DE102010046804A1 - Tube bundle heat exchanger - Google Patents

Abstract

The invention relates to tube bundle heat exchangers with a plurality of tube windings which start from a common inlet space for a heating medium and open into a common outlet space, each tube winding comprising an alternating sequence of tube pieces and tube bends; and wherein the pipe bends are designed as a deflection by 180 ° with respect to an assigned bend axis and have the same bending radii. The invention is characterized in that the arc axes of pipe bends which are connected to the same pipe section are at an angle to each other along each pipe winding and the arc axes of pipe bends between which a pipe section, a pipe bend and another pipe section are arranged in direct succession run parallel.

Description

The invention relates to a shell and tube heat exchanger, in particular for forming an evaporator for an exhaust heat recovery device.

Heat exchangers are known in different configurations. For waste heat utilization of internal combustion engines, for example, a heat exchanger can be charged with a hot exhaust gas flow in order to transfer a working medium from the liquid phase into the vapor phase, which subsequently relaxes in an expander while performing mechanical work. Such steam powered energy recovery systems for internal combustion engines of vehicles may be used to power auxiliary consumers or to assist propulsion. Further applications of evaporators in vehicles relate to cooling and air conditioning systems.

Heat exchangers that serve as evaporators may be in the form of a plate stack in which flow channels for the heating medium, for example for an exhaust gas flow, and separate channels for a heat transfer medium in the form of interruptions in the individual plates of the stacking sequence are applied. Typical designs provide heat exchangers according to the countercurrent or cross-countercurrent principle. This is exemplified in the DE 10 2008 029 096 A1 directed.

Alternative designs of heat exchangers use tube bundles in which the heat medium is guided, wherein the heat exchange takes place via the lateral surfaces of the individual tube windings of the tube bundle. For the preferred application in an exhaust heat recovery system for internal combustion engines such shell and tube heat exchangers are made, for example DE 41 41 051 A1 . EP 1 321 644 B1 and DE 10 2009 011 847 A1 known.

The invention has for its object to further develop a heat exchanger in Rohrböndelbauweise such that for a compact design, which allows in particular the placement in existing exhaust ducts of internal combustion engines, a high effective heat exchange surface is available. In this case, the heat exchanger should be usable for use as an evaporator of an exhaust heat recovery device and have easy to produce, stackable tube windings. In addition to facilitating the production of the holder of the tube bundle heat exchanger should be connected to existing components of an exhaust system with a low design cost. Furthermore, the stacking sequence of the tube windings should allow geometrically simple inlet and outlet tubes for the heat medium.

The object underlying the invention is solved by the features of independent claim 1. Advantageous embodiments emerge from the subclaims.

In this case, stackable tube windings in a serpentine design according to the above-mentioned features form the basis of the invention. Correspondingly, the tube windings forming a tube bundle of the heat exchanger, which extend between a common inlet space and a common outlet space for the supply and removal of the heat medium, have an alternating sequence of tube pieces and tube bends. The pipe bends cause a deflection of the heat medium substantially by 180 ° with respect to an associated arc axis and have the same bending radii. Preference is given to a cohesive connection of separately produced pipe sections and pipe bends for the formation of the pipe windings. Alternatively, a pipe winding can be applied in one piece, wherein the pipe bends are produced by a suitable forming process.

Are pipe sections used with straight alignment and matching length and each connected in an alternating sequence with pipe bends that describe a semicircle, creates a flow path for the heat medium, the essential route length across the heating medium, such as the exhaust stream of an internal combustion engine, orientable to a cross-countercurrent principle to realize.

The invention is characterized by thus formed pipe bends for connecting pipe sections of each individual pipe windings, the bow axes of adjacent pipe bends are in angular position to each other and are designed to extend parallel pipe elbows in next but one neighborhood. Preferably, the angular position of the arc axes of adjacent pipe bends occupies an angle in the range of 60 ° -150 ° and more preferably in the range of 70-140 °. Furthermore, the tube windings are preferably designed such that each tube piece for the respective tube winding is assigned to a first tube piece group or a second tube piece group. In this case, a projection direction can be defined, for which the projections of all belonging to a pipe section group of pipe sections are congruent.

Furthermore, straight pipe sections are preferably used, since these are advantageously easy to manufacture and can be handled to form pipe windings. Furthermore, it can be used to simple Way geometric matching, stackable tube windings are produced, which form a zigzag pattern according to the invention for a perpendicular to the straight pipe sections extending cutting plane due to the alternating angular position of the arc axes of the pipe bends. As a result, an improved stackability of the tube windings is achieved, resulting in a tube bundle heat exchanger with an increased proportion of parallel flow paths. These parallel flow paths are then applied to realize the cross-countercurrent principle of the heat-introducing fluid flow with respect to an average flow direction substantially perpendicular.

For a simplified stackability and in view of a compact arrangement of the tube windings, the pipe bends preferably have a matching geometry, wherein particularly preferably the pipe bends are formed as easy to be produced semicircular arches with a plane extending central line.

Deviations from a straight design of the pipe sections and a semicircular design of the pipe bends form embodiments of the invention, which are more expensive with respect to the production of the tube bundle heat exchanger. However, a turn matching but twisted geometry of the individual pipe bends and / or pipe pieces allows an improvement of the positive engagement in the stacking, which increases the overall stability of the tube bundle heat exchanger. This is an improvement especially for vehicle applications for which constantly act on the tube bundles of the heat exchanger vibrations and shocks, since the individual tube windings of the tube bundle support each other stronger and so the support structures that summarize the tube bundle of the heat exchanger and install in the associated space, can be performed structurally simplified.

The invention will be explained in more detail below with reference to an embodiment in conjunction with figure representations. These details show:

1a shows an inventively designed tube winding a tube bundle heat exchanger in plan view.

1b shows a sectional view 1a along the section line AA.

2 shows the tube winding of the 1a and 1b in spatial view.

3 shows a part of the sectional view 1b ,

4 shows an enlarged view 1b

5a shows a tube bundle heat exchanger with a plurality of tube windings in plan view.

5b shows a sectional view taken along the line CC 5a ,

6 shows the tube bundle heat exchanger from the 4a and 4b in enlarged, spatial view.

7 shows a tube bundle heat exchanger according to the invention for an exhaust heat recovery device.

8th shows a connection part for the evaporator 7 ,

1a represents a single tube winding 1 for a tube bundle heat exchanger designed according to the invention. The tube winding 1 is through an alternating sequence of pipe sections 6.1 - 6.n and pipe bends 7.1 - 7.n educated. From the in 1b illustrated sectional view taken along the line AA in 1a , results in a zigzag-shaped configuration, which results from that adjacent to each other elbows 7.1 - 7.n that is those pipe bends 7.1 - 7.n attached to the same piece of pipe 6.1 - 6.a close, in an angular position α to each other. This is exemplified in 1b based on the adjacent pipe sections 6.1 and 6.2 respectively 6.2 and 6.3 seen. In addition, the arc axes of pipe bends 7.1 - 7.n , the next neighbor form, that is, such a pairing, for which between two pipe bends in a direct sequence a pipe section, a pipe bend and another piece of pipe are arranged, running parallel running.

For the protruding and receding shape of a pipe winding according to the invention 1 Compared to a flat, serpentine winding a reduced transverse distance h of the pipe sections 6.1 - 6.n , In this direction, the main direction of flow through the thermal fluid, which takes place in the pipe winding 1 guided heat medium in the heat exchange occurs. This will be explained in more detail below.

A further advantage for a zigzag-shaped, serpentine tube winding according to the invention 1 results from an improved stackability. This is going out 2 clearly, the pipe winding the 1a and 1b in spatial view shows. Out 1b is evident that for every single pipe winding 1 due to the angular position of the pipe bends 7.1 - 7.n the pipe pieces 6.1 - 6.n can be divided into two groups. Each pipe section group includes pieces of pipe 6.1 - 6.n that are aligned with each other. This can be seen from an assignment of the pipe sections 6.1 and 6.3 to a first pipe section group 14 and the pipe pieces 6.2 and 6.4 to a second pipe section group 15 whose projections for a predetermined projection direction 16 , in this case the direction for determining the transverse distance h, are congruent

Further shows 3 a sketch to define the concept of a bow axis 17 for a pipe bend 7 , For the simplest case, the pipe bend 7 a flat semicircular arc, so the bow axis 17 is defined by the normal vector through the center of the associated semicircle. Nevertheless, deviating embodiments are conceivable for which a pipe bend 7 is curved in several directions in space. In this case, a bow axis 17 starting from a central line 18 assigned as the threading line 18 the centroids of the cross-sectional areas 19 along the pipe bend 7 is defined. For sufficiently small circular arc sections 20 along the threading line 18 can radial vectors 22.1 . 22.2 that from a center point 21 starting at the circular arc section 20 be rich, be determined. To the radial vectors 22.1 . 22.2 standing vertically, a vector is set, which contributes to the bow axis 17 determined, that the considered arc section 20 assigned. The entire pipe bend 7 associated bow axis 17 then results from a weighted averaging of the above contributions. The weighting takes place over the circular arc lengths of the circular arc sections used for the determination 20 ,

4 provides an enlarged view of 1b are outlined are trimmed pipe sections in the transverse direction 6.1 . 6.2 . 6.3 . 6.4 . 6.5 with interposed pipe bends 7.1 . 7.2 . 7.3 . 7.4 , The pipe bends 7.1 . 7.2 . 7.3 . 7.4 associated bow axes 17.1 . 17.2 . 17.3 . 17.4 have an alternating angle deviation from the projection direction 16 on. There are adjacent pieces of pipe 7.1 . 7.2 with respect to their bow axes, for example 17.1 and 17.2 , in a predetermined angular position α zueinnander and pipe sections in next but one neighborhood, about 7.1 . 7.3 , have essentially parallel bow axes 17.1 and 17.3 on. Certain angle deviations for a pipe winding 1 are tolerable if the stackability is not impaired.

Furthermore, every pipe bend 7 . 7.1 - 7.n associated with a bending radius R, wherein advantageously all bending radii R of the pipe bends 7 . 7.1 - 7.n to match. In the case of a pipe section not designed as a semicircular arc ( 7 . 7.1 - 7.n ), the bending radius R is a weighted average of the length of all radial vectors 22.1 . 22.2 educated.

5a shows a tube bundle heat exchanger according to the invention 8th in plan view, as a stack of the tube windings 1.1 - 1.n with a geometry corresponding to 1a . 1b and 2 is trained. In particular, from the sectional view along the line CC, in 5b is shown, the compact mutual conditioning of the tube windings 1.1 - 1.n can be seen, resulting from the alternating angular position of the pipe bends 7.1 . 7.n along the individual pipe windings 1.1 - 1.n results. For an exemplary embodiment, the pipe bends 7.1 . 7.n at an alternating angle of +/- 45 ° to the projection direction 16 created. This corresponds to an angular position α of the bow axes 17.1 . 17.n adjacent pipe bends 7.1 . 7.n of 90 °. The positive engagement of the tube windings 1.1 - 1.n and the compact design with a reduced transverse distance h of the parallel pipe sections 6.1 . 6.n for each of the tube windings 1.1 - 1.n results particularly clearly from the in 6 shown spatial representation of a tube bundle heat exchanger according to the invention 8th ,

Out 7 schematically simplified, the use of a tube bundle heat exchanger according to the invention 8th for forming an evaporator of an exhaust heat recovery device. For this purpose, the tube bundle heat exchanger 8th an inlet space 2 for a heat medium connected to a supply line 4 stands up. A preferred embodiment of the inlet space 2 is in the enlarged view of 8th shown. This has a connection part 12 on, which is formed for example as a milled part. This connection part 12 includes on the to the ends of the pipe sections 6.1 - 6.n indicative side supply channels for the heat medium. Furthermore, at the to the supply line 4 indicative front of the connection part 12 for liquid-tight completion of the inlet space 2 a lid 11 intended. Alternatively, the connection part 12 be designed as a piece of pipe, which is not shown in detail in the figures.

Accordingly, the outlet space 3 for the heat medium, the output-side end pieces of the pipe sections 6.1 - 6.n sum up. From this outlet room 3 goes a trigger line 5 from, for the illustrated embodiment, one opposite the supply line 4 extended cross-section, since the discharge of the heat medium takes place as a gas phase.

The tube bundle heat exchanger is acted upon 8th of the evaporator 13 for the illustrated embodiment of an exhaust gas flow. This is in 7 the main flow direction of Waste gas flow WG drawn. This runs substantially perpendicular to the pipe sections 6.1 - 6.n the individual pipe windings 1.1 - 1.n , In this case, due to the angular position of adjacent pipe sections according to the invention 7.1 - 7.n the distance between the pipe sections 6.1 - 6.n be reduced in the main flow direction of the exhaust gas flow WG. This results in a concurrently compact tube bundle heat exchanger advantageously an enlarged heat exchanger surface with crossing flow guidance of the heat medium relative to the heating fluid, in this case the exhaust gas flow.

Further shows 7 Components of a holder for the individual pipe windings 1.1 - 1.n of the tube bundle heat exchanger 8th , Illustrated are lateral brackets 9.1 - 9.2 , the peg-shaped projections in the interstices of adjacent pipe sections 6.1 - 6.n intervention. In addition, the stacking sequence is by cross bars 10.1 - 10.n stabilized by the stacking sequence of the tube windings 1.1 - 1.n through rich.

Further embodiments of the invention are conceivable. For example, the tube windings 1.1 - 1.n from a sequence of pipe sections 6.1 - 6.n with adjoining pipe bends 7.1 - 7.n be formed in the angular position according to the invention, wherein the pipe pieces 6.1 - 6.n have different lengths, so not all pipe bends 7.1 - 7.n aligned with each other. In this way individually projecting pipe bends on the tube bundle 7.1 - 7.n are formed, where additional support elements for stabilizing the tube bundle heat exchanger 8th are provided. Further embodiments of the invention will become apparent from the following claims.

LIST OF REFERENCE NUMBERS

1, 1.1-1.n

pipe winding

2

inlet space

3

outlet space

4

supply

5

withdrawal line

6.1-6.n

pipe section

7, 7.1-7.n

Elbows

8th

Tube bundle heat exchanger

9.1, 9.2.

lateral bracket

10.1, 10.2

cross bar

11

cover

12

connector

13

Evaporator

14

first pipe section group

15

second pipe section group

16

projection direction

17, 17.1-17.n

arc axis

18

Central line

19

Querscnittsfläche

20

Arc section

21

Focus

22.1, 22.2

radial vector

H

transverse distance

WG

Main flow direction of an exhaust gas flow Angular position

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 102008029096 A1 [0003]
• DE 4141051 A1 [0004]
• EP 1321644 B1 [0004]
• DE 102009011847 A1 [0004]

Claims (12)

Tube bundle heat exchanger with 1.1 a plurality of tube windings ( 1 . 1.1 - 1.n ), shared by a common inlet ( 2 ) emanate for a heat medium and into a common outlet space ( 3 ); 1.2 wherein each pipe winding ( 1 . 1.1 - 1.n ) an alternating sequence of pipe sections ( 6.1 - 6.n ) and pipe bends ( 7 . 7.1 - 7.n ); and 1.3 the pipe bends ( 7 . 7.1 - 7.n ) as a deflection by 180 ° with respect to an associated arc axis ( 17 . 17.1 - 17.n ) are formed and have the same bending radii (R); characterized in that 1.4 along each tube winding ( 1 . 1.1 - 1.n ) the bow axes ( 17 . 17.1 - 17.n ) of pipe bends which are connected to the same pipe section ( 6.1 - 6.n ) are in angular position (α) to each other and the bow axes ( 17 . 17.1 - 17.n ) of pipe bends ( 7 . 7.1 - 7.n ), between which in immediate succession a piece of pipe ( 6.1 - 6.n ), a pipe bend ( 7 . 7.1 - 7.n ) and another piece of pipe ( 6.1 - 6.n ), are parallel. Tube bundle heat exchanger according to claim 1, characterized in that the tube pieces of each tube winding ( 1 . 1.1 - 1.n ) either a first pipe section group ( 14 ) or a second pipe section group ( 15 ) are assigned, wherein for a predetermined projection direction ( 16 ) the projections of all to a pipe section group ( 14 . 15 ) belonging pipe pieces ( 6.1 - 6.n ) are congruent. Tube bundle heat exchanger according to claim 1 or 2, characterized in that the tube pieces ( 6.1 - 6.n ) have a matching length. Tube bundle heat exchanger according to one of the preceding claims, characterized in that the tube pieces ( 6.1 - 6.n ) as straight pieces of pipe ( 6.1 - 6.n ) are formed. Tube bundle heat exchanger according to one of the preceding claims, characterized in that the tube bends ( 7 . 7.1 - 7.n ) have a matching geometry. Tube bundle heat exchanger according to one of the preceding claims, characterized in that the tube bends ( 7 . 7.1 - 7.n ) as semicircular arches with a plane central line ( 18 ) are formed. Tube bundle heat exchanger according to one of the preceding claims, characterized in that the tube windings ( 1 . 1.1 - 1.n ) have a matching geometry and adjacent to each other form a winding stack. Tube bundle heat exchanger according to one of the preceding claims, characterized in that the angular position of the bow axes ( 17 . 17.1 - 17.n ) of pipe bends ( 7 . 7.1 - 7.n ) connected to the same piece of pipe ( 6.1 - 6.n ) are connected, an angular position (α) of 60 ° -150 °. Tube bundle heat exchanger according to one of the preceding claims, characterized in that the tube pieces ( 6.1 - 6.n ) and pipe bends ( 7 . 7.1 - 7.n ) each pipe winding ( 1 . 1.1 - 1.n ) are cohesively connected or the pipe winding ( 1 . 1.1 - 1.n ) is integrally formed. Exhaust gas heat recovery apparatus having a heat medium evaporator to which an exhaust gas stream of an internal combustion engine is subjected, characterized in that the evaporator comprises a shell and tube heat exchanger according to any one of the preceding claims. Exhaust gas heat recovery apparatus according to claim 10, characterized in that the main flow direction of the exhaust gas flow substantially perpendicular to the pipe sections ( 6.1 - 6.n ) of the tube bundle heat exchanger. Exhaust gas heat recovery device according to one of claims 10 or 11, characterized in that the tube windings ( 1 . 1.1 - 1.n ) of the tube bundle heat exchanger are made of stainless steel.

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