DE102011050865A1 - Pipe and lamella heat exchangers - Google Patents

Abstract

The present application provides a tube and fin heat exchanger (210). The tube and fin heat exchanger (210) may include a number of tubes (220) with a number of fins (230) positioned on each of the tubes (220). The tubes (220) may include a first set of tubes (240) and a second set of tubes (250), the first set of tubes (240) being in an offset position (305) compared to the second set of tubes (250 ) having.

Description

TECHNICAL AREA

The present application relates generally to tube and fin heat exchangers, and more particularly to a semi-offset compact tube and fin heat exchanger having rectangular fins and vortex generators for maximizing heat transfer while minimizing pressure loss therethrough.

BACKGROUND TO THE INVENTION

There are widely varied heat exchanger of the type with tubes and fins or ribs and similar structures commercially available. One of the major design goals in the design of finned tube and fin-to-plate heat exchangers is to maximize heat transfer while minimizing pressure loss thereon. In general, the degree of pressure loss may be directly related to the operating costs and overall energy losses as well as the efficiency of the heat exchanger and its use.

An example of known tube-fin heat exchanger designs involves the use of tube bundles with closely spaced and spirally wound round fins. However, the use of such round fins may cause relatively strong bypass flows, wake turbulence regions, and low heat transfer coefficients due to the substantially reduced air velocity. In addition, the bypass flow can increase fouling problems on the fins and the spaces between them and reduce the heat transfer coefficients. The round ribs may further limit the fin spacing and consequently the total usable surface area per tube.

Continuous, continuous plate-shaped fins and substantially square fins have also been used. Such continuous plate-shaped fins usually have a lower pressure loss per unit of transmitted heat compared to typical fret-shaped lamellae. Continuous slats have been used to produce very compact and efficient heat exchangers, but the continuous slats and square slats are generally not suitable for large scale power plant applications such as heat recovery steam generators or similar types of equipment, generally large heat transfer surfaces, larger diameter pipes and the like / or slats made of steel have been adapted.

Known tube bundle assemblies are generally arranged in either a line aligned or offset relationship. The staggered arrangement may be generally preferred since such an arrangement will provide a higher heat transfer coefficient with slightly less bypass flow as compared to an in-line arrangement. However, the pressure loss of such a staggered arrangement may be relatively high due to the profile resistance caused by the tubes. When arranged in a line, each tube is placed in the vortex zone of the previous tube so as to reduce the total resistance. Also, oval and elliptical shaped tubes and fins have been used to reduce resistance and pressure losses, however, such tubes generally can not withstand the very high pressures commonly found in power plant equipment.

Various methods have been explored to improve heat transfer on a fin surface, including the use of vents or orifices, corrugations, corrugations, notches, winglet vortex generators, and the like. Most of these enhancement technologies are used on continuous-fin heat exchangers, while recesses and notches can be used on individual round fins. Some of these enhancement technologies may also be combined on a given fin or set of fins.

Thus, there is a desire for an improved compact tube and fin heat exchanger to increase the heat transfer rate per unit pressure loss so as to provide a smaller and less expensive heat exchanger with lower energy losses and lower life cycle costs. Such a pipe-fin heat exchanger may be preferably used for a variety of gas-to-liquid or gas-to-steam heat transfer applications, and may be used particularly for power plant operation and the like.

BRIEF DESCRIPTION OF THE INVENTION

The present application thus provides a tube and fin heat exchanger. The tube-fin heat exchanger may include a number of tubes with a number of louvers positioned on each of the tubes. The pipes can a first set of tubes and a second set of tubes, wherein the first set of tubes has a staggered position compared to the second set of tubes.

The present application further provides a tube and fin heat exchanger. The tube-fin heat exchanger may include a number of tubes having a number of rectangular fins positioned on each of the tubes. The rectangular louvers may contain one or more vortex generators on them.

The present application further provides a pipe-fin heat exchanger. The tube-fin heat exchanger may include a number of tubes having a first set of tubes that has a staggered position compared to a second set of tubes and a number of rectangular lobes positioned on each of the tubes. The rectangular louvers may contain a number of vortex generators on them.

These and other features and improvements of the present application will become apparent to those skilled in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

1 shows a schematic view of a gas turbine.

2 shows a perspective view of a portion of a semi-displaced tube-fin heat exchanger, as may be described herein.

3 shows a perspective view of a single rectangular plate-shaped plate with vortex generators, as in the semi-displaced tube-fin heat exchanger after 2 can be used.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, wherein like reference numbers indicate like elements throughout the several views, there is shown 1 a schematic view of a gas turbine 100 as described herein. The gas turbine 100 can a compressor 110 contain. The compressor 110 compresses an incoming airflow 120 , The compressor 110 provides the compressed air flow 120 to a combustion chamber 130 , The combustion chamber 130 mixes the compressed air flow 120 with a compressed fuel flow 140 and ignites the mixture to a flow of combustion gases 150 to create. Although only a single combustion chamber 130 is illustrated, the gas turbine 100 a number of combustion chambers 130 contain.

The flow of combustion gases 150 in turn becomes a turbine 160 delivered. The flow of combustion gases 150 drives the turbine 160 so about turning a turbine rotor 170 to do mechanical work. The one in the turbine 160 performed mechanical work drives the compressor 110 and an external load, such as an electric generator 180 and the like, about the turbine rotor 170 at.

The flow of the now exhausted combustion gases 150 can then become a heat recovery steam generator 190 or to heat exchangers of other types. The influx of spent combustion gases 150 to the heat recovery steam generator 190 can be a flowing through this steam flow 200 for use, for. B. in a steam turbine, a Brennstoffvorheizeinrichtung and / or for other types of work. The flow of combustion gases 150 can then be omitted or disposed of in any other way.

The gas turbine 100 can use natural gas, various types of synthesis gas or other types of fuels. The gas turbine 100 may be formed by any number of different turbines offered by the General Electric Company of Schenectady, New York, or otherwise. The gas turbine 100 can have other configurations and can use other types of components. Other types of gas turbines may be used herein. There may be several gas turbines herein 100 Other types of turbines and other types of power generation facilities are shared.

Generally, the heat recovery steam generator 190 be a non-contact heat exchanger that allows feed water for the steam generating process and the like, by the otherwise wasted flow of spent combustion gases 150 to be heated. The heat recovery steam generator 190 may be a large channel with tube bundles disposed therein so that water is heated to steam while the flow of the combustion gases 150 passes through the channel. Other heat recovery steam generator configurations and other types of heat exchanger devices may be used herein.

2 shows a part of a semi-staggered or semi-offset tube and fin heat exchanger 210 as described herein. The half-offset tube-fin heat exchanger 210 can be considered part of the heat recovery steam generator 190 or for any type of heat exchanger device or purpose.

The half-offset tube-fin heat exchanger 210 contains a number of pipes 220 projecting therethrough with a number of ribs or fins positioned thereon 230 , (In 2 is for clarity only a single projecting pipe 220 It can be any number of tubes 220 and lamellae 230 used herein. The half-offset tube-fin heat exchanger 210 may be relatively compact compared to existing tube-fin heat exchangers, but may be of any desired size, shape and / or configuration.

The half-offset tube-fin heat exchanger 210 can the pipes 220 which are arranged in a staggered relationship to each other. In particular, a first sentence 240 of pipes 220 over a second sentence 250 of pipes 220 staggered or staggered. The first sentence 240 the pipes 220 can be a first row 260 and a second row 270 included, with the pipes 220 a line aligned position 275 in terms of a flow of air 280 through this. The second sentence 250 of pipes 220 can a third row 290 and a fourth row 300 included, with the pipes 220 in it likewise the position aligned in a line 275 exhibit. Although pairs of pipes 220 in the first sentence 240 and the second sentence 250 can be any number of rows 260 . 270 and 290 . 300 with any number of pipes provided therein 220 used herein. The first sentence 240 and the second sentence 250 can be a staggered position 305 in relation to each other to form the semi-staggered relationship. The staggered position 305 can be in about half the transverse distance of the slats 230 be. Other offset dimensions, spacings, and configurations may be used herein.

As in the 2 and 3 illustrated, the slats 230 half offset tube and plate heat exchanger 210 the shape of substantially rectangular slats 310 taking. Each rectangular slat 310 may have a number of vortex generators positioned at one corner thereof 320 exhibit. In this example, the vortex generators 320 a substantially triangular shape 330 exhibit. Furthermore, an opposing pair of vortex generators 320 an upward angle 340 and an opposing pair of vortex generators 320 can be a downward angle or a downward angle 350 exhibit. It can be any number of vortex generators 320 with other sizes, configurations and / or angles used herein.

The rectangular slats 310 may also have a substantially eccentric position 360 on every pipe 220 taking. Consequently, the distance between the rows 260 . 270 and 290 . 300 every sentence 240 . 250 be minimized (and consequently the distance between the pipes 220 every sentence 240 . 250 be enlarged). Other positions may be used herein. Between all rectangular slats 310 can a gap or a gap 370 to be available. The size and shape of the gap 370 may vary. The gap 370 can be dimensioned such that the rectangular slats 310 in use act as a substantially continuous lamella.

As described above, a line aligned pipe assembly generally has the advantage of less pressure loss, while a staggered arrangement generally results in greater heat transfer. In use, the half-offset tube-fin heat exchanger unites 210 as described herein, thus the advantages of the two positions. In particular, in this example, the second row 270 of the first sentence 240 and the fourth row 300 of the second sentence 250 essentially in the vortex zone of the first row 260 of the first sentence 240 or the third row 290 of the second sentence 250 positioned. This staggered or staggered position 305 thus reduces the aerodynamic profile drag, which may account for some of the pressure loss, especially given the relatively small distances between the aligned lines 260 . 270 and 290 . 300 the pipes 220 based partly on the eccentric position 360 the slats 230 of the ranks 260 . 270 and 290 . 300 , Similarly, an offset of the first sentence 240 and the second sentence 250 the pipes 220 create or reinforce horseshoe-shaped vortexes and wake vortices so as to transfer heat to the fins 230 to reinforce.

The rectangular slats 310 of the half-offset tube-fin heat exchanger 210 For the most part, they act as a continuous plate-shaped fin so as to allow close spacing of fins without altering the flow field or creating a large proportion of or any bypass flow. The size of the gap 370 between the rectangular slats 310 can be the installation of individual pipes 220 into the compact bundle, while permitting a much smaller bypass flow as compared to, for example, the round lamella and tube bundles as described above. In particular, the gap 370 be sufficiently small to form the semi-continuous plate-shaped fins, but sufficiently large to significantly defuse the boundary layers. The gap 370 thus allows a certain mixing and destruction of the boundary layer between the slats 310 so as to have a positive effect on the heat transfer behavior.

The triangular peaks 330 the vortex generators 320 of the half-offset tube-fin heat exchanger 210 also produce and / or reinforce horseshoe-shaped and / or drag-like vortices relative to the staggered sets 240 . 250 , It can also generate longitudinal swirls and other types of vertebrae. These vortices usually improve the overall heat transfer to the rectangular lamellae 310 , The use of alternating up and down angles 340 . 350 can redirect the flow, so that these on the upper or lower lamella 310 incident. Such flow can defuse the boundary layers while enhancing the longitudinal vortices and further intensifying heat transfer.

The half-offset tube-fin heat exchanger 210 thus gives the staggered or staggered sentences 240 . 250 the pipes 220 with the offset position 305 , Every tube 220 can be a number of rectangular slats 310 with a number of vortex generators provided thereon 320 exhibit. The slats 310 can be an eccentric position 360 so as to increase the distance between the rows 260 . 270 and 290 . 300 every sentence 240 . 250 minimize while the slats 210 furthermore small gaps or gaps 370 may have between. The semi-offset tube-fin heat exchanger thus provides a smaller pressure drop compared to conventional tube and fin constructions with a higher heat transfer per tube. The half-offset tube-fin heat exchanger 210 Further, for a given performance, it may be made more compact, with lower operating costs and fewer rows of tubes.

The half-offset tube-fin heat exchanger 210 Thus, it can be used for a variety of gas-to-liquid or gas-to-steam heat transfer applications and can be used in particular for power plant operation and the like. Smaller, better and cheaper heat exchangers generally enable a lower cost power system with a smaller footprint and lower operating costs.

It should be understood that the foregoing is merely to the preferred embodiments of the present application and that numerous changes and modifications thereto may be made by those skilled in the art without departing from the general scope of the invention as defined by the following claims. and their equivalents.

The present application provides a tube and fin heat exchanger 210 , The tube and plate heat exchanger 210 can be a number of pipes 220 with a number of at each of the tubes 220 positioned lamellae 230 contain. The pipes 220 can use a first set of pipes 240 and a second set of pipes 250 contain, being the first set of pipes 240 a staggered position 305 compared to the second set of pipes 250 having.

LIST OF REFERENCE NUMBERS

100

gas turbine

110

compressor

120

airflow

130

combustion chamber

140

fuel flow

150

Flow of combustion gases

160

turbine

170

rotor

180

Electric generator

190

heat recovery steam generator

200

steam flow

210

Semi-offset tube-fin heat exchanger

220

Tube

230

slats

240

First sentence

250

Second sentence

260

First row

270

Second row

275

In-line position

280

airflow

290

Third row

300

Fourth row

305

Offset position

310

Rectangular slat

320

vortex generator

330

Triangular shape

340

Upward angle

350

Downward angle

360

Eccentric position

370

Gap, gap

Claims (12)

Pipe-fin heat exchanger ( 210 ) comprising: a plurality of tubes ( 220 ); and several fins ( 230 ) attached to each of the several tubes ( 220 ) are positioned; the several tubes ( 220 ) a first set of pipes ( 240 ) and a second set of tubes ( 250 ) exhibit; the first set of tubes ( 240 ) an offset position ( 305 ) compared to the second set of tubes ( 250 ) having. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein the first set of pipes ( 240 ) a first row of tubes ( 260 ) and a second row of tubes ( 270 ) having. Pipe-fin heat exchanger ( 210 ) according to claim 2, wherein the first row of tubes ( 260 ) and the second row of tubes ( 270 ) a line-aligned position ( 275 ) relative to a flow ( 280 ) above the first row of tubes ( 260 ) and the second row of tubes ( 270 ) exhibit. Pipe-fin heat exchanger ( 210 ) according to claim 2, wherein the second sentence ( 250 ) of pipes a third series of pipes ( 290 ) and a fourth row of tubes ( 300 ) having. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein the offset position ( 305 ) about half the length of a lamella ( 230 ) having. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein the plurality of fins ( 230 ) several rectangular slats ( 310 ) exhibit. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein the plurality of fins ( 230 ) several vortex generators ( 320 ) have at this. Pipe-fin heat exchanger ( 210 ) according to claim 7, wherein the plurality of vortex generators ( 320 ) has a substantially triangular shape ( 330 ) exhibit. Pipe-fin heat exchanger ( 210 ) according to claim 7, wherein the plurality of vortex generators ( 320 ) one or more upwardly directed angles ( 340 ) and one or more downwardly directed angles ( 350 ) exhibit. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein the plurality of fins ( 230 ) a substantially eccentric position ( 360 ) on each pipe ( 220 ) exhibit. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein a plurality of first fins ( 230 ) attached to a first pipe ( 220 ), and a plurality of second fins ( 230 ) attached to a second tube ( 220 ), a gap ( 370 ) between each other. Pipe-fin heat exchanger ( 210 ) according to claim 1, wherein the tube-fin heat exchanger ( 210 ) a heat recovery steam generator ( 190 ) having.

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