EP3825636A1 - Heat exchanger and method for its production or design - Google Patents

Abstract

A method for producing or designing a heat exchanger with several ribbed pipe sections arranged next to one another, in particular parallel to one another, characterized by the following steps: Obtaining or creating information on the heat exchange behavior of the pipe sections on the basis of a predetermined or selected pipe section arrangement, preferably by performing a Simulation, • Selection of different ribs for the pipe sections, based on said information.

Description

According to a first aspect, the invention relates to a method for manufacturing or designing a heat exchanger.

A heat exchanger is a device that transfers thermal energy from one material flow to another. The substances are usually fluids, i.e. liquids or gases. Typically, one of the substances is a liquid (e.g. water), the other a gas (usually air).

For good efficiency, the component that separates the substances must have good thermal conductivity and, in particular, a large surface. The component is usually provided by pipe sections in which one of the substances, typically a liquid, is guided.

In order to increase the surface or the thermal conductivity of the pipe section, it is also known from the prior art to rib the pipe or to provide it with circumferential ribs, which leads to improved energy transfer.

A typical heat exchanger has spiral fin tube sections which are bundled to form compact heat exchangers. Spiral rib tubes are thin-walled, metallic tubes that have spiral or helical ribs to increase the surface area. The density of ribs is also known as the "rib pitch" and has a significant influence on the thermal properties.

Since the installation environments of heat exchangers vary with regard to their conditions, it is also known, depending on the application, Combine finned tubes of a given pitch to form heat exchangers. Depending on the requirements, a (common) rib pitch can be selected for the pipe sections. Also, depending on the application, the fin height can be adjusted jointly for all finned tube sections.

Said prior art heat exchangers usually work sufficiently well. However, there is a constant urge to optimize the efficiency and also the production costs of such a heat exchanger.

• Erlangen beziehungsweise Erstellen von Informationen zum Wärmetauschverhalten der Rohrabschnitte auf Basis einer vorgegebenen oder gewählten Rohrabschnittsanordnung (vorzugsweise durch die Durchführung einer Simulation),
• Auswahl unterschiedlicher Rippen für die Rohrabschnitte, basierend auf besagten Informationen.

The invention solves this problem according to the first aspect with the features of claim 1, in particular with those of the characterizing part, and is accordingly characterized by the following steps:

• Obtaining or creating information on the heat exchange behavior of the pipe sections on the basis of a specified or selected pipe section arrangement (preferably by performing a simulation),
• Selection of different ribs for the pipe sections based on said information.

In other words, the idea of the invention consists in using tube sections with different ribs to produce the heat exchanger. The sections can, for example, have different rib inclinations.

Alternatively or additionally, the ribs of the pipe sections can each have a different height.

As an alternative or in addition, the pipe sections can have ribs made of a different material.

According to the invention, the aforementioned or other parameters are selected on the basis of information that the designer or manufacturer has obtained about the heat exchange behavior of the pipe sections (especially in the area of the fins) depending on their arrangement in the heat exchanger:
For example, pipe sections which, according to said information (for example due to their arrangement) have particularly good heat exchange behavior, can be ribbed particularly closely and / or provided with particularly high ribs, because it is particularly worthwhile for these pipe sections.

Pipe sections which, according to the said information (for example due to their arrangement), have particularly poor heat exchange behavior, can have, for example, a lower fin density and / or fin height (in extreme cases even no fins at all), because it may not be worthwhile to use expensive fin material for said finned pipe section "to waste".

Of course, exactly the opposite finned situations are also conceivable: It could be that pipe sections which already have good heat exchange behavior are provided with less fin material than those which, according to the information obtained or generated, have poor heat exchange behavior. This applies, for example, to the case that a particularly uniform heat exchange behavior is to be achieved by comparing the pipe sections (in other words, the temperature of the fluids transported in the pipes is to be uniform).

In this sense, at least two of the pipe sections should have different ribs in comparison to one another. In particular, however, all pipe sections can also have different ribs. However, depending on the target and the information available, it is also possible that a pipe section is not provided with ribs at all (for example in the event that this is not worthwhile).

Taking the information into account when selecting the different ribs can in this way on the one hand lead to an improved temperature transfer result (for example by providing pipe sections with a particularly high or low rib slope or with particularly high or flat ribs due to their arrangement), and on the other hand, a Cost optimization takes place in such a way that the fin material is only used where it can work effectively (on the other hand, the more expensive fin material is minimized for other pipe sections).

The selection of the different ribs is made on the basis of information that is typically obtained or created in a previous method step.

This information preferably takes into account the pipe section arrangement (in the heat exchanger). The pipe section arrangement relates in particular to the arrangement of the pipe sections to one another or to one another.

In particular, the direction of flow of the fluid flowing outside the pipe sections can advantageously be taken into account.

In some applications, the arrangement of the pipe sections is specified depending on the installation space or customer requirements. In other cases a standard pipe section arrangement may be chosen or one any, even optimized, arrangement can be made. This arrangement is then typically the basis for the information on the heat exchange behavior or has a significant influence on it.

Corresponding information can be obtained by carrying out simulations (in particular computer-aided) or, alternatively or additionally, by carrying out tests (on real test arrangements).

The creation of information only on the basis of assumptions or empirical values is also included in the invention.

The information obtained or created relates to the heat exchange behavior of the pipe sections, in particular pipe sections can be determined which enable or have better heat exchange behavior or better heat transfer between the two substances or fluids in the specified or selected arrangement.

If a pipe section has a relatively poor heat exchange behavior due to its arrangement (for example because it is arranged downstream in the flow direction of the external fluid), this can be taken into account when selecting the ribs of this pipe section (as described above).

In order to obtain the information, it has been found to be particularly advantageous if computer-aided simulations are carried out for this purpose. For example, a computer program or an app can be used. In this program, for example, the specified pipe section positions can be stored or entered and based on assumptions about the direction of flow of the external medium (i.e. the fluid that is located outside the pipe sections and is currently not being conducted into them), knowledge about the heat exchange behavior of the different finned pipe sections can then be obtained.

In particular, a predetermined rib height can initially be assumed in the simulation. Here, after the result of the simulation, the rib height can then be adjusted.

Such a program can display the result of a simulation in particular graphically, preferably color-coded. In particular, the display can show data on the simulated or calculated heat exchange behavior in the area of the finned tube sections, in particular relating to the heat flow (for example, values relating to the heat flow density can be displayed in a color-adjusted manner).

Particularly advantageously, it can be provided that such a computer-aided simulation is compared with measurement data from a real test, and consequently the program is calibrated or calibrated with these data.

In this sense, it could be provided that real measurements take place in a preceding process step and that these measurements are taken into account in a further process step when configuring a computer program (with a computer-aided simulation then being able to take place). This has the particular advantage that a real test does not have to be carried out for changed or future test arrangements. Rather, the computer-aided program can then be used.

The method according to the invention relates in particular to the production of a heat exchanger in the sense that, in principle, a method step could also be provided in which the differently ribbed pipe sections are combined to form a heat exchanger or housed or installed in a heat exchanger housing or the like.

Alternatively, the method according to the invention is only used for drafting or designing a heat exchanger, for example in the event that a user only wants to determine data about the arrangement to be selected (or the ribs to be used) for a specific application (but not the heat exchanger itself but only forwards the data created about the design of the heat exchanger or the design of the heat exchanger - internally or externally).

A heat exchanger according to the invention has at least two (differently) ribbed pipe sections. Of course, the heat exchanger can also have more pipe sections than two (for example four, six, eight or even more pipe sections). In any case, two of these must differ in terms of their ribbing.

The finned tube sections are arranged next to one another in the heat exchanger, that is to say essentially assigned to one another. Only in this case does it make sense to obtain information, for example in the context of a simulation.

The ribbed pipe sections are preferably arranged parallel to one another. This is the typical configuration of a tube bundle in a heat exchanger and is also easy to obtain or creating information, for example as part of a simulation.

The finned tube sections can be assigned to completely separate finned tubes: For example, a heat exchanger can have several tube sections which - at least within the heat exchanger housing - are not connected to one another.

For economic reasons, however, it makes sense that said pipe sections of the heat exchanger (at least outside of a housing) are brought together, for example in order to enable a common inlet or outlet of the substance carried in them.

Basically, the invention also includes pipe sections that actually belong to the same finned tube: For example, straight, parallel pipe sections can be provided by a meander-shaped overall finned tube: In this case, the individual finned tube sections are arranged straight and parallel to one another. But these are all part of the same overall finned tube. Of course, a number of such total finned tubes can also be provided in a heat exchanger.

An overall finned tube that is, for example, helical is also conceivable. Individual turns (or turn sections) can represent the pipe sections which run next to one another (and in particular essentially parallel to one another).

According to the most preferred embodiment of the invention, however, the pipe sections are essentially straight (their main direction of extent therefore extends along a straight line).

The pipe sections can in particular be arranged offset to one another or in alignment with one another.

The base bodies of the pipe sections are typically made of copper (or another suitable metal, in particular stainless steel). The ribs can then, for example, consist of the same material (that is to say also copper) or another suitable material, in particular stainless steel (aluminum can also be used as a strip material).

The ribs of a pipe section are advantageously provided by more than one band (in particular by two bands or more). In this way, a finned tube section can be completed much more quickly given a given distance between two adjacent fins. On the other hand, the belts can have a higher gradient for the same amount of time (for example, twice as high in the case of two belts as in the prior art method, in which only one belt is arranged on the finned tube).

The strips that provide the ribs are typically welded to the basic pipe bodies with the aid of (at least) one laser.

The basic pipe body of a pipe section is typically provided by an externally smooth round pipe, which is in the form of a straight line or rod-like, and which is then further processed, in particular ribbed. The ribbed band is then attached to the basic pipe body, usually with the aid of a laser, typically in a helical shape.

According to a particularly advantageous embodiment of the invention, it is provided that the ribs of the pipe sections in comparison to one another have a different height. In this sense, at least one pipe section has a different rib height than another pipe section. The height of the ribs essentially corresponds to the width of the strip that is used to create the ribs.

In this case, it can basically be assumed that the heat exchange behavior of the corresponding pipe section improves the higher the rib is formed. However, in practice there are maximum heights which should not be exceeded for reasons of stability.

According to a further advantageous embodiment of the invention, it is additionally or alternatively advantageous that the ribs of the pipe sections consist of a different material. In this sense, a first tube section can be provided which has a rib made of a first material and a second tube section which has a rib made of a different material.

As already indicated, the rib materials can be, for example, stainless steel or copper or titanium or aluminum or similar materials.

The different materials can advantageously be a rustproof material and a non-rustproof material. In this sense, by changing the material, heat exchangers can be produced which are only equipped with rustproof (more expensive) ribs for areas of high humidity. In this way, expensive alloys in particular can be saved.

In principle, however, it is also possible for an individual pipe section to have strips made of different materials, so that the ribs of this pipe section, for example, consist of a first and consist of a second material. In this sense, another pipe section which has ribs only from one of these materials (or another material), that is to say in the sense of the invention, would represent a pipe section with ribs made from a different or a different material.

A configuration according to the invention is particularly advantageous in which the ribs of the pipe sections have a different pitch compared to one another. In this sense, at least one pipe section is provided with a first pitch, and another or second pipe section with a different pitch.

The pitch indicates the number of ribs per unit of length (for example inches). The higher the slope, the closer the ribs are together and the more rib material is used.

Typically, therefore, a higher gradient is used in the pipe sections, which according to the information obtained or created (due to their arrangement) have better heat exchange behavior, since the use of the fin material is more worthwhile or more efficient here.

According to a particularly advantageous embodiment of the invention, the pipe sections originate from the same pipe. In particular, they were cut off from this original pipe. This means that at least two pipe sections still belonged together to one pipe before a cutting process. After the separation process, for example after cutting off or cutting through or the like, the pipe sections are then used separately in the heat exchanger as (separate) pipe sections.

The pipe from which the at least two pipe sections originate is preferably already finned before a cutting process takes place. This facilitates manufacturability.

It is particularly advantageously provided that the tube is ribbed in a varying manner, in particular in a gradually varying manner. This enables particularly easy and economical producibility, since in this way pipe sections originating from a pipe or can be separated, which have a different slope to one another. The manufacturing process is kept as simple as possible, since only one tube is actually used.

The original pipe can be designed in particular straight or as a straight line in terms of its longitudinal extension. The separated pipe sections then also have a straight shape in terms of their longitudinal extension.

For example, a (straight) pipe a few meters long can be ribbed in one piece (preferably ribbed in varying degrees) in this way. A first area of the finned tube can have a first slope, a second area a second slope (possibly a third area, a third slope, etc.). A separation process can then then take place, which separates the first area from the second (and possibly the second from the third, etc.). For example, the pipe can be cut off. In the case of a gradual variation in the slope, it of course makes sense that each pipe section then has a constant slope, the slope of the pipe sections varying in comparison to one another.

Such a varying rib pitch of the original pipe body can in particular be achieved in that one of the The variable tape guide developed by the applicant is used, which can vary the angle of incidence of the tape or tapes during the welding process.

Regardless of the type of ribbing, the primary pipe can preferably be separated, in particular cut, evenly or into pieces of equal length. This enables the production of a bundle of pipe sections of equal length.

According to a further preferred embodiment of the invention, it is provided that at least one pipe section is not ribbed at all based on the information mentioned. In other words, on the basis of the information obtained or created, it can be decided that it makes no sense at all to rib a certain pipe section, for example because it does not have any noteworthy heat exchange behavior or the like. In this way, a particularly large amount of rib strip material can be saved.

According to a particularly advantageous embodiment of the invention, the ribs of at least one pipe section consist of at least two strips. Ribbons are typically welded to pipe bodies to produce ribs. The width of the band determines the height of the rib, for example.

According to the invention, it is now provided according to this embodiment that the ribs of a pipe section are provided by at least two strips, which are typically formed separately (that is in this case in particular that these run parallel to one another, preferably helically). In other words, the ribs assigned to one side of the pipe section are always provided alternately by one of the bands.

This embodiment has the particular advantage that it facilitates a varying rib incline for the ribbing of the original pipe (from which the pipe sections can be cut out). In practice it is difficult to achieve a varying, in particular a gradually varying, rib pitch on a pipe if only one band is used. This embodiment thus enables a significantly more reliable control of the rib fastening process, which in the end also enables varying rib slopes in a reliable manner.

In this way - as described above - for example a ribbed original pipe can be produced, which is then divided into several pipe sections by a cutting process, which in turn can be built into the heat exchanger, so that the individual pipe sections actually have different slopes compared to each other.

The information on the heat exchange behavior of the pipe sections can preferably be obtained by means of a computer-aided simulation. For this purpose, for example, a computer program can be used, for example a computer program that can be executed on a conventional PC, notebook, tablet, mobile phone or the like. In this program, pipe sections can preferably be arranged according to certain specifications, and on the basis of this arrangement the heat exchange behavior of these pipe sections can be calculated taking into account the flow behavior of the fluid flowing outside the pipe sections.

The simulation can, of course, take into account any parameters that can be sensibly selected for the simulation, such as the type of flowing medium, the direction of flow, condensation effects and / or a prescribable rib height.

Such a simulation can advantageously be offered, embedded or executed as a tool or app or the like in a CAD program. This has the advantage that the designer who operates the CAD program can use the information obtained via this simulation directly to define different ribs for different pipe sections and to specify, save or take into account directly in the CAD program. In other words, the simulation tool is integrated into a design program. For example, the results of the simulation are displayed directly to the CAD program user, in particular color-coded, in order to clarify the calculated / expected heat exchange behavior of the pipe sections.

Such a computer-aided program can particularly advantageously be calibrated, adapted or configured at the factory or by the user by taking real measurement data into account. A measurement can thus take place in an actual wind tunnel or the like, and these real results can then be taken into account in order to adjust, correct or calibrate the computer-aided simulation.

In such an experiment, for example, data such as the pressure loss of the medium when flowing through the finned tube bundle (using an inclined tube manometer) and / or the amount of condensate (using a calibrated measuring vessel and stopwatch) and / or the vapor pressure (using a primary tube manometer) and / or air inlet - and outlet, steam and condensate temperatures (with thermocouples) are measured and then taken into account in a simulation.

Furthermore, the object on which the invention is based is achieved by a heat exchanger according to claim 10, which accordingly has the peculiarity that the finned tube sections are ribbed differently.

In this sense, the heat exchanger thus has finned tube sections which are provided with different fins. For example, the rib height and / or the slope of the ribs and / or the material of the ribs can differ. In addition to the finned tube sections, the heat exchanger can in particular also have a housing or the like, or corresponding connections for the finned tube sections and / or for the substance conducted within the finned tubes.

At this point it should be noted that all of the advantages and subclaims or special designs explained in connection with the methods described above can of course also be transferred to the independent claim directed to a heat exchanger.

Merely by way of example, it should be pointed out in this sense that heat exchangers in which the pipe sections have a different pitch and / or a different height and / or a different material compared to one another should also be considered to be disclosed. The pipe sections can belong to the same pipe or come from the same pipe. Regardless of this, they can be formed separately - at least within the housing. For example, they can then be brought together outside the housing (or inside) for a common connection or drain or the like. This list is to be understood explicitly but not conclusively.

Further advantages of the invention emerge from the dependent claims, which may not be cited, and from the description of the figures which now follows.

Fig. 1a

in einer sehr schematischen, teilgeschnittenen Seitenansicht einen Wärmetauscher mit einem in einem Gehäuse angeordneten Rippenrohrabschnittsbündel, wobei der Übersichtlichkeit halber lediglich zwei der Rippenrohrabschnitte (mit unterschiedlicher Rippensteigung) dargestellt sind,

Fig. 1b

eine sehr schematische Aufsicht auf einen Schnitt durch die in Fig. 1a dargestellte Vorrichtung, etwa gemäß den Ansichtspfeilen Ib in Fig. 1a, wobei die Rippenhöhe aller Rippenrohrabschnitte identisch ist,

Fig. 2

eine sehr schematische Ansicht des Ergebnisses einer Simulation des Wärmetauschverhaltens von vier exemplarischen Rippenrohrabschnitten in einer Aufsichtsdarstellung, etwa gemäß Fig. 1b, samt Legende,

Fig. 3

in einer Ansicht, etwa gemäß Fig. 1b, ein anderes Ausführungsbeispiel eines erfindungsgemäßen Wärmetauschers mit unterschiedlich hohen Rippen,

Fig. 4

eine sehr schematische Seitenansicht eines berippten Urrohres zur Herstellung von vier separaten Rippenrohrabschnitten,

Fig. 5

in einer sehr schematischen Darstellung vier Rohrabschnitte, welche einem gemeinsamen Rippenrohr eines ansonsten nicht dargestellten Wärmetauschers zugeordnet sind, und

Fig. 6

ein wendelartiges Rippenrohr eines Wärmetauschers eines ansonsten nicht dargestellten weiteren Ausführungsbeispiels.

Therein show in the figures:

Fig. 1a

In a very schematic, partially sectioned side view, a heat exchanger with a finned tube section bundle arranged in a housing, only two of the finned tube sections (with different fin inclinations) being shown for the sake of clarity,

Figure 1b

a very schematic plan view of a section through the in Fig. 1a shown device, for example according to the view arrows Ib in Fig. 1a , where the fin height of all finned tube sections is identical,

Fig. 2

a very schematic view of the result of a simulation of the heat exchange behavior of four exemplary finned tube sections in a top view, for example according to FIG Figure 1b , including legend,

Fig. 3

in a view, roughly according to Figure 1b , Another embodiment of a heat exchanger according to the invention with ribs of different heights,

Fig. 4

a very schematic side view of a finned original pipe for the production of four separate finned pipe sections,

Fig. 5

in a very schematic representation, four pipe sections which are assigned to a common finned pipe of a heat exchanger which is otherwise not shown, and

Fig. 6

a helical finned tube of a heat exchanger of a further embodiment not shown otherwise.

The following description of the figures should be preceded by the fact that the same or comparable parts may be provided with identical reference symbols, in some cases with the addition of small letters or apostrophes. The same also applies to the subsequent claims.

Fig. 1a shows first a very schematic side view of a first embodiment of a heat exchanger 10 according to the invention.

The heat exchanger 10 essentially consists of a housing 11 with an inlet 12 and an outlet 13 for a first fluid 14 flowing through the housing of the heat exchanger, which can in particular be a gas, for example air, such as smoke air or the like.

The first fluid 14 flows from the inlet 12 to the outlet 13 of the housing 11 and flows around a finned tube bundle 15 in the main flow direction H.

Such a finned tube bundle 15 typically consists of a plurality of finned tube sections 16 arranged next to one another.

In the view according to Fig. 1a two finned tube sections 16a and 16b are shown by way of example, which in this exemplary embodiment are straight and are arranged parallel to one another.

The main direction of extent E, or the longitudinal extent of the finned tube sections 16, is oriented transversely or orthogonally to the main direction of flow H of the first fluid 14. The finned tube sections 16 run through the interior of the housing 11 so transversely to the main flow direction H.

At their ends, the finned tube sections 16 are aligned with the outlets 17 of the housing 11, respectively. In the area of the inputs and outputs, typically in the Fig. 1a Seals not shown may be arranged to seal the interior of the housing 11 from the atmosphere.

Outside the housing 11, the finned tube sections 16 can be continued as desired. For example, further tubes, in particular smooth tubes, can be connected to the finned tube sections and can further transport a second fluid 18 transported in the finned tube sections 16.

Fig. 1a deliberately leaves open with the dashed lines outside the housing 11 whether the channels formed by the finned tube sections 16a and 16b are brought together outside the housing 1a (as with regard to FIG Fig. 1a indicated below the housing 11) or whether these are continued separately (as with respect to Fig. 1a indicated above the housing 11). This is not important for the main aspect of the invention. Rather, it is important that the second fluid is transported within the finned tube sections 16, whereby it is the second fluid can, for example, be a liquid such as water or the like.

The heat exchanger 10 according to the invention enables heat to be transferred between the first fluid 14 inside the housing 11 (but outside the finned tube sections 16) and the second fluid 18 inside the finned tube sections 16 Surface of the pipe section) ribs 19.

These ribs 19 are provided by bands that run in a spiral around the respective pipe section, which bands are typically welded to the pipe section base body (in particular with the aid of lasers).

The ribs 19, or bands, can typically consist of copper or stainless steel or another suitable material. The basic pipe bodies of the finned pipe sections 16 are usually made of stainless steel or copper or some other suitable material, in particular metal.

While the rib height h of the ribs of the two finned tube sections 16a and 16b is evidenced Fig. 1a is identical for both finned tube sections 16a and 16b, the finned tube sections 16a and 16b differ according to the invention in that they have a different fin pitch. The rib slope essentially describes the density of the ribs, that is to say the number of ribs per unit of length (for example per inch or per centimeter or the like).

Fig. 1a it can be seen in this regard that the finned tube section 16a has a higher fin pitch than the finned tube section 16b. This has in particular to do with the fact that the finned tube section 16a is closer to the inlet of the first fluid than the second finned tube section 16b. It is based on the assumption that the heat flow density or the heat flow behavior at the fins 19a of the first finned tube section 16a tends to be greater than at the fins 19b of the second finned tube section 16b.

Under this assumption, more strip material is assigned to the first finned tube section 16a (or a higher fin pitch), while strip material is saved on the second finned tube section 16b, from which effective heat transfer is not expected anyway (i.e. a smaller fin pitch is present).

The heat transfer takes place here between the first fluid 14 and the second fluid 18, in the exemplary embodiment according to FIG Fig. 1a for example from the first gaseous fluid 14 to the liquid fluid 18 conducted in the finned tube sections 16. For example, the water conducted in the tubes 16 is heated by hot gas 14.

The efficiency of the heat exchanger can be increased by assigning more strip material to the finned tube section 16a and less to the finned tube section 16b (assuming that the same amount of strip material is to be used as with an even distribution of the strip material between the two finned tube sections 16).

To Fig. 1a Finally, for the sake of completeness, it should be noted that the ribs 19a and 19b can be formed from just a single band. But there is also the Possibility that the ribs 19a and / or 19b are each formed by a plurality of strips, which then typically run parallel in a helical manner.

Figure 1b shows, for the sake of completeness, a very schematic, sectioned plan view of the device 10 according to FIG Fig. 1a , approximately along the view arrows Ib in Fig. 1a. Figure 1b clearly shows that the finned tube bundle 15 does not only consist of a pair of finned tube sections 16a and 16b, but typically a larger number, namely in the illustrated case of exemplary four finned tube sections 16a to 16d (in practice, however, these are actually for a finned tube bundle 15 even more finned tube sections are provided).

In the Figure 1b The configuration or arrangement of finned tube sections 16 shown for the finned tube bundle is merely an example of an offset arrangement of the tubes. Of course, depending on the application, an aligned pipe arrangement or an aligned offset pipe arrangement can also be provided. In the exemplary embodiment, two rows of finned tube sections (each with two finned tube sections) are provided. In practice, however, finned tube bundles 15 actually have more rows, in particular each with more tube sections than two in a row. In this respect, the configuration is in accordance with Figures 1a and 1b only to be understood as very exemplary.

As already to Fig. 1a noted, can also Figure 1b it can be seen that the finned tube sections 16a and 16b (like the other finned tube sections 16c and 16d) each have the same fin height h. The finned tube sections 16 differ, however - as also to Fig. 1a executed - in the rib slope, which in the plan according to Figure 1b is indistinguishable. But it is related to this it is acceptable that the finned tube section 16c should have a higher pitch than the finned tube sections 16d and 16b.

As indicated above, in the exemplary embodiment according to Figures 1a and 1b the finned tube sections 16 are provided with different slopes, based on information that the user himself has created on the basis of considerations and assumptions (finned tube sections in an arrangement closer to the inlet 12 ensure a more effective heat exchange).

Typically, however, simple assumptions and considerations can sometimes also prove to be insufficient or incorrect, so that it could be advantageous according to the invention not to base the information on which the choice of the rib slope is based on assumptions, but on knowledge obtained through experiments or simulations.

In particular, the applicant has found that a computer-aided simulation of the heat transfer behavior, in particular the heat flux density, on the fins can provide particularly meaningful information about the fins to be selected for a finned tube section:

So shows Fig. 2 a schematic representation of the result of a computer-aided simulation of the heat flow density along the fins 19 of finned tube sections 16, in a configuration approximately according to FIG Figure 1b . The result of the computer-aided simulation demonstrably shows Fig. 2 a broken window area, for example in the manner of a flow channel, a main flow direction H for the first fluid 14 being specified.

Taking into account various parameters, such as pipe and fin materials (e.g. copper), surface properties of pipe and / or ribs (for example smooth), the temperature, the flow rate of the first fluid, possibly the density and / or the type of the first fluid, a (saturated) steam temperature, the consideration of possible condensation effects and / or a fundamental one Taking into account the temperature coupling between a finned tube and the air, knowledge about the flow behavior outside the tubes can be gained in the context of a simulation. These include in particular the pressure loss but also the heat transfer and / or the temperatures in the heat exchanger in general.

Fig. 2 shows here an example of the distribution of the heat flux density at the ribs 19 of the four exemplary finned tube sections 16 given the specification of specific parameters that are not specified at this point.

The legend also shown clarifies the hatching with increasing heat density, whereby in practice a display uses colored coding instead of hatching.

According to the result Fig. 2 It can be seen that the fins 19a and 19c of the finned tube sections 16a and 16c (as expected) have much higher heat flux densities and therefore also participate more effectively in a heat transfer between the two fluids (inside and outside the finned tube sections) than the fins 19b and 19d of the finned tube sections 16b and 16d.

On the basis of this simulation result, a user could now, in order to increase the effectiveness, arrive at the result of providing a higher rib slope for the finned tube sections 16a and 16c than for the finned tube sections 16b and 16d.

Instead of or in addition to the rib slope, other rib parameters can also be changed depending on the simulation results (to achieve a more effective heat exchanger or to save strip material):

So shows Fig. 3 in a very schematic plan view, which roughly corresponds to the plan view Figure 1b corresponds to a second embodiment 10 'of a heat exchanger according to the invention. The finned tube sections 16 are shown in FIG Fig. 3 identical in terms of their position to those in terms of their position Figure 1b arranged in a housing 11. Instead of or in addition to a different rib inclination, the finned tube sections 16 now have different fin heights h - which can be seen very clearly in the top view Fig. 2 participates particularly well in a heat transfer, or supports it particularly effectively, this finned tube section 16a has now been assigned a particularly large fin height h ₁ , which is, for example, much greater than the fin height h _{2 of} the finned tube section 16d following in the flow direction H. In this way, finned tube material can be saved in the finned tube section 16d, which in any case does not take part particularly effectively in a heat transfer.

Since the finned tube section 16b evidenced Fig. 2 participates particularly little in the heat transfer or, due to its arrangement, does not have particularly good heat transfer properties, in the exemplary embodiment according to FIG Fig. 3 ribs are completely dispensed with in this finned tube section, so that the finned tube material can be saved particularly effectively.

While the device 10 'according to Fig. 3 thus (also) different fin heights of the different finned tube sections 16, should at this point once again refer to the exemplary embodiment of the heat exchanger 10 according to FIGS Figures 1a and 1b be jumped back: The finned tube sections 16 show there Figure 1b an identical rib height h. The fin slopes of the individual finned tube sections 16 differ, however. According to a further aspect of the invention, the applicant has now developed a particularly elegant manufacturing method for such a configuration: In this sense, FIG Fig. 4 a (still connected) original pipe 21 with a length I (typically a few meters), which has a gradual, variable ribbing:

A first sector 22a has a particularly high rib slope, sector 22b has a medium rib slope and sector 22c has a low rib slope. The sector 22d then has no ribs at all. The ribs in this exemplary embodiment generally have an identical height h and are typically provided by more than one band. In this exemplary embodiment, the length of the sectors is 1/4.

The applicant has found that such a (gradual) ribbing of a single primary pipe 21 is advantageously possible using a plurality of strips (and then typically a plurality of lasers for welding the plurality of strips). Gradual ribbing of this type thus allows the particularly simple manufacture of a heat exchanger according to the invention, namely in that the in Fig. 4 shown, gradually finned, typically a few meters long original pipe 21 is separated along its sector boundaries.

If the original pipe 21 according to Fig. 4 Separated along the sector boundaries, there are thus four independent, typically straight, finned tube sections of length l / 4, which then according to FIG Figure 1b can be installed in a corresponding heat exchanger.

At this point it should be noted that the sectoring and ribbing of the original pipe 21 according to FIG Fig. 4 is to be understood only as an example and in particular the sector 22d without any ribbing certainly represents a special case (which relates to the exemplary embodiment according to FIG Figure 1b is not directly transferable, since there all finned tube sections 16 are ribbed). The heat exchanger 10 according to FIG Figures 1a and 1b produced, but a not shown heat exchanger with an identical finned tube section arrangement but with from Figure 1b deviating ribs (especially deviating rib incline).

As an alternative or in addition to a variation of the rib height and / or the rib slope between the individual rib tube sections, the invention also includes heat exchangers whose rib tube sections (at least partially) have different materials: Since this cannot or can hardly be represented graphically, a corresponding Figure omitted. It is only indicated that, for example, in the Fig. 1a and 1b or 3 finned tube sections 16 shown could have different materials: For example, in Fig. 1a the rib material of the ribs 19a may be different from the rib material of the ribs 19b (but this also applies to the Figure 3 ).

In particular, the fins of an individual finned tube section (for example of the finned tube section 16a according to FIG Fig. 1a consist of several strips of different materials; In contrast to this, the ribs 19b of the finned tube section 16b could then only consist of one material, completely regardless of whether the finned tube sections 16 have the same fin pitch and / or height).

Fig. 5 is then intended to make it clear that the finned tube sections 16 are not as shown in FIG Fig. 1a (indicated there in particular above the housing 11) must run independently of one another. Rather, they can be assigned to a common pipe or be formed from sections of this pipe: So shows Fig. 5 that the finned tube sections 16 ′ are all integral components of an overall tube 23 which, in addition to the straight finned tube sections 16 ′, also has curved finned tube sections 24. Also such finned tube sections, or such an overall tube 23, can in principle be used in heat exchangers, the arrangement in a housing then of course being somewhat different from that according to FIG Fig. 1a deviates. Nevertheless, they are basically suitable for guiding the second fluid 18 in their interior.

Another different exemplary embodiment of an overall pipe 23 ′ is then shown Fig. 6 : Here the finned tube sections 16 belong as in Fig. 5 to a common overall pipe 23 '. In this case, however, they are not straight, or their main direction of extent is not aligned along a straight line, but rather curved in an arc-like manner. The reason for this is that the overall pipe 23 has an essentially helical configuration. However, FIG. 9 is intended to make it clear that finned tube sections 16 arranged next to one another (for example finned tube sections 16i, 16ii and 16iii) can also have different ribs: Even if this cannot be seen in FIG. 9 for the sake of clarity, the rib pitch and / or vary the height of the ribs. In particular, the overall pipe 23 'could be ribbed in a manner similar to that in FIG Fig. 4 represented (i.e. gradually or continuously variable) and then converted or bent into its helical end shape. This is also intended to be encompassed by the invention.

Claims (10)

A method for producing or designing a heat exchanger (10) with a plurality of ribbed pipe sections (16) arranged next to one another, in particular parallel to one another, characterized by the following steps: • Obtaining or creating information on the heat exchange behavior of the pipe sections (16) on the basis of a predetermined or selected pipe section arrangement, preferably by performing a simulation, • Selection of different ribs (19) for the pipe sections (16) based on said information. Method according to Claim 1, characterized in that the ribs (19) of the pipe sections (16) have a different height (h) compared to one another. Method according to Claim 1, characterized in that the ribs (19) of the pipe sections (16) consist of a different material. Method according to one of the preceding claims, characterized in that the ribs (19) of the pipe sections (16) have a different pitch compared to one another. Method according to one of the preceding claims, characterized in that the pipe sections (16) originate from the same, preferably already finned, pipe (21), in particular are cut off from it. Method according to Claim 5, characterized in that the tube (21) has a rib slope that varies, in particular gradually. Method according to one of the preceding claims, characterized in that a pipe section (16b) is not ribbed based on said information. Method according to one of the preceding claims, characterized in that the ribs (19) of a pipe section (16) consist or are produced from at least two, in particular separate, strips. Method according to one of the preceding claims, characterized in that the information on the heat exchange behavior of the pipe sections (16) is obtained by a computer-aided simulation, in particular in a CAD program. Heat exchanger (10) with several finned tube sections (16) arranged next to one another, in particular parallel to one another, characterized in that the finned tube sections (16) are ribbed differently.

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