DE102020131023A1 - Fluid guide element and fluid heater - Google Patents

Abstract

A fluid guide element and a fluid heater designed with such a fluid guide element are disclosed, wherein the fluid guide element is designed with heat transfer optimization regions, each of which has at least one throttle section and a flow path formed downstream thereof with an enlarged flow cross section.

Description

The invention relates to a fluid guiding element according to the preamble of claim 1 and a fluid heater with such a fluid guiding element.

Such fluid heaters are preferably used for heating gaseous or liquid media, such as air or water. The basic structure of this fluid heater is, for example, in the publication that goes back to the applicant DE 10 2016 122 767 A1 explained. This fluid heater designed for heating air has a heating element designed as a tubular heating element, the heat from which is transferred to the fluid to be heated via a heat exchanger, also known as a heat distribution element. In the concrete in the DE 10 2016 122 767 A1 described fluid heater, this heat distributing element is designed as a metal sponge or wire mesh/wire mesh, with the pores or channels formed thereby being flowed through by the fluid. Of course, other heat distribution elements, such as extruded profiles or corrugated fins, can also be used for heat exchange. The heating element is controlled via control and power electronics, the circuitry of which is formed on a circuit board/printed circuit board and which is arranged in an electronics housing which is attached to a housing which accommodates the heating element and the heat distribution element. An inlet and an outlet for the fluid to be heated are also formed on this.

In the DE 10 2018 108 407 A1 describes a fluid heater in which an aluminum die-cast body is arranged inside the fluid space, which is designed as a heat sink and via which the heat from the heating elements is transferred to the fluid that flows through the channels of the die-cast part.

the DE 10 2017 129 749 A1 discloses a fluid heater in which a turbulator designed as an expanded metal sheet metal is arranged in the fluid space. In contrast to the solution described above, this does not serve as a heat sink, but rather to swirl the fluid flow. Both of the fluid heaters described above only have an insufficient degree of efficiency.

In the pamphlet DE 10 2012 209 936 A1 describes a thick-film heater in which conductor tracks are applied to a substrate by an additive process. These conductor tracks form a heating resistor of a heating device.

In the going back to the applicant DE 10 2018 106 354 A1 it is proposed to use power semiconductors arranged on the circuit board as heating elements, so that the heat generated during operation of the power semiconductors is transferred to the fluid to be heated via a heat distribution element.

These disadvantages are overcome by a fluid heater as disclosed in the post-published DE 10 2019 133 043 A1 is disclosed to the applicant. In this fluid heater, a printed circuit board forming the control circuit and power electronics is also designed as a heating element and is arranged in the fluid heater in such a way that it delimits a section of a fluid channel through which the fluid flows.

In contrast, the invention is based on the object of creating a fluid guide element and a fluid heater designed with such a fluid guide element, by means of which the heat transfer to a fluid to be heated is improved with little outlay in terms of device technology.

This object is achieved with regard to the fluid guiding element by the features of patent claim 1 and with regard to the fluid heater by the features of independent patent claim 20 .

Advantageous developments of the invention are the subject matter of the dependent claims.

The fluid guiding element according to the invention has a fluid chamber through which fluid flows, with a fluid guiding structure being arranged in the fluid chamber, which delimits at least one fluid channel in sections, along which the fluid is guided in the direction of an outlet. According to the invention, the guide structure is designed in such a way that at least one, preferably several, heat transfer optimization regions are formed one behind the other in the flow direction, each of which has a defined throttle section, with flow paths with a defined enlarged flow cross section being provided upstream or downstream of this throttle section, for example for turbulence and/or smoothing the flow are formed.

The fluid flow in the region of the throttle section is accelerated by these throttle sections according to the invention, with the pressure loss increasing. In the area of the adjoining flow paths, the flow velocity is then reduced again and, accordingly, the pressure loss is also reduced. It is found that this defined flow cross-section change optimizes the fluid flow in terms of heat transfer, so that a fluid guide element of this type ment running fluid heater has a compared to the prior art described above significantly improved efficiency.

Due to the flow guidance according to the invention, an effective heat dissipation of the heating elements to the fluid to be heated is achieved with a low pressure loss at the same time.

In a particularly preferred exemplary embodiment, the flow path adjoining the throttle section is designed as a turbulence area and/or relaxation area, with the flow cross section of the relaxation area being larger than that of the turbulence area.

It was found that this choice of flow cross sections (flow cross section of the throttle section smaller than the flow cross section of the turbulence area and this in turn smaller than the flow cross section of the relaxation area) can further improve the efficiency of the fluid heater.

The relaxation area can be formed downstream or upstream of the turbulence area. According to the invention, however, it is preferred if a relaxation area arranged downstream of the turbulence area is formed in each flow path.

The relaxation area and the turbulence area can merge directly into one another. According to the invention, however, it is preferred if a throttle section is again arranged between the turbulence area and the relaxation area.

In such an embodiment, the fluid-guiding structure is thus formed by a throttling section, a turbulence or relaxation area adjoining it, a further throttling section and an adjoining relaxation or turbulence area. Following this, corresponding further guide structures of this type are then preferably formed.

In a particularly preferred embodiment, the flow cross section of the turbulence area is 1.5 to 3.5 times the flow cross section of the throttle section.

The flow cross section of the relaxation area can be approximately two to four times the flow cross section of the throttle section.

The formation of the guide structure is particularly simple if the variation of the aforementioned flow cross-sections takes place solely by changing the height of the fluid channel, i.e. the distance between the fluid guide element and the adjacent wall of the fluid heater.

In a variant of the invention, the product of the heights of the flow cross sections in the area of the throttle section, the turbulence area and the relaxation area is less than or equal to 4.

The heat transfer can be further improved if in the area of the flow path, i.e. in the area of the turbulence and/or relaxation area, turbulence bodies, for example knobs or webs, are formed, around which and/or the fluid flows.

The efficiency of the fluid heater is optimal when the fluid-guiding structure delimits two fluid channels which are spaced apart from one another and each have the structure described above with a number of throttle sections and a number of flow paths (turbulence area, relaxation area).

In order to ensure optimal distribution of the fluid, flow dividers or flow collectors can be formed in the area of an inlet and outlet to and from the fluid channel, which distribute or combine the flow transversely to the flow direction along the fluid-guiding structure.

In the case in which the fluid guiding structure delimits two fluid channels, the flow divider or flow collector can also be formed on the guiding structure, so that the flow towards the fluid channels is correspondingly divided or combined downstream of the fluid channels.

The structure of the fluid heater is particularly compact if a fluid inlet and a fluid outlet each open into an inlet or outlet channel, which is oriented transversely to the direction of flow in the fluid channel.

The fluid inlet and/or the fluid outlet can be oriented essentially in the direction of flow (relative to the flow along the guide structure) or transversely thereto or also inclined to the direction of flow. In principle, an arrangement with a fluid inlet and fluid outlet oriented in the flow direction has the advantage that pressure losses due to deflections in the inlet and outlet are reduced. From square green However, from or by specification of the fluidic interface to the next component, it can certainly also be provided that the fluid inlet and/or the fluid outlet are formed in an orientation that differs from the direction of flow.

The outlay in terms of device technology is minimal if the fluid channel is delimited at least in sections by a heating element, preferably a surface heating element.

Since, according to the concept according to the invention, the fluid-guiding structure is not designed as a heat sink but only serves to guide fluid, it can be made of almost any material, for example plastic.

In one embodiment of the invention, the fluid-guiding structure is designed as a three-dimensional body in which the throttle sections are formed by webs arranged transversely to the direction of flow, while the adjacent flow paths (turbulence area, relaxation area) are formed by depressions or grooves.

The fluid guiding element can be designed in one piece with the fluid guiding structure or in several parts, for example with a frame into which the fluid guiding structure is inserted.

The flow path is preferably designed with a greater length (seen in the direction of flow) than the throttle section. The turbulence area and the relaxation area can each be designed with approximately the same length, which in turn is greater than the length of the throttle section.

The fluid heater can be designed with several such fluid guiding elements, whereby these can be arranged in several levels and/or connected in series. A fluid inlet and a fluid outlet are then preferably assigned to the fluid guiding elements.

• 1 eine dreidimensionale Darstellung eines Fluidheizers;
• 2 eine Einzeldarstellung eines Heizkerns des Fluidheizers gemäß 1 ;
• 3 eine Explosionsdarstellung des Heizkerns gemäß 2;
• 4 einen Schnitt entlang der Linie A-A in 2;
• 5 eine schematische Detailansicht des Schnittes gemäß 4, anhand der die Strömungsquerschnitte erläutert werden;
• 6 einen Schnitt entlang der Linie B-B in 2 und
• 7 einen Schnitt entlang der Linie C-C in 2.

Preferred exemplary embodiments of the invention are explained in more detail below using schematic drawings. Show it:

• 1 a three-dimensional representation of a fluid heater;
• 2 an individual view of a heater core of the fluid heater according to FIG 1 ;
• 3 an exploded view of the heater core according to 2 ;
• 4 a cut along the line AA in 2 ;
• 5 a schematic detailed view of the section according to FIG 4 , on the basis of which the flow cross-sections are explained;
• 6 a cut along line BB in 2 and
• 7 a cut along the line CC in 2 .

1 shows a three-dimensional representation of a fluid heater 1 according to the invention, for example a high-voltage heater, which can be used for example for heating water or another liquid. The fluid heater 1 has a multi-part housing 2 with a lower housing part 4 and a housing cover 6, which is placed on the lower housing part 4 so that an interior space enclosed by this is covered. As will be explained in detail below, a heating core with a fluid guiding element through which the fluid flows and is in heat exchange with at least one heating element is arranged in this. at a 1 Two recesses 10, 12 are formed in the rear side wall 8 of the housing 2 pointing towards the viewer, through which two connecting pieces of the fluid-guiding element accommodated in the interior of the housing 2 extend. The in 1 left-hand connection piece as a fluid inlet 14 and the right-hand connection piece as a fluid outlet 16, these being connected to a line system carrying the fluid to be heated. The outlet 16 is in the vertical direction (as viewed from 1 ) arranged slightly offset from the inlet 14. Of course, the in 1 right-hand connection piece can be designed as a fluid inlet and the other connection piece can be designed accordingly as a fluid outlet.

The housing 2 is preferably made of a metallic material so that the EMC protection is optimized. The housing cover 6 is connected to the housing bottom part 4, for example, by flanging, welding, soldering, gluing or another suitable material/non-positive method, so that reliable sealing is ensured. The area in which the inlet 14 or the outlet 16 pass through the recesses 10, 12 is also advantageously sealed.

As explained below, two heating plates are accommodated in the housing 2, which are designed with at least one heating circuit for heating the fluid and with the in 1 not visible fluid guide element form the heater core and thereby limit a fluid channel in sections. Such a concept is in the initially mentioned post-published DE 10 2019 133 043 A1 explained to the applicant. Of course, a conventional design can also be implemented, in which the heating element is not designed as a circuit board but as a separate component, for example a surface heating element. In addition to the heating circuit, the circuit board can also have additional electronic components for controlling this heating circuit and other heater components. A low-voltage plug 18 and a high-voltage plug 20 are formed on the rear side wall 8 for the power supply of the fluid heater together with its control and/or power electronics. A grounding bolt is identified by reference number 22 .

2 shows a three-dimensional representation of the heating core 24 accommodated in the housing 2, which in principle consists of two heating plates 26, 28 (the latter not visible in 2 ) consists, which are attached to the fluid guide element 30 mentioned at the outset. As explained above, these heating plates/heating elements 26, 28 are preferably in the form of surface heating elements, which can be in the form of the aforementioned IMS heating circuit board, a thick-film heater, a PTC heating plate or any other electrical heating element.

In the specific solution, the two heating plates 26, 28 form part of the fluid guiding element 30 and thus, as explained in more detail below, delimit a section of the fluid channel formed in the fluid guiding element 30. The inlet 14 and the outlet 16 are each connected downwards via a (not visible in 2 ) bulging intake port 32 (see 4 ) or one in 2 outlet channel 34 , which bulges upwards, is connected to the approximately cuboid fluid guiding element 30 .

Its structure is revealed quite clearly from the 3 10 showing an exploded view of the heater core 24. FIG. Accordingly, the roughly cuboid fluid guiding element 30 has a guiding housing 36 to which the aforementioned inlet channel 32 and the outlet channel 34 with the inlet 14 and the outlet 16 are attached. The guide housing 36 delimits an interior space 38 in which a guide structure 40 , explained in more detail below, is arranged, via which the fluid is guided from the inlet 14 to the outlet 16 . The guide structure 40 and the guide housing 36 can be designed in one piece or in multiple parts.

In the illustrated embodiment, the heating element is formed by two IMS circuit boards, which extend the guide housing 36 upwards (as viewed from 3 ) or cover towards the bottom and thus form part of the fluid channel. However, as explained at the outset, the invention is by no means limited to the use of IMS circuit boards, but other heating elements can also be used. These also do not have to form a part of the fluid guiding element 30 or supplement it. This can, for example, be closed, so that the heating elements are then attached flat to the areas of the guide housing 36, which are formed by the IMS circuit boards in the exemplary embodiment shown.

In the exemplary embodiment shown, the guide structure 40 is used to optimize the heat transfer by forming a plurality of heat transfer optimization regions 42a, 42b, 42c, 42d that are essentially the same in terms of geometry and will be discussed in more detail below. Such heat transfer optimization areas 42a, 42b, 42c, 42d are according to the sectional view in 4 also at the in 3 trained non-visible underside. These lower optimization areas are provided with reference number 44 below. The fluid flows over these optimization areas 42, 44 and exchanges heat with the two heating plates 26, 28.

In the transition area from the inlet channel 32 to the guide structure 40, ie in its inlet, longitudinal flow dividers are provided, of which 3 only one is provided with the reference number 46 . These longitudinal flow dividers 46 deflect the fluid from the inlet channel 32 approximately at right angles to the guide structure 40 . Accordingly, these longitudinal flow dividers 46 act in the longitudinal direction of the inlet channel 32. The fluid flow is divided in the horizontal direction (top ↔ bottom) via at least one further flow divider 48. The longitudinal flow divider 46 and the flow divider 48 can be formed on the guide structure 40. In principle, however, it is also possible to design these flow dividers separately and to use them in the interior 38 of the guide housing. Corresponding flow guide elements are also formed in the area of the outlet channel 34 (outlet); these are referred to below as flow collectors 50 or longitudinal flow collectors 52 . The flow divider 48 and the flow collector 50 are perpendicular to the plane of the drawing in 4 running side edges of the guide structure 40, these tapering towards the adjacent longitudinal flow divider/collector 46, 52 and towards the adjacent inlet/outlet area.

At the in the 2 and 3 illustrated embodiment, the inlet 14 and the outlet 16 are transverse to the in 2 Arranged with an arrow indicated main flow direction within the guide structure 40, the inlet 14 and the outlet 16 approximately in the direction of the Füh tion structure 40 spanned level. However, the invention is not limited to such a relative positioning of the inlet 14 or the outlet 16 . As in 2 indicated by dashed lines, the inlet 14 and/or the outlet 16 can also be positioned approximately parallel to the direction of flow or approximately perpendicular to the plane spanned by the guide structure 40 . In the latter case, the inlet 14 and/or the outlet 16 are then pointing upwards or downwards in the vertical direction (view according to 2 ) arranged. In principle, the sockets forming the inlet 14 and the outlet 16 can also be arranged in corner areas, for example on opposite corner areas of the fluid guiding element 30 . The choice of the inlet/outlet orientation can thus be chosen with regard to the space requirement and the optimal hydrodynamic design.

4 shows a section through the heater core 24 along the section line AA in 2 . The interior space 38 surrounded by the guide housing 36, in which the above-mentioned guide structure 40 is accommodated or formed, can be clearly seen in this sectional illustration. As explained above, the inlet channel 32 arches in the illustration 4 downwards from the guide housing 36, while the outlet channel 34 offset in the transverse direction and in the vertical direction bulges upwards. The guide structure 40 is arranged in the region of the interior 38 extending between the inlet duct 32 and the outlet duct 34, with reference to its structure 5 will be dealt with in more detail.

As explained above, the said heat transfer areas 42, 44 are formed on this guide structure 40, which is based on 5 be explained in more detail. In this exemplary embodiment, the flow divider 48 on the inlet channel side and the flow collector 50 on the outlet channel side are formed in one piece on the guide structure 40 . The longitudinal flow dividers/collectors 46, 52 are inserted into the interior space 38 as separate components, with the longitudinal flow dividers 46 projecting upwards away from a base 49, while the longitudinal flow collectors 52 on the outlet side extend downwards from an overhead base 51 of the guide housing 36. The longitudinal flow dividers/collectors 46, 52 can also be formed in one piece on the guide structure 40. The interior 38 is closed by the two flat heating plates 26, 28, which are inserted into windows 58, 60 of the guide housing 36 in a sealing manner via seals 54 and 56, so that the interior 38 is sealed off from the outside. Instead of the seals 54, 56, another type of seal can also be used. For example, a sealing compound can be applied to the guide structure 40 or the heating plates 26, 28. To support the two heating plates 26, 28, support knobs 62 can also be provided on the guide structure 40, which can be distributed along the guide structure 40 to stabilize the fluid-carrying regions. As 4 removable, the two heating plates 26, 28 and the central guide structure 40 delimit two fluid channels 64, 66, along which the fluid is guided from the inlet channel 32 to the outlet channel 34, thereby flowing over the above-mentioned heat transfer optimization areas 42, 44, in which the essential Heat exchange with the heating plates 26, 28 takes place.

In the exemplary embodiment shown, the guide structure 40 is produced as a solid body, which is made of plastic, for example. The guide housing 36 can also be made of plastic, so that on the one hand the weight of the heating core 24 is optimal and, on the other hand, the production costs are significantly reduced compared to the solutions mentioned at the outset, in which metallic heat sinks have to be used. As explained, the guide housing 36 and the guide structure 40 can be made in one piece or in multiple parts.

5 shows the in 4 The area marked with X in an enlarged detail view on the basis of which the optimization areas 42, 44 are explained. The direction of flow of the fluid flowing through the fluid channels 64, 66 is identified by the horizontal arrows.

According to the invention, each optimization area 42, 44 is designed with at least one throttle section 68, 69, through which the flow cross section of the fluid channel 64, 66 is reduced. In the exemplary embodiment shown, these two throttle sections 68 , 69 are each formed by a web (flow strip) 70 , 72 of the guide structure 40 . In the exemplary embodiment shown, these webs 70, 72 reduce the height of the fluid channel 64, 66 to the dimension A, so that the fluid flow is correspondingly accelerated and the pressure loss Δp is increased in this area. In the exemplary embodiment shown, this throttle section 68 is adjoined by a turbulence region 74 (or 76), in which the flow cross section is again enlarged compared to the throttle section 68 (or 69). In the illustrated embodiment, these two turbulence areas 74, 76 are in turn delimited in the direction of flow by a web 78, 80, through which the flow cross section is reduced again, so that a further throttle section 82, 84 is formed, the flow cross section of which is approximately that of the throttle sections 68, 69 is equivalent to. Each of the webs 70, 72, 78, 80 has a flattening 86 (only the web 70 is provided with a reference number 86), the length l of which is significantly less than that Length L of the adjoining turbulence area 74, 76. In the illustrated embodiment, the webs 70, 72, 78, 80 are beveled towards the flattened areas 86, so that the respective throttle section 68, 69, 82, 84 seen in the direction of flow continuously towards the Flattening 86 reduced and then expanded again to the adjacent area accordingly.

According to the invention, a relaxation area 88, 90 is provided downstream of the two throttle sections 82, 84, in which the flow cross-section is expanded again. The flow cross section in the relaxation area is larger than in the turbulence area 74, 76 and in the throttle section 68, 69. Accordingly, in the illustrated embodiment, the height H of the relaxation area 88, 90 is greater than the height B of the turbulence area 74, 76, which in turn is greater than the Height A of the throttle section 68, 69. The length M of the relaxation area 86, 88 corresponds approximately to the length L of the turbulence area 74, 76.

In the exemplary embodiment shown, the flow cross sections are changed by appropriate profiling of the central guide structure 40. In principle, this profiling can also be achieved by appropriate design of the heating plates 26, 28. In principle, it is also possible to carry out the profiling by appropriately designing both the guide structure 40 and the heating plates 26, 28.

As explained above, the flow speed is increased in the area of the throttle sections 68, 69, 82, 84, so that the heat transfer coefficient increases accordingly and more heat can thus be transferred into the fluid. As a side effect, the pressure loss increases. In the adjoining turbulence area 74, 76 the fluid is then swirled, with the mixing of the fluid being increased in these areas due to the geometry of the flow cross-section and thus more heat being able to be transferred into the fluid.

As explained above, the flow speed in the throttle sections 68, 69, 82, 84 is increased due to the smaller flow cross section, so that flow separation and thus local turbulence occur in the region of the channel walls. This causes the essentially laminar flow within the throttle section to turn into a turbulent flow, so that the heat transfer coefficient increases accordingly and thus more heat is transferred from the heating plates 26, 28 to the fluid. However, as mentioned above, this advantage of improved heat transfer is “bought” at the cost of an increased pressure loss.

In the subsequent turbulence areas 74, 76, the flow cross section is increased compared to the throttle sections 68, 69, 82, 84, so that an average flow rate is set that is higher than that in the throttle sections 68, 69, 82 and 84 Turbulence areas 74, 76 provided nubs 92 mix the fluid, so that due to the higher mixing rate, a temperature mixing takes place and accordingly in the turbulence area 74, 76 even more heat is transferred to the fluid. The pressure loss Δp compared to the pressure loss in the throttle section 68, 69, 82, 84 is reduced because of the enlarged flow cross section.

The relaxation area 86, 88 adjoining the turbulence area 74, 76 in the described embodiment has a larger cross-section compared to the flow cross sections described above, so that the flow velocity in the relaxation area 86, 88 is further reduced, although the heat transfer coefficient is then also reduced and thus less heat can be transferred to the fluid than is the case in the areas described above. However, the pressure loss is significantly reduced by the relaxation areas 86, 88, which are designed with a comparatively large flow cross section, so that the increase in pressure loss in the throttle section 68, 69, 82, 84 and in the adjoining turbulence area 74, 76 is almost compensated, so that the total pressure loss is no less favorable than with conventional solutions.

It has been shown that such multiple throttling and turbulence and calming of the flow significantly improves the heat transfer from the heating plates 26, 28 to the fluid compared to conventional solutions. According to the invention, this effect is further intensified by the fact that a plurality of such optimization regions 42, 44 are arranged one behind the other in the direction of flow.

According to the invention, the heat transfer is optimal when the flow cross section of the turbulence area 74, 76 is approximately 1.5 to 3.5 times the flow cross section of the throttle section 68, 69, 82, 84. According to the invention, it is furthermore preferred if the flow cross section of the relaxation area 86, 88 is approximately two to four times the flow cross section of the throttle section 68, 69, 82, 84.

In one embodiment of the present invention, it is preferred if the product of the heights of the throttling section 68, 69, 82, 84, the turbulence region 74, 76 and the relaxation region Reichs 86, 88 A x B x H is less than or equal to 4 (A x B x H ≤ 4). The dimensions are preferably used in millimeters, so that the dimension of the code number 4 is corresponding to ³ mm. This small size of the key figure is only achieved if the heights are designed accordingly.

In the exemplary embodiment shown, the flow cross sections in the optimization regions 42, 44 are thus varied according to the sequence of the fluid channel heights A→B→A→H. However, the invention is in no way limited to this sequence of throttle sections, turbulence areas, relaxation areas. In principle, other sequences can also be used, for example the height in the optimization area can be varied according to the patterns A→B→C... or B→A→C... or C→B→A.... Each of these patterns and each flow cross-section variation according to the above specifications ensures optimal heat transfer without hot spots or overheating or damage to the fluid. This is a new finding that is unparalleled in the prior art.

In the exemplary embodiment shown, nubs 92 are also formed in the turbulence regions 74, 76, around which the fluid flows and over which they flow, thus causing partial turbulence and thus improving the heat transfer. The height of these knobs 92 is as shown in 5 less than the height B, so that an overflow is allowed. Instead of the knobs 92, continuous strips or the like can also be provided. Corresponding knobs 92 can also be provided in the relaxation area 86, 88. Such nubs 92 can of course also be formed in the area of the heating plates 26 , 28 .

6 shows a section along section line BB in 2 . This section runs parallel to the inlet port 32 and extends, for example, along the webs 70, 72, which protrude from the guide structure 40 in the vertical direction and form the throttle sections 68, 69. As explained, the fluid channels 64, 68 (of which are shown in 6 only the throttle sections 68, 69 can be seen) are closed to the outside by the two heating plates 26, 28, which seal the two windows 58, 60 via the seals 54, 56. As in 6 indicated, the fluid flows through these two throttle sections 68, 69 perpendicular to the plane of the drawing towards the viewer in the direction of the outlet 16, which is not visible.

7 finally shows the section CC in 2 , which runs through the outlet channel 34 therethrough. In the section plane behind this outlet channel 34, the inlet channel 32 with the inlet 14 is visible uncut. The sectional view shows the longitudinal flow divider 52 via which the fluid is deflected towards the outlet channel 34 on the outlet side. According to the illustrations in the 7 and 3 these flow dividers are tapered in the direction of flow and opposite to the direction of flow, so that the flow around is optimized in terms of pressure loss and minimal turbulence.

Upstream (behind the sectional plane) of the flow divider 52 is the guide structure 40 with the longitudinal flow divider 50 formed thereon, which brings the fluid flowing over the optimization regions 42 , 44 described above back together in the direction of the outlet channel 34 . In this representation, only the heating plate 28 is visible, which is attached to the guide housing 36 via the seal 56 and thus delimits the lower fluid channel, of which the representation according to FIG 7 also only the clear width of the throttle section 69 is visible.

A fluid guide element and a fluid heater designed with such a fluid guide element are disclosed, wherein the fluid guide element is designed with heat transfer optimization regions, each of which has at least one throttle section and a flow path formed downstream thereof with an enlarged flow cross section.

Reference List

1

fluid heater

2

Housing

4

housing base

6

housing cover

8th

sidewall

10

recess

12

recess

14

fluid inlet

16

fluid outlet

18

low voltage plug

20

high-voltage plug

22

grounding bolt

24

heater core

26

hotplate

28

hotplate

30

fluid guide element

32

inlet channel

34

exhaust port

36

guide housing

38

inner space

40

management structure

42

Heat transfer optimization area

44

Heat transfer optimization area

46

longitudinal flow divider

48

flow divider

49

Base

50

flow collector

51

Base

52

longitudinal flow collector

54

poetry

56

poetry

58

window

60

window

62

support knob

64

fluid channel

66

fluid channel

68

throttle section

69

throttle section

70

web

72

web

74

turbulence area

76

turbulence area

78

web

80

web

82

throttle section

84

throttle section

86

flattening

88

relaxation area

90

relaxation area

92

nubs

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102016122767 A1 [0002]
• DE 102018108407 A1 [0003]
• DE 102017129749 A1 [0004]
• DE 102012209936 A1 [0005]
• DE 102018106354 A1 [0006]
• DE 102019133043 A1 [0007, 0038]

Claims (20)

Fluid guide element for a fluid heater, which is designed to heat a fluid by means of at least one heating element, with a fluid chamber through which the fluid flows, in which a guide structure (40) is arranged, which delimits at least one fluid channel (64, 66) in sections, along which the fluid in the direction of the fluid outlet (16), characterized in that in the fluid channel (64, 66), preferably on the guide structure (40), at least one, preferably a plurality of heat transfer optimization regions (42, 44) lying one behind the other in the direction of flow are formed each having a defined throttle section (68, 69, 82, 84), flow paths with an enlarged flow cross section being formed upstream and/or downstream of this throttle section (68, 69, 82, 84). Fluid guiding element after Claim 1 wherein the flow path has a turbulence region (74, 76) and/or a relaxation region (86, 88), the flow area of the relaxation region (86, 88) being greater than that of the turbulence region (74, 76). Fluid guiding element after patent claim 2 wherein the relaxation area (86, 88) is formed downstream or upstream of the turbulence area (74, 76). Fluid guiding element after patent claim 2 or 3 , A throttle section (68, 69, 82, 84) being formed between the turbulence area (74, 76) and the expansion area (86, 88). Fluid guiding element according to one of the preceding claims, wherein the flow cross section of the turbulence area (74, 76) is 1.5 to 3.5 times the flow cross section of the throttle section (68, 69, 82, 84). Fluid guiding element according to one of the preceding patent claims, wherein the flow cross section of the relaxation area (86, 88) is approximately two to four times the flow cross section of the throttle section (68, 69, 82, 84). Fluid guiding element according to one of the preceding claims, wherein the product of heights A x B x H of the flow cross sections of the throttle section (68, 69, 82, 84), the turbulence area (74, 76) and the relaxation area (86, 88) (A x B x H) ≤ 4. Fluid guiding element according to one of the preceding patent claims, turbulence bodies, for example knobs (92) or strips, being arranged in the flow path. Fluid guide element according to one of the preceding claims, wherein the guide structure (40) delimits two fluid channels (64, 66) spaced apart from one another in sections. Fluid guiding element after Claim 9 , flow dividers (48) for dividing the fluid flow in the direction of the two fluid channels (64, 66) or flow collectors (50) for combining the fluid flow in the direction of the outflow being formed in the area of an inflow and/or outflow. Fluid guide element according to one of the preceding claims, wherein a fluid inlet (14) and a fluid outlet (16) each open into an inlet or outlet channel (32, 34) which is preferably transverse to the direction of flow in the fluid channel (64, 66) is oriented. Fluid guiding element after Claim 11 , wherein the fluid inlet (14) and/or the fluid outlet (16) is oriented in the direction of flow or employed thereto or formed transversely to the direction of flow. Fluid guiding element after Claim 11 or 12 , With a longitudinal flow divider (46) between the inlet channel (32) and the guide structure (40) and a longitudinal flow collector (52) between the guide structure (40) and the outlet channel (34). Fluid guiding element according to one of patent claims 10 until 13 , wherein the flow divider (48) and/or the flow collector (50) and/or the longitudinal flow divider (46, 52) is formed on the guide structure (40). Fluid guiding element according to one of the preceding claims, wherein the fluid channel (64, 66) is delimited at least in sections by the heating element, preferably a heating plate (26, 28). Fluid guide element according to one of the preceding claims, wherein at least the guide structure (40) is made of plastic. Fluid guiding element according to one of the preceding claims, wherein the throttle sections (68, 69, 82, 84) are formed by webs (70, 72) of the guiding structure (40) arranged transversely to the direction of flow, the adjacent flow paths being formed by adjacent to the webs (70, 72) arranged depressions are executed. Fluid guiding element according to one of the preceding claims, wherein the length (L, M) of the flow path is significantly greater than the length (I) of the throttle section (68, 69, 82, 84). Fluid guiding element according to one of the preceding claims, wherein this is made in one piece. Fluid heater with a heating core (24) which has at least one fluid guiding element (1) according to one of the preceding claims with at least one heating element.

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