Design method of heat exchange material of plate heat exchanger

Abstract

The invention provides a design method of a heat exchange material of a plate heat exchanger. Chemical components, mechanical properties and other technical requirements of the material should meet the regulations of corresponding standards; according to the characteristics and application range of materials, the materials are correctly and reasonably selected, that is, the properties and working conditions of heat exchange media and the forming machining performance and corrosion resistance of the materials need to be considered, the whole heat exchange plate can be filled with fluid with small flow by arranging the flow dividing component, so that some heat exchange areas with fluid short circuits are avoided, and the heat exchange efficiency is improved. Therefore, the heat exchange coefficient is increased, the heat exchange coefficient of the whole heat exchanger is improved, and a new heat exchange plate material is developed.

Description

Technical Field

[0001] The present application relates to the technical field of heat exchangers, and in particular to a design method for heat exchange materials of plate heat exchangers. Background Art

[0002] Plate heat exchanger is a new type of high-efficiency heat exchanger assembled by stacking a series of metal sheets with a certain corrugated shape. Thin rectangular channels are formed between various plates, and heat is exchanged through the plates. Plate heat exchanger is an ideal equipment for heat exchange between liquid-liquid and liquid-steam. It has the characteristics of high heat exchange efficiency, low heat loss, compact and lightweight structure, small footprint, easy installation and cleaning, wide application, and long service life. Under the same pressure loss, its heat transfer coefficient is 3-5 times higher than that of tubular heat exchanger, and the floor area is only one-third of that of tubular heat exchanger, and the heat recovery rate can be as high as 90% or more.

[0003] Corner holes are provided on the corrugated metal heat exchange plates of the heat exchanger to facilitate the flow of the medium. When these heat exchange plates are stacked and assembled together, these corner holes will form corner hole channels for the heat exchange medium in the plate heat exchanger. When the medium flows between the plates, it is in a fully turbulent state.

[0004] In some types of plate heat exchangers, the plates have holes forming channels extending through the stack. In the case of heat exchange between two fluids, each channel communicates with every other plate interspace. A first fluid flows from a first channel, through each alternating plate interspace, over the heat exchange surface of the plate, to a second channel at the opposite side of the stack. A second fluid flows from a third channel, through each other alternating plate interspace, over the heat exchange surface on the opposite side of the plate, to a fourth channel at the opposite side of the stack. In other types of plate heat exchangers, the fluids may be passed to the plate interspaces in a different manner than by holes and channels. The fluids may, for example, be passed from the edge of the heat transfer plate into the plate interspaces by means of a suitable arrangement. The main heat transfer portion of the heat transfer plate has a corrugation pattern. These corrugations can have many different forms, but generally include elevations and depressions. The corrugation pattern has a depth extending between two planes (a first outer plane and a second outer plane), both of which are parallel to a plane extending in the general direction of the plate. The plate is typically manufactured from sheet metal, which may be provided with the corrugation pattern in one or more pressing operations.

[0005] WO93 / 15369 discloses a welded plate heat exchanger, in which the heat transfer plates are welded together in the peripheral edge portions along the inner lines and along the outer lines. The ridges and grooves in the edge portions of the plates abut against each other and are specifically used to weld the plates together. Thus, the weld joints perpendicular to the general plane of the plates are arranged along the inner and outer lines and are centered in the ridges and grooves. In practice, the weld joints are produced by a welding head that follows a preprogrammed trajectory, wherein a pressing device is arranged along the bottom of the grooves so as to press together two adjacent plates to be connected by the welding head. Two relatively wide ridges and grooves are necessary in the edge portions of the plates to allow the welding operation.

[0006] US 5327958 discloses a plate heat exchanger in which the plates are welded together at the periphery of the plates along the transverse ridges of the plates and along the transverse flanges of the plates. The transverse ridges are arranged inside the transverse flanges. Several methods of welding the plates together are described. What most of the methods have in common is that the two plates are first welded together along the transverse ridges. The transverse flanges are welded together along the outer edges of the transverse flanges. According to one embodiment, all the plates are welded together along the outer edges of the transverse flanges. This is made possible by arranging U-shaped bars along the outer edges between every other plate. The type of welding equipment used to weld the plates together is not mentioned, nor is the direction in which the weld joint is produced. In an embodiment in which the internal weld joint is produced before the external weld joint, the internal weld joint is produced perpendicularly to the general plane of the plate along the transverse edge.

[0007] At least two flow channels are formed on the existing gas-to-gas heat exchanger, so that high-temperature gas and low-temperature gas can be introduced into different flow channels respectively, so that the heat of the high-temperature gas can be transferred to the low-temperature gas through the gas-to-gas heat exchanger, thereby achieving heat exchange. However, due to the low heat transfer efficiency of the existing gas-to-gas heat exchanger, it is far from meeting people's needs. Summary of the invention

[0008] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a design method for heat exchange materials of plate heat exchangers, and to provide plate heat exchanger materials with less surface contamination and better thermal conductivity.

[0009] To achieve the above objectives and other related objectives, the present application provides a method for designing a heat exchange material for a plate heat exchanger, the method comprising: Establish a model for the reduction in thermal conductivity of different thermally conductive materials under operating conditions; Screening plate heat exchanger materials with good thermal conductivity and certain mechanical strength; The heat exchange plates used in the plate heat exchanger are designed according to the above-mentioned plate heat exchanger materials; during the exhaust process, the waste hot gas and the supplementary cold air exchange heat through the heat energy recovery device, and the heat of the waste gas is used to preheat the intake air, increase the intake air temperature, save energy consumption, and thus achieve the purpose of heat energy recovery; In one embodiment of the present application, the plate heat exchanger is a high-efficiency heat exchanger formed by stacking a series of metal sheets with a certain corrugated shape, and thin rectangular channels are formed between various plates, and heat exchange is performed through the plates.

[0010] In one embodiment of the present application, the plate heat exchanger is often stamped into a concave and convex corrugated shape to make the fluid flow evenly through the plate surface, increase the heat transfer area, and promote the turbulence of the fluid. There are dozens of corrugated shapes, and commonly used corrugated shapes include horizontal corrugations, herringbone corrugations, and arc-shaped corrugations. Horizontal corrugations are preferably used.

[0011] In one embodiment of the present application, the metal sheet is made of stainless steel alloy material.

[0012] In one embodiment of the present application, the research on plate heat exchanger materials mainly includes three aspects: thermal conductivity of heat exchanger materials; chemical composition, mechanical properties and other technical requirements of materials should comply with the provisions of relevant standards; correct and reasonable selection based on the characteristics and applicable scope of materials, that is, it is necessary to consider the properties of the heat exchange medium, working conditions, and the molding and processing properties and corrosion resistance of the materials.

[0013] In one embodiment of the present application, the heat exchange index of the heat exchanger reaches: gas-fired setting machine: exhaust gas emission temperature drop: ≥50°C, heat recovery efficiency: >20%.

[0014] In one embodiment of the present application, the heat exchanger includes at least three corrugated heat exchange plates stacked in sequence, and a flow channel with openings at both ends is formed between any two adjacent corrugated heat exchange plates; a protrusion extending toward the interior of the flow channel is provided on the inner wall of the flow channel; and a supporting structure located in the flow channel is provided between any two adjacent corrugated heat exchange plates.

[0015] In one embodiment of the present application, the two opposite side edges of any one corrugated heat exchange plate of the heat exchanger are connected to the two side edges of the adjacent corrugated heat exchange plate in a one-to-one correspondence manner by gluing.

[0016] It has the following beneficial effects: The design method of the plate heat exchanger heat exchange material of the present invention can achieve good thermal conductivity, specifically, the exhaust gas emission temperature drop: ≥50 °C; heat recovery efficiency: >20%; The present invention adopts a corrugated heat exchange plate and a combination of raised parts to increase the heat exchange area and make the airflow in the flow channel move irregularly and chaotically, which can greatly increase the contact probability between the fluid molecules and the corrugated heat exchange plate, thereby improving the heat transfer efficiency; moreover, the present invention is simple and convenient to assemble, has a stable structure, and is conducive to promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a flow chart according to an example embodiment is shown.

[0018] Figure 2 A schematic diagram is shown of a corrugated heat exchange plate according to an example embodiment. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. Although the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation, the type, quantity and proportion of each component in actual implementation may be changed arbitrarily, and the component layout may also be more complicated.

[0021] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless there is an indication to the contrary in the context. It should be further understood that the terms "comprise", "include" indicate the presence of the described features, steps, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Therefore, "A, B or C" or "A, B and / or C" means "any of the following: A; B; C; A and B; A and C; B and C; A, B and C". Exceptions to this definition will only occur when the combination of elements, functions, steps or operations is inherently mutually exclusive in some way. Embodiment 1:

[0022] Reference Figure 1 As shown, the present invention provides a method for designing heat exchange materials for a plate heat exchanger, the method comprising: Step S1: Establish a model of the reduction in thermal conductivity of different thermally conductive materials under operating conditions; for example, by constituting the influence of different thermally conductive materials on the thermal performance under different heat exchange conditions, establish a model of the thermal conductivity of different materials in different heat exchange environments Step S2: Screening plate heat exchanger materials with good thermal conductivity and certain mechanical strength, and selecting them correctly and reasonably according to the characteristics and applicable scope of the materials, that is, it is necessary to consider the properties of the heat exchange medium, working conditions, and the molding and processing properties, corrosion resistance of the materials, etc. In the present invention, the heat conductive metal sheet is preferably made of stainless steel alloy material.

[0023] Step S3: designing heat exchange plates used in the plate heat exchanger according to the above-mentioned plate heat exchanger materials; At least two flow channels are formed on the existing gas-to-gas heat exchanger, so that high-temperature gas and low-temperature gas can be introduced into different flow channels respectively, so that the heat of the high-temperature gas can be transferred to the low-temperature gas through the gas-to-gas heat exchanger, thereby realizing heat exchange. However, due to the low heat transfer efficiency of the existing gas-to-gas heat exchanger, it is far from meeting people's needs; the present invention forms a flow channel with two ends open between any two adjacent corrugated heat exchange plates by stacking at least three corrugated heat exchange plates in sequence; a protrusion extending toward the inside of the flow channel is provided on the inner wall of the flow channel; a support structure located in the flow channel is provided between any two adjacent corrugated heat exchange plates, which can increase the heat exchange area and make the movement of the airflow in the flow channel irregular and disorderly, which can greatly increase the contact probability between the fluid molecules and the corrugated heat exchange plates, thereby improving the heat transfer efficiency; moreover, the present invention is simple and convenient to assemble, and the structure is stable, which is conducive to promotion.

[0024] Step S4: During the exhaust process, the waste hot gas and the supplementary cold air exchange heat through the heat energy recovery device, and the heat of the waste gas is used to preheat the intake air, thereby increasing the intake air temperature and saving energy, thereby achieving the purpose of heat energy recovery.

[0025] In a preferred embodiment of the present invention, the plate heat exchanger is a high-efficiency heat exchanger formed by stacking a series of metal sheets with a certain corrugated shape, and thin rectangular channels are formed between various plates, and heat exchange is performed through the plates. It preferably includes at least three corrugated heat exchange plates stacked in sequence, and a flow channel with two ends open is formed between any two adjacent corrugated heat exchange plates; a protrusion extending toward the inside of the flow channel is provided on the inner wall of the flow channel; a support structure located in the flow channel is provided between any two adjacent corrugated heat exchange plates; Reference Figure 2As shown in the figure, thin rectangular channels are formed between various plates, and heat is exchanged through the plates. Plates are the core components of plate heat exchangers. In order to make the fluid flow evenly through the plate surface, increase the heat transfer area, and promote the turbulence of the fluid, the plate surface is often stamped into a concave and convex corrugated shape. There are dozens of corrugated shapes, and the commonly used corrugated shapes include horizontal corrugations, herringbone corrugations, and arc-shaped corrugations. Embodiment 2:

[0026] A method for designing heat exchange materials for a plate heat exchanger, the method comprising: Establish a model for the reduction in thermal conductivity of different thermally conductive materials under operating conditions; Screening plate heat exchanger materials with good thermal conductivity and certain mechanical strength; The heat exchange plates used in the plate heat exchanger are designed according to the above-mentioned plate heat exchanger materials; during the exhaust process, the waste hot gas and the supplementary cold air exchange heat through the heat energy recovery device, and the heat of the waste gas is used to preheat the intake air, increase the intake air temperature, save energy consumption, and thus achieve the purpose of heat energy recovery; Among them, the research on plate heat exchanger materials mainly includes three aspects: thermal conductivity of heat exchanger materials; chemical composition, mechanical properties and other technical requirements of materials should comply with the provisions of relevant standards; correct and reasonable selection according to the characteristics and applicable scope of materials, that is, it is necessary to consider the properties of the heat exchange medium, working conditions, and the molding and processing performance and corrosion resistance of the materials; the heat exchange index of the heat exchanger reaches: gas-type finalizer: exhaust gas emission temperature drop: ≥50 ℃, heat recovery efficiency: >20%. Embodiment 3:

[0027] Reference Figure 1 , Figure 2 As shown, a method for designing heat exchange materials for a plate heat exchanger, the method comprising: Establish a model for the reduction in thermal conductivity of different thermally conductive materials under operating conditions; Screening plate heat exchanger materials with good thermal conductivity and certain mechanical strength; The heat exchange plates used in the plate heat exchanger are designed according to the above-mentioned plate heat exchanger materials; during the exhaust process, the waste hot gas and the supplementary cold air exchange heat through the heat energy recovery device, and the heat of the waste gas is used to preheat the intake air, increase the intake air temperature, save energy consumption, and thus achieve the purpose of heat energy recovery; The plate heat exchanger includes at least three corrugated heat exchange plates 1 stacked in sequence, and a flow channel 11 with two ends open is formed between any two adjacent corrugated heat exchange plates 1; a protrusion extending toward the inside of the flow channel 11 is provided on the inner wall of the flow channel 11, and since the flow channel 11 is located between two adjacent corrugated heat exchange plates 1, the inner wall of the flow channel 11 is the facing surface of the two adjacent corrugated heat exchange plates 1; a supporting structure located in the flow channel 11 is provided between any two adjacent corrugated heat exchange plates 1. In the actual design process, the heat exchanger generally uses multiple corrugated heat exchange plates 1 to form multiple flow channels 11, thereby improving work efficiency.

[0028] During operation, the high-temperature airflow and the low-temperature airflow flow into different flow channels 11 of the heat exchanger respectively. At this time, the heat of the high-temperature airflow can be transferred to the low-temperature airflow through the corrugated heat exchange plate 1, thereby realizing heat exchange between the high-temperature airflow and the low-temperature airflow. When the airflow flows through the flow channel 11, it bypasses when passing through the raised portion. Therefore, the present invention utilizes the corrugations of the corrugated heat exchange plate 1 and the raised portion to make the movement of the airflow in the flow channel 11 irregular and disorderly, and forms turbulence, which can greatly increase the contact probability between the fluid molecules and the corrugated heat exchange plate. Therefore, compared with the existing heat exchanger using a smooth flat plate heat exchange plate, the present invention can improve the heat exchange efficiency. Moreover, compared with the smooth flat plate heat exchange plate, the present invention can also increase the heat exchange area by using the corrugated heat exchange plate 1, thereby further improving the heat exchange efficiency. In addition, the present invention can also improve the stability and reliability of the heat exchanger structure by using a support structure to avoid the deformation of the flow channel 11 during use.

[0029] Preferably, the support structure includes two support bosses 2 which are arranged on two adjacent corrugated heat exchange plates 1 in a one-to-one correspondence and abut against each other. During manufacturing, one corrugated heat exchange plate 1 is stacked on the other corrugated heat exchange plate 1. At this time, the support bosses 2 on the two corrugated heat exchange plates 1 abut against each other. By utilizing the support of the support bosses 2, the structural stability of the heat exchanger can be ensured while facilitating assembly.

[0030] Specifically, a plurality of supporting structures are arranged between any two adjacent corrugated heat exchange plates 1 to further improve the structural stability.

[0031] Preferably, the extension directions of any two adjacent flow channels 11 are perpendicular to each other. When in use, the high-temperature airflow and the low-temperature airflow can be introduced into the flow channels 11 in different directions, so that the flow directions of the high-temperature airflow (along direction A) and the low-temperature airflow (along direction B) are perpendicular to each other, thereby further improving the heat exchange effect.

[0032] Preferably, any two adjacent corrugated heat exchange plates 1 are connected by gluing. Specifically, the opposite side edges of any corrugated heat exchange plate 1 are connected to the opposite side edges of the adjacent corrugated heat exchange plate 1 by gluing, and by adopting the above structure, the sealing performance can be improved to reduce the probability of air leakage, and the assembly is simpler and more convenient. In this embodiment, in order to make the extension directions of the two adjacent flow channels 11 perpendicular to each other, during processing, the left and right side edges or the front and rear side edges of the corrugated heat exchange plate 1 can be connected to the adjacent corrugated heat exchange plate 1 accordingly, so that the extension directions of the two adjacent flow channels 11 are perpendicular to each other. Specifically, during the gluing process, the side edge of one of the corrugated heat exchange plates 1 can be folded into a dead edge to press the side edge of the adjacent corrugated heat exchange plate 1 for gluing.

[0033] Preferably, the corrugated heat exchange plate 1 is made of aluminum foil to improve the heat transfer coefficient of the corrugated heat exchange plate 1, thereby further improving the heat exchange efficiency.

[0034] Specifically, a plurality of protrusions are arranged at intervals on both sides of each flow channel 11, so that the flow path of the airflow is more complicated. Specifically, the number of protrusions on both sides of the flow channel 11 is the same and they are arranged opposite to each other.

[0035] Preferably, the angle between the extension direction of the corrugations on the corrugated heat exchange plate 1 and the length direction of the corrugated heat exchange plate 1 is 40-50 degrees. As the best solution of the present invention, the angle between the extension direction of the corrugations on the corrugated heat exchange plate 1 and the length direction of the corrugated heat exchange plate 1 is 45 degrees, so as to further improve the heat transfer effect.

[0036] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those of ordinary skill in the art without departing from the spirit and technical ideas disclosed by the present invention shall still be covered by the claims of the present application.

Claims

1. A method for designing heat exchange materials for a plate heat exchanger, characterized in that: The method comprises: Establish a model for the reduction in thermal conductivity of different thermally conductive materials under operating conditions; Screening plate heat exchanger materials with good thermal conductivity and certain mechanical strength; Design the heat exchange plates used in the plate heat exchanger according to the above-mentioned plate heat exchanger materials; During the exhaust process, the waste hot gas and the supplementary cold air exchange heat through the heat recovery device, and the heat of the waste gas is used to preheat the intake air, increase the intake air temperature, save energy, and thus achieve the purpose of heat recovery.

2. The method for designing heat exchange materials for plate heat exchangers according to claim 1, characterized in that: The plate heat exchanger is a high-efficiency heat exchanger formed by stacking a series of metal sheets with a certain corrugated shape. Thin rectangular channels are formed between various plates, and heat exchange is carried out through the plates.

3. The method for designing heat exchange materials for plate heat exchangers according to claim 1, characterized in that: In order to make the fluid flow evenly through the plate surface, increase the heat transfer area, and promote the turbulence of the fluid, the plate surface of the plate heat exchanger is often punched into a concave and convex corrugated shape. There are dozens of corrugated shapes, and the commonly used corrugated shapes include horizontal corrugations, herringbone corrugations, and arc-shaped corrugations.

4. The method for designing heat exchange materials for a plate heat exchanger according to claim 1, characterized in that: The metal sheet is made of stainless steel alloy material.

5. The method for designing heat exchange materials for plate heat exchangers according to claim 1, characterized in that: The research on plate heat exchanger materials mainly includes three aspects: thermal conductivity of heat exchanger materials; chemical composition, mechanical properties and other technical requirements of materials should comply with the provisions of relevant standards; correct and reasonable selection based on the characteristics and applicable scope of materials, that is, it is necessary to consider the properties of the heat exchange medium, working conditions, and the molding and processing properties and corrosion resistance of the materials.

6. The method for designing heat exchange materials for a plate heat exchanger according to claim 1, characterized in that: The heat exchange index of the heat exchanger reaches: gas-fired setting machine: exhaust gas emission temperature drop: ≥50°C, heat recovery efficiency: >20%.

7. The method for designing heat exchange materials for a plate heat exchanger according to claim 1, characterized in that: The heat exchanger comprises at least three corrugated heat exchange plates stacked in sequence, a flow channel with openings at both ends is formed between any two adjacent corrugated heat exchange plates; a protrusion extending toward the inside of the flow channel is arranged on the inner wall of the flow channel; a supporting structure located in the flow channel is arranged between any two adjacent corrugated heat exchange plates.

8. The method for designing heat exchange materials for a plate heat exchanger according to claim 1, characterized in that: The opposite side edges of any one of the corrugated heat exchange plates of the heat exchanger are connected to the opposite side edges of the adjacent corrugated heat exchange plates in a one-to-one correspondence manner by gluing.

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