Plate-fin heat exchanger and lubrication and cooling system for wind turbine gearbox

Abstract

The present invention discloses a plate-fin heat exchanger and a lubricating and cooling system for a wind turbine gearbox, aiming 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 during the heat exchange process. It includes: a core, a target medium input part, and a target medium output part; the target medium input part includes an input channel disposed inside the core, and the input channel divides the core into two heat exchange regions located on both sides of the input channel respectively, and the input channel is simultaneously communicated with the target medium inlet ends of each heat exchange region in the two heat exchange regions; the target medium output part includes 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 communicated with the target medium outlet ends of each heat exchange region in the two heat exchange regions. By dividing the core into two heat exchange regions, the flow path of the target medium is shortened, thereby reducing the flow resistance of the target medium during the heat exchange process.

Description

Technical Field

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

[0002] A plate fin heat exchanger (PFHE) is composed of several heat exchange units arranged in a layered manner. These heat exchange units have corrugated fins placed between adjacent partition plates. The shape and structure of the corrugated fins are similar to corrugated paper, with alternately arranged peak portions and valley portions formed thereon. Side walls are formed between adjacent peak portions and valley portions, and on both sides of each side wall are medium channels for the target medium or the working medium to flow. The target medium refers to the temperature-controlled object that exchanges heat through the plate fin heat exchanger; while the working medium is the heat exchange medium that exchanges heat with the target medium. Figure 3 It is a schematic diagram of the heat exchange principle of the plate fin heat exchanger. Taking Figure 3 as an example: Figure 3 The solid arrows in it represent the flow direction of the target medium, and the hollow arrows represent the flow direction of the working medium. Among them, the target medium passes through the medium channel (target medium flow channel) between two adjacent partition plates in the middle, while the working medium passes through the medium channels (working medium flow channels) between adjacent partition plates on both sides of the target medium flow channel respectively.

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

[0004] Figure 1 It is a schematic diagram of the structure of the plate fin heat exchanger in the existing lubricating and cooling system of a wind turbine gearbox. As Figure 1As shown, the plate-fin heat exchanger specifically includes: a core part 1, a target medium input part 2, and a target medium output part 3. The core part 1 (the working principle is as Figure 3 shown) is used to realize the 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 part 1 (specifically arranged at one side edge of the core part 1) and is used to convey the target medium to be heat-exchanged to the target medium inlet end of the core part 1; the target medium output part 3 (specifically arranged at the other side edge of the core part 1) is connected to the core part 1 and is used to output the heat-exchanged target medium at the target medium outlet end of the core part 1. Figure 1 The shown plate-fin heat exchanger adopts a one-in-one-out design, and the flow distance of the target medium in the core part 1 is long. Figure 2 For Figure 1 the temperature gradient diagram of the target medium in the shown plate-fin heat exchanger (red represents the high-temperature target medium, and yellow represents the low-temperature target medium). As Figure 2 shown, the target medium to be heat-exchanged (represented in red) enters each small flow channel in the target medium flow channel from the target medium inlet end of the core part 1 through the distribution of the target medium input part 2, and then the temperature gradually decreases during the process of flowing towards the target medium output part 3.

[0005] According to the heat dissipation principle of the plate-fin heat exchanger, the lower the ambient temperature, the better the cooling effect of the plate-fin heat exchanger on the lubricating oil (according to the heat exchange balance formula, the ambient temperature has the most obvious influence 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 lubricating and cooling system of the wind turbine gearbox operates at a very low ambient temperature, the gearbox will alarm or even shut down due to overheating, resulting in the wind turbine generating set being unable to generate electricity normally and causing economic losses. The inventor analyzed and found that the reason for this problem is that when the ambient temperature is low (generally below -10°C), if the lubricating oil reaches the second set temperature (such as 60°C), the lubricating oil flow path control device in the lubricating and cooling system of the wind turbine gearbox will close the bypass of the lubricating oil cooling device, making the lubricating oil flow in the lubricating oil cooling device the largest. Since the external ambient temperature is very low, the temperature of the lubricating oil inside the plate-fin heat exchanger is instantly cooled to a very low level (generally below 35°C). At this time, the flow resistance of the lubricating oil inside the plate-fin heat exchanger suddenly increases, causing the lubricating oil operating pressure in the lubricating oil circulation loop to rise and exceed the opening force of the lubricating oil overflow valve (such as 12 bar). Then, the lubricating oil will directly flow back to the gearbox oil sump through the overflow pipeline, and each lubrication point of the gearbox cannot be lubricated and cooled by the lubricating oil, resulting in the overheating of the gearbox. Summary of the Invention

[0006] The object of the present invention is to provide an improved plate-fin heat exchanger and a lubricating and cooling system for a wind turbine gearbox, so as 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 during the heat exchange process.

[0007] In a first aspect, a plate-fin heat exchanger is provided, including: a core for realizing heat exchange between a target medium and a working medium so that the target medium reaches a preset temperature, the target medium being the temperature-controlled object of the heat exchange and its viscosity gradually increasing during the heat exchange process; a target medium input part connected to the core and used to convey 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 heat-exchanged target medium at the target medium outlet end of the core; the target medium input part includes an input channel disposed inside the core, the input channel separating the core into two heat exchange areas located on both sides of the input channel respectively, and the input channel being simultaneously communicated with the target medium inlet ends of each heat exchange area in the two heat exchange areas; the target medium output part includes a first output channel and a second output channel distributed at the edge of the core, the first output channel and the second output channel being respectively communicated with the target medium outlet ends of each heat exchange area in the two heat exchange areas.

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

[0009] The beneficial effects of the above plate-fin heat exchanger and the lubricating and cooling system for a wind turbine gearbox are as follows: 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 ensured, and the problem of uneven heat exchange caused by the long flow distance of the target medium in the core is avoided; 3) The sudden change of the flow resistance of the lubricating oil in the lubricating and cooling system for a wind turbine gearbox is reduced, the risk of lubricating oil pressure fluctuation is lowered, and it is helpful to maintain a stable lubricating oil circulation; 4) The reliability of the lubricating and cooling system for a wind turbine gearbox in a low-temperature environment is improved.

[0010] The following further describes the present invention in conjunction with the drawings and specific embodiments. The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through practice. Description of the Drawings

[0011] The accompanying drawings forming a part of this specification are used to assist in the understanding of the present invention. The content provided in the accompanying drawings and the related descriptions in this specification can be used to explain the present invention, but do not constitute an improper limitation of the present invention.

[0012] Figure 1 It is a schematic structural diagram of a plate-fin heat exchanger in an existing lubrication and cooling system for a wind turbine gearbox.

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

[0014] Figure 3 It is a schematic diagram of the heat exchange principle of the plate-fin heat exchanger.

[0015] Figure 4 It is a schematic structural diagram of a plate-fin heat exchanger according to an embodiment of the present invention. Detailed implementation manners

[0016] The present invention will be described clearly and completely below with reference to the accompanying drawings. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the accompanying drawings, it should be particularly noted that:

[0017] The technical solutions and technical features provided in each part 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 given specific technical themes and be protected by relevant patents.

[0018] The embodiments of the present invention involved in the following description are usually only some embodiments rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on these embodiments should fall within the scope of patent protection.

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

[0020] Figure 1 It is a schematic structural diagram of a plate-fin heat exchanger in an existing lubrication and cooling system for a wind turbine gearbox. As Figure 1As shown in the figure, the plate-fin heat exchanger specifically includes: a core part 1, a target medium input part 2, and a target medium output part 3. The core part 1 is used to achieve 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 part 1 (specifically arranged at one side edge of the core part 1) and is used to convey the target medium to be heat-exchanged to the target medium inlet end of the core part 1; the target medium output part 3 (specifically arranged at the other side edge of the core part 1) is connected to the core part 1 and is used to output the heat-exchanged target medium at the target medium outlet end of the core part 1. Figure 1 The shown plate-fin heat exchanger adopts a one-in-one-out design, and the flow distance of the target medium in the core part 1 is long. Figure 2 For Figure 1 The temperature gradient diagram of the target medium in the shown plate-fin heat exchanger (red represents the high-temperature target medium, and yellow represents the low-temperature target medium). As Figure 2 shown, the target medium to be heat-exchanged (represented in red) enters each small flow channel in the target medium flow channel from the target medium inlet end of the core part 1 through the distribution of the target medium input part 2, and then the temperature gradually decreases during the process of flowing towards the target medium output part 3.

[0021] According to the heat dissipation principle of the plate-fin heat exchanger, the lower the ambient temperature, the better the cooling effect of the plate-fin heat exchanger on the lubricating oil (it can be known from the heat exchange balance formula that the ambient temperature has the most obvious influence 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 lubricating and cooling system of the wind turbine gearbox operates under very low ambient temperature conditions, the gearbox will alarm or even shut down due to overheating, resulting in the wind turbine unit being unable to generate electricity normally and causing economic losses. The inventor analyzed and found that the reason for this problem is that when the ambient temperature is low (generally below -10°C), if the lubricating oil reaches the second set temperature (such as 60°C), the lubricating oil flow path control device in the lubricating and cooling system of the wind turbine gearbox will close the bypass of the lubricating oil cooling device (reference can be made to the patent document of the applicant with the publication number CN209540464U), so that the lubricating oil flow in the lubricating oil cooling device is the largest. Due to the very low external ambient temperature, the temperature of the lubricating oil inside the plate-fin heat exchanger is instantly cooled to a very low level (generally below 35°C). At this time, the flow resistance of the lubricating oil inside the plate-fin heat exchanger suddenly increases, causing the operating pressure of the lubricating oil in the lubricating oil circulation circuit to rise and exceed the opening force of the lubricating oil overflow valve (the current opening force of the overflow valve is set to 12 bar). Then, the lubricating oil will directly flow back to the gearbox oil sump through the overflow pipeline, and each lubrication point of the gearbox cannot 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 lubricating and cooling system for a wind turbine gearbox 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 as the heat exchange process progresses.

[0023] Figure 4 It is a schematic structural diagram of a plate-fin heat exchanger according to an embodiment of the present invention. As Figure 4 shown, a plate-fin heat exchanger includes: a core 1 for realizing heat exchange between a target medium and a working medium so that the target medium reaches a preset temperature, the target medium being the temperature-controlled object of the heat exchange and its viscosity gradually increasing as the heat exchange process progresses; a target medium input part 2 connected to the core and used to convey the target medium to be heat-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 heat-exchanged target medium at the target medium outlet end of the core; wherein, the target medium input part 2 includes an input channel 21 disposed inside the core, the input channel 21 divides the core 1 into two heat exchange regions 11 located on both sides of the input channel, and the input channel 21 is simultaneously communicated with the target medium inlet ends of each heat exchange region 11 in the two heat exchange regions 11; and, the target medium output part 3 includes a first output channel 31 and a second output channel 32 distributed at the edge of the core 1, and the first output channel 31 and the second output channel 32 are respectively communicated with the target medium outlet ends of each heat exchange region 11 in the two heat exchange regions 11.

[0024] The working principle of the above core 1 is as Figure 3 shown. Figure 3 The solid arrows in indicate the flow direction of the target medium, that is, flowing through the target medium flow channel; the hollow arrows indicate the flow direction of the working medium, that is, flowing through the working medium flow channel. The usual way is that: the target medium flow channel and the working medium flow channel in the core 1 are both composed of corrugated fins disposed between adjacent partition plates.

[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 flow disturbance 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 channels in each heat exchange region 11 of the two heat exchange regions 11.

[0027] By vertically arranging the input channel 21 with respect to the target medium flow channels in each heat exchange area 11, and making both 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, it is possible to evenly distribute the flow rate, shorten the flow path, improve the heat exchange efficiency, reduce the pressure loss, and at the same time maintain the structural symmetry.

[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] Moreover, the preset temperature of the target medium output from the first output channel 31 and the preset temperature of the target medium output from the second output channel 32 are within the same range.

[0030] By making the distances 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 areas 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 areas 11 on both sides consistent.

[0031] Since the temperatures of the target medium output from the two output channels are within the same range, it further ensures that the heat exchange effects of the heat exchange areas 11 on both sides are consistent.

[0032] The target medium can be a kind of lubricating oil. The working medium can be ambient air. More specifically, the target medium can be the lubricating oil of 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 ensured, and the problem of uneven heat exchange caused by the long flow distance of the target medium in the core 1 is avoided.

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

[0035] In one implementation, the lubricating and cooling system of the wind turbine gearbox includes a lubricating oil circulation loop, a lubricating oil flow path control device (such as a temperature control valve in the patent document with the publication number CN209540464U of the applicant) provided on the lubricating oil circulation loop, and the lubricating oil cooling device, and the lubricating oil flow path 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 temperature.

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

[0037] The actual verification of the lubrication and cooling system of the wind turbine gearbox in the above embodiments 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, greatly improving the problem of overheating of the gearbox. At the same time, when operating in a relatively high ambient temperature (summer temperature), the plate-fin heat exchanger can also fully ensure the cooling effect on the lubricating oil.

[0038] The above has described the relevant content of the present invention. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Based on the above content of this specification, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of patent protection.

Claims

1. Wind turbine gearbox lubrication and cooling system, including a lubricating oil circulation circuit, and a lubricating oil flow path control device and a lubricating oil cooling device provided on the lubricating oil circulation circuit. The lubricating oil flow path 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 temperature. It is characterized in that: The lubricating oil cooling device adopts a plate-fin heat exchanger, and the plate-fin heat exchanger includes: A core part for realizing 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 progresses; A target medium input part, connected to the core part and used to transport 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; Among them, the target medium input part includes an input channel placed inside the core part. The input channel divides the core part into two heat exchange areas located on both sides of the input channel respectively. The input channel is simultaneously communicated with the target medium inlet ends of each heat exchange area in the two heat exchange areas; The target medium output part includes a first output channel and a second output channel distributed at the edge of the core part. The first output channel and the second output channel are respectively communicated with the target medium outlet ends of each heat exchange area in the two heat exchange areas; The target medium is lubricating oil, and the working medium is ambient air.

2. The lubrication and cooling system of a wind turbine gearbox 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 are distributed on both sides of the input channel. The input channel is arranged perpendicular to the target medium flow channels in each heat exchange area of the two heat exchange areas.

3. The lubricating and cooling system for a wind turbine gearbox according to claim 2, characterized in that: The distance between the center line of the input channel and the center line of the first output channel is equal to the distance between the center line of the input channel and the center line of the second output channel.

4. The lubricating and cooling system of a wind turbine gearbox according to claim 2, characterized in that: The preset temperature of the target medium output by the first output channel and the preset temperature of the target medium output by the second output channel are within the same range.

5. The lubricating and cooling system for a wind turbine gearbox according to any one of claims 1 to 4, characterized in that: The target medium flow channels and the working medium flow channels in the core part are both composed of corrugated fins placed between adjacent partitions.

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