, the arrow 8 may refer to the external flow direction. [0061] When the external flow passes over a tube, the velocity may be reduced at the back of the tube, called the weak region. Since the local Nusselt number is a function of the flow velocity, the convective heat transfer mechanism may be weakened at the back of the tube. As a result, in front of the tube, the mean local Nusselt number may be higher than the back of the tube and, therefore, more heat may transfer between the air and the fins installed in front of the tube, compared to the back of the tube. The reduction of the local heat transfer may be more noticeable at the separation points where the velocity of air equals zero. As, the local heat transfer at the back part of the tube is somewhat negligible, removing these areas may help saving material and reducing the weight of the heat exchangers as well as reducing the pressure drop.

[0062] As previously detailed, disclosed partially finned tube 100 may be designed as a partially wrapped fin tube intended for use in heat exchangers. For purpose of reference, it may be understood that these heat exchangers may be used in numerous industrial applications such as power plants, oil, and gas, petrochemical, food industries, etc. Unlike conventional fully wrapped annular fin tubes, only specific sections of the tube exhibiting significant heat transfer potential are covered with fins. Within the structure of disclosed partially finned tube 100, a noteworthy reduction in pressure drops and the overall weight of the heat exchanger is achieved, all while substantially maintaining thermal performance and the heat transfer rate from the fin surface at levels comparable to traditional configurations. This innovation may translate to a potential decrease in both raw material costs for finning and the electricity required to drive external flow, contributing to a substantial overall cost reduction.

[0063] While the foregoing has described what may be considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that the teachings may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all applications, modifications and variations that fall within the true scope of the present teachings.

[0064] Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

[0065] The scope of protection is limited solely by the claims that now follow. That scope is intended and should be interpreted to be as broad as is consistent with the ordinary meaning of the language that is used in the claims when interpreted in light of this specification and the prosecution history that follows and to encompass all structural and functional equivalents. Notwithstanding, none of the claims are intended to embrace subject matter that fails to satisfy the requirement of Sections 101, 102, or 103 of the Patent Act, nor should they be interpreted in such a way. Any unintended embracement of such subject matter is hereby disclaimed.

[0066] Except as stated immediately above, nothing that has been stated or illustrated is intended or should be interpreted to cause a dedication of any component, step, feature, object, benefit, advantage, or equivalent to the public, regardless of whether it is or is not recited in the claims.

[0067] It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective spaces of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0068] The Abstract of the Disclosure is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims . In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various implementations. This is for purposes of streamlining the disclosure, and is not to be interpreted as reflecting an intention that the claimed implementations require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed implementation. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.

[0069] While various implementations have been described, the description is intended to be exemplary, rather than limiting and it will be apparent to those of ordinary skill in the art that many more implementations and implementations are possible that are within the scope of the implementations. Although many possible combinations of features are shown in the accompanying figures and discussed in this detailed description, many other combinations of the disclosed features are possible. Any feature of any implementation may be used in combination with or substituted for any other feature or element in any other implementation unless specifically restricted. Therefore, it will be understood that any of the features shown and/or discussed in the present disclosure may be implemented together in any suitable combination. Accordingly, the implementations are not to be restricted except in light of the attached claims and their equivalents. Also, various modifications and changes may be made within the scope of the attached claims.

Claims

What is claimed is:

1. A partially finned tube for a heat exchanger, comprising: a base tube; and a plurality of finned sections attached to an outer surface of the base tube and along a main longitudinal axis of the base tube, a finned section from the plurality of finned sections comprising: a main fin, the main fin comprising: an inner curved edge, the inner curved edge attached to an outer surface of the base tube, a radius of the inner curved edge corresponding to an outer radius of the base tube, a center of the inner curved edge coinciding with a center of the base tube; an outer curved edge, a center of the outer curved edge coinciding with the center of the base tube; a first straight edge at a first side of the fin, a first end of the first straight edge attached to a first end of the inner curved edge, a second end of the first straight edge attached to a first end of the outer curved edge, the first straight edge extended along a first axis, the first axis passes through the center of the base tube; and a second straight edge at a second side of the fin, a first end of the second straight edge attached to a second end of the inner curved edge, a second end of the second straight edge attached to a second end of the outer curved edge, the second straight edge extended along a second axis, the second axis passes through the center of the base tube; and a secondary fin, the secondary fin comprising: a secondary inner curved edge, the secondary inner curved edge attached to the outer surface of the base tube, a radius of the secondary inner curved edge corresponding to the outer radius of the base tube, a center of the secondary inner curved edge coinciding with the center of the base tube; a secondary outer curved edge, a center of the secondary outer curved edge coinciding with the center of the base tube; a third straight edge at a first side of the secondary fin, a first end of the third straight edge attached to a first end of the secondary inner curved edge, a second end of the third straight edge attached to a first end of the secondary outer curved edge, the third straight edge extended along a third axis, the third axis passes through the center of the base tube; and a fourth straight edge at a second side of the secondary fin, a first end of the fourth straight edge attached to a second end of the secondary inner curved edge, a second end of the fourth straight edge attached to a second end of the secondary outer curved edge, the fourth straight edge extended along a fourth axis, the fourth axis passes through the center of the base tube; wherein: the first axis and the second axis define an exterior angle between the first axis and the second axis, the exterior angle being equal to 180°; and the first axis and the third axis define a first recess angle between the first axis and the third axis, the first recess angle being equal to 45°; and the second axis and the fourth axis define a second recess angle between the second axis and the fourth axis, the second recess angle being equal to 45°.

2. A partially finned tube for a heat exchanger, comprising: a base tube; and a plurality of finned sections attached to an outer surface of the base tube and arranged along a main longitudinal axis of the base tube, a finned section from the plurality of finned sections comprising a main fin, the main fin comprising: an inner curved edge, the inner curved edge attached to the outer surface of the base tube, a center of the inner curved edge coinciding with a center of the base tube, a radius of the inner curved edge corresponding to an outer radius of the base tube; an outer curved edge, a center of the outer curved edge coinciding with the center of the base tube; a first straight edge at a first side of the main fin, a first end of the first straight edge attached to a first end of the inner curved edge, a second end of the first straight edge attached to a first end of the outer curved edge, the first straight edge extended along a first axis, the first axis passes through the center of the base tube; and a second straight edge at a second side of the fin, a first end of the second straight edge attached to a second end of the inner curved edge, a second end of the second straight edge attached to a second end of the outer curved edge, the second straight edge extended along a second axis, the second axis passes through the center of the base tube; wherein the first axis and the second axis define an exterior angle between the first axis and the second axis.

3. The partially finned tube of claim 2, wherein the finned section further comprises a secondary fin, the secondary fin comprising: a secondary inner curved edge, the secondary inner curved edge attached to the outer surface of the base tube, a center of the secondary inner curved edge coinciding with the center of the base tube, a radius of the secondary inner curved edge corresponding to the outer radius of the base tube; a secondary outer curved edge, a center of the secondary outer curved edge coinciding with the center of the base tube; a third straight edge at a first side of the secondary fin, a first end of the third straight edge attached to a first end of the secondary inner curved edge, a second end of the third straight edge attached to a first end of the secondary outer curved edge, the third straight edge extended along a third axis, the third axis passes through the center of the base tube; and a fourth straight edge at a second side of the secondary fin, a first end of the fourth straight edge attached to a second end of the secondary inner curved edge, a second end of the fourth straight edge attached to a second end of the secondary outer curved edge, the fourth straight edge extended along a fourth axis, the fourth axis passes through the center of the base tube.

4. The partially finned tube of claim 3, wherein the exterior angle is between 40° and 180°.

5. The partially finned tube of claim 4, wherein: the exterior angle between the first axis and the second axis is 180°; the first axis and the third axis define a first recess angle between the first axis and the third axis, the first recess angle being between 20° and 80°; and the second axis and the fourth axis define a second recess angle between the second axis and the fourth axis, the second recess angle being between 20° and 80°.

6. The partially finned tube of claim 5, wherein the exterior angle is 180°.

7. The partially finned tube of claim 6, wherein the first recess angle is equal to the second recess angle.

8. The partial finned tube of claim 7, wherein the first recess angle and the second recess angle are both equal to 45°.

9. A partially finned tube for a heat exchanger, comprising: a base tube; and a plurality of finned sections attached to an outer surface of the base tube and arranged along a main longitudinal axis of the base tube, a finned section from the plurality of finned sections comprising a main fin, the main fin comprising: an inner edge, the inner edge attached to the outer surface of the base tube; an outer edge; a first edge at a first side of the main fin, a first end of the first edge attached to a first end of the inner edge, a second end of the first edge attached to a first end of the outer edge, the first edge extended along a first axis; and a second edge at a second side of the fin, a first end of the second edge attached to a second end of the inner edge, a second end of the second edge attached to a second end of the outer edge, the second edge extended along a second axis; wherein the first axis and the second axis define an exterior angle between the first axis and the second axis.

10. The partially finned tube of claim 9, wherein the finned section further comprises a secondary fin, the secondary fin comprising: a secondary inner edge, the secondary inner edge attached to the outer surface of the base tube; a secondary outer edge; a third edge at a first side of the secondary fin, a first end of the third edge attached to a first end of the secondary inner edge, a second end of the third edge attached to a first end of the secondary outer edge, the third edge extended along a third axis; and a fourth edge at a second side of the secondary fin, a first end of the fourth edge attached to a second end of the secondary inner edge, a second end of the fourth edge attached to a second end of the secondary outer edge, the fourth edge extended along a fourth axis.

11. The partially finned tube of claim 10, wherein the exterior angle is between 40° and 180°.

12. The partially finned tube of claim 11, wherein: the exterior angle between the first axis and the second axis is 180°; the first axis and the third axis define a first recess angle between the first axis and the third axis, the first recess angle being between 20° and 80°; and the second axis and the fourth axis define a second recess angle between the second axis and the fourth axis, the second recess angle being between 20° and 80°.

13. The partially finned tube of claim 12, wherein the exterior angle is 180°.

14. The partially finned tube of claim 13, wherein the first recess angle is equal to the second recess angle.

15. The partial finned tube of claim 14, wherein the first recess angle and the second recess angle are both equal to 45°.