CN213880375U

CN213880375U - Printed circuit board heat exchanger core for reducing stress

Info

Publication number: CN213880375U
Application number: CN202022390220.3U
Authority: CN
Inventors: 吴家荣; 李红智; 张旭伟; 乔永强; 姚明宇; 张磊
Original assignee: Xian Thermal Power Research Institute Co Ltd
Current assignee: Xian Thermal Power Research Institute Co Ltd
Priority date: 2020-10-25
Filing date: 2020-10-25
Publication date: 2021-08-03
Anticipated expiration: 2030-10-25

Abstract

A printed circuit board heat exchanger core for reducing stress comprises a plurality of hot plates with hot fluid channels and cold plates with cold fluid channels; the upper surface and the lower surface of the hot plate sheet and the cold plate sheet are respectively provided with a surface A with a semi-circular arc and a surface B, and the surface A with the semi-circular arc are symmetrically connected to form a circular section channel; the plane B is connected with the plane B to form a wall surface between cold and hot fluid channels. The utility model discloses can reduce the stress that the core received by a wide margin, also can reduce the core volume for heat exchanger structure is compacter, can bear bigger pressure and higher temperature.

Description

Printed circuit board heat exchanger core for reducing stress

Technical Field

The utility model relates to a heat transfer device technical field, in particular to a printed circuit board heat exchanger core for reducing stress.

Background

Printed circuit board heat exchangers (PCHE) are widely used in many fields such as chemical engineering, aerospace, petroleum, electric power, refrigeration, etc. due to their features of compact structure, high temperature and pressure resistance, and large heat exchange capacity per unit volume. As a core component of a printed circuit board heat exchanger, the core provides a place for cold and hot (low temperature, high temperature) fluids to flow for heat exchange, and bears the high temperature and high pressure of the heat exchange fluids. In the industry, a semi-circular micro-channel with an equivalent diameter of about 1mm is etched on a metal plate by a photochemical etching method to form a cold-hot plate, and the cold-hot plate is sequentially connected by a diffusion welding technology to form a core.

Because the core body works in a high-temperature or high-pressure environment for a long time, the core body can bear mechanical stress caused by high-pressure working media for a long time and thermal stress caused by the fact that the metal material cannot freely expand with heat and contract with cold in a temperature field. Particularly, at the joint of the semicircular channel of the next layer of plate and the bottom of the previous layer of plate, the circular arc and the diameter of the semicircle form two sharp corners causing stress concentration, as shown in fig. 1, although the sharp corners have small circular arc transition during diffusion welding, the mechanical stress and the thermal stress at the sharp corners are still far greater than those at other positions, so that local excessive plastic deformation is easily caused, and the material failure core body is scrapped. Generally, the higher the temperature is, the lower the allowable stress of the metal material is, and for a printed circuit board heat exchanger working under a certain high-temperature condition (such as a high-temperature gas cooled reactor, the temperature of a high-temperature working medium is more than 1100K), how to reduce the stress borne by the core body and ensure that the core body material does not fail constitutes a new technical challenge.

Disclosure of Invention

In order to overcome the technical problem, the utility model aims to provide a printed circuit board heat exchanger core for reducing stress can reduce the stress that the core received by a wide margin, also can reduce the core volume for heat exchanger structure is compacter, can bear bigger pressure and higher temperature.

In order to realize the purpose, the utility model discloses a technical scheme is:

a printed circuit board heat exchanger core for stress reduction comprising a number of hot plates 3 'with hot fluid (high temperature fluid) channels 1' and cold plates 4 'with cold fluid (low temperature fluid) channels 2';

the upper surface and the lower surface of the hot plate piece 3 'and the cold plate piece 4' are respectively provided with a surface A with a semicircular arc and a surface B, and the surface A with the semicircular arc are symmetrically connected to form a circular section channel;

the plane B is connected with the plane B to form a wall surface between cold and hot fluid channels.

Further, the hot plate 3 'and the cold plate 4' are metal plates.

Further, the hot fluid (high temperature fluid) channel 1 'and the cold fluid (low temperature fluid) channel 2' are formed by etching micro-channels with semicircular cross sections on the metal plate by adopting a photochemical etching method, the shape of the channels in the flow direction can be in a straight line, a positive (cosine) shape, a zigzag shape or other combination forms, and the etched metal plate forms the hot plate 3 'and the cold plate 4'.

Further, the hot plate 3 'and the cold plate 4' are symmetrically connected on the a-plane and the a-plane of the two hot plate 3 'or the cold plate 4' during diffusion welding.

Further, the B-side of the hot plate 3 'and the B-side of the cold plate 4' are connected at the time of diffusion welding of the hot plate 3 'and the cold plate 4'.

Further, the hot plates 3 'and cold plates 4' are periodically connected in turn to form a complete core and the cover plate 5 is removed.

The utility model has the advantages that:

a printed circuit board heat exchanger core for reducing stress, on the basis of traditional semicircle cross-section passageway slab etching technology, adjust diffusion welded surface to make original semicircle cross-section passageway become new circular cross-section passageway, eliminated the closed angle of semicircle cross-section circular arc and plane junction, reduced cold and hot fluid passage's thermal stress and mechanical stress by a wide margin, make the core can bear higher temperature and pressure, simple process on the unchangeable basis of material.

On the other hand, the novel core body adjusts the surface of diffusion welding, so that the cover plate 5 at the topmost layer of the traditional core body is not needed; under the same equivalent diameter, the radius of the circle is smaller than that of the semicircle, so more micro-channels can be etched on a thinner metal plate, the volume of the core body is reduced to a certain extent, and the structure of the heat exchanger is more compact.

Drawings

Fig. 1 is a schematic view of a stress concentration location.

Fig. 2a is a schematic view of a conventional core.

Fig. 2b is the schematic diagram of the core structure of the present invention.

Fig. 3 is a schematic view of the diffusion welding process of the present invention.

Fig. 4a is a diagram showing a thermal stress distribution of a conventional core.

Fig. 4b is a thermal stress distribution diagram of the core body of the present invention.

Fig. 5a is a graph showing the mechanical stress distribution of a conventional core.

Fig. 5b is the core mechanical stress distribution diagram of the present invention.

Wherein, 1 and 2 are traditional semicircle cross-section passageway, 3 and 4 are traditional core hot plate or cold plate piece, 5 are the apron, 1 'is novel core hot fluid passageway, 2' is novel core cold fluid passageway, 3 'is novel core hot plate piece, 4' is novel core cold plate piece.

Wherein A is a surface with a semicircular arc on the plate, and B is a plane on the plate.

Detailed Description

The present invention will be described in further detail with reference to examples.

As shown in fig. 2a and 2b, the present invention provides a printed circuit board heat exchanger core for reducing stress, said core comprising a number of hot plates 3 'with hot fluid (high temperature fluid) channels 1' and cold plates 4 'with cold fluid (low temperature fluid) channels 2'. The hot fluid (high temperature fluid) channel 1 'and the cold fluid (low temperature fluid) channel 2' are formed by etching micro-channels with semicircular sections on the metal plate by adopting a photochemical etching method, the shape of the channels along the flow direction can be in a straight line, a positive (cosine) shape, a Z (zigzag) shape or other combination forms, and the etched metal plate forms a hot plate 3 'and a cold plate 4'.

As shown in fig. 3, the hot plate 3 'and the cold plate 4' both have a plane a with a semicircular arc and a plane B, the a plane and the a plane of the two hot plate 3 'or the cold plate 4' are symmetrically connected when the hot plate 3 'and the cold plate 4' are diffusion welded, and the two symmetrical planes a form a circular cross-section channel; the surface B of the hot plate 3 'and the surface B of the cold plate 4' are connected to form a wall surface between cold and hot fluid channels when the hot plate 3 'and the cold plate 4' are diffusion-welded. The hot plate 3 'and the cold plate 4' are periodically connected in turn to form a complete core, with the top cover plate 5 removed. And finally, arranging end sockets and connecting pipes at two ends of the core body of the heat exchanger to obtain the complete printed circuit board heat exchanger.

Under the premise that the temperature of a hot fluid channel (hot channel) and the temperature of a cold fluid channel (cold channel) are 810.25K and 760.75K respectively, the pressure of the hot fluid channel (hot channel) and the pressure of the cold fluid channel (cold channel) are 8.4MPa and 21.3MPa respectively, the metal material is SUS316, and the equivalent diameter of the heat exchange channel and the total number of the channels are not changed, the stress size and distribution of a traditional semicircular section channel core and a novel core are calculated and compared by adopting a finite element method, and the stress size and distribution along the path of the cold and hot channels are analyzed in a key way, as shown in fig. 4 and 5.

Fig. 4a and b are the thermal stress size and distribution of traditional semicircular section passageway core and novel core along cold and hot passageway route respectively, and can know that novel core thermal stress is obviously less than traditional core thermal stress, and the ratio of maximum thermal stress and minimum thermal stress also obviously is less than the former, and this shows that novel core thermal stress distributes more evenly than traditional core, and thermal stress reduces by a wide margin.

Fig. 5a and b are the mechanical stress magnitude and distribution of the traditional semicircular section channel core and the novel core along the path of the cold and hot channel respectively, and it can be known that the mechanical stress of the novel core is obviously less than that of the traditional core, especially the cold channel, the maximum mechanical stress of the novel core is only 1/10 of the maximum mechanical stress of the traditional core, the stress distribution is very uniform, and the phenomenon of sharp stress increase at two sharp corner positions in fig. 5a does not occur.

The results of fig. 4 and 5 show that the novel core can greatly reduce the thermal stress and the mechanical stress on the basis of unchanged core material, and can work under the conditions of higher pressure and higher temperature without exceeding the specified allowable stress. On the other hand, under the same equivalent diameter, the radius of the circle is smaller than that of the semicircle, more micro-channels can be etched on a thinner metal plate, and the volume of the core body is reduced to a certain extent due to the removal of the top cover plate, so that the structure of the heat exchanger is more compact.

It should be noted that the above description is only a preferred example of the present invention, and the present invention is not limited thereto, and any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A printed circuit board heat exchanger core for stress reduction, characterized by a number of hot plates (3 ') with hot fluid channels (1') and cold plates (4 ') with cold fluid channels (2');

the upper surface and the lower surface of the hot plate sheet (3 ') and the cold plate sheet (4') are respectively provided with a surface A with a semicircular arc and a surface B, and the surface A with the semicircular arc are symmetrically connected to form a circular section channel;

2. A printed circuit board heat exchanger core for reducing stress according to claim 1, characterized in that the hot plate sheet (3 ') and the cold plate sheet (4') are metal sheets.

3. A printed circuit board heat exchanger core for reducing stress according to claim 1, wherein the hot fluid channels (1 ') and the cold fluid channels (2') are micro-channels of semicircular cross-section etched in the metal sheet using a photochemical etching method, the shape of the channels in the flow direction is linear, sinusoidal or zigzag, and the etched metal sheets constitute the hot sheet (3 ') and the cold sheet (4').

4. A printed circuit board heat exchanger core for stress reduction according to claim 1, wherein the hot plate sheet (3 ') and the cold plate sheet (4') are connected symmetrically at a-plane and a-plane of two hot plate sheets (3 ') or cold plate sheets (4') at diffusion welding.

5. A printed circuit board heat exchanger core for reducing stress according to claim 1, wherein the B-side of the hot plate (3 ') and the cold plate (4') are connected at diffusion welding of the hot plate (3 ') and the cold plate (4').

6. A printed circuit board heat exchanger core for reducing stress according to claim 1, characterized in that the hot plates (3 ') and cold plates (4') are periodically connected in turn to form a complete core and the cover plate (5) is removed.