WO2018041424A1

WO2018041424A1 - Arrangement for controlling the temperature of a fluid

Info

Publication number: WO2018041424A1
Application number: PCT/EP2017/061705
Authority: WO
Inventors: Philipp NEIDHARDT
Original assignee: Zf Friedrichshafen Ag
Priority date: 2016-08-30
Filing date: 2017-05-16
Publication date: 2018-03-08
Also published as: DE102016216245A1; EP3507561A1

Abstract

An arrangement for controlling the temperature of a fluid is described, which comprises a heat exchange surface (16), an inlet conduit arrangement (20) for supplying a fluid inflow (122) to the heat exchange surface (16) in a main inlet conduit (22), and a return conduit arrangement (40) having a main return conduit (42) for carrying a fluid return flow (142) away from the heat exchange surface (16). The inlet conduit arrangement (20) has a plurality of supply sections (24), which are fluidically connected to the main inlet conduit (22) and through which the fluid flow is directed at an angle onto the heat exchange surface (16) in a plurality of spatially separate partial fluid inflows (124). The arrangement is characterized in that, in a region interacting with the heat exchange surface (16), the return conduit arrangement (40) comprises draining sections (44), which are configured and arranged in such a way that partial fluid outflows (144) carried away from the heat exchange surface (16) are carried therein spatially separately from the partial fluid inflows (124).

Description

Arrangement for fluid temperature control

The invention relates to an arrangement for fluid temperature control according to the preamble of patent claim 1.

Such a generic arrangement has already become known from EP 2 541 737 A2, where it is designed in particular for fluid cooling of a rotor of an electric machine. In this case, the rotor has a hollow rotor shaft with an inner surface to be cooled, which forms a heat exchange surface and in which a designed as a hollow cylindrical insert part fluid guide is used. Within the insert part runs a Hinhauptkanal of the cooling fluid, which emanate from this at an angle to the central axis of the rotor, a plurality of Zuleitabschnitten forming branch channels, which direct the cooling fluid through a radial gap space on the surface to be cooled and wherein the standing in the heat exchange cooling fluid through this space axially removed from the assembly out.

Although the arrangement disclosed in EP 2 541 737 A2 has already been able to provide an improvement in heat dissipation compared to wave internal cooling by means of a single or double axial flow through a cooling fluid through the rotor shaft, the heat transfer coefficient achievable thereby remains as a proportionality factor Intensity of the heat transfer on the inner surface of the rotor shaft determined to fall short of expectations. When relatively high power losses of a rotor occur, heat dissipation is insufficient and needs improvement.

Based on this state of the art, the invention in an arrangement according to the preamble of the independent claim has the fundamental object to achieve a more effective temperature control of a heat exchange surface and thus one of these thermally associated object, in particular, a heat transfer coefficient of the arrangement should be increased. The above object is achieved by means of a generic arrangement with the features specified in the independent claim.

Advantageous embodiments and further developments of the invention are the dependent claims and the following description of the figures removed.

In the description, with respect to a fluid flow or fluid channel as word constituent executed to a heat exchange surface, unless otherwise explained or otherwise inferred from the context, the syllables "back" and "to" and with respect to one of the Heat exchange surface away fluid flow using the syllables "back" and "down".

Thus, there is proposed a fluid temperature control arrangement which comprises first a heat exchange surface, a downcomer arrangement for supplying a flow of fluid to the heat exchange surface with a main passage and a return passage arrangement for discharging a fluid return flow from the heat exchange surface with a return passage. In this case, the Hinkanalanordnung several Zuleitabschnitte, which are in fluid communication with the Hinhauptkanal and through which the fluid flow is directed in a plurality of spatially separate fluid partial inflows at an angle to the heat exchange surface.

In accordance with the present invention, it is provided that the return channel arrangement has objectively formed discharge sections in an interaction region with the heat exchange surface. These diverting sections are provided for guiding individual fluid partial outflows discharged from the heat exchange surface, which are thereby guided, in particular spatially, separately from the partial fluid inflows.

The invention is based on the finding that an effective heat transfer from the considered heat exchange surface to a fluid is significantly dependent on an unimpeded spread of the partial fluid inflows in the direction of the heat exchange surface. In the arrangement mentioned above and known from the prior art, the individual partial fluid inflows in their propagation in Direction of the heat exchange surface within a gap space very disturbed by a transverse to this and these individual flow paths crossing fluid flow. In the process, these partial fluid inflows undergo a change in the flow direction and are thereby deflected axially in the direction of an intersecting fluid return flow and approximately parallel to the heat exchange surface. By such, to a considerable extent parallel flow guidance on the heat exchange surface and the associated formation of a stable boundary layer, the heat transfer coefficient is comparatively low. In addition, the pressure loss undesirably increases due to the constant mixing of the axial return flow with the partial fluid inflows outside this boundary layer.

In order to locally increase the wall heat transfer coefficient significantly, it is proposed to spatially separate the fluid partial flows and the transverse flow influencing them in a region of interaction with the heat exchange surface designed as a gap space, so that an intersection of the fluid flows involved is avoided.

The term temperature is to be understood as meaning both heating and cooling, the proposed arrangement being equally suitable for both possibilities.

A heat exchange surface may be an immediate surface of an object to be tempered or a surface which is in contact with it at least in the heat exchange contact, for example a surface or mounting surface of a cooling or heating body acting as a heat exchange surface with which an object to be tempered may be in direct or for example can also be located on intermediate layers in indirect plant for heat exchange.

The heat exchange surface may be an inner or an outer surface and flat or curved in shape, in particular a cylindrical inner or outer surface. Also in this regard, the proposed arrangement is basically independent of the type and shape of the heat exchange surface. Further, the Zuleitabschnitte are not parallel, but at an angle to the considered Heat exchange surface out. Otherwise, the Zuleitabschnitte can form any arrangement and form, for example, a linear, that is cell-shaped arrangement or a two-dimensional arrangement in the form of an array or a matrix. In the case of a cylindrical arrangement, a distribution of the supply sections in the circumferential direction may additionally be present.

With regard to the flow guidance of the fluid is now in relation to the interaction with the heat exchange surface before a symmetry, since a division of the fluid is divided into partial flows both before and after the interaction with the heat exchange surface. The flow direction in the return duct arrangement may correspond to the flow direction of the main duct arrangement, be opposite to it or extend in another direction. In principle, fluids and gases are considered as a fluid, it being possible with advantage to use water, oil or other known agents as the medium.

Advantageously, a supply section may be assigned at least one discharge section, which adjoins the supply section in terms of flow. That is, a partial fluid flow directed toward the heat exchange surface may be conducted on its return path from the heat exchange surface in one or more diverting sections and, correspondingly, in one or more partial fluid outflows. An interaction with further partial fluid inflows does not occur. Likewise, the partial fluid outflows of a plurality of partial fluid inflows may be conducted separately at least over a certain distance.

According to an advantageous embodiment, the return duct arrangement can have at least one return duct, which is in fluid communication with the rear main duct or forms it and in which a plurality of discharge ducts can lead from different partial fluid outflows. Thus, in a return channel, a reunification of a plurality of partial fluid inflows having flowed through different supply sections takes place with formation of a return channel flow. Finally, a plurality of return channels may be provided, which together open into a fluid return flow in a return main channel. In order to maximize the heat transfer coefficient, it is particularly advantageous to design a fluid sub-inflow channel as a stagnation flow channel, the fluid sub-inflow of which is directed substantially perpendicular to the heat exchange surface in question.

For constructive design of the channel arrangement, a fluid guide element is proposed with an associated heat exchange surface, wherein the Zuleitabschnitte the Hinkanalanordnung are formed in the fluid guide. Furthermore, the discharge sections and the at least one return channel are advantageously limited by the fluid guide element and / or by the heat exchange surface. For this purpose, corresponding structures can be provided either on the considered heat exchange surface and / or on the fluid guide element, so that a further heat exchange with the fluid can take place when flowing through the discharge sections and the at least one return channel.

The fluid guide element can favorably consist of a metallic material, for example a copper material, with a high thermal conductivity and can be in abutting contact with the considered heat exchange surface at least regionally, ie with individual surface regions on which no fluid channels are provided. This can be done by means of heat conduction, a direct transition of a loss of heat in the fluid guide and from there into a fluid.

According to one embodiment, the previously explained arrangement for fluid cooling of a rotor of an electric machine can be designed with particular advantage, wherein the rotor has a hollow rotor shaft with an internal heat exchange surface to be cooled. In this case, the fluid guide can be designed as a hollow cylindrical insert part, in particular as an inner shaft, wherein the Hinhauptkanal is formed within and preferably centrally within the insert part and extending axially therein. As the axial extent increases, an effective flow cross-section in the direction of flow of the fluid can be designed to decrease in order to maintain the pressure conditions of the fluid inflow. Furthermore, the supply sections can preferably be used as radial from radially inward to radially outward. be executed aldurchgänge. Still further, at least one return channel and discharge sections can also run on the outer surface of the insert part.

The invention will be explained by way of example with reference to embodiments shown in the figures.

Show it:

1 shows a schematic arrangement for fluid temperature control with a Fluidlei- telement and an associated heat exchange surface.

Fig. 2 is a schematic representation of fluid flows occurring on the arrangement of Fig. 1;

Fig. 3 is a detailed view of the Fluidleitelements of Fig. 1;

4 is an axial sectional view of a rotor of an electric machine with an arrangement for internal shaft cooling;

5 shows the arrangement for internal shaft cooling with a fluid guide element arranged in the rotor shaft;

6a shows a radial section of the fluid guide element of FIG. 4 with supply and discharge sections arranged thereon for a fluid;

6b shows a further radial section of the fluid guide element in one of

Fig. 5a deviating cutting position;

7 is a perspective view of the Fluidleitelements of Fig. 4th

Identical objects, functional units or comparable components are denoted by the same reference numerals across the figures. Further, summary reference numbers are used for components and objects that occur multiple times in one embodiment or in one representation, but are described together in terms of one or more features. In order to avoid repetition, a multiple description of identical objects, functional units or comparable components in various exemplary embodiments is dispensed with and only differences of the exemplary embodiments are described in this regard. 1 shows an arrangement 10a for fluid temperature control, which is designed overall as a tempering body 12, that is to say as a cooling and / or heating body, and which comprises a fluid-conducting element 50 with an attached cover element 14. In this case, a flat surface 14a of the cover element 14 directed toward the fluid-conducting element 50 forms a heat exchange surface 16. The fluid guide element 50 and in particular the cover element 14 are here made of a copper material and are at least partially in direct mutual contact. The cover element 14 can be in contact with a free surface 14b with an object to be tempered and thus in heat exchange contact or even form the object to be tempered.

In the arrangement 10 a, a heat flow 18 occurs in the direction of the fluid-conducting element 50 through the cover element 14 and thus through the heat exchange surface 16. The fluid guiding element 50 is designed to convey a fluid, in particular a cooling fluid, introduced into the arrangement 10a to the surface 14a or the heat exchange surface 16 and to absorb a quantity of heat therefrom, thus removing the heat exchange surface 16 and a optionally with it to cool thermally connected object or to temper.

The guidance of the fluid within the arrangement 10a of FIG. 1 will be explained in more detail below in connection with and on the basis of fluid flows involved by means of the schematic arrangement 10b shown in FIG. Other elements of the arrangement, such as connecting pipes, at least one fluid pumping device and a heat exchanger and their basic interconnection to achieve a functional arrangement for fluid temperature control are well known to those skilled in the art and are therefore not further explained here for reasons of clarity.

The assembly 10b initially includes a downcomer assembly 20 having a main passage 22 in which a fluid feed 122 is directed to the heat exchange surface 16. The heat exchange surface 16 to be cooled is shown in FIG. 2 only schematically simplified as a dashed line. The assembly 10b comprises a return channel arrangement 40 with a return main channel 42 for discharging a fluid return flow 142 from the heat exchange surface 16.

It can be seen that the down channel arrangement 20 has a plurality of feed sections 24, which branch off from the main channel 22 and are in fluid communication therewith and through which the fluid feed 122 is directed at a plurality of spatially separate partial fluid inflows 124 at an angle to the heat exchange surface 16 , The Zuleitabschnitte 24 form in the scheme shown a linear, that is a cell-shaped arrangement. In the present case, the supply sections 24 are designed as stagnation point flow channels, wherein the partial fluid inflows 124 routed therein are directed essentially perpendicular to the heat exchange surface 16 and, ideally, also impinge perpendicular thereto. The individual partial fluid inflows 124 thus form a plurality of accumulation flows, as a result of which a particularly high value for the heat transfer coefficient can be set for the removal of heat and the heat exchange surface 16 and a thermally connected object can thus be effectively cooled.

It can further be seen that the return duct arrangement 40 has, in an interaction region with the heat exchange surface 16 considered here, a plurality of diverting sections 44 which are designed and arranged such that partial fluid outflows 144 discharged from the heat exchange surface 16 are conducted spatially separate from the partial fluid inflows 124 become. In this case, the partial fluid outflows 144 are conducted at an angle α, β to the partial fluid inflows 124, so that these fluid flows do not intersect in their propagation and can not interfere with one another.

In FIG. 2, a supply section 24 is assigned exactly one discharge section 44, which adjoins the supply section 24 in terms of flow. The existing there Ableitabschnitte 44 are arranged in two groups I, II. The discharge sections 44a form a first group and open into a first return channel 46a of the return channel arrangement 40, while the discharge sections 44b form a second group and open into a second return channel 46b. Both return channels 46 are in fluid communication with the return main channel 42. Returning to the arrangement 10a shown in FIG. 1, this has the approximately cuboidal fluid-conducting element 50 shown in detail in FIG. 3, which rests in sections on the heat exchange surface 16 with a contact surface 51 and is in direct heat transfer there. The main passage 22 is formed by a space region on the outside of the heat exchange surface 16 facing away from the surface or provided there.

The supply sections 24 of the down channel arrangement 20 are arranged here as a two-dimensional matrix in the form of an array and extend from the main channel 22 in a thickness direction through the fluid guide element 50 to emerge approximately perpendicularly from the contact surface 51 or the exit surface in the direction of the heat exchange surface 16 to be tempered ,

Lateral, a plurality of parallel first grooves 52 are introduced in the contact surface 51, which intersect with their groove bottom in each case the outlet openings of the Zuleitabschnitte 24. Perpendicular to these first grooves 52 also a plurality of parallel second grooves 54 are introduced, which intersect the first grooves 52 and which are also adjacent to and arranged parallel to a row of the array of Zuleitabschnitte 24. The first grooves 52 are thus each separated into a plurality of sections 521, wherein a Zuleitabschnitt 24 is assigned in each case a groove portion 521, which in terms of flow two opposite Ableitabschnitte 44a, b for guiding two fluid partial outlets 144a, b forms. The Zuleitabschnitte 24 open respectively in the second grooves 54, wherein the number of second grooves 54 is noticeably smaller than the number of Zuleitabschnitte 24th

The second grooves 54 are made larger in cross section than the first grooves 52 and thus form individual return channels 46, the return channel flows 146 open in a in Fig. 1 only schematically illustrated return main channel 42. In the example being treated, there is a ratio of the number of feed sections 24 to the number of second slots 54 and return channels 46 of 15: 4. However, it is also essential that the corresponding channel cross-sections in the forward and rearward channel arrangement 20, 40 are dimensioned such that a supplied fluid flow 122 is to be cooled from the one to be cooled. the heat exchange surface 16 can be discharged again as a fluid backflow 142 without the formation of a congestion. In this respect, the dimensioning of the entire channel arrangement is subject to the mass flow maintenance of the fluid.

In a synopsis of FIGS. 1 and 3, it is further clear that the discharge sections 44 and the return channels 46 are bounded on one side both by the fluid guide element 50 and by the heat exchange surface 16 to be tempered. The cover member 14 may be applied to the remaining between the grooves 52, 54 ridges 53, for example by soldering, welding, bonding or the like. Such a sandwich construction with a comparatively thin-walled cover element 14 in contact with an object to be tempered results in only a small heat transfer resistance between the object and the fluid, so that, despite this intermediate layer, a very effective heat exchange is possible. A temperature control body 12 with a fluid guide element 50 and a cover element 14 can alternatively also be produced monolithically.

According to a further and with the Fig. 4-7 illustrated embodiment, a basically constructed and operating according to the above-described embodiment arrangement 10c is presented for fluid cooling of a rotor of an electric machine.

Fig. 4 shows this designed as an asynchronous electrical machine 60 with a cylindrical stator 64 which carries a stator winding 66 and with a rotatably mounted in a central cavity about an axis A rotor 62, which carries a cage winding. In this case, the rotor 62 has a hollow rotor shaft 67 with an inner surface 67a to be cooled by means of fluid, which forms the heat exchange surface 16 in this case.

The fluid guide element 50 is in this case according to FIGS. 5-7 designed as a hollow cylindrical insert 68, in particular as an inner shaft of a copper material and inserted into the hollow shaft 67, that this comparable to the previously discussed embodiment at least in sections on the hollow shaft 67th is applied, thereby also allowing a direct heat transfer. The insert member 68 has a multi-diameter stepped central recess 70 in the form of a blind hole which forms the main passage 22 for guiding a low-temperature fluid flowing into the assembly. From this Hinhauptkanal 22 go from a plurality of radially outwardly extending Zuleitabschnitte 24, which open at a cylindrical Au ßenumfangsf laugh the insert 68. The Zuleitabschnitte 24 are designed as radial bores and are thus directed perpendicular to the inner peripheral surface 67a of the rotor shaft 67 to be cooled, whereby the guided in these Zuleitabschnitten 24 individual fluid partial flows 124 meet as Staupunktströme on the inner heat exchange surface 16 of the rotor shaft 67.

The illustrated with Fig. 3 system of first and second grooves 52, 54 and the resulting Ableitabschnitte 44 and return channels 46 is equally realized here, the arrangement of Fig. 3 as a two-dimensional development of the insert part 68 of FIG. 7 are considered can. In the radial section shown with Fig. 6a, the axially centrally extending main channel 22, radial Zuleitabschnitte 24, extending in the circumferential direction Ableitabschnitte 44 and axially extending return channels 46 are visible. Fig. 6b shows a radial section axially outside of Zuleitabschnitte 24, wherein the insert member 68 abuts with portions or webs 53 directly to the hollow shaft 67 and is in heat transfer contact with this. In the perspective view of Fig. 7, the visible fluid channels and fluid flows therein are indicated.

The return channel flows 146 guided in the return channels 46 in turn combine in the return main channel 42 to a fluid return flow 142 having a higher temperature compared to the fluid flow 122, which initially proceeds from the axial end region of the insert 68 in the rotor shaft 67 and then into further fluid lines (not shown here) goes to a heat exchanger.

The explained fluid guide element 50 in the form of the insert part 68 can be manufactured as a cylindrical solid part. Alternatively, it can also be assumed that a flat semi-finished product, which after generating the explained Channel structure is bent around and thus brought into a cylindrical shape. Thus, geometries with comparatively large radii can be produced easily and without undercuts.

Bezuaszeichen

Arrangement for fluid temperature control

temperature conditioning

cover element

a surface

b surface

Heat exchange surface

heat flow

Hinkanalanordnung

Hinhauptkanal

conductive portion

Back-channel arrangement

Rear main channel

inferring

backchannel

fluid guide

contact area

first groove

web

second groove

electric machine

rotor

stator

rotor shaft

a inner surface

insert

central opening

2 fluid flow

4 partial fluid flow

2 fluid reflux

4 partial fluid flow Return channel current groove section

Angle angle

Claims

claims

1 . Arrangement for fluid temperature control, comprising

a heat exchange surface (16),

- An Hinkanalanordnung (20) for supplying a fluid flow (122) to the heat exchange surface (16) with a Hinhauptkanal (22);

- A return duct arrangement (40) for discharging a fluid return flow (142) from the heat exchange surface (16) with a return main channel (42), wherein

- The Hinkanalanordnung (20) comprises a plurality Zuleitabschnitte (24) which are in fluid communication with the Hinhauptkanal (22) and through which the id id in a plurality of spatially separate fluid partial inflows (124) directed at an angle to the heat exchange surface (16) becomes,

characterized in that

- The return channel assembly (40) in an area of interaction with the heat exchange surface (16) Ableitabschnitte (44) which are formed and arranged so that therein from the heat exchange surface (16) discharged fluid partial outflows (144) spatially separate from the fluid Teilzuströmen (124) are guided.

2. Arrangement according to claim 1, characterized in that a Zuleitabschnitt (24) is associated with at least one Ableitabschnitt (44), which is fluidly connected to the Zuleitabschnitt (24)

3. Arrangement according to claim 1 or 2, characterized in that the return duct arrangement (40) has at least one return duct (46) which is in fluid communication with or forms the return main duct (42) and into which several discharge ducts of different partial fluid outlets ( 144).

4. Arrangement according to one of claims 1-3, characterized in that a feed section (24) is designed as a stagnation flow channel, wherein the fluid partial flow (124) is directed substantially perpendicular to the heat exchange surface (16).

5. Arrangement according to one of claims 1-4, characterized in that the arrangement comprises a fluid guide element (50) with an associated heat exchange surface (16), wherein the Zuleitabschnitte (24) of the Hinkanalanordnung (20) in the Fluidleitelement (50) are formed and wherein the discharge sections (44) and the at least one return channel (46) are delimited by the fluid guide element (50) and / or by the associated heat exchange surface (16).

6. Arrangement according to claim 5, characterized in that the fluid guide element (50) consists of a metallic material and is at least partially in abutment with the associated heat exchange surface (16).

7. Arrangement according to one of claims 1-6, characterized in that the arrangement for fluid cooling of a rotor (62) of an electrical machine (60) is formed, wherein the rotor (62) has a hollow rotor shaft (67) with an inner to be cooled Heat exchange surface (16) and wherein the Fluidleitelement (50) is designed as a hollow cylindrical insert part (68) and wherein the Hinhauptkanal (22) within the insert part (68) is formed, the Zuleitabschnitte (24) are guided from radially inward to radially outward and wherein at least one return channel (46) and discharge sections (44) extend on the outer surface of the insert part (68).