RU2596685C2 - Heat exchange module - Google Patents

Abstract

FIELD: heat engineering.

SUBSTANCE: invention relates to heat engineering and can be used for creation of high-efficiency small-sized heat exchangers. In heat exchange module, comprising hollow cylindrical housing confined by face end plates with holes for passage of a first medium via through channels inside housing and having in side wall near face end plates holes for inlet and outlet of a second medium, as well as adjacent to outer sides of face end plates closed cavities for supply and discharge of first medium, all adjacent channels for passage of first medium are interconnected by lengthwise ribs, dividing channel space into separate longitudinal channels for passage of second medium and having length, less than length of channels for passage of first medium to form annular chambers for accumulation of second medium, including holes in housing wall for inlet and outlet of second medium.

EFFECT: technical result is providing maximum heat transfer with minimum dimensions of heat exchanger.

3 cl, 2 dwg

Description

The invention relates to the field of heat engineering and can be used to create highly efficient small-sized heat exchangers for various purposes for various industries, such as shipbuilding, construction, chemical and other industries.

An urgent task in the field of development of heat exchangers is to increase the efficiency of heat transfer with a simultaneous decrease in their dimensions and weight reduction.

A patent is known (RU 2006780, F28D 7/00, publ. 01/30/1994) - a tubular heat exchanger in which a bundle of channels (pipes) for passing the first medium is composed of pipes of larger and smaller diameters, spaced evenly on alternating planes so that ( section) pipes of one diameter are staggered relative to pipes of another diameter. The pipes are fixed by the ends in the tube plates to which the cavities for the entry and exit of the first medium are adjacent on the outside. In this design, the heat exchange surface increases and, accordingly, the heat transfer efficiency and there is the possibility of reducing the dimensions of the heat exchanger. Such a heat exchanger can be used as a single module to create a larger heat exchanger.

The disadvantages of this solution are the lack of counterflow, which reduces the efficiency of heat transfer, and the complexity and high enough complexity of the design.

A shell-and-tube heat exchanger is known, including a hollow cylindrical closed case, to the ends (ends) of which there are adjacent cavities for the inlet and outlet of the first medium (patent RU 2391613, F28D 7/00, F28F 1/10, publ. 06/10/2010). Inside the case, in a staggered manner, there is a bundle of heat exchange pipes (channels) for passing the first medium, fixed in tube boards, which are the ends of the closed case. Pipes have a variable longitudinal profile, consisting of straight and protruding sections, and the protrusions of the profile of one pipe are located between the protrusions of the profile of adjacent pipes. The relative position of the pipes is determined depending on the size of the profile according to a given formula. On the lateral cylindrical surface of the housing near its ends are openings for the entry and exit of the second medium. The selected configuration of the pipe profile and their mutual arrangement create conditions for the turbulization of the flow of media, ensuring the achievement of the goal is to increase the efficiency of heat transfer and achieve optimal intensification of heat transfer. A heat exchanger of this design can serve as a single module to create a heat exchanger of greater power.

The disadvantages of this solution are the uneven distribution of the flow of the second medium over the cross section of the housing and the likelihood of stagnant zones in the region of motion of the second medium near the ends of the housing; increased aerodynamic resistance to movement of the second medium; the probability of the formation of stagnant zones in the channels for the passage of the first medium due to a variable cross-section along the length; high complexity of the design. These disadvantages limit the ability to achieve the highest heat transfer efficiency.

The problem solved by the invention is the creation of a highly efficient small-sized heat-exchange module.

The technical effect that provides the solution to the problem is to ensure maximum heat transfer with the minimum dimensions of the heat exchanger due to the maximum increase in the heat exchange surface and heat transfer conditions. The achievement of this result is due to the new design of the heat exchange module.

This result is achieved by the fact that in the known heat exchange module, comprising a hollow cylindrical body limited by end end plates with openings for passing the first medium through the through channels located inside the body and having openings in the side wall near the end end plates for entering and exiting the second medium, and also closed cavities adjacent to the outer sides of the end end plates for supplying and discharging the first medium, in contrast to the known all adjacent channels for passing the first of the medium are interconnected by longitudinal ribs dividing the interchannel space into separate longitudinal channels for the passage of the second medium and having a length shorter than the length of the channels for the passage of the first medium with the formation of annular chambers for accumulating the second medium, including openings in the wall of the housing for entry and exit of the second medium .

The module can be made monolithic, for example, using 3D printing technology using selective laser melting.

In addition, the module may have at least one continuous partition separating the cavity and the chamber for entry of the first and second media, respectively, providing multi-pass passage of the media.

The claimed invention meets the criterion of novelty, since at the present time similar devices characterized by the given combination of essential features are not known from the prior art. The differences of the proposed solutions are a new form of implementation of structural elements and the relationships between them.

The proposed solution is disclosed presented in figures 1, 2 options for the proposed heat exchange module, as well as a description of the process of its operation.

In FIG. 1 shows the proposed heat exchange module - an option with channels for the passage of the first medium in the form of pipes arranged in a checkerboard pattern.

In FIG. 2 shows a variant of a two-way heat exchange module.

In the figures, the positions indicated:

1 - cylindrical body,

2 - end end plates with holes,

3 - through channels for the passage of the first medium,

4, 5 - cavity for, respectively, the input and output of the first medium,

6, 7 - holes in the wall of the housing 1 for, respectively, the input and output of the second medium,

8 - longitudinal ribs connecting adjacent channels for the passage of the first medium,

9 - longitudinal channels for the passage of the second medium,

10 - an annular chamber for accumulating a second medium at the inlet, including a hole 6,

11 - an annular chamber for accumulating a second medium at the outlet, including an opening 7,

12 - a solid partition that provides two-way passage of media,

13 - camera for the output of the first medium in a two-way embodiment,

14 is a chamber for outputting a second medium in a two-way embodiment.

The direction of movement of the media: a solid line with an arrow - the movement of flows of the first medium, a line with a filled arrow - the movement of flows of the second medium. The relative position of the channels inside the housing 1 can be any; staggering is the best option. The solid partitions 12 provide for the separation of flows and a change in the direction of their movement. In the case of a two-way execution (Fig. 2), one partition 12 divides into two cavity 4 for the entrance of the first medium and the input chamber 10 for accumulating the second medium. As a result, for the flow of the first medium: one part of the cavity 4 is the input and the second part 13 is the output; cavity 5 becomes transitional. For the flow of the second medium: part of the chamber 10 is the input and the second part 14 is the output; chamber 11 becomes transitional.

The number of partitions determines the number of strokes and the location of the inlet and outlet openings in various cavities and chambers for the flow of both media.

The essence of the proposed solution is as follows. The differences of the proposed design - adjacent channels (usually in the form of pipes) are interconnected by ribs with a length shorter than the length of the channels, with the formation of annular chambers for the accumulation of the second medium, including holes in the wall of the inlet and outlet of the second medium. The ribs connecting the channels divide the inter-channel space into separate channels (moves) for the flow of the second medium coming from the input annular chamber. Each rib has two maximum lengths of the thermal contact line with the walls of the channels along which heat is removed. Since the ribs are not elements that provide strength, they can have a minimum thickness. As a result, the distribution of heat along the entire height and length of the rib becomes close to uniform and tends to align with the temperature of the walls of the channels. Due to the ribs, the total heat transfer area between the media increases as much as possible. However, the highest heat transfer efficiency is achieved not only by increasing the heat transfer area, but also because each rib has thermal contact with the channel walls along the entire length of both sides, that is, along the entire stroke length for the second medium. As a result, maximum heat transfer from the walls of the channels to the ribs is achieved. As a result, in this design, high heat transfer efficiency is achieved with significantly smaller module sizes than, for example, in the case of the prototype structure. Formed due to the fact that the ribs are shorter than the channels, the annular chambers near the end end plates defining the cylindrical body of the module primarily provide countercurrent flow with a uniform distribution of the flow of the second medium over the cross section of the body and its full use. It also eliminates the possibility of the formation of stagnant zones at the inlet and outlet of the second medium, slowing its passage through the module.

The processes described above make it possible (while ensuring good thermal contact between all structural elements) to achieve the maximum increase in heat transfer efficiency with the minimum dimensions of the heat exchanger, and thus differences in the design of the invention under consideration determine the specified technical effect.

The specified technical effect is achieved by a new set of essential features not known from the prior art and, therefore, the claimed invention has an inventive step.

The execution of the module in one piece is the best option because it provides the highest possible heat transfer between all structural elements, including heat transfer between the walls of the channels for the passage of the first and second environments. Monolithic design - guaranteed absence of thermal resistances arising when connecting parts due to the presence of air gaps between them for different types of connections, assemblies, and the ability to work at high pressures of interacting media. The use of modern technologies for manufacturing monolithic structures, for example, using 3D printing technology using selective laser melting, makes it possible to expand the range of materials used and remove restrictions on the dimensions, for example, the distances between adjacent channels, associated with the technological capabilities of manufacturing and wall thicknesses of channels and ribs. Such technologies allow the use of modern materials, for example, composite materials with good thermal conductivity.

The use of solid partitions separating the cavity and the chamber for entry of the first and second media, respectively, provides multi-pass passage of media (example - Fig. 2). This, as you know, also works to increase the efficiency of heat transfer, as it allows you to choose the optimal speed of movement of the media, eliminates the formation of stagnant zones.

The execution of the multi-pass module as monolithic according to 3D technology removes structural limitations: you can arrange any desired number of partitions in any desired way, for example, crossing channels for the flow of media (Fig. 2).

The heat exchange module shown in FIG. 1, works as follows. The first medium enters the cavity 4, passes through the channels 3 (pipes) located inside the closed cavity of the housing 1, and enters the cavity 5. The walls of the channels 3 are heated by the first medium and heat from the first medium through the walls of the channels 3 is removed by fins 8 connecting adjacent channels 3 and dividing the spaces between the channels 3 into separate channels 9 for the passage of the second medium. With a small wall thickness of the channels 3 and ribs 8, the heat removal process is quite intense. The second medium is fed into the closed cavity of the housing 1 through the opening 6 and enters the annular chamber 10, where it accumulates, then through the channels 9 enters the annular chamber 11 and exits through the opening 7. It is obvious that in this design, in comparison with previously known, the maximum possibly increases the efficiency of heat transfer between environments.

An example of a specific implementation can serve as a heat exchanger for heating diesel fuel with hot water, designed to operate under the following conditions:

inlet hot water temperature, ° C 60 inlet fuel temperature, ° C 5 outlet fuel temperature, ° C 40 water consumption, g / s 167 fuel consumption, g / s 40 water pressure, MPa 1,5 fuel pressure, MPa 3,5

The heat exchanger is made one-way, in accordance with FIG. 1. Channels for the passage of the first medium - pipes located in the cavity of the body in a checkerboard pattern. Connections of adjacent pipes - ribs; connection geometry — corresponds to FIG. one; material - aluminum. The specific dimensions of the structure were calculated based on the specified operating conditions. As a result, due to the increase in the efficiency of heat transfer between the media in the selected design, the specified conditions are satisfied by the heat exchanger, the heat exchange module of which has dimensions ⌀200 × 260 mm with a heat exchange surface area of 2.5 m ² and a weight of 16 kg. The heat transfer module of the prototype for these purposes has 2.2 times large dimensions and 5 times the mass.

The present invention can be optimally implemented using modern technologies of 3D printing, for example, using selective laser melting. These technologies provide great opportunities for variations in the size of the structure and the materials used and, therefore, expand the scope of application of such heat-exchange modules. Obviously, the present invention is industrially applicable and can provide a solution to a wide range of problems - from household appliances to, for example, complex marine equipment.

Claims (3)

1. A heat exchange module comprising a hollow cylindrical body bounded by end end plates with openings for passing the first medium through the through channels located inside the body and having openings in and out of the second medium in the side wall near the end end plates, as well as adjacent to the outer sides of the end end plates closed cavities for supplying and discharging the first medium, characterized in that all adjacent channels for the passage of the first medium are interconnected by longitudinal ribs, fissioning interchannel space into separate longitudinal channels for passage of a second medium and having a length less than the length of the channel for the passage of a first medium to form an annular chamber for accumulating the second medium comprising a hole in the housing wall for entry and exit of the second medium. 2. The heat exchange module according to claim 1, characterized in that it is made monolithic, for example, using 3D printing technology using selective laser melting. 3. The heat exchange module according to claim 1, characterized in that it further has at least one continuous partition separating the cavity and the chamber for entry of the first and second media, respectively, providing multi-pass passage of the media.

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