CN217560442U - Finned tube structure for integral brazing - Google Patents

Abstract

The utility model relates to an air cooling condenser. The purpose is to provide an integrally brazed finned tube structure which has the characteristics of high rigidity, good sealing effect and no rise of air side wind resistance. The technical scheme is as follows: an integrally brazed finned tube structure comprises a plurality of base tubes which are arranged in parallel; the method is characterized in that: the pipe walls of two sides of the base pipes are provided with fin units, and two adjacent base pipes share one fin unit.

Description

Finned tube structure integrally brazed

Technical Field

The utility model relates to an air cooling condenser specifically is a finned tube structure of whole brazing.

Background

A big flat tube type finned tube for A frame type air cooling condenser at present mainly includes following two kinds of structures: the structure I (see figures 8 and 9) and the finned tubes are mutually separated, but the tube plates are welded at the two ends of the finned tubes to form a whole; in the second structure (see fig. 10 and 11), an aluminum plate 5 is brazed at the fin tips of adjacent finned tubes, a plurality of finned tubes are connected into a whole through the aluminum plate, and tube plates are welded at two ends of the finned tubes. The two structures have the following defects:

in the first structure, because adjacent finned tubes are not directly connected, the overall rigidity is low, and the finned tubes are easily deformed under the influence of lateral force; meanwhile, gaps exist among the finned tubes, and resistance at the gaps is small, so that part of air can leak out from the gaps, and the heat exchange effect is reduced;

the second structure solves the problems of low rigidity and air leakage of the first structure, but also generates two other problems:

1. the aluminum plates between the finned tubes resulted in an increase in the air friction surface, and the second fin tube structure was found by finite element analysis to increase the static pressure by about 30% compared to the first fin tube structure under otherwise identical conditions;

2. the aluminum plate has higher cost, but the heat exchange effect is improved a little; according to the heat exchange principle, the temperature difference is the prime power of heat exchange, the temperature of the fin root of the fin is high, the temperature of the fin tip is close to the ambient temperature, the aluminum plate is positioned at the fin tip and is close to the ambient temperature, and therefore the heat exchange effect is poor; therefore, the improvement of the heat exchange effect is negative optimization compared with the increase of power consumption caused by the rise of static pressure.

SUMMERY OF THE UTILITY MODEL

The utility model aims at overcoming not enough among the above-mentioned background art, providing a fin tube structure of whole brazing, this structure should have the characteristics that rigidity is high, sealed effectual, air side windage does not rise.

The technical scheme of the utility model is that:

an integrally brazed finned tube structure comprises a plurality of base tubes which are arranged in parallel; the method is characterized in that: the pipe walls of two sides of the base pipes are provided with fin units, and two adjacent base pipes share one fin unit.

The fin unit comprises a plurality of radiating fins which are arranged in parallel and are perpendicular to the central axis of the base pipe.

In the fin units, an airflow channel for heat exchange is formed between two adjacent radiating fins.

All the radiating fins of the fin unit are fixed into a whole.

The base tube is a flat tube.

In the fin unit, one side edge of the head and tail radiating fins is fixed with the tube wall of the base tube through an arc-shaped bent part, and the other side edge of the head and tail radiating fins is fixed with the tube wall of the base tube through a U-shaped bent part.

In the fin unit, the edges of two sides of the middle radiating fin are fixed with the pipe wall of the base pipe through the U-shaped bent part.

In the fin unit, the U-shaped bent portion connects two adjacent radiating fins front and back.

All the radiating fins in the fin unit are formed by bending the same metal sheet.

The utility model has the advantages that:

the utility model increases the height of the fins, so that two adjacent base pipes are directly connected through the fins, thereby not only improving the rigidity of the pipe bundle and simplifying the whole structure, but also solving the problem of air leakage while ensuring the finned ratio to be unchanged; according to the finite element analysis result, the energy consumption ratio of the structure is even improved, namely, the energy consumption is reduced while the heat exchange quantity is increased.

Drawings

Fig. 1 is a schematic perspective view of the present invention.

Fig. 2 is a schematic view of the front view structure of the present invention.

Fig. 3 is a schematic top view of the present invention.

Fig. 4 is a schematic diagram of the right-side view structure of the present invention.

Fig. 5 is a schematic perspective view of the base tube of the present invention.

Fig. 6 is a schematic perspective view of the fin unit of the present invention.

Fig. 7 is a schematic diagram of the welding position of the present invention.

Fig. 8 is a schematic perspective view of a conventional fin tube.

Fig. 9 is an enlarged schematic view of the portion C in fig. 8.

FIG. 10 is a schematic perspective view of another prior art finned tube.

Fig. 11 is an enlarged schematic view of a portion D in fig. 10.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

As shown in fig. 1, an integrally brazed finned tube structure includes a base tube 1 and a fin unit 2. The base pipes are arranged in parallel, fin units are arranged on two sides of each base pipe, and one fin unit is shared between every two adjacent base pipes. The base tube adopts flat pipe, and the fin unit is fixed on the pipe wall 1.1 of the both sides of flat pipe. The figure shows that the utility model discloses be equipped with 3 parent tubes and 4 fin units altogether.

The fin unit comprises a plurality of fins 2.1 made of metal and arranged in parallel with each other; the radiating fins are also vertical to the central axis of the base pipe. Arrow a in fig. 1 indicates the medium flow direction in the substrate pipe, the central axis of the substrate pipe being parallel to arrow a.

All the radiating fins of the fin unit are connected into a whole, and as shown in fig. 6, the two side edges of each radiating fin are provided with bent parts; the edge of one side of each of the two radiating fins positioned at the head and the tail of the fin unit is provided with a U-shaped bent part 2.2, the edge of the other side of each of the two radiating fins is provided with an arc-shaped bent part 2.3, and the two radiating fins are fixed on the tube walls of the base tubes at two sides through the U-shaped bent parts and the arc-shaped bent parts respectively; the edges of two sides of the radiating fins positioned in the middle of the fin units are provided with U-shaped bent parts, and the radiating fins are fixed with the tube walls of the base tubes on two sides through the U-shaped bent parts; the U-shaped bent portion connects two adjacent radiating fins front and back.

For the fin units arranged between two adjacent base tubes, an airflow channel for heat exchange is formed between every two adjacent radiating fins, the arrow B in figure 1 indicates the air flowing direction of the airflow channel, and the airflow channel is formed by enclosing the two radiating fins, the tube walls of the base tubes and the U-shaped bent parts.

The fin unit is made of the same heat radiating fin (metal sheet) through continuous bending. The fin units are fixed with the tube wall of the base tube through brazing. As shown in fig. 7, the U-shaped bent portion and the arc-shaped bent portion of the fin are fixed to the tube wall of the base tube by brazing, a welding position (indicated by reference numeral 3 in fig. 7) is provided between the outer arc surface of the arc-shaped bent portion and the tube wall of the base tube, and a welding position (indicated by reference numeral 4 in fig. 7) is provided between the outer arc surface of the U-shaped bent portion and the tube wall of the base tube.

The utility model discloses a change is not done to the parent tube, and the parent tube interval is unchangeable, connects fixedly through the fin unit of brazing between the adjacent parent tube, and the fin unit is shared by two adjacent parent tubes, has lengthened the height of each fin of fin unit (highly be the horizontal direction of figure 2), and the height of fin is the twice of original structure to keep the wing ratio unchangeable.

The utility model makes a finite element comparative analysis research on three finned tubes as follows;

1. parameter setting of finned tube research:

1. fluids are a steady state problem of incompressible ideal gases of constant nature.

2. The fins are made of aluminum and the base tube is made of carbon steel, the thermal conductivity coefficient is set to be constant, AL is 227 (w/m-k), the carbon steel is 59.35 (w/m-k), and the thermal contact resistance is neglected;

3. the design working condition is the outdoor temperature of 30 ℃, namely the air side inlet temperature is 30 ℃;

4. the frontal wind speed of the finned tubes is 2.5m/s, and the inlet boundary is defined as a speed boundary condition;

5. setting the backpressure of a steam turbine to be 20kPa, wherein the inner wall of a finned tube is a constant temperature boundary for simplifying calculation, and the temperature is 60 ℃;

6. the finned tubes with three structures are modeled, the three finned tubes are named as finned tubes A (the utility model),

a finned tube B (shown in FIGS. 8 and 9), a finned tube C (shown in FIGS. 10 and 11);

the base pipe parts of the three finned tubes are the same, and only the fins are different in shape.

2. Adding an air domain in the fin model;

in order to ensure the stability and reliability of calculation, the inlet effect and the outlet backflow phenomenon are avoided, and the inlet and outlet flow channels are prolonged.

3. The boundary conditions are set as follows:

1. the inlet is a speed type inlet with the speed of 2.5m/s, and the outlet is a pressure type outlet;

2. the inner wall of the base pipe is a constant temperature wall surface, and the temperature is set to be 60 ℃;

3. the air domain is a periodic boundary except the inlet and outlet wall surfaces.

4. Comparative data were obtained as follows:

evaluation index of comprehensive performance

According to the evaluation method commonly adopted in academia and industry, the equal flow resistance evaluation index eta is given _r

In the formula:

w: the heat exchange amount of the unit fin;

Δ P: the resistance to gas flow outside the tubes of the fins.

This value can be used for comparing the advantages and disadvantages of different sheet types, and which sheet type has a large value means that which sheet type (equal flow resistance) has better comprehensive performance.

The heat exchange quantity and the pressure drop of the three fins are substituted into a formula, so that the heat exchange quantity and the pressure drop of the three fins can be obtained:

therefore, the finned tube A has the highest energy efficiency index, namely the structure is optimal.

The utility model has the advantages that:

1, rigidity is improved; the base tubes are integrated through the brazing fin units, and compared with a single finned tube, the rigidity of the finned tube is improved;

2, the cost is reduced; due to the fact that the rigidity is improved, the using amount of the supporting structure can be reduced, namely the manufacturing cost is reduced;

3, the heat exchange effect is improved; the base tubes are gapless, so that the heat exchange effect between air and the fin units is improved;

4, static pressure does not rise; since the air friction surface is not increased, the static pressure is not increased, i.e., the energy consumption is not increased.

Claims (5)

1. An integrally brazed finned tube structure comprises a plurality of base tubes (1) which are arranged in parallel; the method is characterized in that: the tube walls of two sides of each base tube are provided with fin units (2), and one fin unit is shared between every two adjacent base tubes;

the fin unit comprises a plurality of radiating fins (2.1) which are arranged in parallel and are vertical to the central axis of the base pipe;

in the fin unit, an airflow channel for heat exchange is formed between two adjacent radiating fins;

all the radiating fins of the fin unit are connected into a whole;

the base tube is a flat tube.

2. An integrally brazed finned tube structure according to claim 1 wherein: in the fin unit, one side edge of the head and tail radiating fins is fixed with the pipe wall of the base pipe through an arc-shaped bent part (2.3) and the other side edge of the head and tail radiating fins is fixed with the pipe wall of the base pipe through a U-shaped bent part (2.2).

3. An integrally brazed finned tube structure according to claim 2 wherein: in the fin unit, the edges of two sides of the middle radiating fin are fixed with the tube wall of the base tube through U-shaped bent parts.

4. An integrally brazed finned tube structure according to claim 3 wherein: in the fin unit, the U-shaped bent portion connects two adjacent radiating fins front and back.

5. An integrally brazed finned tube structure according to claim 4 wherein: all the radiating fins in the fin unit are formed by bending the same metal sheet.

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