Plate-fin heat exchanger and wind driven generator gearbox lubricating and cooling system

Abstract

The invention discloses a plate-fin heat exchanger and a lubricating and cooling system for a gearbox of a wind driven generator. The technical problem that the flow resistance of a target medium in the plate-fin heat exchanger is too large when the viscosity of the target medium is gradually increased along with the proceeding of a heat exchange process is solved. Comprising a core part, a target medium input part and a target medium output part, the target medium input part comprises an input channel arranged on the inner side of the core part, the input channel divides the core part into two heat exchange areas located on the two sides of the input channel respectively, and the input channel is communicated with the target medium inlet ends of the two heat exchange areas at the same time. The target medium output part comprises a first output channel and a second output channel which are distributed on the edge of the core part, and the first output channel and the second output channel communicate with the target medium outlet ends of the two heat exchange areas correspondingly. By dividing the core part into the two heat exchange areas, the flowing path of the target medium is shortened, and therefore the flowing resistance of the target medium in the heat exchange process is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of plate-fin heat exchangers, and in particular to a plate-fin heat exchanger and a lubrication cooling system for a wind turbine gearbox. Background Art

[0002] Plate fin heat exchanger (PFHE) is composed of several heat exchange units arranged in layers, and these heat exchange units have corrugated fins placed between adjacent partitions. The shape and structure of the corrugated fins are similar to corrugated paper, with alternating crests and troughs formed on them, and side walls formed between adjacent crests and troughs. Both sides of each side wall are medium channels for the flow of target medium or working medium. The target medium refers to the temperature control object for heat exchange through the plate fin heat exchanger; and the working medium is the heat exchange medium that exchanges heat with the target medium. Figure 3 This is a schematic diagram of the heat transfer principle of a plate-fin heat exchanger. Figure 3 As shown below: Figure 3 The solid arrows in the figure indicate the flow direction of the target medium, and the hollow arrows indicate the flow direction of the working medium, wherein the target medium passes through the medium channel (target medium flow channel) between the two adjacent partitions in the middle, and the working medium passes through the medium channels (working medium flow channels) between the adjacent partitions on both sides of the target medium flow channel.

[0003] At present, in the lubrication and cooling system of the wind turbine gearbox, a plate-fin heat exchanger is generally used to cool the lubricating oil of the wind turbine gearbox. In the existing wind turbine gearbox lubrication and cooling system, a lubricating oil flow control device and a lubricating oil cooling device (using a plate-fin heat exchanger) are provided on the lubricating oil circulation loop, and the lubricating oil flow control device adaptively adjusts the flow of the lubricating oil entering the lubricating oil cooling device according to the change of the viscosity of the lubricating oil with the temperature. Generally speaking, when the temperature of the lubricating oil entering the lubricating oil flow control device is ≤ the first set temperature (such as 45°C), the lubricating oil flow control device fully opens the bypass of the lubricating oil cooling device, and the lubricating oil flow in the lubricating oil cooling device is the smallest; when the temperature of the lubricating oil entering the lubricating oil flow control device is higher than the first set temperature, the viscosity of the lubricating oil decreases, and at this time, the lubricating oil flow control device can gradually increase the flow entering the lubricating oil cooling device as the temperature rises. When the temperature of the lubricating oil entering the lubricating oil flow control device reaches the second set temperature (such as 60°C), the lubricating oil flow control device closes the bypass of the lubricating oil cooling device, and the lubricating oil flow in the lubricating oil cooling device is the largest.

[0004] Figure 1 The following is a schematic diagram of the structure of a plate-fin heat exchanger in the existing wind turbine gearbox lubrication and cooling system. Figure 1As shown, the plate-fin heat exchanger specifically comprises: a core 1, a target medium input part 2 and a target medium output part 3, wherein the core 1 (working principle is as follows Figure 3 The target medium input portion 2 is connected to the core 1 (specifically arranged at one side edge of the core 1) and is used to transport the target medium to be heat exchanged to the target medium inlet end of the core 1; the target medium output portion 3 (specifically arranged at the other side edge of the core 1) is connected to the core 1 and is used to output the heat-exchanged target medium at the target medium outlet end of the core 1. Figure 1 The plate-fin heat exchanger shown adopts a one-inlet-one-outlet design, and the target medium has a long flow distance in the core 1 . Figure 2 for Figure 1 The temperature gradient diagram of the target medium in the plate-fin heat exchanger shown in the figure (red represents high-temperature target medium, and yellow represents low-temperature target medium). Figure 2 As shown, the target medium to be heat exchanged (indicated in red) enters various tiny flow channels in the target medium flow channel from the target medium inlet end of the core 1 through the distribution of the target medium input part 2, and then the temperature gradually decreases in the process of flowing to the target medium output part 3.

[0005] According to the heat dissipation principle of plate-fin heat exchangers, the lower the ambient temperature, the better the cooling effect of the plate-fin heat exchanger on the lubricating oil (according to the heat balance formula, the ambient temperature has the most obvious effect on the cooling performance of the plate-fin heat exchanger, and the lower the ambient temperature, the better the cooling effect). However, when the existing wind turbine gearbox lubrication cooling system is running under very low ambient temperatures, the gearbox will alarm or even shut down due to excessive temperature, making the wind turbine unable to generate electricity normally and causing economic losses. The inventor analyzed and found that the reason for this problem is: when the ambient temperature is low (generally below minus 10°C), if the lubricating oil reaches the second set temperature (such as 60°C), the lubricating oil flow control device in the lubrication and cooling system of the wind turbine gearbox will close the bypass of the lubricating oil cooling device, so that the lubricating oil flow in the lubricating oil cooling device is maximized. Due to the low external ambient temperature, the lubricating oil temperature inside the plate-fin heat exchanger is instantly cooled to a very low temperature (generally below 35°C). At this time, the lubricating oil flow resistance inside the plate-fin heat exchanger suddenly increases, causing the lubricating oil operating pressure in the lubricating oil circulation loop to increase and exceed the opening force of the lubricating oil overflow valve (such as 12 bar). As a result, the lubricating oil will flow directly back to the gearbox oil pool through the overflow pipe, and the various lubrication points of the gearbox will not be lubricated and cooled by the lubricating oil, resulting in overheating of the gearbox. Summary of the invention

[0006] The purpose of the present invention is to provide an improved plate-fin heat exchanger and a wind turbine gearbox lubrication cooling system to solve the technical problem of avoiding excessive flow resistance of the target medium in the plate-fin heat exchanger when the viscosity of the target medium gradually increases with the progress of the heat exchange process.

[0007] In a first aspect, a plate-fin heat exchanger is provided, comprising: a core part, used to realize heat exchange between a target medium and a working medium so that the target medium reaches a preset temperature, the target medium is the temperature control object of the heat exchange and its viscosity gradually increases as the heat exchange process proceeds; a target medium input part, connected to the core part and used to convey the target medium to be heat exchanged to the target medium inlet end of the core part; a target medium output part, connected to the core part and used to output the heat-exchanged target medium at the target medium outlet end of the core part; the target medium input part comprises an input channel disposed on the inner side of the core part, the input channel divides the core part into two heat exchange areas respectively located on both sides of the input channel, and the input channel is simultaneously connected to the target medium inlet end of each of the two heat exchange areas; the target medium output part comprises a first output channel and a second output channel distributed on the edge of the core part, and the first output channel and the second output channel are respectively connected to the target medium outlet end of each of the two heat exchange areas.

[0008] In a second aspect, a lubrication and cooling system for a wind turbine gearbox is provided, comprising a lubricating oil cooling device, wherein the lubricating oil cooling device adopts the plate-fin heat exchanger of the first aspect.

[0009] The beneficial effects of the above-mentioned plate-fin heat exchanger and wind turbine gearbox lubrication and cooling system are: 1) by dividing the core into two heat exchange areas, the flow path of the target medium is shortened, thereby reducing the flow resistance of the target medium during the heat exchange process; 2) since the target medium is distributed to two heat exchange areas, the heat exchange effect can be guaranteed, and the problem of uneven heat exchange caused by the long flow distance of the target medium in the core is avoided; 3) reducing the sudden change of the lubricating oil flow resistance in the wind turbine gearbox lubrication and cooling system, reducing the risk of lubricating oil pressure fluctuations, and helping to maintain a stable lubricating oil circulation; 4) improving the reliability of the wind turbine gearbox lubrication and cooling system in low temperature environments.

[0010] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings constituting a part of this specification are used to assist the understanding of the present invention. The contents provided in the drawings and the related descriptions in this specification can be used to explain the present invention, but do not constitute improper limitations on the present invention.

[0012] Figure 1 The present invention is a schematic diagram of the structure of a plate-fin heat exchanger in an existing wind turbine gearbox lubrication and cooling system.

[0013] Figure 2 for Figure 1 The temperature gradient diagram of the target medium in the plate-fin heat exchanger shown (red represents high-temperature target medium and yellow represents low-temperature target medium).

[0014] Figure 3 Schematic diagram of the heat transfer principle of plate-fin heat exchanger.

[0015] Figure 4 The figure is a schematic structural diagram of a plate-fin heat exchanger according to an embodiment of the present invention. DETAILED DESCRIPTION

[0016] The present invention is described clearly and completely below in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0017] The technical solutions and technical features provided in each section, including the following description, can be combined with each other without conflict. In addition, where possible, these technical solutions, technical features and related combinations can be assigned specific technical themes and protected by relevant patents.

[0018] The embodiments of the present invention involved in the following description are generally only a part of the embodiments rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of patent protection.

[0019] Regarding the terms and units in this specification: The terms "include", "comprises" and any variations thereof in this specification and the corresponding claims and related parts are intended to cover non-exclusive inclusions. In addition, other relevant terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0020] Figure 1 The following is a schematic diagram of the structure of a plate-fin heat exchanger in the existing wind turbine gearbox lubrication and cooling system. Figure 1As shown, the plate-fin heat exchanger specifically includes: a core 1, a target medium input part 2 and a target medium output part 3, wherein the core 1 is used to realize heat exchange between the target medium (i.e., lubricating oil) and the working medium (heat exchange air) so that the target medium reaches a preset temperature; the target medium input part 2 is connected to the core 1 (specifically arranged at one side edge of the core 1) and is used to transport the target medium to be heat exchanged to the target medium inlet end of the core 1; the target medium output part 3 (specifically arranged at the other side edge of the core 1) is connected to the core 1 and is used to output the heat-exchanged target medium at the target medium outlet end of the core 1. Figure 1 The plate-fin heat exchanger shown adopts a one-inlet-one-outlet design, and the target medium has a long flow distance in the core 1 . Figure 2 for Figure 1 The temperature gradient diagram of the target medium in the plate-fin heat exchanger shown in the figure (red represents high-temperature target medium, and yellow represents low-temperature target medium). Figure 2 As shown, the target medium to be heat exchanged (indicated in red) enters various tiny flow channels in the target medium flow channel from the target medium inlet end of the core 1 through the distribution of the target medium input part 2, and then the temperature gradually decreases in the process of flowing to the target medium output part 3.

[0021] According to the heat dissipation principle of plate-fin heat exchangers, the lower the ambient temperature, the better the cooling effect of the plate-fin heat exchanger on the lubricating oil (according to the heat balance formula, the ambient temperature has the most obvious effect on the cooling performance of the plate-fin heat exchanger, and the lower the ambient temperature, the better the cooling effect). However, when the existing wind turbine gearbox lubrication cooling system is running under very low ambient temperatures, the gearbox will alarm or even shut down due to excessive temperature, making the wind turbine unable to generate electricity normally and causing economic losses. The inventor analyzed and found that the reason for this problem is: when the ambient temperature is low (generally below minus 10°C), if the lubricating oil reaches the second set temperature (such as 60°C), the lubricating oil flow control device in the lubrication and cooling system of the wind turbine gearbox will close the bypass of the lubricating oil cooling device (refer to the applicant's patent document with publication number CN209540464U), so that the lubricating oil flow in the lubricating oil cooling device is maximized. Due to the low external ambient temperature, the lubricating oil temperature inside the plate-fin heat exchanger is instantly cooled to a very low temperature (generally below 35°C). At this time, the lubricating oil flow resistance inside the plate-fin heat exchanger suddenly increases, causing the lubricating oil operating pressure in the lubricating oil circulation loop to increase and exceed the opening force of the lubricating oil overflow valve (the current overflow valve opening force is set to 12 bar). As a result, the lubricating oil will flow directly back to the gearbox oil pool through the overflow pipe, and the various lubrication points of the gearbox will not be lubricated and cooled by the lubricating oil, resulting in overheating of the gearbox.

[0022] The following embodiments of the present invention will provide an improved plate-fin heat exchanger and a wind turbine gearbox lubrication cooling system to solve the technical problem of avoiding excessive flow resistance of the target medium in the plate-fin heat exchanger when the viscosity of the target medium gradually increases with the progress of the heat exchange process.

[0023] Figure 4 FIG. 1 is a schematic diagram of the structure of a plate-fin heat exchanger according to an embodiment of the present invention. Figure 4 As shown, a plate-fin heat exchanger comprises: a core 1, used to realize heat exchange between a target medium and a working medium so that the target medium reaches a preset temperature, the target medium is the temperature control object of the heat exchange and its viscosity gradually increases as the heat exchange process proceeds; a target medium input part 2, connected to the core and used to transport the target medium to be exchanged to the target medium inlet end of the core; a target medium output part 3, connected to the core and used to output the target medium that has been exchanged at the target medium outlet end of the core; wherein the target medium input part 2 comprises An input channel 21 is disposed on the inner side of the core, the input channel 21 divides the core 1 into two heat exchange areas 11 respectively located on both sides of the input channel, and the input channel 21 is simultaneously connected to the target medium inlet end of each of the two heat exchange areas 11; and the target medium output part 3 includes a first output channel 31 and a second output channel 32 distributed on the edge of the core 1, and the first output channel 31 and the second output channel 32 are respectively connected to the target medium outlet end of each of the two heat exchange areas 11.

[0024] The working principle of the core 1 is as follows Figure 3 shown. Figure 3 The solid arrows in the figure indicate the flow direction of the target medium, i.e., flowing through the target medium flow channel; the hollow arrows indicate the flow direction of the working medium, i.e., flowing through the working medium flow channel. In a common manner, the target medium flow channel and the working medium flow channel in the core 1 are both formed by corrugated fins placed between adjacent partitions.

[0025] The corrugated fins of the target medium flow channel and / or the working medium flow channel in the core 1 can be selected to have a turbulent effect.

[0026] In this embodiment, the first output channel 31 and the second output channel 31 are arranged in parallel with the input channel 21 and distributed on both sides of the input channel 21, and the input channel 21 is arranged perpendicular to the target medium flow channel in each of the two heat exchange areas 11.

[0027] By arranging the input channel 21 perpendicularly to the target medium flow channel of each heat exchange area 11, and making the first output channel 31 and the second output channel 31 parallel to the input channel 21 and distributed on both sides of the input channel 21, the flow rate can be evenly distributed, the flow path can be shortened, the heat exchange efficiency can be improved, the pressure loss can be reduced, and the structural symmetry can be maintained.

[0028] On this basis, the distance between the center line of the input channel 21 and the center line of the first output channel 31 is equal to the distance between the center line of the input channel 21 and the center line of the second output channel 32 .

[0029] Furthermore, the preset temperature of the target medium outputted by the first output channel 31 and the preset temperature of the target medium outputted by the second output channel 32 are within the same range.

[0030] By making the distance from the input channel 21 to the two output channels (the first output channel 31 and the second output channel 31) equal, the two heat exchange regions 11 obtain the same heat exchange area and flow path length, which can not only balance the fluid distribution, but also make the heat exchange effects of the heat exchange regions 11 on both sides consistent.

[0031] Since the target medium temperatures output by the two output channels are within the same range, the heat exchange effects of the heat exchange areas 11 on both sides are further ensured to be consistent.

[0032] The target medium may be a lubricating oil. The working medium may be ambient air. More specifically, the target medium may be a lubricating oil in a wind turbine gearbox.

[0033] In the plate-fin heat exchanger of the above embodiment, by dividing the core 1 into two heat exchange areas 11, the flow path of the target medium is shortened, thereby reducing the flow resistance of the target medium during the heat exchange process; since the target medium is distributed to the two heat exchange areas 11, the heat exchange effect can be guaranteed, and the uneven heat exchange problem caused by the long flow distance of the target medium in the core 1 is avoided.

[0034] The lubrication and cooling system of the wind turbine gearbox of the present invention comprises a lubricating oil cooling device, wherein the lubricating oil cooling device adopts the plate-fin heat exchanger of the above embodiment.

[0035] In one embodiment, the wind turbine gearbox lubrication and cooling system includes a lubricating oil circulation loop and a lubricating oil flow control device (for example, a temperature control valve in the patent document of the applicant with publication number CN209540464U) and the lubricating oil cooling device arranged on the lubricating oil circulation loop, wherein the lubricating oil flow control device adaptively adjusts the flow rate of the lubricating oil entering the lubricating oil cooling device according to the change of the viscosity of the lubricating oil with the temperature.

[0036] The wind turbine gearbox lubrication and cooling system of the above-mentioned embodiment can reduce the sudden change of lubricating oil flow resistance in the wind turbine gearbox lubrication and cooling system, reduce the risk of lubricating oil pressure fluctuation, help maintain a stable lubricating oil circulation, and improve the reliability of the wind turbine gearbox lubrication and cooling system in low temperature environment.

[0037] The actual verification of the wind turbine gearbox lubrication and cooling system of the above embodiment shows that when operating in a low temperature environment (below -10°C), the flow resistance of the lubricating oil inside the plate-fin heat exchanger is significantly reduced, which greatly improves the gearbox overheating problem. At the same time, when operating in a higher ambient temperature (summer temperature), the plate-fin heat exchanger can also fully ensure the cooling effect of the lubricating oil.

[0038] The above is a description of the relevant contents of the present invention. A person skilled in the art will be able to implement the present invention based on these descriptions. Based on the above contents of this specification, all other embodiments obtained by a person skilled in the art without making any creative work shall fall within the scope of patent protection.

Claims

1. Plate-fin heat exchanger, including: The core is used to realize heat exchange between the target medium and the working medium so that the target medium reaches a preset temperature. The target medium is the temperature control object of the heat exchange and its viscosity gradually increases as the heat exchange process proceeds; A target medium input part, connected to the core and used to transport the target medium to be heat exchanged to the target medium inlet end of the core; A target medium output part, connected to the core and used to output the target medium that has undergone heat exchange at the target medium outlet end of the core; Features: The target medium input part comprises an input channel disposed inside the core, the input channel divides the core into two heat exchange areas located on both sides of the input channel, and the input channel is simultaneously connected to the target medium inlet end of each heat exchange area of ​​the two heat exchange areas; The target medium output portion comprises a first output channel and a second output channel distributed at the edge of the core, and the first output channel and the second output channel are respectively connected to the target medium outlet end of each of the two heat exchange areas.

2. The plate-fin heat exchanger according to claim 1, characterized in that: The first output channel and the second output channel are arranged in parallel with the input channel and distributed on both sides of the input channel. The input channel is arranged perpendicular to the target medium flow channel in each of the two heat exchange areas.

3. The plate-fin heat exchanger according to claim 2, characterized in that: A distance between a center line of the input channel and a center line of the first output channel is equal to a distance between a center line of the input channel and a center line of the second output channel.

4. The plate-fin heat exchanger according to claim 2, characterized in that: A preset temperature of the target medium outputted by the first output channel is within the same range as a preset temperature of the target medium outputted by the second output channel.

5. The plate-fin heat exchanger according to claim 1, characterized in that: The target medium is a lubricating oil.

6. The plate-fin heat exchanger according to claim 5, characterized in that: The target medium is wind turbine gearbox lubricating oil.

7. The plate-fin heat exchanger according to any one of claims 1 to 6, characterized in that: The working medium is ambient air.

8. The plate-fin heat exchanger according to any one of claims 1 to 6, characterized in that: The target medium flow channel and the working medium flow channel in the core are both formed by corrugated fins placed between adjacent partitions.

9. Wind turbine gearbox lubrication and cooling system, including lubricating oil cooling device, characterized in that: The lubricating oil cooling device adopts the plate-fin heat exchanger as described in any one of claims 1 to 9.

10. The wind turbine gearbox lubrication and cooling system according to claim 9, characterized in that: It comprises a lubricating oil circulation loop, a lubricating oil flow path control device and a lubricating oil cooling device arranged on the lubricating oil circulation loop. The lubricating oil flow path control device adaptively adjusts the flow of the lubricating oil entering the lubricating oil cooling device according to the change of the viscosity of the lubricating oil with the temperature.

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