DE102017119119A1 - heat exchangers - Google Patents

Abstract

The invention relates to a heat exchanger, comprising - a heat exchanger block (1), - a first collecting box (3) arranged on a first end face of the heat exchanger block (1), - a second collecting box (4) located on one of the first end faces of the Heat exchanger block (1) opposite the second end face of the heat exchanger block (1) is arranged, - wherein the heat exchanger block (1) a plurality of mutually parallel, the first collection box (3) with the second collection box (4) connecting process channels (2, 6) for the flow through a Process medium and a plurality of cooling medium channels (5) for the flow of a cooling medium, - wherein the cooling medium channels (5) between the process channels (2, 6) are arranged, - adjacent process channels (2, 6) with different material masses and / or heat transfer of different sizes Surfaces and / or different sized structural st mung resistors and / or cooling medium channels (5) are formed with different masses of material and / or heat transfer surfaces of different sizes, so that in operation at a cyclic temperature change of the process medium, an equal or nearly equal material temperature gradient between adjacent process channels (2, 6) and side parts ( 7) in the heat exchanger block (1).

Description

The present invention relates to a heat exchanger according to the preamble of claim 1.

Generic heat exchangers used for high temperature applications, such as in intercoolers, water coolers and oil coolers of automobiles and construction machinery, are subject to significant cyclic thermal stresses due to cyclic changes in temperature and flow rate of process media passed through the heat exchanger.

The cyclic change of temperature and flow rate of the process medium accordingly leads to a cyclic change in the temperature of the individual components of the heat exchanger, in particular the components of a consisting of process channels, cooling medium channels, end plates, side panels and the like heat exchanger block and the adjacent thereto headers, and concomitantly a cyclic material expansion or compression of the various heat exchanger components.

These components are firmly connected together by soldering or otherwise to a rigid block, so that in and between the individual components high thermal stresses occur, which has a negative effect on the life of the cooler.

To increase the life of such a heat exchanger, it is important to reduce the thermal stresses occurring due to the cyclic thermal expansions described above primarily in block longitudinal and block width directions.

A reduction of the thermal stresses can be achieved by the use of flexible components in the heat exchanger block. Such heat exchangers are for example from DE 202 08 748 U1 and 20 2011 052 186 U1 known in which in an edge region of the heat exchanger block, adjacent to a collecting box, flexible block profiles are used, keep the parallel arranged process channels of the heat exchanger block at a distance and form together with arranged between the process channels fins the flow channels of the cooling medium.

In these heat exchangers, a reduction in cyclic thermal expansion stresses in the block width direction by about 50% is achieved over heat exchangers with non-flexible block profiles.

However, it has been shown that, despite the flexibly designed block profile, the maximum stresses occurring in the longitudinal direction of the block are only slightly reduced.

To reduce the maximum stresses in peripheral process channels of a heat exchanger block, in particular in the longitudinal direction of the block, it is out of EP 0 748 995 B1 known to provide end or end plates of the heat exchanger block, which close the heat exchanger block on a top and a bottom to provide slots. However, the tension in the edge process channels can only be reduced by about 1.1 to 1.3 times.

It is also known, for stiffening the edge process channels in the longitudinal direction of the block, to produce these from thicker dividing plates than the dividing plates further inserted in the interior of the heat exchanger block. However, this does not change the maximum material temperature difference between the edge process channels and the process channels arranged adjacent to these further inside the heat exchanger block. Consequently, a further reduction in voltage can not be achieved by this measure.

The maximum material temperature difference between two adjoining process channels can reach up to 20 K or even up to 40 K during operation in critical block areas in the case of the heat exchangers considered here.

Object of the present invention is to provide a heat exchanger with increased life and lower risk of cracks.

This object is achieved by the heat exchangers having the features of claim 1.

A heat exchanger according to the invention comprises a heat exchanger block, a first header disposed on a first end face of the heat exchanger block, and a second header disposed on a second end face of the heat exchanger block opposite the first end face of the heat exchanger block.

The heat exchanger block has a plurality of parallel to each other, the first collection box with the second collection box connecting process channels for flow of a process medium and a plurality of cooling medium channels for flow through a cooling medium, wherein the cooling medium channels are arranged between the process channels, wherein adjacent process channels with different material masses and / or different huge heat-transferring surfaces and / or different sized structural flow resistances and / or cooling medium channels are formed with different masses of material and / or heat transfer surfaces of different sizes, so that in operation at a cyclic temperature change of the process medium an equal or nearly equal material temperature gradient between adjacent process channels and side parts in Heat exchanger block sets.

Due to the combinations of different material masses, heat-transferring surfaces and / or constructive flow resistances, the process channels, cooling medium channels and side parts are designed so that an identical or almost identical cyclic change in the material temperatures of adjacent process channels is achieved, whereby the maximum temperature difference between the process channels, in particular the critical block areas, by at least two to three times compared to the known from the prior art construction of heat exchangers is reduced.

In the longitudinal direction of the block, this allows a reduction of the thermally induced stresses in the heat exchanger block by up to 2 times.

Advantageous embodiments of the invention are the subject of the dependent claims.

According to a preferred embodiment, the process channels with a higher heat transfer rate than the adjoining process channels with up to three times greater material mass and / or with a smaller heat transfer surface 3 times smaller and / or up to 5 times greater constructive flow resistance than the adjacent process channels educated.

Such different material masses, for example, by the use of similar passage components such as dividers, turbulators or longitudinal profiles with different structural dimensions and optionally additional components such. Intermediate profiles or the use of pipes with different pipe dimensions, for example, different pipe thicknesses or pipe heights achieved in a process channel relative to two adjacent process channels.

This makes it possible to reduce the maximum difference between the material temperatures of adjacent process channels by up to 2.5 times with a thermal cyclic load.

According to a further preferred embodiment variant, the process channels, which adjoin a process channel having a higher heat transfer rate than those adjacent to the process channels, are formed with a heat transfer area 3 times smaller than the adjacent adjacent process channels in the heat exchanger block.

Such a heat-transferring surface, which is up to 3 times smaller, can be achieved, for example, by correspondingly different structural dimensions, in particular cam pitches of the turbulators or different fin pitches.

As a result, differently sized heat transfers from the process medium to the cooling medium channels take place in adjacent process channels, with the result that the maximum difference between the cyclic material temperatures of the adjoining process channels is reduced during a thermal cyclic load.

According to a further preferred embodiment, the cooling medium channels, which are adjacent to a process channel with a higher heat transfer, formed with up to about 3 times smaller heat-transmitting surface.

The reduction of the heat transfer surface in the o.g. Cooling medium channels is achieved, for example, by a reduction of the height of the cooling medium channels to 3 times and / or the use of lamellae or baffles in the cooling medium channels with a lamellar cam plate or baffle plate divider up to approximately 5 times larger.

This reduces the difference between the heat transfers in two adjacent process channels, with the result that the maximum difference between the cyclic material temperatures of the adjacent process channels decreases by a factor of 2.

According to yet another preferred embodiment, the process channels, which allow a higher heat transfer than the adjacent process channels, with up to five times higher constructive flow resistance for process medium compared to these og. formed adjacent process channels.

This is achieved, for example, by the use of different turbulators, longitudinal profiles or additional components such as e.g. Intermediate profiles and pipes with a smaller flow cross-section for the flow of the process medium achieved.

This increases a ratio between the flow rates of the process medium in the adjacent process channels. As a result, the maximum difference between the cyclic material temperatures in the adjacent process channels decreases by up to 3-fold, resulting in a significant reduction in thermal stresses.

According to yet another preferred embodiment, the end plates / side parts are formed with a material mass of up to 5 times smaller than the material mass of the edge process channels. This reduces the negative impact of the end panel / side panel on the cyclic change in the material temperature of the edge process channels, resulting in the maximum material temperature difference between the edge process channels and adjacent process channels in the heat exchanger block being reduced.

Embodiments of the invention will be explained in more detail with reference to the accompanying drawings.

Show it:

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

2 a sectional view AA of the heat exchanger 1 transverse to the flow direction of the process medium with process channels with a rectangular channel cross section,

3 a sectional view AA of the heat exchanger 1 transverse to the flow direction of the process medium with process channels with oval channel cross section,

4 a sectional view AA of the heat exchanger 1 transverse to the flow direction of the process medium with process channels with a circular channel cross section,

5 a sectional view of the heat exchanger 2 along a line BB, parallel to the flow direction of the process medium,

6 a sectional view of the heat exchanger 3 along a line CC parallel to the flow direction of the process medium,

7 a sectional view of the heat exchanger 4 along a line DD parallel to the flow direction of the process medium.

In the following description of the figures, terms such as top, bottom, left, right, front, back, etc. refer exclusively to the exemplary representation and position of the heat exchanger, the process channels, cooling medium channels, side parts and the like chosen in the respective figures. These terms are not intended to be limiting, that is to say, by different working positions or the mirror-symmetrical design or the like, these references may change.

In 1 is with the reference numeral 1 a total called a heat exchanger block. The heat exchanger block 1 has a plurality of separate process channels arranged parallel to one another 2 on, the flow of a process medium in a direction X from an inlet box 3 located at a first end face of the heat exchanger block 1 is arranged, to a discharge box 4 located at a second end face of the heat exchanger block 1 is arranged serve. The process channels 2 protrude with respective open ends in the inlet box 3 and the exit box 4 ,

The heat exchanger block 1 furthermore has several cooling medium channels 5 for the flow of a cooling medium. The cooling medium channels 5 are between inner process channels 2 and between at an outer edge of the heat exchanger block 1 arranged edge process channels 6 as well as side parts 7 , preferably designed as end plates, in the heat exchanger block 1 arranged.

The cooling medium channels 5 are in the heat exchanger block 1 arranged so that a flow of the cooling medium between the process channels 2 takes place in a transverse direction or a direction parallel to the directional flow Y of the process medium.

As in 1 furthermore, is at a head side of the entrance box 3 an inlet nozzle 8th provided by the process medium in the inlet box 3 can be fed.

Accordingly, on a head side of the exit box 4 an outlet 9 provided by the process medium from the outlet box 4 is feasible.

The inlet nozzle 8th and the outlet can also on one of the other sides of the inlet box 3 or exit box 4 be arranged.

The inlet nozzle 8th and the outlet nozzle 9 are in a cross section of the inlet nozzle 8th or the outlet 9 corresponding receiving opening in the head side of the inlet box 3 or the exit box 4 added.

As in the 2 to 4 shown, the process channels 2 be formed with different cross sections. So are the process channels 2 in the in 2 shown embodiment of respective dividing plates 10 formed between which turbulators 12 or ribs are arranged. A lateral closure of these process channels 2 is here by the use of ledges or longitudinal profiles 11 reached.

At the in 3 embodiment shown are the process channels 2 as formed with oval channel cross-section tubes 13 educated. In the tube interior of these tubes 13 are in the embodiment shown here turbulators 12 used.

At the in 4 embodiment shown are the process channels 2 formed in the form of tubes with a circular cross-section. Here are, as well as in the 3 shown embodiment, several such process channels 2 perpendicular to the flow direction next to each other and arranged one above the other.

As in 4 furthermore, they are at an outer edge of the heat exchanger block 1 arranged process channels with the reference numeral 6 while that of the edge process channels 6 enclosed process channels with the reference numeral 13 are provided.

In the 5 to 7 is shown that also the cooling medium channels 5 preferably with slats 15 or baffles 16 are provided.

For all in the 2 - 7 shown embodiments, that adjacent process channels 2 . 6 and cooling medium channels 5 are formed with different material masses and / or heat transfer surfaces of different sizes and / or constructive flow resistances of different sizes, so that in operation a temperature change of the process medium an equal or almost equal material temperature gradient between adjacent process channels 2 . 6 and side panels 7 in the heat exchanger block 1 which achieves that the maximum temperature difference between individual adjacent process channels is reduced by at least 2 to 3 times compared with heat exchanger blocks known from the prior art.

Thus, according to a variant embodiment of a heat exchanger according to the invention, the material mass of process channels 2 . 6 with a higher heat transfer rate than the adjacent process channels 2 . 6 formed with a material mass up to three times greater than at this adjacent process channels.

Alternatively or additionally, the heat-transferring surface of the process channels 2 . 6 with a higher heat transfer rate than the adjacent process channels 2 . 6 up to 3 times smaller than the heat transfer surface of adjacent process channels 2 . 6 , This is achieved, for example, by increasing the cam pitch of turbulators or by using only a few heat-transmitting ribs 14 in the process channels 2 . 6 , in which the hottest proportion of process medium flows in against the process channels, through which an already partially cooled portion of the process medium flows, achieved.

Alternatively or additionally, respective cooling medium channels 5 connected to a process channel 2 . 6 with a higher heat transfer rate than the adjacent process channels 2 . 6 adjacent, with a heat transfer surface up to 3 times smaller than adjacent cooling medium channels 5 in the heat exchanger block 1 educated.

So are in particular the cooling medium channels 5 between edge process channels 6 and side panels 7 with a heat transfer surface smaller by up to 3 times than other cooling medium channels 5 in the heat exchanger block 1 educated.

Furthermore, the side parts are preferred 7 with up to 5 times smaller material mass than the material mass of the edge process channels 6 educated.

In any case, it is achieved by the formation of the process channels and cooling medium channels with different material masses or heat transfer surfaces of different sizes that the flow of the process channels with the process medium and the flow of cooling medium channels with a cooling medium of the material temperature gradient between adjacent process channels 2 . 6 and side panels 7 in the heat exchanger block 1 constant or nearly constant, can be kept as small as possible, whereby thermally induced stresses in the heat exchanger block are significantly reduced and thus the life of such heat exchangers is increased.

LIST OF REFERENCE NUMBERS

1

heat exchanger coil

2

process channels

3

entry box

4

 outlet box

5

Coolant channels

6

Edge process channels

7

End plates / side panels

8th

inlet connection

9

outlet connection

10

partitions

11

longitudinal profiles

12

turbulators

13

Tube

14

ribs

15

lamella

16

baffles

L

Length of the heat exchanger block

B

Width of the heat exchanger block

T

Depth of the heat exchanger block

X

Direction of flow of the process medium to be cooled

Y

Flow direction of the cooling medium

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 20208748 U1 [0006]
• DE 202011052186 U1 [0006]
• EP 0748995 B1 [0009]

Claims (5)

Heat exchanger comprising - a heat exchanger block ( 1 ), - a first collection box ( 3 ), which at a first end face of the heat exchanger block ( 1 ), - a second collection box ( 4 ) located at one of the first end face of the heat exchanger block ( 1 ) opposite the second end face of the heat exchanger block ( 1 ), wherein - the heat exchanger block ( 1 ) a plurality of mutually parallel, the first collection box ( 3 ) with the second collection box ( 4 ) connecting process channels ( 2 . 6 ) for the flow through a process medium and several cooling medium channels ( 5 ) to the flow of a cooling medium, - wherein the cooling medium channels ( 5 ) between the process channels ( 2 . 6 ), characterized in that - adjacent process channels ( 2 . 6 ) with different material masses and / or heat transfer surfaces of different sizes and / or different sized structural flow resistances and / or cooling medium channels ( 5 ) are formed with different material masses and / or heat transfer surfaces of different sizes, so that during operation with a cyclic temperature change of the process medium, an identical or nearly equal material temperature gradient between adjacent process channels ( 2 . 6 ) and side parts ( 7 ) in the heat exchanger block ( 1 ). Heat exchanger according to claim 1, characterized in that the process channels ( 2 . 6 ) with a higher heat transfer rate than the adjacent process channels ( 2 . 6 ) with a material mass up to three times greater and / or with a heat-transferring surface which is smaller by up to 3 times and / or with a constructional flow resistance which is up to 5 times greater than the adjacent process channels ( 2 . 6 ) are formed. Heat exchanger according to one of the preceding claims, characterized in that the cooling medium channels ( 5 ) connected to a process channel ( 2 . 6 ) with a higher heat transfer rate than the adjacent process channels ( 2 . 6 ), with a heat transfer surface smaller by up to 3 times than other cooling medium channels ( 5 ) are formed in the heat exchanger block. Heat exchanger according to one of the preceding claims, characterized in that the cooling medium channels ( 5 ) between boundary process channels ( 6 ) and side parts ( 7 ) with a heat transfer surface smaller by up to 3 times than other cooling medium channels ( 5 ) are formed in the heat exchanger block. Heat exchanger according to one of the preceding claims, characterized in that the side parts ( 7 ) with a material mass of up to 5 times smaller than the material mass of the edge process channels ( 6 ) are formed.

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