Low-loss pipe and use of said pipe in a vehicle

Abstract

The invention relates to a pipe (1), in particular for conducting a fluid, which has an inner wall (2) the surface of which has, in cross section, a plurality of projections (4) projecting into the pipe interior (3). The projections (4) are each spaced apart from one another at a highest point (5) by a width (W) and have a height (H). According to the invention, the ratio of the width (W) to the height (H) is > 1.5, preferably > 1.75 and particularly preferably > 2.0.

Description

[0001] Low-loss pipe and use of this pipe in a vehicle

[0002] Description:

[0003] The invention relates to a pipe, in particular a pipe for conducting a fluid, wherein the pipe has an inner wall whose surface in cross section has a plurality of projections projecting into the pipe interior, wherein the projections are each spaced apart from one another at a highest point by a width W and wherein the projections each have a height H. The invention further relates to a use of this pipe in a vehicle and in particular in an electric or hybrid vehicle.

[0004] A fluid line with a multitude of microscopic grooves on its inner wall is known from US Pat. No. 4,759,516 A. The described pipeline has a cascaded profile formed by larger grooves, creating an inner wall profile with protrusions. On the surface, the protrusions, in turn, have a profile of smaller grooves, which correspond to a sawtooth profile in cross-section. Thus, the cascaded profile also has a pronounced surface topography. Such lines are used as pipelines with a pipe diameter of 20 inches to reduce turbulent flow and pressure drops. The introduction of protrusions on the inner wall profile promotes the development of laminar flow.

[0005] Furthermore, JP 2000097211 A describes a fluid line consisting of a tubular body and an inner wall with several projections. The projections extend in the flow direction and thus reduce the

[0006] Frictional resistance of the fluid. The surface profile can be formed by either round or triangular protrusions, with the individual protrusions positioned directly next to each other. Such fluid lines are used as kerosene lines in aircraft. By reducing the frictional resistance between the fluid and the surface, an aircraft's fuel consumption can be reduced.

[0007] In the automotive industry, the need for improved fluid transport is constantly growing. Further optimization of fluid lines is particularly desirable in the field of e-mobility. To shorten the charging times of electric vehicle batteries, higher charging power is required. However, this results in greater thermal stress on the drive battery, requiring more efficient temperature control or cooling to dissipate the heat. In addition, the fluid lines are also used to control the temperature or heat the drive battery, for example, when the outside temperature is low.

[0008] To ensure adequate temperature control, larger-diameter pipes can be used, allowing a larger volume flow of fluid to pass through the pipe. However, this is not a satisfactory alternative, as the automotive industry is primarily concerned with developing space-saving and weight-saving solutions. A larger-diameter pipe or a larger pump should therefore be avoided.

[0009] Based on the known prior art, the object of the invention is to create a fluid line of the type described above which enables more efficient temperature control.

[0010] This object is achieved according to the invention in that the ratio of the width W to the height H is > 1.5, preferably > 1.75 and particularly preferably > 2.0.

[0011] The invention is based on the realization that, for optimized flow in the pipe, it is expedient not to provide the entire surface of the inner wall with projections, but rather to arrange them at such a distance from one another that a sufficient volume space is created between the projections, resulting in ideal flow conditions. By specifying a corresponding minimum distance between the projections using the previously defined width W, it is ensured that this volume is sufficiently large. The result is an improved volume flow by minimizing turbulent flow and pressure losses in the pipe. In particular, excessively narrow passages at the groove base between two projections, which cause particularly large pressure losses, are avoided. As a result, the object stated above is achieved.

[0012] Within the scope of the invention, the width W is preferably defined by the minimum distance between the highest points of two adjacent projections, relative to the horizontal or tangential direction. Viewed in cross section, the width W is defined by a horizontal connecting line.

[0013] between the highest points of the projections. In relation to the geometry of the pipe, this generally corresponds to the tangential direction, so that horizontal and tangential are used synonymously in the context of the invention. This preferably means that in the case of two adjacent projections which have different heights H, the respective highest points are not connected via a diagonal in order to determine the width W, but that the width W is determined along the horizontal or tangential distance between the respective highest points of the projections. The highest point is preferably the point furthest away from the inner wall or outer side of the pipe or the point of the projection which projects furthest radially into the interior of the pipe. If a projection does not have a peak but rather a plateau, the width W is preferably determined in relation to the highest point of the projection which has the shortest distance to the adjacent projection.The width W is advantageously determined by the minimum distance between the highest points. The ratio W / H is expediently determined based on two directly adjacent projections. It is preferable to use the height H of the larger projection to determine the W / H ratio.

[0014] The inner pipe wall expediently has a point that is furthest away from the pipe axis in the radial direction. The pipe axis preferably refers to the center of mass in the cross-section of the pipe, which is particularly preferably designed to be rotationally symmetrical. In other words, this point is the minimum of the inner pipe wall with the smallest distance to a preferably cylindrical outer wall of the pipe. This minimum of the profile of the inner pipe wall preferably serves as a reference value from which the

[0015] The highest point of the projection or the height H of a projection can be determined. The height H of a projection is preferably defined by the radial distance from the plane or the orbit of the minimum of the pipe inner wall to the highest point of the projection in the radial direction. How the tangential width W and the radial height H are to be determined is also illustrated in the figures using exemplary embodiments.

[0016] The height H of the projections of the inner wall profile can vary within the scope of the invention. However, the projections of the inner wall can have a specific height ratio to one another. For this purpose, the pipe can have at least one projection that has a maximum height Hmax. If all projections of the inner wall profile are considered, the reference height Hmax is defined by the height of that projection that projects furthest radially into the interior of the pipe, starting from the pipe inner wall or the minimum of the pipe inner wall, and accordingly has the greatest value for the height H. Several projections can have the height Hmax. All other projections can be defined such that the individual projections each deviate in their height H by a maximum of 10%, 15%, 25%, 40%, 50%, 60% or 75% from the maximum height Hmax.Thus, the minimum possible height H of the projections is limited by the projection with the maximum height Hmax, which serves as the reference. This ensures that the projections are sufficiently large, especially in terms of their height, to adequately influence the flow conditions inside the pipe.

[0017] It is preferably provided that the height H of the projections is at least 5 pm, 10 pm, 15 pm, 20 pm, 25 pm or 30 pm. Furthermore, the height H of the projections is preferably a maximum of 500 pm, 200 pm, 150 pm, 100 pm or 80 pm. The height H of an individual projection is measured in each case starting from the minimum of the surface of the inner wall up to the highest point of the projection. The selected height H promotes laminar flow and accordingly a reduction in turbulent flow. On the other hand, the height H of the projections or the overall dimensioning of the projections is selected such that they do not protrude too far into the pipe and become too unstable. The purpose of this is to ensure that the pipe has sufficiently high wear resistance so that the pipe has an appropriate durability. In addition, the carryover of broken-off small particles into downstream fluid components is prevented.Particularly very small and locally very narrow protrusions on the inner pipe wall, such as those in US Pat. No. 4,759,516 A, can have a negative impact on the wear behavior of the pipe. Due to the constant stress on the material caused by the flow, the material is eroded more quickly due to the larger surface area exposed to the flowing medium, and the required surface profile is worn away. Appropriate design of the protrusions, including a specific height H, reliably reduces this risk.

[0018] Preferably, the tube has an outer diameter D of at most 50 mm, 40 mm, 30 mm, 20 mm, or 10 mm. The outer diameter D can be at least 1 mm, 2 mm, 4 mm, 6 mm, or 8 mm.

[0019] An outer diameter D in this range is particularly suitable for use in the automotive sector as a fluid line. The fluid line can carry, for example, a temperature control medium or fuel.

[0020] It is preferred that the projections run in the axial direction parallel to the flow direction S in the interior of the pipe, wherein the pipe has a total length and wherein at least one, preferably a plurality of and more preferably all of the projections preferably extend over at least 10 or 30 or 50 or 70 or 90 or 95 or 99% of the total length of the pipe. A longitudinal extent of at least one, preferably a plurality of and more preferably all of the projections can extend within the pipe in the axial direction. The projections or the at least one projection preferably run parallel to the flow direction S in the interior of the pipe. The pipe can have a total length, wherein the at least one of the projections can extend over the entire length of the interior of the pipe. The projections can in the flow direction orThey must be continuous in the axial direction, so that there are no structural interruptions, for example in the form of recesses, over the entire length of the pipe. The projections can be designed such that they each extend over more than 1%, 5%, 10%, 25%, 50%, 75%, 90%, or 95% of the total length. Thus, interruptions within the individual projections in the axial direction are also possible. To achieve the desired influence on the flow conditions, the projections must also extend over a sufficient area in the axial direction.

[0021] The inner wall can advantageously have a continuous area of ​​at least 100mm 2have a surface roughness Rz for which the following applies everywhere in the connected surface: Rz < H • 0.05, Rz < H • 0.04, Rz < H • 0.03, Rz < H • 0.02, Rz < H • 0.015 or Rz < H * 0.01. The surface roughness Rz is to be understood as the roughness depth, which defines the distance from the highest to the lowest point of the profile. The roughness Rz is preferably set in relation to the height H - in particular to the height Hmax. Optionally, the roughness of the surface can also be described by the arithmetic mean roughness value Ra. However, the surface does not necessarily have to have a measurable roughness. The surface can have a surface roughness Rz or Ra of < 30 pm, < 25 pm, < 20 pm, < 15 pm or < 10 pm.

[0022] The surface roughness Rz or Ra is preferably determined according to EN ISO 25178. Preferably, the surface roughness can correspond to a value determined by the material used. By avoiding the targeted introduction of a surface topography on the projections and in the area of ​​the width W, the manufacturing process can be made more economical. Furthermore, an excessive number of elevations in the fluid line, which are also arranged too closely together, can even have a detrimental effect on the flow conditions inside the pipe, noticeably worsening them.

[0023] The width W between the adjacent projections can be chosen such that its value is at least 50 pm, 70 pm, 90 pm, 100 pm or 125 pm

[0024] The maximum width W can be 150 pm, 200 pm, 300 pm, 500 pm, 750 pm or 1000 pm. According to the invention, the width W is defined by the minimum distance between the highest points of two adjacent projections, based on the horizontal or tangential direction. If two adjacent projections have a different geometry and / or a different height, the width W is determined as the horizontal or tangential distance between the highest points. If the projection is designed with a plateau, the minimum distance between the highest points is used to determine the width W. The width W should be selected such that there is sufficient volume between the projections, but should not be too large either, since in this case there may be too few projections.

[0025] It is preferred that in a cross-section, the width W and the height H of two projections define a total area AG, wherein the two projections define a projection-free area AF within the total area AG and wherein: AF > 0.5 • AG, preferably > 0.6 » AG, particularly preferably > 0.7 » AG. The projection-free area AF preferably means a material-free area, which can also extend above a section of a projection. Within the projection-free cross-sectional area or area AF, there are no projections that project radially into the pipe interior. The projection-free area AF is preferably determined between the respective highest points of two adjacent projections. The minimum distance is preferably used for the determination, provided the projection has a plateau. In the case,

[0026] that the neighboring projections have a different height H, the direct connection of the highest points is not used to determine the area, but rather the horizontal or tangential direction. This horizontal connection is expediently drawn at the height of the highest point of the projection that has the greater height H, so that the projection-free area AF also covers the area above the smaller projection. This is sensible because this area also contributes to the volume that favors the flow conditions inside the pipe. Maintaining the previously described relationship between the projection-free area AF and the total area AG can ensure that the space between two projections is not too narrow, which has a detrimental effect on the flow. If the volumes or areas between two projections are too narrow, the groove base or the groove base between two projections that is too narrow is particularly prone to turbulence.

[0027] Furthermore, the projections are preferably designed such that they have a shape that tapers radially from the inner wall into the pipe interior, at least in sections and preferably continuously. Thus, the shape of the projections can be selected such that they become narrower toward the pipe interior. This allows, for example, the formation of a tip. A tapered shape of the projections results in the volume through which the fluid flows becoming larger toward the pipe interior. This can ensure optimal flow conditions, in particular the reduction of turbulent flow and the promotion of laminar flow.

[0028] The projections themselves can have a variety of designs. For example, each of the projections, or at least one of the projections, can have a tip, wherein the tip preferably has a rounded contour with a radius R. The ratio of the height H to the radius R can be > 1.0, > 1.5, > 2.0, > 3.0 or > 5.0. However, other geometries of the projections are also possible. For example, instead of a tip, a plateau can be formed, or the tip can be angular, e.g. triangular. Furthermore, an individual projection does not have to be mirror-symmetrical starting from its central axis. It is certainly conceivable for the projection to have a contour in the form of a curve on its first side and a surface leading vertically to the inner pipe wall on its second side. Two adjacent projections do not have to be identical.These can each have different heights (H) or different basic geometries. A variety of options for the design of the projections and the combination of different projections are conceivable in order to specifically adjust the flow conditions in the pipe.

[0029] The pipe can comprise a plastic, particularly a thermoplastic. For this purpose, the pipe can be manufactured by extrusion. This makes it possible to efficiently manufacture multiple pipes in series production. Production takes place using an extruder.

[0030] The invention further encompasses the use of a pipe for use in a vehicle, in particular an electric vehicle or a hybrid vehicle. Especially when using battery coolants with

[0031] With higher flow rates, customers' demands for low pressure losses in the fluid line are very high and constantly increasing. This is primarily due to the fact that e-mobility requires ever shorter charging times, which makes more intensive cooling absolutely necessary.

[0032] However, within the scope of the invention, it is also possible to use the pipe in a combustion-engine vehicle, for example, as a fuel line. Even when fuels such as gasoline or diesel flow through the fluid line, the flow conditions must be continuously optimized.

[0033] The invention is explained in more detail below using several embodiments and several drawings. They show:

[0034] Figure 1 : a pipe according to the invention in a perspective view,

[0035] Figure 2: an enlarged cross-section of a first embodiment of a pipe according to the invention,

[0036] Figure 3: an enlarged cross-section of a second embodiment of a pipe according to the invention,

[0037] Figure 4: an enlarged cross-section of a third embodiment of a pipe according to the invention,

[0038] Figure 5: an enlarged cross-section of a fourth embodiment of a pipe according to the invention and

[0039] Figure 6: an enlarged cross-section of a fifth embodiment of a pipe according to the invention.

[0040] Figure 1 shows a pipe 1 according to the invention in a plan view. The inner wall 2 of the pipe 1 can be seen. On the surface of the inner wall 2, a plurality of projections 4 are arranged, which project into the pipe interior 3. These projections 4 are spaced from one another by a width W. The pipe has an outer diameter D and the introduced fluid flows through the pipe along the flow direction S. It can be seen from the figure that the projections 4 or longitudinal extensions of the projections 4 in the pipe interior run axially or parallel to the flow direction S. The projections 4 can be formed over the entire length of the pipe and do not have any interruptions in the form of recesses or other contours deviating from the basic geometry.

[0041] A first embodiment of the profile of the inner wall 2 of a pipe 1 according to the invention is shown in Figure 2. Two adjacent projections 4 can be seen which have the same geometry and dimensions. In the embodiment shown, the projections 4 have a tip 6 with a rounded contour. The projections 4 have a height H and are spaced from each other by a width W. The height H is determined starting from the minimum of the inner wall up to the highest point 5 or, in this example, the tip 6. The width W is defined by the minimum measured distance between the respective highest points 5, which are represented here by the tips 6 and are at the same height H due to the identical geometry.

[0042] Figures 3 to 6 show further embodiments of the profile of the pipe inner wall 2 according to the invention.

[0043] Figure 3 shows a plateau configuration of two projections 4. In this embodiment, the height H is also determined from the minimum of the inner wall to the highest point 5 of the projection 4. The projections 4 are each identical and have a plateau, so that the highest point 5 of the projection 4 extends over a larger area. In this case, the width W is not determined from the center of the projections 4, but rather the minimum distance between the highest points 5 of the projections 4 is determined. This is illustrated in Figure 3.

[0044] Figure 4 shows that the individual projections 4 do not have to be mirror-symmetrical with respect to their central axis. Within the scope of the invention, a geometry of the projections 4 is certainly conceivable in which the projection 4 has two different lateral configurations on the left and right, starting from its center. Here, too, the width W and the height H are determined with respect to the highest point 5.

[0045] Figure 5 shows a triangular configuration in which the highest point 5 is pointed. Therefore, both the height H and the width W are to be determined starting from this point. The width W and the height H define a total area AG, which can be rectangular in shape. A projection-free area AF between the two projections 4 is part of the area AG and, due to the area share of the projections 4 in the

[0046]

[0047] The total area of ​​the AG is always less than or equal to the area of ​​the AG. In this embodiment, the ratio of the AF to the AG is 0.68.

[0048] Finally, Figure 6 shows that two adjacent projections 4 can also differ from each other in height H. Although the projections 4 have a similar basic geometry, they differ in their dimensions, especially in height H. The width W between the two projections 4 is determined, as can be seen from the figure, starting from a horizontal or tangential connecting line of the highest points.

[0049] In all exemplary, schematic embodiments of Figures 2 to 6, the surface of the projections is formed in such a way that no additional surface roughness is introduced that differs from the natural topography of the material used. Nevertheless, the targeted adjustment of a surface topography in these areas is also covered by the invention.

[0050] However, with regard to the design of the profile of the inner layer with the projections, the invention is not limited to the previously described embodiments. These merely represent a few examples. Further combinations of different geometries and dimensions are conceivable within the scope of the invention. For example, projections with different contours can also be combined, so that the first projection has a rounded contour, while the adjacent projection has a triangular profile.

[0051]

[0052] List of reference symbols:

[0053] 1 pipe

[0054] 2 inner wall 3 pipe interior

[0055] 4 projections

[0056] 5 highest point of 4

[0057] 6 top of 4

[0058] W Width H Height

[0059] D outer diameter

[0060] S Flow direction

[0061] AG total area

[0062] AF protrusion-free area

Claims

Patent claims:

1. Pipe (1), in particular a pipe for conducting a fluid, the pipe (1) having an inner wall (2) whose surface in cross-section has a plurality of projections (4) projecting into the pipe interior (3), the projections (4) each being spaced from one another at a highest point (5) by a width (W) and the projections (4) each having a height (H), characterized in that the ratio of the width (W) to the height (H) is > 1.5, preferably > 1.75 and particularly preferably > 2.

0.

2. Pipe (1) according to claim 1, characterized in that the pipe has at least one projection (4) which has a maximum height (Hmax), wherein the projections (4) each deviate in their height (H) by a maximum of 10%, preferably by a maximum of 50%, particularly preferably by a maximum of 75% from the maximum height (H max ).

3. Pipe (1) according to one of claims 1 or 2, characterized in that the height (H) of the projections (4) is at least 10 pm, preferably at least 40 pm.

4. Pipe (1) according to one of claims 1 to 3, characterized in that the pipe (1) has an outer diameter (D), wherein the outer diameter (D) is a maximum of 50 mm, preferably a maximum of 20 mm.

5. Pipe (1) according to one of claims 1 to 4, characterized in that the projections (4) extend in the axial direction parallel to the flow direction (S) in the pipe interior (3), wherein the pipe (1) has a total length and wherein at least one, preferably several and more preferably all of the projections (4) preferably extend over at least 10 or 50 or 90% of the total length of the tube (1).

6. Pipe (1) according to one of claims 1 to 5, characterized in that the inner wall (2) has at least a continuous area of 100mm 2has a surface roughness Rz for which the following applies everywhere in the connected area: Rz < H • 0.03, preferably Rz < H • 0.02 and particularly preferably Rz < H • 0.01 .

7. Pipe (1) according to one of claims 1 to 6, characterized in that the width (W) between the projections (4) is a maximum of 150 pm or 300 pm or 500 pm.

8. Pipe (1) according to one of claims 1 to 7, characterized in that in a cross section the width (W) and the height (H) of two projections (4) define a total area (AG), wherein the two projections (4) define a projection-free area (AF) within the total area (AG) and wherein: AF > 0.5 • AG, preferably > 0.6 • AG, particularly preferably > 0.7 • AG.

9. Pipe (1) according to one of claims 1 to 8, characterized in that the projections (4) have a shape which tapers from the inner wall (2) radially into the pipe interior (3) at least in sections and preferably continuously.

10. Pipe (1) according to one of claims 1 to 9, characterized in that at least one of the projections (4) has a tip (6), wherein the tip (6) preferably has a rounded contour with a radius (R), wherein the ratio of the height (H) to the radius (R) is > 3.0, preferably > 5.

0.

11. Pipe (1) according to one of claims 1 to 10, characterized in that the pipe (1) comprises a plastic, in particular a thermoplastic.

12. Use of a pipe (1) according to one of claims 1 to 11 for use in a vehicle, in particular an electric vehicle or a hybrid vehicle.

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