Plate heat exchanger and generator fixed cooling water system

Abstract

The application provides a plate heat exchange device and a generator stator cooling water system. The plate heat exchange device comprises: a plate heat exchange device body; an ultrasonic transducer arranged on the outer surface of the plate heat exchange device body; a conductive liquid arranged between the ultrasonic transducer and the plate heat exchange device body, used for realizing coupling transmission of ultrasonic waves to the fluid inside the plate heat exchange device body; and a temperature monitoring mechanism used for monitoring the outlet water temperature of stator cooling water in the plate heat exchange device body and connected with the ultrasonic transducer in control. The temperature monitoring mechanism is configured to: start the ultrasonic transducer when the outlet water temperature of the stator cooling water exceeds a preset threshold range; and turn off the ultrasonic transducer when the outlet water temperature of the stator cooling water is within the preset threshold range. The device not only has a simple structure and low modification cost, but also can effectively improve the heat exchange efficiency, so as to ensure that the generator stator cooling water system can still maintain a safe and stable operation state in an extreme environment such as high temperature in summer.

Description

Technical Field

[0001] This invention belongs to the technical field of heat exchange equipment, and specifically relates to a plate heat exchanger and a generator constant cooling water system. Background Technology

[0002] The stator cooling water system of a thermal power plant generator (hereinafter referred to as the stator cooling water system) is one of the core auxiliary systems for the safe operation of the generator. Its core function is to remove the heat generated by the stator winding during the generator's rotation in a timely manner, so that the stator winding temperature is controlled within a safe range (usually not exceeding 90°C), and to avoid overheating leading to aging and damage of the winding insulation, which in turn affects the normal operation of the generator or even causes a shutdown.

[0003] In existing stator cooling water systems, heat exchange between internal cooling water (high-purity water flowing through the stator windings) and external cooling water is mainly achieved by plate heat exchangers. Plate heat exchangers are typically composed of multiple corrugated metal plates in contact with each other, with adjacent plates forming flow channels. Internal and external cooling water flow alternately within the flow channels, and heat transfer is achieved through plate conduction.

[0004] However, in hot summer weather or high-temperature indoor environments, the external cooling water temperature rises significantly, reducing the heat exchange temperature difference of the plate heat exchanger. Simultaneously, the high temperature environment exacerbates changes in fluid viscosity, reducing convective heat transfer efficiency, causing the plate heat exchanger to fail to meet expected heat exchange requirements. Insufficient heat exchange can lead to excessive stator cooling water outlet temperature, affecting the heat dissipation of the generator stator windings. Long-term operation can accelerate winding insulation aging, reduce generator lifespan, and even cause serious safety accidents such as stator winding burnout.

[0005] Currently, the main technologies for improving the heat exchange efficiency of plate heat exchangers include optimizing plate geometry parameters, adopting surface modification technology, and using passive enhancement methods such as nanofluids. However, these technologies have problems such as high difficulty in modification, high cost, limited heat exchange enhancement effect, and inapplicability to the modification of existing equipment. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a plate heat exchanger that is not only simple in structure and low in modification cost, but also can effectively improve heat exchange efficiency, thereby ensuring that the generator stator cooling water system can maintain a safe and stable operating state under extreme environments such as high temperatures in summer.

[0007] Another object of the present invention is to provide a generator constant cooling water system.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A plate heat exchanger, used in a generator stator cooling water system, includes: Plate heat exchanger body; An ultrasonic transducer is disposed on the outer surface of the plate heat exchanger body. A conductive fluid is disposed between the ultrasonic transducer and the plate heat exchanger body to achieve the coupling and transmission of ultrasonic waves to the fluid inside the plate heat exchanger body. A temperature monitoring mechanism is used to monitor the outlet temperature of the stator cooling water in the plate heat exchanger body and is connected to the ultrasonic transducer for control. The temperature monitoring mechanism is configured as follows: When the outlet temperature of the stator cooling water exceeds a preset threshold range, the ultrasonic transducer is activated. When the outlet temperature of the stator cooling water is within the preset threshold range, the ultrasonic transducer is turned off.

[0009] Optionally, the number of ultrasonic transducers is multiple, and the multiple ultrasonic transducers are symmetrically arranged on the outer surface of the plate heat exchanger body.

[0010] Optionally, the number of ultrasonic transducers is four, and the four ultrasonic transducers are symmetrically arranged on the four sides of the plate heat exchanger body.

[0011] Optionally, the conductive fluid is coated between the ultrasonic transducer and the plate heat exchanger body, and the coating thickness of the conductive fluid is 0.5 mm to 1 mm.

[0012] Optionally, a fixed bracket is also included, which is fixedly connected to the plate heat exchanger body and the ultrasonic transducer respectively.

[0013] Optionally, the fixing bracket has a conformal fitting surface that matches the shape of the outer surface of the plate heat exchanger body, and the conformal fitting surface abuts against the outer surface of the plate heat exchanger body.

[0014] Optionally, the fixing bracket is made of corrosion-resistant metal.

[0015] Optionally, the ultrasonic transducer operates at a frequency of 10kHz to 40kHz and has a power of 300W to 800W.

[0016] Optionally, a plane is provided on the outer surface of the plate heat exchanger body corresponding to the installation position of the ultrasonic transducer, and the area of ​​the plane is larger than the area of ​​the contact surface between the ultrasonic transducer and the plate heat exchanger body.

[0017] A generator constant water cooling system includes a plate heat exchanger as described in any of the above claims.

[0018] As can be seen from the above technical solution, when the plate heat exchanger is working, the heated stator cooling water enters the plate heat exchanger body for heat exchange. At the same time, the ultrasonic transducer set on the outer surface of the plate heat exchanger body couples high-frequency mechanical vibration into the plate heat exchanger body through the conductive fluid. The acoustic cavitation effect and acoustic flow effect are used to destroy the thermal boundary layer on the surface of the plate heat exchanger body and enhance fluid disturbance, thereby reducing the heat transfer resistance and improving the heat exchange efficiency. During this process, the temperature monitoring mechanism 400 monitors the stator cooling water outlet temperature in real time. When the stator cooling water outlet temperature exceeds the preset threshold range, the ultrasonic transducer is automatically activated to enhance heat exchange. When the stator cooling water outlet temperature is within the preset threshold range, the ultrasonic transducer is automatically shut down. Thus, while ensuring the stable operation of the generator stator cooling water system under high temperature environment, intelligent control of energy consumption is achieved.

[0019] Compared with the prior art, the plate heat exchanger disclosed in the embodiments of the present invention has the following technical effects: 1) The ultrasonic transducer is placed outside the plate heat exchanger body, which does not require modification of the constant cooling water and external cooling water circuits, nor does it require replacement of the plates of the plate heat exchanger, which greatly reduces the amount of modification work and investment costs. (2) By actively destroying the thermal boundary layer and enhancing fluid turbulence through acoustic cavitation and acoustic flow effects, the overall heat transfer coefficient of the plate heat exchanger can be effectively improved without increasing the heat transfer area and flow rate, thus significantly alleviating the problem of constant cooling water overheating under high temperature conditions in summer. (3) By linking the temperature monitoring mechanism with the ultrasonic transducer, ineffective energy consumption can be avoided while ensuring the cooling effect, thus improving the economic efficiency of system operation; (4) High-frequency ultrasonic vibration can effectively inhibit the deposition of dirt on the plate surface of the plate heat exchanger, slow down the decline of heat exchange performance, and extend the cleaning cycle and service life of the plate heat exchanger. (5) The plate heat exchanger has a simple overall structure, strong anti-interference ability, low maintenance workload, and can operate stably in the complex industrial environment of power plants for a long time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the plate heat exchanger disclosed in the embodiments of the present invention.

[0022] Explanation of reference numerals in the attached figures: 100. Plate heat exchanger body; 200. Ultrasonic transducer; 300. Conductive fluid; 400. Temperature monitoring agencies; 500. Fixed bracket; 600. Internal cooling water inlet; 700. Internal cooling water outlet; 800. External cooling water inlet; 900. External cooling water outlet. Detailed Implementation

[0023] In view of this, the core of the present invention is to provide a plate heat exchanger that is not only simple in structure and low in modification cost, but also can effectively improve heat exchange efficiency, thereby ensuring that the generator stator cooling water system can maintain a safe and stable operating state under extreme environments such as high temperatures in summer.

[0024] Another core aspect of this invention is to provide a generator constant cooling water system.

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Please refer to Figure 1 The plate heat exchanger disclosed in this embodiment of the invention is applied to a generator stator cooling water system. It includes a plate heat exchanger body 100, an ultrasonic transducer 200, a conductive fluid 300, and a temperature monitoring mechanism 400. The ultrasonic transducer 200 is disposed on the outer surface of the plate heat exchanger body 100. The conductive fluid 300 is disposed between the ultrasonic transducer 200 and the plate heat exchanger body 100 to achieve coupling and transmission of ultrasonic waves to the fluid inside the plate heat exchanger body 100. The temperature monitoring mechanism 400 monitors the outlet temperature of the stator cooling water in the plate heat exchanger body 100 and is connected to the ultrasonic transducer 200 for control. The temperature monitoring mechanism 400 is configured to: activate the ultrasonic transducer 200 when the outlet temperature of the stator cooling water exceeds a preset threshold range; and deactivate the ultrasonic transducer 200 when the outlet temperature of the stator cooling water is within the preset threshold range.

[0027] When the plate heat exchanger is in operation, the heated stator cooling water enters the plate heat exchanger body 100 for heat exchange. At the same time, the ultrasonic transducer 200, which is set on the outer surface of the plate heat exchanger body 100, couples high-frequency mechanical vibration into the plate heat exchanger body 100 through the conductive fluid 300. It uses the acoustic cavitation effect and acoustic flow effect to break the thermal boundary layer on the surface of the plate heat exchanger body 100 and enhance fluid turbulence, thereby reducing the heat transfer resistance and improving the heat exchange efficiency. During this process, the temperature monitoring mechanism 400 monitors the outlet temperature of the stator cooling water in real time. When the outlet temperature of the stator cooling water exceeds the preset threshold range, the ultrasonic transducer 200 is automatically activated to enhance heat exchange. When the outlet temperature of the stator cooling water is within the preset threshold range, the ultrasonic transducer 200 is automatically shut down. This ensures the stable operation of the generator stator cooling water system under high temperature environment and realizes intelligent control of energy consumption.

[0028] Compared with the prior art, the plate heat exchanger disclosed in the embodiments of the present invention has the following technical effects: 1) The ultrasonic transducer 200 is externally placed on the plate heat exchanger body 100, which does not require modification of the constant cooling water and external cooling water circuits, nor does it require replacement of the plates of the plate heat exchanger, greatly reducing the amount of modification work and investment costs. (2) By actively destroying the thermal boundary layer and enhancing fluid turbulence through acoustic cavitation and acoustic flow effects, the overall heat transfer coefficient of the plate heat exchanger can be effectively improved without increasing the heat transfer area and flow rate, thus significantly alleviating the problem of constant cooling water overheating under high temperature conditions in summer. (3) By linking the temperature monitoring mechanism 400 with the ultrasonic transducer 200, the system avoids ineffective energy consumption while ensuring the cooling effect, thus improving the economic efficiency of system operation. (4) High-frequency ultrasonic vibration can effectively inhibit the deposition of dirt on the plate surface of the plate heat exchanger, slow down the decline of heat exchange performance, and extend the cleaning cycle and service life of the plate heat exchanger. (5) The plate heat exchanger has a simple overall structure, strong anti-interference ability, low maintenance workload, and can operate stably in the complex industrial environment of power plants for a long time.

[0029] It is understood that the plate heat exchanger disclosed in the embodiments of the present invention also includes a controller, wherein the controller can be set separately and connected to the temperature monitoring mechanism 400 for control, or it can be integrated into the temperature monitoring mechanism 400.

[0030] The temperature monitoring unit 400 is preferably located at the internal cooling water outlet 700.

[0031] It should be noted that the plate heat exchanger body 100 used in this embodiment is equipped with an internal cooling water inlet 600, an internal cooling water outlet 700, an external cooling water inlet 800, and an external cooling water outlet 900.

[0032] The internal cooling water flows into the plate heat exchanger body 100 through the internal cooling water inlet 600, absorbs the heat from the generator stator winding, and then returns to the generator through the internal cooling water outlet 700. The external cooling water enters through the external cooling water inlet 800 and is arranged in a counter-current or cross-flow manner with the internal cooling water channel. After completing the heat exchange, it is discharged through the external cooling water outlet 900.

[0033] As a further embodiment, the plate heat exchanger disclosed in this embodiment of the invention has a plurality of ultrasonic transducers 200, and the plurality of ultrasonic transducers 200 are symmetrically arranged on the outer surface of the plate heat exchanger body 100.

[0034] This configuration eliminates the vibration blind zone caused by single-point excitation through multi-point coordinated vibration, allowing ultrasonic energy to be more evenly distributed in the internal flow channels of the plate heat exchanger body 100. This enhances the fluid disturbance and thermal boundary layer disruption effect across the entire range, avoiding insufficient local heat exchange efficiency. At the same time, the symmetrical mechanical structure helps to balance the vibration modes of the plate heat exchanger body 100, improving overall heat exchange performance while preventing equipment fatigue damage caused by local stress concentration.

[0035] As a specific embodiment of the present invention, the number of ultrasonic transducers 200 disclosed in this embodiment is four, and the four ultrasonic transducers 200 are symmetrically arranged on the four sides of the plate heat exchanger body 100. This arrangement forms a full-circumferential three-dimensional ultrasonic field, allowing vibration energy to penetrate uniformly along the main heat transfer direction of the plates of the plate heat exchanger body 100, maximizing the coverage of the heat exchange area and avoiding the problem of insufficient heat transfer enhancement in the far-end flow channel caused by a single-sided arrangement. Simultaneously, the symmetrical layout of the four sides effectively matches the geometry of the plate heat exchanger body 100, enabling standardized installation without additional machining of the plate heat exchanger body 100. This ensures optimal descaling and enhanced heat transfer effects while also considering structural compactness and ease of construction.

[0036] As a further embodiment, the conductive liquid 300 disclosed in this embodiment of the invention is coated between the ultrasonic transducer 200 and the plate heat exchanger body 100, and the coating thickness of the conductive liquid 300 is 0.5 mm to 1 mm. For example, the coating thickness of the conductive liquid 300 can be specifically 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm or 1 mm.

[0037] If the coating thickness of the conductive fluid 300 is too small, it will be difficult to fully fill the microscopic unevenness and machining tolerance gaps between the ultrasonic transducer 200 and the outer surface of the plate heat exchanger body 100, which will easily result in local uncovering or air residue, causing strong reflection or even complete blockage of ultrasonic waves at the interface, reducing the transmission efficiency of ultrasonic energy to the interior of the plate heat exchanger body 100. At the same time, it is prone to drying and decoupling during long-term operation, affecting the sustainability of enhanced heat exchange and anti-scaling effects. If the coating thickness of the conductive fluid 300 is too large, the coupling medium layer itself will significantly attenuate the high-frequency ultrasonic waves, thereby reducing the actual vibration amplitude obtained on the plate surface of the plate heat exchanger body 100, and thus weakening the destructive ability of acoustic cavitation and acoustic flow effects on the thermal boundary layer. The coating thickness setting of the conductive fluid 300 disclosed in the embodiments of the present invention can ensure that the microscopic gaps are fully filled and the air is removed, while minimizing ultrasonic attenuation, and taking into account both acoustic energy transmission efficiency and long-term operational stability.

[0038] As a further embodiment, the plate heat exchanger disclosed in this invention also includes a fixed bracket 500, which is fixedly connected to both the plate heat exchanger body 100 and the ultrasonic transducer 200. By setting the fixed bracket 500, the ultrasonic transducer 200 can be firmly locked in a predetermined installation position, effectively resisting mechanical vibration and fluid impact during generator operation, preventing the transducer from shifting, tilting, or falling off due to long-term vibration, thereby avoiding acoustic coupling failure. Simultaneously, the fixed connection ensures a constant contact pressure between the ultrasonic transducer 200 and the outer surface of the plate heat exchanger body 100, ensuring a uniform and uninterrupted thickness of the conductive fluid layer 300, thus maintaining the stability and efficiency of the ultrasonic transmission path, effectively improving the reliability and service life of the plate heat exchanger.

[0039] As a further embodiment, the fixed bracket 500 disclosed in the present invention has a conforming fitting surface that matches the shape of the outer surface of the plate heat exchanger body 100, and the conforming fitting surface abuts against the outer surface of the plate heat exchanger body 100.

[0040] This design allows for a large-area contact between the conformal fitting surface and the outer surface of the plate heat exchanger body 100. Compared to traditional point or line contact fixing methods, this significantly increases the contact area and friction between the fixing bracket 500 and the plate heat exchanger body 100. This effectively suppresses the swaying and displacement of the bracket when the generator set experiences severe vibration, preventing deformation and misalignment of the plate heat exchanger body 100's outer shell due to localized stress concentration. Simultaneously, the conformal fitting surface ensures that the clamping force of the fixing bracket 500 on the ultrasonic transducer 200 is uniformly transmitted perpendicularly to the outer surface of the plate heat exchanger body 100, preventing the ultrasonic transducer 200 from tilting or warping due to uneven force. This ensures that the thickness of the conductive fluid layer 300 remains consistent, thereby guaranteeing the efficient and uniform transmission of ultrasonic energy.

[0041] As a further embodiment, the fixed bracket 500 disclosed in this embodiment of the invention is made of corrosion-resistant metal. This design allows the fixed bracket 500 to withstand the relatively humid operating environment and potential corrosive media present in the generator stator chiller room, preventing a decrease in clamping force or breakage due to corrosion of the fixed bracket 500. Simultaneously, the metal material has high rigidity and strength, maintaining shape stability and clamping force under long-term thermal cycling and vibration conditions, preventing decoupling of the ultrasonic transducer 200 due to bracket creep or loosening, thereby extending the service life of the entire plate heat exchanger and its associated fixed components, and reducing the frequency of maintenance and replacement.

[0042] As a further embodiment, the plate heat exchanger disclosed in this embodiment of the invention has an ultrasonic transducer 200 with a working frequency of 10kHz to 40kHz and a power of 300W to 800W.

[0043] This configuration, by limiting the operating frequency of the ultrasonic transducer 200 to 10kHz–40kHz and the power to 300W–800W, achieves an optimal balance between enhanced heat exchange and energy consumption. If the frequency is too low, it can easily cause strong noise and mechanical resonance, affecting the safety of surrounding instruments and equipment; if the frequency is too high, it weakens the acoustic cavitation and acoustic flow effects, making it difficult to effectively disrupt the thermal boundary layer. The frequency band and power range settings disclosed in this embodiment of the invention ensure that sufficient acoustic energy penetrates the plates of the heat exchanger body 100 and acts on the fluid, achieving significant enhanced heat exchange and anti-scaling effects, while keeping energy consumption and noise within an acceptable engineering range, thereby ensuring the long-term stable operation of the generator's stator cooling water system.

[0044] As a further embodiment, the outer surface of the plate heat exchanger body 100 disclosed in this embodiment of the invention is provided with a plane corresponding to the installation position of the ultrasonic transducer 200, and the area of ​​the plane is greater than the area of ​​the contact surface between the ultrasonic transducer 200 and the plate heat exchanger body 100.

[0045] This design eliminates the adverse effects of the original reinforcing ribs, rounded corners, or corrugations on the outer shell of the plate heat exchanger body 100 on the fit of the ultrasonic transducer 200, allowing the ultrasonic transducer 200 to be completely placed in a flat area. This ensures uniform coating of the conductive fluid 300 layer and surface contact between the ultrasonic transducer 200 and the plates of the plate heat exchanger body 100, avoiding poor acoustic coupling or vibration stress concentration caused by local suspension, thereby improving ultrasonic transmission efficiency and long-term operational reliability.

[0046] This invention also discloses a generator constant water cooling system, including a plate heat exchanger as disclosed in any of the above embodiments.

[0047] Since the generator constant water cooling system adopts the plate heat exchanger disclosed in the embodiments of the present invention, the generator constant water cooling system also has the technical advantages of the plate heat exchanger disclosed in the embodiments of the present invention, and the embodiments of the present invention will not elaborate on them one by one.

[0048] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0050] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A plate heat exchanger, applied to a generator constant cooling water system, characterized in that, include: Plate heat exchanger body (100); An ultrasonic transducer (200) is disposed on the outer surface of the plate heat exchanger body (100). A conductive fluid (300) is disposed between the ultrasonic transducer (200) and the plate heat exchanger body (100) to realize the coupling and transmission of ultrasonic waves to the fluid inside the plate heat exchanger body (100). Temperature monitoring mechanism (400) is used to monitor the outlet temperature of stator cooling water in the plate heat exchanger body (100) and is connected to the ultrasonic transducer (200) for control. The temperature monitoring mechanism (400) is configured as follows: When the outlet temperature of the stator cooling water exceeds the preset threshold range, the ultrasonic transducer (200) is activated. When the outlet temperature of the stator cooling water is within the preset threshold range, the ultrasonic transducer (200) is turned off.

2. The plate heat exchanger according to claim 1, characterized in that, The number of ultrasonic transducers (200) is multiple, and the multiple ultrasonic transducers (200) are symmetrically arranged on the outer surface of the plate heat exchanger body (100).

3. The plate heat exchanger according to claim 2, characterized in that, The number of ultrasonic transducers (200) is four, and the four ultrasonic transducers (200) are symmetrically arranged on the four sides of the plate heat exchanger body (100).

4. The plate heat exchanger according to claim 1, characterized in that, The conductive fluid (300) is coated between the ultrasonic transducer (200) and the plate heat exchanger body (100), and the coating thickness of the conductive fluid (300) is 0.5 mm to 1 mm.

5. The plate heat exchanger according to claim 1, characterized in that, It also includes a fixed bracket (500), which is fixedly connected to the plate heat exchanger body (100) and the ultrasonic transducer (200) respectively.

6. The plate heat exchanger according to claim 5, characterized in that, The fixed bracket (500) has a conformal fitting surface that matches the shape of the outer surface of the plate heat exchanger body (100), and the conformal fitting surface abuts against the outer surface of the plate heat exchanger body (100).

7. The plate heat exchanger according to claim 5, characterized in that, The fixed bracket (500) is made of corrosion-resistant metal.

8. The plate heat exchanger according to claim 1, characterized in that, The ultrasonic transducer (200) operates at a frequency of 10kHz to 40kHz and has a power of 300W to 800W.

9. The plate heat exchanger according to claim 1, characterized in that, The outer surface of the plate heat exchanger body (100) is provided with a plane corresponding to the installation position of the ultrasonic transducer (200), and the area of ​​the plane is greater than the area of ​​the contact surface between the ultrasonic transducer (200) and the plate heat exchanger body (100).

10. A generator constant water cooling system, characterized in that, Includes the plate heat exchanger as described in any one of claims 1-9.

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