WO2017029211A1

WO2017029211A1 - Flow conducting elements in a channel

Info

Publication number: WO2017029211A1
Application number: PCT/EP2016/069214
Authority: WO
Inventors: Edgar Hansjosten; Walther Benzinger; Andreas Hensel; Achim Wenka
Original assignee: Karlsruher Institut für Technologie
Priority date: 2015-08-14
Filing date: 2016-08-12
Publication date: 2017-02-23
Also published as: DE102015113432A1; EP3334993A1; EP3334993B1

Abstract

The present invention relates to a device for achieving a defined guide of a volume flow of a fluid through a channel-shaped element, characterized in that micro-channel structured flow conducting elements for dividing the volume flow and guiding the resulting partial streams of fluids are arranged in the channel-shaped element.

Description

Flow guide in a channel

The present invention relates to a flow channel provided with flow guide.

In the prior art, a plurality of flow channels are presented in which internals are present. These serve to mix the material flow. For example, a device for the heat exchange is known from the patent DE 2808854 C3. In this device, mainly the material flow is mixed. For this purpose, static mixing elements are incorporated in this. Such installations are, for example, in the form of webs or web slats, which are assembled as packages one behind the other in the channel. It is therefore fixed installations, by which the channel flow is deflected. At the edges, for example, flow vortices form, which improve cross-mixing. In such static mixers, the heat exchange with the channel wall as a result of the increased cross-mixing is improved at the same time.

Further examples of fixed installations can be found in EP 1 067 352 A1, DE 1 032 6381 A1, EP 1 332 794 B1, DE 195 116 93 A1, US Pat. No. 7,552,741 B, US Pat. No. 5,595,712 A, US 2012/00370 A1 and US Pat DE 195 368 56 A1. There are also the essays Norbert Schwesiger, Thomas Frank and Helmut Wurmus: "A modular microfluid system with the integrated micromixture", Journal of micromechanisms and microengineering (996) 1, p. 99-102, Hessel, V., Ehrfeld, W , Freimuth, H., Haferkamp, V., Löwe-Richter, Th., Stadel, M. and Wolf, A., "Publication and Interconnection of Ceramic Microreaction Systems for High Temperature Applications", Proc. 1 St. INT. Conf. on microreaction technology, 1997, pp. 156-157. All documents indicate that the heat exchange is improved and turbulences are generated. In all cases, however, a defined guidance of the volume flow is not realized. Rather, they are mixing elements, with the side effect of improved heat exchange.

Object of the present invention is accordingly, flow guides in one Channel to be designed so that a defined guidance of the volume flow is achieved and at the same time the required heat and / or mass transfer z. B. is ensured by diffusion. This object is achieved by a device for achieving a defined guidance of a volume flow of a fluid through a channel-shaped element, wherein in the channel-shaped element microchannel structured flow guide elements for dividing the volume flow and the guidance of the resulting partial flows of fluids are arranged.

Furthermore, the object is achieved by a method, wherein

the fluid flows into the channel-shaped element (a flow channel),

the fluid is divided into (preferably laminar) substreams,

the division is achieved by means of microchannel-structured (micronized) flow guides,

- The partial flows are guided by micro-channel-structured (micro-structured) flow guide defined, and

- The partial flows are guided so that they with the inner wall of the channel-shaped element (wall of the flow channel) and with each other in

Be brought into contact (in contact).

The invention relates to a device for achieving a defined guidance of a volume flow of a fluid through a flow channel, in which microchannel-structured (microstructured) flow guide elements for dividing the volume flow and the defined guidance of the resulting partial flows of fluids are arranged.

By means of the method according to the invention and the device according to the invention, exchange processes can take place both with the channel wall and between the part streams. By dividing the volume flow into partial flows and depending on the Form of Sirömungsieiteiemente the contact distance with the pipe wall and between the individual partial streams is specified. By varying the geometric shape along the channel, the contact distance can be changed depending on the process and thus the process can be influenced. In contrast to the prior art, the channel flow is accordingly not only deflected locally, but it is guaranteed a defined flow guidance in the channel.

According to the invention, microstructured flow guide elements are present in the flow channel. Flow directors are thin-walled components that are installed in a flow channel (e.g., a pipe). The task of the flow guide is to make the flow guide in a channel so that a fluid flow divided into partial streams and these partial streams are alternately guided to the wall of the flow channel. As a result, exchange processes can take place with the duct wall and / or between partial flows. The flow guide elements are constructed from basic elements.

The result is that the subject of the invention are not mixing elements, but flow guide elements in a flow channel. The goal is the subdivision of a channel flow in defined guided partial flows, with a targeted heat exchange of all guided partial flows to take place on the wall.

By means of the first flow guide element installed in the flow channel, a fluid flow flowing into the flow channel is subdivided into partial flows. If a flow-guiding element is constructed from only one basic-form element, two partial flows are generated. If the flow guide element has been constructed from a plurality of basic form elements, their arrangement determines the number of partial flows.

The microstructured flow guide elements are with the so-called. 3D printing technology produced. In other words, with the help of 3D printing technology, it is possible to construct complex shaped surfaces (free-form surfaces.) In preferred embodiments, the microstructured flow-guiding elements have a circular, annular, elliptical or rectangular cross-section.

The channel height of the microstructured flow guide elements is 0.1-100 mm, preferably 0.1-5 mm.

In the same area, the width of the micro-channel-structured flow guide is zuzusiedein.

The length of the microstructured flow guide elements is 3 - 300 mm, preferably 5 - 50 mm

The wall thickness of the microchannel-structured flow guide elements is 0.01-0.5 mm, preferably 0.1-0.3 mm.

The flow guide elements are inserted into the flow channel in such a way that they occupy about 5 to 50%, preferably 5 to 30%, of the channel-shaped element (flow channel).

The microstructured flow guide elements according to the invention can also comprise or consist of a catalytically active material. Likewise, it is possible that the flow guide elements are provided with catalytically active material, a corrosion protection or an antifouling layer or are subjected to any desired combinations of the layers mentioned. It is also possible that the flow guide elements consist of the materials mentioned.

As preferred materials for the production of the microchannel-structured flow guide these may contain or consist of metal, ceramics or plastics, or have any combinations of these substances or consist of these. By the microstructured flow guide the Voiumenstrom a Fiuids can be divided in any way. From two to infinity, any partial flows are conceivable. For example, four or six partial streams may be provided. By the flow guide a guide (defined flow guidance) of the partial flows is achieved. In this case, the construction is carried out so that the partial flows are alternately brought into contact with the inner wall of the channel-shaped element (wall of the flow channel) and with the other partial flows. The heat exchange with the wall of the flow channel is improved as follows by the flow guide elements installed in the flow channel:

A partial flow is guided to the wall of the flow channel. As a result of an existing temperature difference between the fluid and the wall of the flow channel, a heat exchange between the fluid and the wall of the flow channel takes place. The resulting heat flow between the fluid and the wall of the flow channel results in heat transport through the fluid layer.

In a flow channel, the thermal conductivity of the fluid limits the heat transfer. In a flow channel with flow guide elements, a partial flow is led away from the wall of the flow channel after a contact path which corresponds to the length of a flow guide, and during the residence time in the interior of the flow channel, a temperature compensation takes place in the partial flow. After flowing through the temperature compensation section of the partial flow is guided back to the wall of the flow channel.

The flow guide elements are manufactured with different microchannel shapes, ie constructed from basic shaped elements. This makes it possible that the partial flows can be performed arbitrarily in the channel-shaped element. Here, however, the microchannel-structured flow guide are permanently installed. This ensures that permanent contact with the duct wall or the other partial flows is guaranteed on defined areas. This can be targeted to achieve a heat or mass transfer. As a result, a controlled reaction and / or process management is included simultaneous Prozesstemperierung within the microstructured flow guide possible. The invention is described in more detail below on the basis of exemplary embodiments: I. List of Reference Signs

1 - 6 = partial flows

7,8 = flow guide

9 = channel-shaped element

10 = pipe wall

11 = half wavelength lambda / 2

10 -14 = part level

15 - channel

16 = fluid flow

17 = cross section of the partial flow

18 = contact surfaces

19 = basic form elements

20 = position 1

21 = position 2

22 = position 3

23 = outer circular ring

24 = inner circular ring

25 = inner circle

26 = fluid 1

27 = fluid 2

II. DETAILED Fibrography: According to FIG. 1, the tube flow is divided into four partial flows for improving the heat transfer between the wall of the channel-shaped element and material flow. In the channel-shaped element are in the example of FIG. 1 two Flow guide 7.8 installed. The Wandstrukiuren the Strömungsieitelemente 7,8 lead the streams 1, 2, 3 and 4. Partial stream 2 penetrates part stream 1 and is directed to the pipe wall 10 of the channel-shaped element. The flow guide elements have no wall at the contact surface between partial flow 2 and partial flow 3. This means that the partial streams can exchange material. On the wall of the channel-shaped element, a heat exchange takes place. The partial flow 1 is guided by the wall 10 of the channel-shaped element in the direction of the center of the channel-shaped element. A corresponding exchange takes place in the partial streams 3 and 4. The corresponding exchange process is repeated in the second microchannel structured flow guide 8. The wavelength for a replacement cycle corresponds to the length of two flow lines. This can be chosen as a design parameter depending on the viscosity of the material flow.

The boundary conditions for carrying out the method according to the invention in a device according to FIG. 1 are as follows:

Number of partial flows n = 4

Inner diameter of the channel-shaped element d = 10 mm

Length of the flow guide elements 7 and 8 1 = 15 mm

Wavelength lambda = 30 mm

Wall thickness of the flow guide elements 7.8 s = 0.3 mm

The microstructured flow element was made of metal using 3D printing technology. The volume consumption by the internals is in the example of Figure 1 8% of the internal volume of the channel-shaped element.

With the system according to FIG. 1, highly viscous fluids can be heated homogeneously with little pressure loss. The distribution of the volume flows in the channel-shaped element 9 takes place according to Figures 2 and 3 in 18 partial streams. This makes it possible to optimize the process control of a heterogeneous gas phase reaction and tempering via the wall 10 of the channel-shaped Reach element 9.

In a cannula-shaped element 9 three micro-channel structured flow guide elements are inserted. The volume flow is subdivided into six sub-levels in the first element. In each part level, the volume flow is again divided into three partial flows, so that a total of 18 partial flows arise.

FIG. 3 shows the profile of the partial flows per part plane (1.1, 2.1, 3.1, 4.1, 5.1, 6.1) over a distance of 3 flow guide element lengths. From the figure it can be seen that the flow guide elements are subdivided into six sub-levels, the sub-streams are systematically guided from part level to part level. Each partial flow is guided once to the wall of the flow channel, as can be seen from FIG. That each microstructured flow guide can once perform a heat exchange on the wall of the flow channel. After a distance of six installation element lengths, the partial flows have again reached the starting position, i. an exchange cycle has been completed. In the example according to FIGS. 2 and 3, the wavelength for an exchange cycle corresponds to the length of six microstructured flow guide elements. The contact distance on the wall of the flow channel and the residence time between two wall contacts is defined by the geometry parameters. All partial flows have equal (equivalent) contact distances.

In the example according to FIGS. 2 and 3, the microstructured flow-guiding element was produced by means of the 3D printing technique made of metal with a constant wall thickness s = 0.2 mm. The microstructured Strömungsleitelementformen and lengths are chosen so that the components are safe to coat with a catalytically active material, or consist of catalytic material.

In the example according to Figures 4 and 5, a circular, channel-shaped element is shown. According to Figure 4 is shown in cross-section of the canula-shaped element, as in the individual circularly arranged part levels of the elements 7, 12 - 14, the partial flows are arranged with the micro-channel structured flow guide elements. Out FIG. 4 shows that three partial flows are defined per part.

According to Figure 5 it can be seen that the part levels 12, 13 and 14 are constructed as internals, between which the partial flows are exchanged radially. Again, it is ensured that in each case a partial flow is passed at least once to the channel wall and gets into contact with other partial streams, so that here a mass transfer can take place.

According to FIG. 6, a flow guiding element 7, 8 in the simplest form consists of exactly one basic shaping element 19 and can be installed in a flow channel 15 with a rectangular cross section. The geometric shape is constructed such that the fluid stream divided into partial flows flows through a flow guide element 7, 8 with minimal pressure loss. According to FIG. 7, the fluid flow 16 can be divided into partial flows 1, 2. The channel cross section 17 is divided by the flow guide 7.8 into two partial streams 1 and 2.

According to Figure 8, an exchange of the partial flows takes place. The partial flow 1 is divided by the flow guide 7,8 again in the partial streams 2.1 and 2.2.

According to FIG. 9, the contact surface 18 of two partial flows 2.1 and 2.2 is shown. The partial flows 2.1 and 2.2 are brought together again after flowing around partial flow 1. Heat transfer and / or mass transfer (for example by diffusion) is possible via the contact surface 18.

FIG. 10 shows the arrangement of the basic form elements 19. By parallel connection in the direction of the X-coordinate axis, the number of partial streams 1 - 6 is increased. A flow element composed of three parallel basic form elements divides a fluid flow 16 into six partial flows 1-6.

According to FIG. 11, a series connection in the direction of the Z coordinate axis is shown. The flow guide elements 7, 8 are arranged one behind the other in the flow direction. The partial streams 1 and 2 are conducted separately through the channel. The partial flow 1 is guided through a flow cross section 17a. In the same way, the partial flow 2 is guided through a flow cross section 17b.

FIG. 12 shows the arrangement of the basic form elements 19 or flow guide elements 7, 8. There is a parallel connection in the direction of the Y-axis and series connection in the direction of the Z-axis. By the parallel connection of basic shaped elements 19 in the direction of the Y-coordinate axis, the number of partial flows is increased to 1 - 3 and by an additional series connection of the flow guide 7.8, the partial streams 1-3 are alternately guided to the channel wall. That a Strömungsleitelement 7.8, constructed of two parallel-connected basic form elements 19 divides a fluid flow into three partial streams 1, 2, 3. Here, the flow guide elements are constructed from basic form elements. The geometric shape is designed so that fluid flows with a minimum pressure loss through a flow guide 7.8. A flow guide element 7, 8 can be constructed from one or more basic form elements 19 connected in parallel.

According to FIG. 13, flow guide elements 7, 8 are arranged in a channel. The flow guidance of the partial flows takes place with parallel and series connection. The flow guide element 7, 8 is constructed from two basic form elements 19 which are connected in parallel in the direction of the y-coordinate axis. The three flow guide elements 7, 8 are connected in series (z-direction). The partial flow 3 is guided in the first and second flow guide of partial flow 3 via the position 20 to position 21. In the third flow guiding element, the partial flow 3 is guided again from position 20 to position 22. The flow guide is marked with the numbers 7,8.

FIGS. 14, 15, 16 are geometrically identical. They snd variants of Figures 4 and 5. According to Figure 14 is a parallel circuit of transformed basic form elements 19 in the radial and circumferential direction in a tube with the tube wall 10 in a channel-shaped element 9. In the example, two curved basic shape element 19 are in radial Direction or three curved Grundformeiemente 19 in the circumferential direction. By the number of parallel connected basic form elements 19, the number of partial streams 1 - 6 is defined. With three basic elements 19, nine partial flows can result. In the illustration according to FIG. 14, the circular flow guide element 7, 8 divides the fluid flow into a circular ring 23. Below this follows a circular ring 24 and an inner circle 25.

Referring to Figure 15, in a circular, channel-shaped element 9, there are divisions of the fluid flow 16. For example. may be constructed of 2 in the radial direction and 3 curved in the circumferential direction basic shape elements a flow guide 7.8. The channel cross section is divided by the flow guide 7.8 in circular or Kreisringteilstromquerschnitt. The entering into the channel-shaped element 9 fluid flow 16 is divided by the first flow guide in 9 sub-streams. In position 1 in the circular ring are the partial flows 20. In position 2 in the circular ring, the partial streams 21 and in position 3, the partial streams 22 are arranged in the inner circle.

FIG. 16 shows a further variation of the function of the flow guide elements in a circular, channel-shaped element 9. The flow guide element is constructed from 2 × 3 curved basic shape elements 19. The channel cross-section (cross-section of the channel-shaped element 9) is divided by the flow guide in circular or circular ring partial flow cross-section. The entering into the channel fluid flow 16 is divided by the first flow in nine part streams. In position 1, the partial flows 20 are shown in the outer annulus. The partial streams 21 are present in the inner circular ring. The partial streams 22 are present in the inner circle. FIG. 17 shows a test setup for the measurement of the thermal efficiency. Here, the temperatures are marked with T. Measured is T _{i0 of} the influent fluid 1 and the temperature Tu of the effluent fluid 1. On the other hand, the fluid 2 is measured at the temperature T ₂₀ and the temperature T ₂ i shows the fluid 2. The fluid 1 has the numeral 26, and the fluid 2 is the numeral 27.

The following table shows the measurement results of the experiments with flow guide elements and without flow guide elements. The last column shows the thermal efficiency. This is considerably greater in the devices according to the invention and with flow guide than without flow guide. The dark shaded lines indicate the results of the tests with flow guide elements. The lines highlighted in light gray indicate the results of the tests without flow guide elements.

Claims

Claims:

Device for achieving a defined guidance of a volumetric flow of a fluid through a channel-shaped element, characterized in that microchannel-structured flow-guiding elements for dividing the volumetric flow and guiding the resulting partial flows of fluids are arranged in the channel-shaped element.

Apparatus according to claim 1, characterized in that in the channel-shaped element for guiding the partial flows at least one micro-channel-structured flow control element is arranged.

Device according to one of the preceding claims, characterized in that the microchannels of the flow guide elements are designed at defined contact surfaces of partial flows without wall in order to exchange the partial flows.

Device according to one of the preceding claims

in that the cross section of the channel-shaped element is circular, annular, elliptical or rectangular in shape.

Device according to one of the preceding claims, characterized in that the flow guide elements comprise catalytically active material or consist thereof.

Apparatus according to claim 5, characterized in that the

Microchannel structured flow guide with catalytically active

Material, corrosion protection or an antifouling layer are provided or are applied to any combination of said layers, or comprise said materials, or consist thereof, or any combination of said materials or from thereof consist.

Method for achieving a defined guidance of a volume flow of a fluid through a channel-shaped element, characterized in that

the fluid flows into the channel-shaped element,

the fluid is divided into (preferably laminar) substreams,

- The division is achieved by means of micro-channel structured flow guide, through the micro-channel structured flow guide in the

Partial flows are defined and managed

- The partial flows are guided so that they are brought into contact with the inner wall of the channel-shaped element and each other.

A method according to claim 7, characterized in that the partial flows are guided so that they are alternately brought into contact with the inner wall of the channel-shaped element and with the other partial streams.

Method according to one of the preceding claims, characterized in that each partial stream is guided at least once to the inner wall of the channel-shaped element.

Use of the device according to any one of claims 4-9 for effecting heat exchange with the inner wall of a channel-shaped element or the other partial flows, and / or for achieving mass transfer with the other partial flows.

Use of the device according to one of claims 4 - 9 for achieving a controlled reaction and / or process management within the microchannel structured flow guide elements and / or

Process temperature control on the inner wall of the channel-shaped element.