DE102013211221A1 - Heat exchanger - Google Patents

Abstract

The invention relates to a heat exchanger (1) with a first collecting box (8), with a second collecting box (9) and with a plurality of tubes (15, 16), wherein the tubes (15, 16) in each case end in one of the collecting tanks (15). 8, 9) are received and create a fluid connection between the first collecting box (8) and the second collecting box (9), wherein a first number of first tubes (15) is provided, each having a first flow cross-sectional area, and at least one second tube (16) is provided, which has a second flow cross-sectional area, wherein the first flow cross-sectional area is substantially smaller than the second flow cross-sectional area.

Description

Technical area

The invention relates to a heat exchanger with a first header, with a second header and with a plurality of tubes, wherein the tubes are respectively received end in one of the header boxes and produce a fluid connection between the first header and the second header, wherein a first number of first tubes is provided, each having a first flow cross-sectional area, and at least one second tube is provided, which has a second flow cross-sectional area.

State of the art

Heat exchangers are used in a variety of ways to transfer heat between two fluids. In this case, a first fluid is brought into a heat exchange with a second fluid, whereby the temperature of the one fluid is relatively increased and the temperature of the other fluid is relatively lowered. Regularly, the fluids used are, for example, air, coolant or a refrigerant.

There are different types of heat exchanger known. Among other things, heat exchangers are used in a tube-fin construction. Here are a plurality of tubes spaced from each other between two headers. A medium to be cooled can flow through the pipes, for example, while a medium to be heated flows around the pipes. In order to improve the heat transfer additional heat transfer elements, such as corrugated fins, may be provided between the tubes.

A known design provides for a heat exchanger, which is flowed through in a so-called I-flow principle. The fluid flows from a collection box into the pipes and from there into the second collection box. The fluid is introduced from a fluid circuit in the first collection box and discharged from the second collection box.

Alternatively, a heat exchanger can be flowed through according to the so-called U-flow principle. Here, a fluid is introduced from a fluid circuit in the first collection box. From there it flows through a first number of tubes in the second collection box and from there via a second number of tubes back into the first collection box. From there, the fluid is discharged from the first collection box. The first collection box is divided, for example by a partition in two independent areas.

The tubes which form the fluid connection from the first collection box into the second collection box usually correspond in size, shape and number to the tubes which form the fluid connection from the second collection box into the first collection box.

The U-flow heat exchanger regularly offers twice the cooling distance compared to a I-flow heat exchanger, but at the same time it offers only half the flow cross-sectional area. Although this is generally positive for the cooling capacity of the heat exchanger, but mostly negative for the pressure loss occurring.

A disadvantage of the solutions in the prior art is in particular that by using the same pipe dimensions both for the fluid connection from the first to the second collection box and for the fluid connection from the second to the first collection box tubes of the same dimensions and often in the same number are used, which has a negative effect on the resulting pressure drop in the U-flow heat exchanger.

Presentation of the invention, object, solution, advantages

It is the object of the present invention to provide a heat exchanger that is optimized over the solutions in the prior art. For this purpose, in particular the resulting pressure loss should be reduced within the heat exchanger.

The object of the heat exchanger is achieved by a heat exchanger with the features of claim 1.

An embodiment of the invention relates to a heat exchanger with a first header, with a second header and with a plurality of tubes, wherein the tubes are each end in one of the header boxes and create a fluid connection between the first header and the second header, wherein a first Number of first tubes is provided, each having a first flow cross-sectional area, and at least a second tube is provided, which has a second flow cross-sectional area, wherein the first flow cross-sectional area is substantially smaller than the second flow cross-sectional area.

The heat exchanger is flowed through by a U-flow principle. The fluid is passed from a collection box over a portion of the pipes in the second collection box, before it over the remaining pipes back into the first collection box is returned. This is particularly advantageous if the space specifications allow only such a heat exchanger. In this case, in particular the position of the fluid connections to only one collecting tank is advantageous.

The flow cross-sectional area of the second flow channel is substantially larger than the flow cross-sectional area of the individual first flow channels. As a result, a return flow can be generated with the lowest possible pressure loss. The second flow channel essentially serves to return the fluid to the first collection box. The heat transfer is realized mainly by the first flow channels.

Furthermore, it is preferable if the total flow cross-sectional area of the first tubes occupies a proportion of the total cross-sectional area of the heat exchanger that is greater than half, wherein the total cross-sectional area of the heat exchanger is formed by the sum of the flow cross-sectional areas of the first tubes and the second tube.

By a larger overall flow cross-sectional area of the first flow channels in comparison to the flow cross-sectional area of the second flow channel, it can be achieved, in particular, that the largest possible flow cross-sectional area is available for cooling the fluid flowing in the flow channels. Thus, the highest possible heat transfer can be realized and still the tree specific advantages of a U-flow heat exchanger can be used.

It is also advantageous if the total flow cross-sectional area of the first tubes compared to the total flow cross-sectional area of the heat exchanger is between 50% and 90%, preferably between 60% and 80%, preferably between 70% and 80%.

The highest possible proportion of the total flow cross-sectional area of the first flow channels is advantageous in order to be able to realize the greatest possible heat transfer. At the same time, the flow cross-sectional area of the second flow channel must be large enough not to create too great a pressure loss for the back-flowing fluid.

Furthermore, it may be particularly advantageous if the heat exchanger can be flowed through by a first fluid, wherein the flow takes place from the first header through the first tubes to the second header and from the second header through the second tube to the first header.

The U-flow principle is particularly advantageous when space restrictions provide for the use of a U-flow heat exchanger.

A preferred embodiment is characterized in that the first header has a fluid inlet and a fluid outlet, wherein the first header is divided into a first chamber and a second chamber and the first chamber is in fluid communication with the first tubes and the second chamber is in fluid communication Tube is in fluid communication.

A division of the first header tank into two chambers is particularly advantageous in order to allow a flow according to the U-flow principle. A fluid-tight separation of the two chambers voneinaner is particularly advantageous to prevent unwanted leakage currents between the two chambers.

It is also preferable if the first tubes are arranged in a juxtaposition of two mutually adjacent tube rows and the second tube is arranged below the two tube rows.

By juxtaposing several rows of tubes to each other, a total of a larger heat transfer surface can be generated than with a smaller number of larger pipes. Therefore, the greatest possible heat transfer can be realized by such an arrangement, in particular on a defined maximum space.

It is also advantageous if a housing is provided, which receives the first tubes and the second tube, and which is bounded laterally by the two header boxes, wherein the first tubes and the second tube of second fluid within the housing are flowed around while they can be traversed by a first fluid.

By providing a housing, which can be traversed by a fluid, such as a coolant, an advantageous heat transfer between a fluid within the tubes and a liquid coolant can be achieved. In this way, regularly larger amounts of heat can be dissipated than in a heat transfer between a first fluid and air in the event that the air serves as a coolant. This can be increased, in particular, when the liquid coolant outside the heat exchanger is actively cooled.

Furthermore, it is preferable if the first fluid can be guided and discharged via a collecting box, wherein a second fluid can be fed into the housing in the region of the first collecting box and can be removed from the housing in the region of the second collecting box.

In this way, a fluid which flows through the tubes, suitable to the U-flow principle of the heat exchanger flowed into this and be discharged therefrom. At the same time, the coolant can be optimally fluidically introduced into the heat exchanger, whereby the greatest possible cooling effect can be achieved.

In an alternative embodiment of the invention, provision may be made for heat transfer elements, such as corrugated ribs, to be provided between the first tubes and the second tube, and / or for heat transfer elements, such as winglets, to be provided in the first tubes.

By the heat transfer elements, the heat transfer between the fluid inside the tubes and the fluid flowing around the tubes can be increased. As a result, the cooling capacity of the heat exchanger can be improved overall.

It may also be expedient if, in addition to the plurality of first tubes, a plurality of second tubes is provided, wherein the number of second tubes is substantially smaller than the number of first tubes.

Advantageous developments of the present invention are described in the subclaims and the following description of the figures.

Brief description of the drawings

In the following the invention will be explained in detail by means of embodiments with reference to the drawings. In the drawings show:

1 a perspective view of a heat exchanger according to the invention,

2 a perspective view of a heat exchanger according to the invention, wherein the viewer facing the collection box is not shown, whereby an insight into the flow channels is achieved, and

3 a further perspective view of a heat exchanger according to 2 in addition, the housing is not shown, whereby an insight into the heat exchanger is achieved.

Preferred embodiment of the invention

The 1 shows a perspective view of a heat exchanger 1 , The heat exchanger 1 is essentially a case 2 formed, to which end a first collection box 8th and a second collection box 9 are connected.

The collection box facing away from the viewer 9 has a fluid connection 3 at its top. About this fluid connection 3 can be a fluid in the heat exchanger 1 supplied or removed from this. At the end of the heat exchanger 1 which faces the viewer is the first collection box 8th arranged. This collection box 8th has a fluid connection 4 on which over the housing 2 with the fluid connection 3 is in fluid communication.

About the fluid connections 3 . 4 can be a fluid in the heat exchanger 1 introduced or from the heat exchanger 1 be derived.

The collection box 8th also has a fluid connection 5 and a fluid port located underneath 6 on. The fluid connections 5 and 6 can be used for the introduction or discharge of a second fluid in the heat exchanger. The first fluid is preferably a coolant and the second fluid, which flows through the fluid ports 5 respectively. 6 can be introduced or discharged, it is preferably an exhaust gas from an internal combustion engine.

Inside the heat exchanger 1 There is a heat transfer between the coolant and the exhaust gas instead.

The fluid connection 6 has a flange 7 on, which makes it possible, not shown in the picture pipeline to the fluid port 6 to join. The fluid connection 5 has holding means to which a pipeline can be connected.

The fluid passing through the fluid port 5 respectively. 6 in the collection box 8th flows in, is distributed within the collecting box on pipes, which within the housing 2 run. The exact structure and arrangement of the tubes are shown in the following figures.

The housing 2 of the heat exchanger 1 has an overall rectangular or cuboid basic shape.

The 2 shows a perspective view of the heat exchanger 1 according to the 1 , In the view of 2 is the collection box facing the viewer 8th not shown. This is a look at the flow channels 11 . 12 allows.

Inside the case 2 is a plurality of first flow channels 11 arranged. In the embodiment of 2 are the first flow channels 11 arranged in two rows next to each other.

Below the two rows of tubes of the first flow channels 11 is a second flow channel 12 arranged. The second flow channel 12 has a much larger flow cross-sectional area than the individual first flow channels 11 ,

Overall, the sum of the flow cross-sectional areas of the individual first flow channels 11 larger from the flow cross-sectional area of the second flow channel 12 , Advantageously, the sum of the flow cross-sectional areas of the first flow channels 11 a proportion of more than 50% of the total flow cross-sectional area of the first flow channels 11 and the second flow channel 12 ,

The heat exchanger 1 as he is in the 1 to 3 is shown, flows through a so-called U-flow principle. This means that the fluid passing through the flow channels 11 respectively. 12 flows over a collection box 8th in the heat exchanger 1 flows. From there it flows over the first flow channels 11 in the second collection box 9 , The second collection box 9 provides fluid communication between the overhead first flow channels 11 and the lower second flow channel 12 ago. Through the second flow channel 12 Finally, the fluid flows back into the first collection box 8th ,

The first collection box 8th is separated in the interior via a partition in two independent areas. The first upper area stands with the first flow channels 11 in fluid communication, the lower second area stands with the lower second flow channel 12 in fluid communication.

The flow direction through the heat exchanger 1 can also be reversed, so that the second flow channel 12 the Hinströmstrecke between the collection box 8th and the collection box 9 forms and the first flow channels 11 the return flow from the collecting tank 9 to the collection box 8th ,

Between the individual pipes 15 , which the first flow channels 11 form, are advantageously heat transfer elements 13 , such as corrugated ribs arranged. These are in the 1 and 2 due to the case 2 not recognizable. Also are between the pipes 15 , which the first flow channels 11 form and the pipe 16 which the second flow channel 12 forms, heat transfer elements 13 , such as corrugated ribs arranged.

The pipes 15 respectively. 16 inside the case 2 are thereby surrounded by a fluid, in particular a coolant. The coolant is thereby via the fluid connection 3 or via the fluid connection 4 in the case 2 flowed in, leaving it inside the case 2 the pipes 15 respectively. 16 can flow around. In this way, an advantageous heat transfer between the exhaust gas, which within the first flow channels 11 or the flow channel 12 flows to the coolant, which flows around the pipes 15 respectively. 16 flows, guaranteed.

Through the return flow, which through the individual flow channel 12 is formed, it is possible to realize the return flow such that only a small pressure loss occurs. The flow channel 12 points in comparison to the flow channels 11 a much lower pressure loss. This is due to the overall large flow cross-sectional area of the second flow channel 12 founded.

Most of the cooling of the exhaust gas, which through the flow channels 11 respectively. 12 flows, is within the flow channels 11 reached. This is due in particular to the larger wall surface and thus the higher heat transfer area between the exhaust gas and the coolant.

Advantageously, the heat exchanger 1 by adjusting the number of first flow channels 11 or the size of the second flow channel 12 be influenced in terms of the resulting pressure loss and the maximum achievable cooling capacity.

The 3 shows a further perspective view of the heat exchanger 1 according to the representation of 2 , Additionally is in 3 the housing 2 not shown. It can be seen that the first flow channels 11 through pipes 15 are formed, which are arranged in two rows next to each other in a stacked arrangement, and the second flow channel 12 through a pipe 16 is formed.

Between the pipes 15 and 16 are intermediate areas 14 formed, which with heat transfer elements 13 are filled. The arrangement of the heat transfer elements is optional. The coolant, which via the fluid connection 3 respectively. 4 in the case 2 can flow in or out, the pipes 15 respectively. 16 flow around. In this way, a maximum possible heat transfer between the exhaust gas in the first and the second flow channel 11 respectively. 12 and the cooling medium within the housing 2 ensured.

In alternative embodiments, in particular the number of channels shown and the geometric design of the individual flow channels of the in the 1 to 3 different embodiments shown. The in the 1 to 3 shown embodiment of the heat exchanger is exemplary and should illustrate in particular the inventive concept. Particularly advantageous in the design of the heat exchanger 1 is the return of the exhaust gas through the second flow channel 12 which has a relatively large flow cross-sectional area. In particular, the occurring pressure loss for the return flow can be kept low on this.

The shown heat exchanger 1 thus combines the installation space technical advantages of a U-flowed heat exchanger 1 , which is characterized in particular in that the fluid connections are arranged on only one of the collecting boxes, with the high efficiency of an I-flowed heat exchanger. Through the second flow channel 12 arises for the return flow only a very small pressure loss. At the same time, the heat exchanger 1 be built very compact.

The 1 to 3 are exemplary and have no limiting character.

Claims (10)

Heat exchanger ( 1 ) with a first collection box ( 8th ), with a second collection box ( 9 ) and with a plurality of tubes ( 15 . 16 ), whereby the tubes ( 15 . 16 ) each end in one of the collecting boxes ( 8th . 9 ) and a fluid connection between the first collection box ( 8th ) and the second collection box ( 9 ), wherein a first number of first tubes ( 15 ) is provided, each having a first flow cross-sectional area, and at least one second tube ( 16 ), which has a second flow cross-sectional area, characterized in that the first flow cross-sectional area is substantially smaller than the second flow cross-sectional area. Heat exchanger ( 1 ) according to claim 1, characterized in that the total flow cross-sectional area of the first tubes ( 15 ) a proportion of the total flow cross-sectional area of the heat exchanger ( 1 ), which is greater than half, wherein the total flow cross-sectional area of the heat exchanger ( 1 ) by the sum of the flow cross-sectional areas of the first tubes ( 15 ) and the second tube ( 16 ) is formed. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that the total flow cross-sectional area of the first tubes ( 15 ) compared to the total flow cross-sectional area of the heat exchanger ( 1 ) is between 50% and 90%, preferably between 60% and 80%, preferably between 70% and 80%. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that the heat exchanger ( 1 ) is flowed through by a first fluid, wherein the flow from the first collecting box ( 8th ) through the first tubes ( 15 ) to the second collection box ( 9 ) and from the second collection box ( 9 ) through the second tube ( 16 ) to the first collection box ( 8th ) takes place. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that the first collection box ( 8th ) a fluid inlet ( 5 . 6 ) and a fluid outlet ( 5 . 6 ), wherein the first collection box ( 8th ) is divided into a first chamber and a second chamber and the first chamber with the first tubes ( 15 ) is in fluid communication and the second chamber with the second tube ( 16 ) is in fluid communication. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that the first tubes ( 15 ) are arranged in a juxtaposition of two mutually adjacent rows of tubes and the second tube ( 16 ) is arranged below the two rows of tubes. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that a housing ( 2 ) is provided, which the first tubes ( 15 ) and the second tube ( 16 ), and the side of the two header boxes ( 8th . 9 ), the first tubes ( 15 ) and the second tube ( 16 ) of second fluid within the housing ( 2 ) are flowed around while they are flowed through by a first fluid. Heat exchanger ( 1 ) according to claim 7, characterized in that the first fluid via a collecting box ( 8th ) can be supplied and discharged, with a second fluid in the region of the first collecting tank ( 8th ) in the housing ( 2 ) can be fed and in the area of the second collecting tank ( 9 ) out of the housing ( 2 ) is dissipatable. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that between the first tubes ( 15 ) and the second tube ( 16 ) Heat transfer elements ( 13 ), such as corrugated fins, are provided and / or that in the first tubes ( 15 ) Heat transfer elements, such as winglets, are provided. Heat exchanger ( 1 ) according to one of the preceding claims, characterized in that in addition to the plurality of first tubes ( 15 ) a plurality of second pipes ( 16 ), the number of second tubes ( 16 ) is substantially less than the number of first tubes ( 15 ).

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