Tubular heat exchanger

Abstract

A tubular heat exchanger includes an inlet, an outlet, and staggered heat transfer tubes positioned axially between the inlet and the outlet. The heat transfer tubes are divided into three groups, and the three groups of tubes have different cross-sectional shapes and different conical characteristics. The first set of tubes has a more sharply tapering forward section, the second set of tubes has a more sharply tapering rearward section, and the third set of tubes has a unique elongated shape different from the first two sets of tubes.

Description

TECHNICAL FIELD

[0001] The present utility model relates to a tube heat exchanger, which comprises an inlet section and an outlet section, and a plurality of heat transfer tubes arranged between the inlet section and the outlet section, between which an flow direction is defined. Furthermore, the present utility model relates to a system or device comprising a tube heat exchanger. BACKGROUND

[0002] Tube heat exchangers are widely used for transferring heat between two or more fluids. Typically, such devices function by enabling one fluid to flow through tubes while another fluid flows outside the tubes. The efficiency and performance of these heat exchangers are influenced by a variety of factors, including the design, arrangement, and geometry of the tubes.

[0003] There are a variety of designs for tube heat exchangers in the prior art, each having its own set of advantages and disadvantages. Conventional designs often face challenges such as inadequate heat transfer, increased propensity for fouling, pressure drop issues, and low flow distribution efficiency. To maximize heat transfer performance, it is crucial to optimize the surface area contact between the fluids and the tubes. Furthermore, the arrangement of the tubes can play a significant role in improving the overall efficiency of the heat exchanger.

[0004] In addition to the arrangement of the tubes, the cross-sectional shape of the tubes can greatly influence the heat transfer performance. The shape of the tubes determines the flow pattern of the fluids, affecting the characteristics of the boundary layer and, in turn, the heat transfer rate. Tubes with regular circular, elliptical, or teardrop-shaped cross-sections can not always provide optimal performance, especially in applications requiring enhanced heat transfer characteristics.

[0005] Furthermore, using a single tube shape or design throughout the heat exchanger can not always yield the desired performance results. Different sections of the heat exchanger can benefit from different tube designs tailored to their specific requirements. Therefore, there is a strong need to improve the design and arrangement of the tubes in tube heat exchangers to address existing limitations and adapt to different requirements of various applications.

[0006] In view of the above challenges, the present utility model seeks to address the need for improved tube heat exchanger designs aimed at enhancing overall efficiency and performance. SUMMARY

[0007] It is an object of the present utility model to provide a system that eliminates at least one of the above-mentioned drawbacks.

[0008] Additionally or alternatively, it is an object of the present utility model to provide an improved tube heat exchanger.

[0009] Additionally or alternatively, it is an object of the present application to provide a tube heat exchanger that works at enhanced efficiency levels.

[0010] Additionally or alternatively, it is an object of the present application to provide a tube heat exchanger with improved tube design that ensures the tubes contribute to achieving enhanced heat exchange performance.

[0011] To this end, the present application provides a tube heat exchanger comprising: an inlet portion and an outlet portion defining a flow direction therebetween; a plurality of heat transfer tubes arranged between the inlet portion and the outlet portion, wherein the plurality of heat transfer tubes extend along an axial path, wherein the plurality of heat transfer tubes are arranged in a staggered pattern in which every other row of heat transfer tubes is offset from the row of heat transfer tubes adjacent thereto; wherein a first group of heat transfer tubes is provided at a front end, a second group of heat transfer tubes is provided at a rear end, and a third group of heat transfer tubes is provided at a location between the first group of tubes and the second group of tubes; wherein, in a cross-sectional view along a transverse plane or an angled plane relative to the axial path, the first group of tubes has an elongated shape with a first intermediate section, a first front section and a first rear section, the first front section and the first rear section each being contiguous with the first intermediate section, wherein the first front section and the first rear section start at a location where the tube begins to taper inwardly and extend to a respective outermost point of the tube, wherein the first intermediate section, the first front section and the first rear section are smoothly connected to form a continuous outer boundary of the first group of tubes, wherein the first front section and the first rear section each exhibit a convex curvature, wherein the first front section has a first taper and the first rear section has a second taper, wherein the first taper is greater than the second taper such that the first front section narrows more sharply relative to the first rear section; wherein, in a cross-sectional view along a transverse plane or an angled plane relative to the axial path, the second group of tubes has an elongated shape with a second intermediate section, a second front section and a second rear section, the second front section and the second rear section each being contiguous with the second intermediate section, wherein the second front section and the second rear section start at a location where the tube begins to taper inwardly and extend to a respective outermost point of the tube, wherein the second intermediate section, the second front section and the second rear section are smoothly connected to form a continuous outer boundary of the second group of tubes, wherein the second front section and the second rear section each exhibit a convex curvature, wherein the second rear section has a third taper and the second front section has a fourth taper, wherein the third taper is greater than the fourth taper such that the rear section narrows more sharply relative to the front section; and wherein, in a cross-sectional view along a transverse plane or an angled plane relative to the axial path, the third group of tubes has an elongated shape that is different from the shape of the first group of tubes and the second group of tubes.

[0012] A tube heat exchanger includes an inlet portion and an outlet portion that together define a flow direction. A plurality of heat transfer tubes are systemically located between the inlet and outlet portions. The tubes are aligned along an axial trajectory and are systemically arranged in a staggered arrangement. In such an arrangement, every other row of tubes is arranged to be offset from the row of tubes adjacent thereto. Specifically, the heat exchanger includes a first set of tubes located at a front end of the heat exchanger, a second set of tubes located at a rear end of the heat exchanger, and a third set of tubes located between the first and second sets of tubes. The first and second sets of tubes exhibit a unique elongated shape when viewed in a cross-sectional view along a plane that is angled relative to the axial path or a transverse plane. The design of the tubes and the unique shape of the tubes provide for maximum surface area contact, ensuring improved heat transfer. This enhancement in heat transfer translates directly into an increase in heat exchanger efficiency.

[0013] In some examples, the tube heat exchanger has staggered tubes of different shapes. The staggered arrangement can ensure that every other row of tubes is offset from the row of tubes adjacent thereto. Three different sets of tubes are provided: a front end set (first set), a rear end set (second set), and a middle set (third set). The front section of the first set of tubes narrows more sharply than the rear section of the first set of tubes, while the rear section of the second set of tubes tapers more sharply than the front section of the second set of tubes. Importantly, the third set of tubes exhibits a different shape than the first and second sets, highlighting the versatility of the heat exchanger design to optimize heat transfer.

[0014] The heat transfer tubes can be aligned in various configurations, for example, the heat transfer tubes can be linearly, helically, or radially aligned. In some examples, the tubes are aligned along an axial path. The tubes can be arranged in various staggered patterns, for example, a zigzag pattern or a concentric pattern. Each set of tubes (first set of tubes, second set of tubes, and third set of tubes) can exhibit unique characteristics.

[0015] In some examples, the first set of tubes and the second set of tubes form elongated heat transfer elements. For example, the cross-sectional two-dimensional geometric profile in the plane of the first set of tubes comprises a semi-elliptic curve at the leftmost border of the tube, wherein the vertical axis of the semi-elliptic curve exceeds its horizontal axis in length. Immediately after the starting configuration of the semi-ellipse, the element extends into two parallel, separate and uninterrupted linear sections, each of which emanates from a respective end point of the aforementioned semi-elliptic curve and proceeds to the right. This is followed by a subsequent section with converging taper. After the straight extension, the subsequent section after the linear sections exhibits a pronounced taper, gradually converging towards each other in a non-parallel direction. This converging trajectory ends at the intersection of the sections, forming an angle of less than 90 degrees and yielding a pronounced pointed end, which is positioned as the rightmost end of the element. However, it is also possible to use a rounded end instead of the pointed end. The second set of tubes can have a similar, but mirrored configuration. Slight variations in size can be allowed. The design and configuration of these heat transfer elements contribute to improved heat conduction and guidance of heat flow.

[0016] Optionally, data representing the optimized geometric design of each heat transfer element is output.

[0017] Optionally, the data representing the optimized geometric design is transmitted to a production device configured for producing the heat transfer arrangement.

[0018] Optionally, the production device comprises an additive manufacturing system.

[0019] Optionally, an additive manufacturing system is employed, which is configured for manufacturing at least certain parts of the optimized heat transfer arrangement based on the optimized design parameters.

[0020] Optionally, the output signal representing the optimized geometric design is transmitted to a production device configured for producing an optimized physical object from the output signal.

[0021] Optionally, the physical object is a heat transfer arrangement or a part of a heat transfer arrangement.

[0022] It is to be understood that the term "physical object" refers to any tangible item that can be produced based on the optimized geometric design obtained from the computer-implemented method. The heat transfer arrangement can be the main product for which the method is designed to be optimized. The heat transfer arrangement can be considered as a component comprising a plurality of heat transfer elements. The optimized design can aim to improve aspects such as efficiency, effectiveness and / or manufacturability of the arrangement.

[0023] It will be appreciated that the optimisation design can be used to manufacture only certain parts or components of the heat transfer device, rather than the entire heat transfer device. For example, if the heat transfer device is composed of several different types of elements, the method can optimise the design of one particular type of element, and only that element can be produced based on the optimised design.

[0024] Optionally, in a cross-sectional view along a transverse plane or an angled plane relative to the axial path, the third set of tubes has only a third front section and a third back section abutting each other.

[0025] In some examples, the tubes in the third set have only a front section and a back section directly abutting each other when viewed in cross-sectional view. This can further improve the heat transfer efficiency in the tube heat exchanger. In various cases and configurations, enhanced flow dynamics and / or heat exchange performance can be achieved.

[0026] This simplification of the shape of the tubes can further improve the heat transfer process by eliminating any distinct intermediate sections, as it provides a more direct path for the heat exchange medium, thereby facilitating faster heat exchange and improved efficiency.

[0027] The absence of a distinct intermediate section in the third set of tubes, i.e. the tubes primarily comprising a third front section and a third back section seamlessly abutting each other, can reduce potential flow resistance introduced by a distinct intermediate section. As such, this design facilitates a more efficient and streamlined flow of the heat exchange medium. In combination with the characteristics of the first set of tubes and the second set of tubes, an improved heat transfer rate can be achieved as the medium is able to interact better with the tube surface.

[0028] Optionally, in a cross-sectional view along a transverse plane or an angled plane relative to the axial path, the third set of tubes has an elongated shape with a third intermediate section, a third front section and a third back section, the third front section and the third back section each abutting the third intermediate section, wherein the third front section and the third back section start at a location where the tube begins to taper inwardly and extend to a respective outermost point of the tube, wherein the third intermediate section, the third front section and the third back section are smoothly connected to form a continuous outer boundary of the third set of tubes, wherein the third front section and the third back section each exhibit a convex curvature, and wherein the third front section and the third back section start at a location where the tube begins to taper inwardly and extend to a respective outermost point of the tube.

[0029] The third set of tubes is further elaborated in some examples of heat exchangers, which have an elongated shape and comprise a middle section flanked by a front section and a back section. These sections transition smoothly, forming a continuous outer boundary. Both the front section and the back section originate at a point where the tube begins to taper inward and exhibit a convex curvature, thereby accentuating an optimized shape for efficient heat transfer.

[0030] The design of these tubes includes a third middle section that seamlessly connects a third front section and a third back section on either side. The curvature of these front and back sections emanates from a specific juncture at which the tube begins to taper inward and seamlessly continues until the front and back sections reach their respective outermost limits. The presence of the third middle section, in conjunction with the adjacent front and back sections, increases the surface area available for heat exchange. This increased surface area can translate into more prolonged contact between the tube walls and the heat exchange medium, which in turn can increase the rate of heat transfer. Furthermore, the specified tube geometry promotes consistent flow dynamics, ensuring uniform flow of the heat exchange medium, minimizing the likelihood of turbulent or unstable flow patterns.

[0031] Optionally, the first middle section and the second middle section both have a convexity that is substantially less convex than the convexity of the third middle section.

[0032] In some examples, the middle sections of the first and second sets of tubes exhibit a substantially less convexity compared to the middle section of the third set of tubes. This difference in convexity provides significant advantages in directing fluid flow and improving the thermal efficiency of the exchanger.

[0033] The middle sections of the first and second sets of tubes are characterized by a substantially reduced convexity, such that the middle sections of the first and second sets of tubes are less convexly outward than the substantially convex middle section. This intentional variation in the curvature of the different sets of tubes can improve the flow dynamics of the heat exchange medium inside the tube heat exchanger. The first and second sets of tubes have a reduced convexity for directing the flow of the heat exchange medium and efficiently channeling the heat exchange medium across the tube surface. On the other hand, the more prominently convex third middle section presents an enlarged surface area that can facilitate more contact with the medium, at least for some operating conditions of the tube heat exchanger. The cumulative effect of these design choices is that the heat exchange medium can be more exposed to various tube surfaces during its flow, thereby ensuring an improved rate of heat transfer. This enhanced interaction between the medium and the tube surfaces inherently amplifies the heat transfer capacity of the tube heat exchanger.

[0034] Optionally, the first middle section and the second middle section are substantially flat.

[0035] In some examples, the intermediate sections of the first set of tubes and the intermediate sections of the second set of tubes are substantially flat or quasi-flat. In some embodiments, only a small curvature or negligible curvature is allowed for these intermediate sections. This means that while the intermediate sections of the first set of tubes and the intermediate sections of the second set of tubes can exhibit slight deviations from a perfectly flat profile, any such deviations are limited to ensure that the primary characteristic of these sections remains substantially planar.

[0036] This flat design ensures that the heat exchange medium is able to flow without significant disturbance, which would otherwise hinder the heat exchange process. Thus, the substantially flat profile can further streamline the flow and promote efficient heat transfer within the exchanger. This design choice promotes smooth flow dynamics and optimizes heat transfer, thereby improving the efficiency of the heat exchanger.

[0037] Optionally, the third intermediate section has a curved portion.

[0038] In some examples, the third intermediate section of the tube comprises a curved section. This curvature can ensure improved flow of the heat exchange medium, thereby promoting better heat transfer. The medium can effectively contact a larger surface area of the tube, thereby improving the overall heat exchange rate and efficiency of the system.

[0039] The third intermediate section of the respective tube can have different curved sections in different ways, for example, selected based on operating conditions (flow rate, flow characteristics, temperature, properties of the medium). The presence of such curvature within the intermediate section can improve the dynamic interaction of the medium with the surface of the tube, enhancing the thermal contact between the medium and the tube, thereby promoting a more efficient and rapid heat exchange process.

[0040] A larger portion of the heat exchange medium can be in direct contact with the surface of the tube, thereby maximizing the heat exchange potential. This increased surface interaction accelerates the heat exchange rate, enabling the system to operate with higher efficiency. Thus, a more consistent and comprehensive thermal interaction can be achieved across the entire length of the tube.

[0041] In some examples, the third intermediate section of the tube in the tube heat exchanger can have different curved designs. In some alternative examples, the curved portion can be semi-circular, parabolic, or even wavy, thereby presenting different heat transfer characteristics.

[0042] Optionally, the first intermediate section and the second intermediate section each extend over a range of 20% to 60% of the total length of their respective tubes.

[0043] In some design variations, the length coverage of the first and second intermediate sections of the respective tubes in the heat exchanger can range from one fifth to more than half of the total tube length. In alternative embodiments, this range can be modified to be narrower or wider, depending on the required heat transfer efficiency and flow dynamics.

[0044] In some examples, the intermediate sections of the first and second groups of tubes extend over a range of 20% to 60% of the total length of the tubes. Advantageously, such a design provides a balance between flow dynamics and maximizing heat transfer efficiency.

[0045] By optimizing this length, the heat exchanger ensures that the medium is optimally exposed to the tubes, thereby facilitating enhanced heat transfer. This length range is specifically chosen to provide a balance between maximizing exposure and ensuring smooth flow dynamics, thereby enhancing efficiency.

[0046] Advantageously, the tubes are able to provide a wide and consistent surface for the medium to interact with, without unnecessarily lengthening the flow path, which can decrease heat exchange rates. While increasing surface area contact is important, it is also important to ensure that the medium flows through the tubes without significant obstruction. By limiting the intermediate sections to the defined range mentioned above, a harmonious coexistence between the heat exchange medium experiencing enhanced exposure for improved heat transfer and unhindered flow for maintaining stable exchange rates is achieved.

[0047] Optionally, the first and second intermediate sections each extend over a range of 30% to 50% of the total length of their respective tubes.

[0048] In some examples, the intermediate sections of the first and second groups of tubes cover a range between 30% and 50% of the entire tube length of these tubes, thereby pinpointing the design sweet spot for achieving improved heat exchange performance.

[0049] This particular range strikes a balance between increasing heat transfer surface area and ensuring that the medium does not face excessive resistance or disturbance during flow. This balance directly impacts the overall efficiency of the heat exchanger in a positive manner.

[0050] In some examples, other ranges can be employed, such as 25% to 55% or even 35% to 45%, thereby enabling customization of heat transfer efficiency on demand.

[0051] Optionally, the third intermediate section extends over a range of 0.5% to 20% of the total length of the respective tube, preferably over a range of 1% to 10%.

[0052] In some examples, the third intermediate section can range from occupying only 0.5% to about 20% of the total length of the tube, preferably in the range of 1% to 10%. This indicates that the third intermediate section is relatively small compared to the length of the first and second intermediate sections.

[0053] The intermediate section of the third set of tubes is an important section that influences the flow and heat transfer dynamics, which ranges only a limited extension of the total length of the tube. In particular, this length falls in the range of 0.5% to 20% or even narrower, preferably only 1% to 10%.

[0054] It is known that turbulence in the flow of the heat exchange medium is beneficial. When the medium moves in a turbulent manner, the medium tends to come into contact with a larger surface area of the tube, thereby increasing the heat transfer rate. The third set of tubes can induce turbulence. However, the challenge is how to ensure that this turbulence is beneficial, but not beyond its limits. Excessive turbulence can lead to flow disturbances, backflow, and even mechanical wear. Therefore, the design choice of limiting the intermediate section of the third set of tubes to a maximum of 20%, preferably even smaller to 10%, becomes very important. This limited range means that while the tubes induce the required turbulence, they do not let the turbulence become uncontrolled or harmful.

[0055] By keeping the turbulence-inducing intermediate section at this optimal length, the present utility finds a balance point between the two opposing requirements of both needing turbulence to improve heat transfer and preventing excessive disturbance that can hinder efficient flow. With this balancing act, the heat exchanger achieves an optimal point where the advantages of turbulence are maximized without compromising the criticality of smooth and consistent flow dynamics. The result is a system that is not only efficient but also reliable, ensuring that the heat exchange process is both effective and sustainable.

[0056] In some examples, the third intermediate section of the tube can extend over a small fraction (e.g., 0.5%) to about one-fifth of the total tube length in cross-section in certain design variations. However, alternative embodiments can adjust this range, for example, from 2% to 15% or from 1% to 5%, depending on the specific use case and desired efficiency.

[0057] Optionally, the first taper and the third taper are substantially the same, and wherein the second taper and the fourth taper are substantially the same.

[0058] The simplification of the structural design of the tube not only enhances the heat exchange performance but also reduces manufacturing complexity, thereby saving production costs.

[0059] In some examples, the taper of the front section of the first set of tubes and the taper of the back section of the second set of tubes are very similar. Similarly, the taper of the back section of the first set of tubes and the taper of the front section of the second set of tubes are also very close. This uniformity / consistency in taper can simplify fluid flow and enhance the thermal performance of the exchanger.

[0060] By maintaining this uniformity, the tubes ensure consistent flow characteristics throughout the heat exchanger. This consistency facilitates a stable and efficient heat exchange process, directly enhancing the overall efficiency of the system.

[0061] The term “taper” can be understood as the angle or gradient at which these sections narrow or widen, affecting how these sections interact with the flowing heat exchange medium.

[0062] Fluids, including heat exchange mediums, have specific flow dynamics as they pass through tubes. If the shape or dimensions of the tubes change, it affects the way the fluid flows. By ensuring that the tapers of these sections are equal, the heat exchanger can maintain consistency in the flow of the medium throughout the device.

[0063] Differences in tube taper can lead to variations in flow rate, turbulence, and even disturbances that can disrupt the heat exchange process. A uniform taper can reduce the likelihood of such disturbances, ensuring smooth flow of the medium.

[0064] Furthermore, stability is a critical component of heat exchanger efficiency. Variations, especially sudden ones, can lead to temperature fluctuations, resulting in an unstable exchange process. The uniform taper of the cross-section within the tubes ensures that the heat exchange remains stable, maximizing the efficiency of the heat exchange process.

[0065] In some examples of tube heat exchangers, the tapers of the front sections of the first and third sets of tubes and the back sections of the second and fourth sets of tubes can be almost identical. However, alternative designs can exhibit slight variations between these tapers, or can incorporate other design features, such as flanges or fins, to alter the thermal performance of the tubes.

[0066] The term “taper” refers to a specific angular measurement or gradient that characterizes the gradual decrease or increase in the cross-sectional diameter or dimension of an elongated structure (see the cross-sectional profile of the tube). This gradient can quantify the rate at which the structure transitions from a wider section to a narrower section (or vice versa). Taper is intrinsically linked to the design and function of the structure, influencing flow dynamics, structural integrity, and other related performance.

[0067] In simpler terms, taper can be understood as the steepness at which the tube narrows (inward) as one moves along its length towards the end. It provides a measurable way to describe and differentiate between tubes that narrow gradually, slowly, and tubes that narrow abruptly.

[0068] Taper provides a precise and objective way to express how the shape of the tube varies. In some examples, the taper can be expressed and / or approximated as an angle or ratio, or expressed and / or approximated by an angle or ratio. The particular taper chosen in the design of the structure will have an impact on the function of the tube. For a tube in a heat exchanger, the taper will affect the flow rate, turbulence, and overall efficiency of heat transfer.

[0069] When the taper is consistent across different sections of the structure, this can ensure uniform flow characteristics, minimizing disruptions and improving the overall efficiency of the tube heat exchanger.

[0070] Optionally, the first set of tubes and the second set of tubes have substantially the same geometric configuration, and wherein the second set of tubes is arranged in a mirror configuration relative to the first set of tubes.

[0071] In some examples, the first set of tubes and the second set of tubes not only share a similar geometric configuration, but are also arranged such that the second set of tubes is a mirror of the first set of tubes. This symmetrical arrangement can play an important role in coordinating the flow dynamics across the exchanger.

[0072] The tubes from the first set and the tubes from the second set can have nearly identical geometric structures. Furthermore, the tubes from the second set are arranged in a mirror image relative to the tubes from the first set. This symmetrical design helps to enhance heat transfer performance, resulting in a more efficient heat exchanger.

[0073] In some examples, the first set of tubes and the second set of tubes share nearly identical geometric designs. This means that the dimensions, shape, and overall configuration of the tubes are virtually indistinguishable. This consistency can simplify the manufacturing process, reduce costs, and ensure that any observations or enhancements made to one set of tubes can be directly applied to the other set of tubes. In addition to having similar structures, the tubes from the second set are arranged such that the tubes from the second set are a mirror image of the tubes from the first set. This is similar to placing an object in front of a mirror and seeing the reflection of the object. This mirror arrangement can be performed in a plane that is perpendicular to the longitudinal length direction of the cross-sectional profile of the tube (i.e., substantially along the direction of the flow direction).

[0074] The symmetrical design facilitates uniform distribution of the heat exchange medium, ensuring that the medium is maximally exposed to the tube surface. This directly impacts the rate of heat transfer and makes it more efficient. Without this symmetry, there is a risk that one section can have hotter or cooler areas than another section, leading to inefficiencies and potential long-term issues.

[0075] Optionally, the first rear section and the second front section have pointed ends.

[0076] In some examples, the rear section of the first set of tubes and the front section of the second set of tubes terminate in a pointed end. These pointed profiles can help to direct fluid flow or minimize flow resistance, thereby aiding the efficiency of the exchanger under various operating conditions.

[0077] This pointed design ensures that the heat exchange medium is directed in a specific path, thereby optimizing the exposure of the heat exchange medium to the tube surface. This increased exposure and directed flow results in improved heat transfer performance, thereby providing a more efficient heat exchanger.

[0078] In some examples, the sections end in a tapered point or a sharp point, rather than having a flat, rounded, or other shaped end. The design of the pointed end can better direct or guide the flow of the heat exchange medium. By directing the flow in a specific direction, the medium can be caused to follow a predetermined path. This directional flow ensures that the heat exchange medium does not spread or divert in an undesired path, but rather flows in a manner that maximizes exposure to the tube surface.

[0079] Due to the pointed design, the medium is directed in a specific path, increasing the likelihood of more of the medium coming into direct contact with the tube surface. This is beneficial, as more surface contact between the medium and the tube means more efficient heat transfer.

[0080] Alternatively, the first rear section and the second front section have a rounded end.

[0081] Alternatively, in other examples, the rear section of the first set of tubes and the front section of the second set of tubes terminate in a rounded end. This rounded end can be key to reducing flow disruption and enhancing heat exchange.

[0082] The rounded design promotes smoother flow dynamics, reducing any sharp bends or disruptions that can impede the flow of the heat exchange medium. By ensuring smoother flow, the heat exchanger enhances its heat transfer performance, enabling improved efficiency under various operating conditions.

[0083] In some examples, instead of a pointed end, the end of the first rear section and the end of the second front section can be rounded. This means that the end is curved or semi-circular, as opposed to sharp or flat. The rounded end can be used to mitigate flow disruption. The flow characteristics of the heat exchange medium can be enhanced. The rounded structure inherently reduces sharp turns or sudden changes in flow direction. This means that the heat exchange medium flows through these rounded ends in a more laminar, less turbulent manner. While some turbulence can be beneficial for heat exchange, excessive turbulence can lead to undesirable effects such as increased pressure drop, or even wear and tear. Thus, the rounded design strikes a balance, providing sufficient exposure without causing excessive turbulence.

[0084] As the heat exchange medium experiences less disturbance and a smoother flow, the likelihood of effective heat transfer between the medium and the tubes increases.

[0085] Optionally, each tube exhibits curvature that is symmetric about a central chord.

[0086] In some examples, each tube is characterized by having curvature symmetrically across a central chord. This symmetric design emphasizes a balanced approach, ensuring uniform flow characteristics and improved heat transfer. This balanced flow contributes to increased heat transfer performance, directly impacting the efficiency of the heat exchanger in a positive manner.

[0087] In geometric terms, a chord is a straight line connecting two points on a curve or circle. Thus, in the context of a tube, this means that if one were to draw a straight line (chord) from one side of the tube to the other, the curvature above this line would mirror the curvature below. This symmetric design ensures uniformity in the tube structure, which is crucial for consistent performance and predictable flow dynamics. Balanced flow translates to uniform distribution of the heat exchange medium over the tube surface. This ensures that all parts of the tube are effectively involved in the heat transfer process. With uniform distribution, the heat exchange medium is also consistently exposed to the tube surface. This means that every section of the tube has an equal opportunity to transfer heat, thereby optimizing the overall heat exchange process.

[0088] Any feature that promotes uniform and balanced flow inherently aims to increase heat transfer performance. By ensuring that the heat exchange medium is uniformly exposed to the tube surface, more effective heat exchange can occur. As a direct result of this increased heat transfer, the efficiency of the heat exchanger is improved.

[0089] In the design of a tube heat exchanger, the structural arrangement of the tubes plays a significant role in determining performance and efficiency. A prevalent configuration is the matrix or array layout. This layout arranges the tubes in a systematic, grid-like pattern, where the tubes can be arranged parallel to each other, perpendicular, or at different angles, resulting in a cohesive matrix. The precise geometry and spacing of this matrix can be customized to optimize fluid flow, maximize surface area exposure, thereby enhancing heat transfer performance. In addition to simple straight-line arrangements, the tubes within the matrix can be staggered or offset, as seen in some described embodiments, to further optimize turbulent flow and enhance heat transfer coefficients. The inherent modularity of the matrix layout allows for scalable designs, facilitating the adaptation of the heat exchanger to various capacities and applications. Furthermore, the array configuration ensures uniform distribution of thermal stress across the tubes, thereby improving the durability and service life of the heat exchanger system. Thus, the matrix / array layout, through its orderly and adaptable structure of arrangement, can provide a balanced fusion of functionality and design flexibility in a tube heat exchanger system.

[0090] Optionally, the tubes are structurally arranged in a radial layout.

[0091] Respective radial layouts are distinguished by arranging the tubes in concentric circles or arcs radiating from a central point or axis. This configuration takes advantage of radial symmetry principles. An inherent advantage of a radial layout is that it can provide consistent heat transfer throughout the exchanger, as each tube is equidistant from the center, thereby ensuring uniform heat distribution and fluid dynamics. This is particularly beneficial in applications requiring central input or output, where the fluid moves radially inward or outward. The spacing between the tubes in this arrangement can be tailored to optimize flow patterns, reduce potential dead zones, and increase overall heat transfer efficiency. Furthermore, the radial configuration can be combined with or integrated into hybrid designs with other layouts, thereby providing a versatile approach to addressing unique thermal challenges.

[0092] According to an aspect, the present invention provides a tube heat exchanger comprising an inlet, an outlet, and interleaved heat transfer tubes axially positioned between the inlet and the outlet. The heat transfer tubes are divided into three groups, and the three groups of tubes have different cross-sectional shapes and different tapering characteristics. The first group of tubes has a more sharply tapered forward section, the second group of tubes has a more sharply tapered rear section, and the third group of tubes has a unique elongated shape that is different from the first two groups.

[0093] It should be understood that the tapers (particularly the first taper, the second taper, the third taper, and the fourth taper) are related to the respective angles of inclination observed in the cross-sectional profile of the heat transfer tubes. Each of the tapers is distinguishable and quantifiable. The first taper corresponds to the tapering angle of the forward section of the first group of tubes, while the second taper delineates the tapering angle of the rear section of the first group of tubes. Conversely, the third taper defines the tapering angle of the rear section of the second group of tubes, while the fourth taper relates to the tapering angle of the forward section of the second group of tubes. Each of these tapers is measured with respect to a reference plane that is perpendicular to the axial path of the tubes.

[0094] The term "tapering" as used in the context of the tapers and angles referred to herein includes not only linear or straight inclinations, but also inclinations of a curved nature. That is, the tapering gradient of the heat transfer tubes, while traditionally envisioned as a straight inclination, can also manifest as a curvilinear descent, thereby introducing a continuous change in diameter over the length of the tapered section, rather than a uniform straight decrease. Depending on the specific application of the tube heat exchanger, this curved tapering can provide advantages in terms of fluid dynamics, heat transfer, and structural integrity.

[0095] Furthermore, whether straight or curved, they are not strictly limited to ending with a pointed or sharp edge. In fact, while in certain embodiments it can be preferable to employ a pointed tip in order to optimize flow dynamics or enhance heat transfer rates, alternative configurations are entirely feasible. Specifically, the taper can end in a rounded or un-sharp surface, thereby mitigating potential issues related to wear, erosion or damage due to fluid turbulence. The choice between a pointed or rounded tip depends largely on design considerations, operational requirements, and the specific conditions that the tube heat exchanger is intended to address. Accordingly, both configurations, i.e., pointed and rounded, are encompassed within the scope of the present patent disclosure.

[0096] It should be understood that, in the context of the present disclosure, the term “adjoining” with respect to the first front section and the first rear section adjoining the first intermediate section, e.g., when referring to a first set of tubes having an elongated shape with a first intermediate section, is to be understood as meaning that the first front section and the first rear section are directly connected to and seamlessly extend from the first intermediate section, without any gap or break in between. It is emphasized that “adjoining” means not only being adjacent or close to the first intermediate section, but also that the first intermediate section extends continuously, without interruption, into the first front section and the first rear section, thereby forming a unified, integral structure.

[0097] It should be understood that the third set of tubes exhibits an elongated geometry that is distinctly different from the configuration of the first and second sets of tubes. While the first and second sets of tubes are characterized by having a specific taper and continuous intermediate, front and rear sections, the third set of tubes exhibits a deviation in profile, taper and / or other structural attributes when viewed in a plane that is transverse to the axial path of the third set of tubes or in a plane that is angled with respect to the axial path of the third set of tubes.

[0098] It should be understood that the tubes can be configured to be hollow. Such a hollow configuration allows for the passage of a fluid therethrough, thereby facilitating enhanced heat transfer performance. The fluid can include various media such as, but not limited to, air, water, refrigerant or combinations thereof. The inner surface of these hollow tubes can be further smooth or textured to alter fluid dynamics or improve heat transfer characteristics. Furthermore, the tubes can be designed to accommodate laminar, turbulent or transitional flow regimes within the tubes. The inner diameter of the hollow tubes can vary based on the desired flow rate and the specific application of the heat exchanger. Furthermore, the hollow nature of the tubes allows for the potential integration of internal fins or other structures designed to further increase the surface area for heat exchange and enhance the efficiency of the heat transfer process.

[0099] Heat flux is an important parameter in the field of heat transfer, particularly for tube heat exchangers. Heat flux represents the rate of heat energy transfer per unit area, typically expressed in Watts per square meter (W / m2). It is a measure of the amount of heat energy that is transferred through a given surface area per unit of time. Heat flux is a critical parameter in the design and operation of tube heat exchangers, as it directly impacts the efficiency of the heat transfer process. 2) units. In the case of a tube heat exchanger, the magnitude and distribution of heat flux has a profound effect on the performance and efficiency of the device. Uniform and high heat flux indicates efficient heat energy transfer between the fluid within the tube and the surrounding environment or another fluid. Factors that affect the heat flux within such a system include the temperature difference between the interacting substances, the material properties of the tube (such as thermal conductivity), the fluid dynamics (laminar or turbulent flow), and the surface characteristics of the tube (smooth, textured, or finned). Adjusting any of these factors, either individually or in combination, can result in an increase in heat flux, thereby enhancing the performance of the heat exchanger.

[0100] It will be appreciated that any of the aspects, features and options described in relation to the tube heat exchanger are equally applicable to the method and to the described devices and systems. It will also be clear that any one or more of the above aspects, features and options can be combined. BRIEF DESCRIPTION OF DRAWINGS

[0101] The present application will be further described with reference to the exemplary embodiments shown in the drawings. The exemplary embodiments are given by way of non-limiting illustration. It should be noted that the drawings are given by way of non-limiting illustration of embodiments of the present application.

[0102] In the drawings:

[0103] Figure 1 schematic representation of a cross-sectional view of a tube of a tube heat exchanger;

[0104] Figure 2 schematic representation of a cross-sectional view of a tube of a tube heat exchanger;

[0105] Figure 3A , Figure 3B schematic representation of a cross-sectional view of a tube of a tube heat exchanger;

[0106] Figures 4A to 4C schematic representation of an exemplary performance analysis for an internal design of a tube heat exchanger. DETAILED DESCRIPTION

[0107] Figure 1 schematic representation of a cross-sectional view of a tube of a tube heat exchanger 1. Only a portion of the tube heat exchanger is shown. The tube heat exchanger 1 comprises an inlet portion 3 and an outlet portion 5, between which a flow direction 7 is defined. A plurality of heat transfer tubes 9 is arranged between the inlet portion 3 and the outlet portion 5, wherein the plurality of heat transfer tubes 9 extends along an axial path. The axial path extends through the plane of the cross-section depicted in Figure 1 The plurality of heat transfer tubes 9 is arranged in a staggered pattern in which every other row of heat transfer tubes is offset from the row of heat transfer tubes adjacent thereto.

[0108] The first set of heat transfer tubes S1 is arranged at the front end. The second set of heat transfer tubes S2 is arranged at the rear end. The third set of heat transfer tubes S3 is arranged at a position between the first set of tubes S1 and the second set of tubes S2.

[0109] It is to be understood that the terms "front end" and "rear end" denote a position arrangement. "Front end" refers to the foremost or initial portion of the (tube) structure. In contrast, "rear end" denotes a rear or last portion that is located after the front portion (see "rear" or "end").

[0110] In a cross-sectional view along a transversal plane with respect to the axial path, the tube 9a of the first set S1 has an elongated shape with a first intermediate section 11a, a first front section 13a and a first rear section 15a, both the first front section 13a and the first rear section 15a being contiguous with the first intermediate section 11a, wherein the first front section 13a and the first rear section 15a start at a position where the tube 9a begins to taper inwardly and extend to the respective outermost point of the tube 9a, wherein the first intermediate section 11a, the first front section 13a and the first rear section 15a are smoothly connected to form a continuous outer boundary of the tube 9a of the first set S1. Both the first front section 13a and the first rear section 15a exhibit a convex curvature. The first front section 13a has a first taper and the first rear section 15a has a second taper, wherein the first taper is greater than the second taper, so that the first front section 13a narrows more sharply with respect to the first rear section 15a.

[0111] In a cross-sectional view along a transversal plane with respect to the axial path, the tube 9b of the second set S2 has an elongated shape with a second intermediate section 11b, a second front section 13b and a second rear section 15b, both the second front section 13b and the second rear section 15b being contiguous with the second intermediate section 11b, wherein the second front section 13b and the second rear section 15b start at a position where the tube begins to taper inwardly and extend to the respective outermost point of the tube 9b, wherein the second intermediate section 11b, the second front section 13b and the second rear section 15b are smoothly connected to form a continuous outer boundary of the tube 9b of the second set S2, wherein both the second front section 13b and the second rear section 15b exhibit a convex curvature, wherein the second rear section 15b has a third taper and the second front section has a fourth taper, wherein the third taper is greater than the fourth taper, so that the second rear section 15b narrows more sharply with respect to the second front section 13b.

[0112] In a cross-sectional view along a transversal plane with respect to the axial path, the tube 9c of the third set S3 has an elongated shape that is different from the shape of the tube 9a of the first set S1 and the tube 9b of the second set S2.

[0113] Advantageously, the tube heat exchanger can provide a reduced pressure drop and / or improved fluid dynamic performance.

[0114] Figure 2 A schematic diagram showing a cross-sectional view of the tubes 9a-c of the tube heat exchanger 1 is shown. In the cross-sectional view along a transversal plane with respect to the axial path, the third group of tubes 9c has only a third front section and a third back section which are contiguous to each other.

[0115] In this example, the third group of tubes 9c has an elongated shape having a third intermediate section 11c, a third front section 13c and a third back section 15c, both the third front section 13c and the third back section 15c being contiguous to the third intermediate section 11c. The third front section 13c and the third back section 15c start at the position where the tube starts to taper inwardly and extend to the respective outermost point of the tube 9c. The third intermediate section 11c, the third front section 13c and the third back section 15c are smoothly connected to form a continuous outer boundary of the tubes 9c of the third group S3, wherein both the third front section 13c and the third back section 15c exhibit a convex curvature, and wherein the third front section 13c and the third back section 15c start at the position where the tube starts to taper inwardly and extend to the respective outermost point of the tube. Further, the first intermediate section 11a and the second intermediate section 11b have a convexity which is substantially lower with respect to the convexity of the third intermediate section 11c.

[0116] In this example, the first intermediate section 11a and the second intermediate section 11b are substantially flat, and wherein the third intermediate section 11c has a curved portion.

[0117] In this example, the first intermediate section 11a and the second intermediate section 11b each extend in the range of 20% to 60% of the total length of their respective tube 9a, 9b. Further, the third intermediate section 11c extends in the range of 0.5% to 20% of the total length of the respective tube, in this example, the third intermediate section 11c extends even lower than 10% of the total length of the respective tube.

[0118] Further, in this example, the first taper and the third taper are substantially the same, and wherein the second taper and the fourth taper are substantially the same. Further, in this example, the first group of tubes and the second group of tubes have substantially the same geometric configuration, and wherein the second group of tubes is arranged in a mirror configuration with respect to the first group of tubes. The mirror line is a vertical line (perpendicular to the length direction L of the tubes).

[0119] In this example, the first rear section 15b and the second front section 13b have a pointed end. In this example, the second front section 13b has a rounded end and the first front section 13a has a pointed end. However, it is also conceivable that both the second front section and the first front section have a pointed end, or alternatively, both the second front section and the first front section have a rounded end, or alternatively, the second front section 13b has a sharp end and the first front section 13a has a rounded end.

[0120] In this example, the curvature of each tube is symmetrical about the central chord line L. However, asymmetrical shapes are also possible, depending on the operating characteristics and / or parameters of the tube heat exchanger.

[0121] Figure 3A A schematic diagram showing a cross-sectional view of the tubes 9a of the first set S1 is shown. Similarly, Figure 3B A schematic diagram showing a cross-sectional view of the tubes 9b of the second set S2 is shown.

[0122] As Figure 3A shown in a cross-sectional view along a transverse or angled plane relative to the axial path of the tubes 9a, the tubes 9a of the first set S1 have an elongated shape with a first intermediate section 11a, a first front section 13a and a first rear section 15a, both the first front section and the first rear section being contiguous with the first intermediate section 11a. The first front section 13a and the first rear section 15a start at a location where the tube begins to taper inwardly (indicated by the node N) and extend to the respective outermost point P of the tube 9c. The first intermediate section 11a, the first front section 13a and the first rear section 15a are smoothly connected to form a continuous outer boundary of the tubes 9a of the first set S1. Both the first front section 13a and the first rear section 15a exhibit a convex curvature. The first front section 13a has a first taper and the first rear section 15a has a second taper, the first taper being greater than the second taper, such that the first front section 13a narrows more sharply relative to the first rear section 15a.

[0123] Furthermore, as Figure 3BAs shown, in a cross-sectional view along a transverse or angled plane relative to the axial path of the tube 9b, the tubes 9b of the second set S2 have an elongated shape with a second intermediate section 11b, and a second front section 13b and a second back section 15b, both contiguous with the second intermediate section 11b. The second front section 13b and the second back section 15b start at the point where the tube begins to taper inwardly (represented by the node N) and extend to the respective outermost point P of the tube 9b. The second intermediate section 11b, the second front section 13b and the second back section 15b are smoothly connected to form a continuous outer boundary of the tube 9b of the second set S2. The second front section 13b and the second back section 15b both exhibit a convex curvature, and the second back section 15b has a third taper, and the second front section 13b has a fourth taper, the third taper being greater than the fourth taper, such that the second back section 15b narrows more sharply relative to the second front section 13b.

[0124] In these examples, the first intermediate section 11a and the second intermediate section 11b are substantially flat. Furthermore, the first intermediate section 11a and the second intermediate section 11b extend over a range of 20% to 60% of the total length of their respective tubes, in exemplary embodiments, the first intermediate section 11a and the second intermediate section 11b even extend over a range of 30% to 50% of the total length D1, D2 of their respective tubes 9a, 9b. In this example, the length of the tubes 9b of the second set S2 is greater than the length of the tubes 9a of the first set S1.

[0125] The rationale behind the above-mentioned ranges stems from an understanding of the dual requirements of the heat exchange process. On one hand, sufficient surface area must be provided to facilitate robust heat transfer. This surface area determines the extent to which the heat exchange medium can effectively interact with the tubes, directly impacting the rate of heat exchange. On the other hand, the necessity of fluid dynamics begins to emerge, where design requirements ensure that the medium flows unimpeded and efficiently through the tubes, thereby minimizing any potential disruptions or bottlenecks. The range of 30% to 50% is chosen precisely to reconcile these dual requirements. By confining the intermediate section within this specific range, the design achieves an optimal point. It ensures that the medium has sufficient surface to achieve effective heat transfer, while not being so long in length that it causes resistance or creates turbulence, thereby avoiding performance degradation. This proportional design characteristic has a direct impact on the performance of the heat exchanger. By facilitating both optimal heat transfer and streamlined flow dynamics, it enhances the overall efficiency of the system. Thus, a heat exchanger configured by implementing this design characteristic not only exhibits enhanced thermal characteristics, but also ensures that the medium flows through the heat exchanger in a manner that is both fast and efficient, thereby maximizing the overall effectiveness of the heat exchange process.

[0126] The general shape of the tubes 9a of the first group SI is similar to the general shape of the tubes 9b of the second group S2, but is mirrored along the vertical line (perpendicular to the line L).

[0127] The overall shape of the cross section of the tubes 9a, 9b, represented by the two-dimensional geometric figure on the plane, is symmetrical. There is a balanced appearance between the top and bottom profiles.

[0128] In the example shown in Figure 3A , starting from the leftmost point, the shape starts with a curve having semi-elliptical features. The semi-ellipse has a vertical axis longer than the horizontal axis. From the end of the semi-elliptical curve, the shape transitions to two substantially linear sections, followed by subsequent sections that converge as they extend to the right. The substantially linear sections at the top and bottom are substantially parallel, while the subsequent sections are non-parallel and converge at a point, forming an acute angle. The shape ends at a sharp point on the rightmost end, formed by the convergence of the aforementioned sections following the substantially linear sections.

[0129] In this example, the body of the tube 9a transitions to bilinear sections, followed by sections that converge in a non-parallel manner as they extend to the right, eventually meeting to form an acute angle, to form a pointed terminus on the rightmost end of the body. However, the convergence point can also be rounded (see the tubes 9b of the second group S2).

[0130] The entire body of the tube 9a remains closed, forming a continuous, uninterrupted boundary. The widened end on the left side of the body gradually transitions to the narrowed end on the right side, with the left side being the leading edge / terminus with respect to the flow direction inside the tube heat exchanger. The unique geometry in the cross section, due to its different characteristics, can provide enhanced heat transfer performance and efficiency.

[0131] In the example shown in Figure 3A , immediately after the semi-elliptical curve, the shape of the heat transfer element begins to evolve into two distinct linear sections. These sections are defined by their straight edge profiles, which diverge from the curvature of the semi-ellipse. The linear sections can be substantially horizontal or flat. However, a small curvature can be allowed. The subsequent sections proceed to the right and approach each other in a deliberate manner, thus not maintaining an equal distance throughout the length of the subsequent sections, indicating that the direction of the subsequent sections is not parallel. This direction ensures that the sections intersect. In this example, the aforementioned subsequent sections continue their trajectories until they converge, forming an angle of less than 90 degrees between them. This acute intersection point ultimately forms a sharp and precise point, which is referred to here as a "pointed terminus". However, a rounded edge is also possible. This structural feature enhances the efficacy of the heat transfer element in directing heat in a specific direction, optimizing its performance in heat distribution applications.

[0132] The intermediate section is a part of the outer geometry of the tube, located between the location where it starts to taper in from the left and the location where it starts to taper in from the right. Tapering refers to the tube getting narrower. In the context of this design, when the tube starts to taper in, this marks the beginning of the intermediate section. The point where the tube is thickest, which can be considered the point of least taper or greatest diameter, is also located within the intermediate section. The intermediate section is located centrally in the tube design, between the front and back sides.

[0133] This shape has an elongated intermediate section. Elongated here refers to the length or stretch of the intermediate section, implying that the intermediate section is more extended or lengthened.

[0134] Figures 4A to 4C A schematic is shown illustrating an exemplary performance analysis for the internal design of a tube heat exchanger. Computational fluid dynamics (CFD) simulations were performed, taking into account thermal modeling. Figure 4A 、 Figure 4B 、 Figure 4C A pressure plot, a velocity plot, and a temperature plot are shown, respectively. To improve efficiency, only a portion of the heat exchanger interior with tubes was simulated. A 2D simulation was also performed.

[0135] The tubes 9a of the first set S1 have an elongated body that begins at its leftmost end with a semi-elliptical curve, the semi-ellipse having a vertical axis that extends primarily with respect to its horizontal axis. After the semi-elliptical curve, there is a relatively straight portion. The body presents a unique straight portion, consisting of two independent straight segments that begin at the termination point of the semi-elliptical curve and extend to the right, each straight segment maintaining a consistent straight path over its length. After the straight portion, the straight segments begin to approach one another in a converging trajectory, exhibiting a tapering property. This tapering continues until the segments intersect, and form an angle between the segments that is less than 90 degrees, thereby forming a sharp pointed tip at the rightmost boundary of the body.

[0136] The tubes 9b of the second set S2 have a similar but different shape than the tubes 9a of the first set S1. The tubes 9b of the second set S2 are more elongated. However, in some examples, the same design can be used for both.

[0137] In some examples, for the tubes belonging to the first and second groups, a unique design characteristic becomes apparent. Specifically, the intermediate sections of these tubes are characterized by a predominantly flat profile. This flat design is chosen for these intermediate sections so that there are inherent advantages for the overall functioning of the heat exchanger. One major benefit of this design is the ability to ensure a stable and undisturbed flow of the heat exchange medium. By eliminating any significant curvature in the intermediate sections, the likelihood of flow disturbances, which are typically caused by abrupt geometric changes, can be greatly reduced. Such disturbances can lead to inconsistent heat transfer rates and reduced efficiency. In contrast, the flat intermediate section design promotes a more stable flow of the medium, which is important for maintaining consistent thermal interaction between the medium and the tube surface. The direct technical effect of this design choice is to make the heat transfer process more uniform, avoiding the pitfalls of flow pattern instability or heat exchange dead zones. As a direct result, the tube heat exchanger benefits from enhanced heat transfer capacity, thereby improving operational efficiency.

[0138] In this document, the utility model is described with reference to specific examples of embodiments of the utility model. However, it is obvious that various modifications, changes, substitutions and changes can be made therein without departing from the essence of the utility model. For the purpose of clear and brief description, the features are described as the same or different embodiments in this document, however, the alternative embodiments with all features or some features described in these different embodiments are also envisaged and understood to fall within the framework of the utility model outlined by the claims. Therefore, the specification, drawings and examples are considered to be illustrative rather than limiting. The utility model is intended to include all alternatives, modifications and changes falling within the scope of the appended claims. In addition, many of the described elements are functional entities, which can be implemented as independent or distributed components, or in any suitable combination and position with other components.

[0139] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. Further, the word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The term 'and / or' includes one or more of the listed items, as well as any combination of these. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. A tube heat exchanger, characterized by, The tube heat exchanger comprises: an inlet portion and an outlet portion defining a flow direction therebetween; and a plurality of heat transfer tubes arranged between the inlet portion and the outlet portion, wherein the plurality of heat transfer tubes extend along an axial path, wherein the plurality of heat transfer tubes are arranged in a staggered pattern in which every other row of heat transfer tubes is offset from the row of heat transfer tubes adjacent thereto; wherein a first group of heat transfer tubes is disposed at a forward end, a second group of heat transfer tubes is disposed at an aft end, and a third group of heat transfer tubes is disposed at a location between the first group of heat transfer tubes and the second group of heat transfer tubes; wherein, in a cross-sectional view along a transverse or angled plane relative to the axial path, the first group of heat transfer tubes has an elongated shape with a first middle section, a first forward section, and a first aft section, the first forward section and the first aft section each contiguous with the first middle section, wherein the first forward section and the first aft section begin where the tube begins to taper inwardly and extend to respective outermost points of the tube, wherein the first middle section, the first forward section, and the first aft section are smoothly connected to form a continuous outer boundary of the first group of heat transfer tubes, wherein the first forward section and the first aft section each exhibit a convex curvature, wherein the first forward section has a first taper and the first aft section has a second taper, wherein the first taper is greater than the second taper such that the first forward section narrows more sharply relative to the first aft section; wherein, in a cross-sectional view along a transverse or angled plane relative to the axial path, the second group of heat transfer tubes has an elongated shape with a second middle section, a second forward section, and a second aft section, the second forward section and the second aft section each contiguous with the second middle section, wherein the second forward section and the second aft section begin where the tube begins to taper inwardly and extend to respective outermost points of the tube, wherein the second middle section, the second forward section, and the second aft section are smoothly connected to form a continuous outer boundary of the second group of heat transfer tubes, wherein the second forward section and the second aft section each exhibit a convex curvature, wherein the second aft section has a third taper and the second forward section has a fourth taper, wherein the third taper is greater than the fourth taper such that the second aft section narrows more sharply relative to the second forward section; and wherein, in a cross-sectional view along a transverse or angled plane relative to the axial path, the third group of heat transfer tubes has an elongated shape that is different from the shape of the first group of heat transfer tubes and the second group of heat transfer tubes.

2. The tube heat exchanger according to claim 1, characterized in that In a cross-sectional view along a transverse or angled plane relative to the axial path, the third group of heat transfer tubes has only a third forward section and a third aft section contiguous with each other. In a cross-sectional view along a transverse or angled plane relative to the axial path, the third group of heat transfer tubes has only a third forward section and a third aft section contiguous with each other.

3. The tube heat exchanger according to claim 1, characterized in that In a cross-sectional view along a transverse plane or an angled plane relative to the axial path, the third set of heat transfer tubes has an elongated shape with a third intermediate section, a third forward section and a third rear section, the third forward and rear sections each being contiguous with the third intermediate section, wherein the third forward and rear sections start at a location where the tube begins to taper inwardly and extend to a respective outermost point of the tube, wherein the third intermediate section, the third forward section and the third rear section are smoothly connected to form a continuous outer boundary of the third set of heat transfer tubes, wherein the third forward and rear sections each exhibit a convex curvature.

4. The tube heat exchanger according to claim 3, characterized in that The first and second intermediate sections have a convexity that is substantially lower relative to the convexity of the third intermediate section.

5. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and second intermediate sections are substantially flat.

6. The tubular heat exchanger according to claim 3 or 4, characterized in that The third intermediate section has a curved portion.

7. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and second intermediate sections each extend over a range of 20% to 60% of the total length of the respective tube.

8. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and second intermediate sections each extend over a range of 30% to 50% of the total length of the respective tube.

9. The tubular heat exchanger according to claim 3 or 4, characterized in that The third intermediate section extends over a range of 0.5% to 20% of the total length of the respective tube.

10. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and third tapers are substantially identical, and wherein the second and fourth tapers are substantially identical.

11. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and second sets of heat transfer tubes have substantially identical geometric configurations, and wherein the second set of heat transfer tubes is arranged in a mirror configuration relative to the first set of heat transfer tubes.

12. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and second rear sections have pointed end portions.

13. The tube heat exchanger according to any one of claims 1 to 4, characterized in that The first and second rear sections have rounded end portions.

14. The tube heat exchanger according to any one of claims 1 to 4, characterized in that Each tube exhibits a curvature that is symmetric about a central chord line.

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