Design method of cooling tower air separation device, cooling tower air separation device and cooling tower

Abstract

The application discloses a design method of a cooling tower air separation device, the cooling tower air separation device and the cooling tower, and relates to the technical field of cooling towers. The design method comprises the following steps: determining the configuration scale of a cooling tower body; determining the spacing between an air separation plate and a cooling tower shaft well, the air separation plate being arranged in an air inlet area inside the cooling tower body; determining the spacing according to the natural wind speed, the dominant wind direction and the configuration scale of the cooling tower body, and optimizing the spacing according to the packing stability under the natural wind; and determining the spacing between the air separation plates according to the wind load force distribution of the air separation plate, so as to arrange a support structure between the air separation plates, under the optimized spacing between the air separation plate and the cooling tower shaft well. The natural wind in the air inlet area is redistributed by arranging non-continuous air separation plates in the air inlet area, the air flow field state of the air inlet area is adjusted, the resistance of the natural wind passing through the air inlet area is increased, the draught is avoided, the flow field distribution of the packing area under the natural wind is more uniform, and the influence of the natural wind on the thermal performance of the cooling tower is reduced.

Description

Technical Field

[0001] This invention relates to the field of cooling tower technology, and in particular to a design method for a cooling tower windbreak device, a cooling tower windbreak device, and a cooling tower. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] Counterflow natural draft cooling towers are cold-end equipment widely used in thermal power generation, nuclear power, metallurgy, and chemical industries. However, the cooling effect of the cooling tower will be reduced under the action of natural wind. This is mainly because it changes the flow field distribution in the air inlet area, forming a through wind and negative pressure in the air inlet area, which leads to a reduction in the cooling tower's ventilation volume. Furthermore, the air inlet area will experience uneven increase under natural wind.

[0004] In existing solutions, the engineering measure of cross-shaped partition walls is applied to reduce the impact of natural wind on the thermal performance of cooling towers. The cross-shaped partition wall solution is essentially a method of blocking cross wind by arranging vertical partition walls in the rain zone of the cooling tower, which divides the rain zone into multiple zones.

[0005] However, since the partition wall under this scheme is located inside the tower, it is always exposed to rain, which is not conducive to construction and maintenance, and also puts a certain load on the tower body and internal structure.

[0006] Moreover, when natural wind arrives, the airflow will rapidly accumulate in the enclosed area formed by the cross-shaped partition wall and the vertical shaft, causing the pressure at the bottom of the packing to increase rapidly and overturn the cooling tower packing. This is especially true during shutdown maintenance or construction, when the packing area is no longer under the downward pressure of the water spray from above, making it more prone to overturning the packing.

[0007] In addition, the enclosed area formed by the cross-shaped partition wall and the vertical shaft amplifies the uneven distribution of the flow field inside the tower under natural wind, resulting in large temperature differences in different areas, especially increasing the risk of freezing during winter operation.

[0008] Furthermore, the traditional cross-shaped partition wall layout completely blocks the natural ventilation channel, resulting in excessive wind pressure load on the windbreak panels and an exponential increase in the installation cost of the cross-shaped partition wall. Summary of the Invention

[0009] To address the aforementioned issues, this invention proposes a design method for a cooling tower wind baffle, a cooling tower wind baffle, and a cooling tower. By installing discontinuous wind baffles in the air inlet area, the natural air in the air inlet area is redistributed, the airflow field state in the air inlet area is adjusted, the resistance of natural air passing through the air inlet area is increased, through drafts are avoided, the flow field distribution in the packing area under natural air is made more uniform, and the impact of natural air on the thermal performance of the cooling tower is reduced.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a design method for a cooling tower windbreak device, comprising:

[0012] Determine the configuration and scale of the cooling tower body;

[0013] The distance between the baffle plate and the cooling tower shaft is determined. The baffle plate is located in the air inlet area inside the cooling tower body. The distance is determined according to the natural wind speed, the prevailing wind direction and the configuration scale of the cooling tower body. The distance is optimized according to the stability of the packing under natural wind.

[0014] After optimizing the spacing between the baffle plate and the cooling tower shaft, the spacing between the baffle plates is determined based on the wind load distribution of the baffle plates, so as to set up a support structure between the baffle plates.

[0015] As an alternative implementation method, the process of determining the distance between the baffle plate and the cooling tower shaft includes:

[0016] Assuming the windbreak panels are arranged continuously;

[0017] The distance between the baffle plate and the cooling tower shaft is preset. At this distance, the stability of the packing is determined by numerical simulation calculation based on the natural wind speed, the prevailing summer wind direction and the configuration scale of the cooling tower body. The distance between the baffle plate and the cooling tower shaft is reduced or increased based on the judgment result.

[0018] As an alternative implementation, if the packing is stable at the current distance between the baffle plate and the cooling tower shaft, the distance between the baffle plate and the cooling tower shaft is reduced, and the numerical simulation calculation is repeated until the packing stability judgment result is reversed.

[0019] If the packing is unstable at the current distance between the baffle plate and the cooling tower shaft, increase the distance between the baffle plate and the cooling tower shaft, and repeat the numerical simulation calculation until the packing stability judgment result is reversed.

[0020] The spacing before the reversal is taken as the final determined spacing between the baffle plate and the cooling tower shaft.

[0021] As an alternative implementation, the height of the baffle plate extends to the top of the cooling tower water distribution tank.

[0022] As an alternative implementation, the process of determining the spacing between windbreaks includes:

[0023] After optimizing the distance between the baffle plate and the cooling tower shaft, the wind pressure on the surface of the baffle plate is obtained through numerical simulation based on the natural wind speed, the prevailing summer wind direction, and the configuration scale of the cooling tower body. The wind load force acting on the baffle plate is obtained based on the wind pressure and the windward area of ​​the baffle plate. The distance between the baffle plates is obtained based on the location of the wind load force and the magnitude of the force.

[0024] As an alternative implementation, the width of the support structure is equal to the distance between the windbreaks.

[0025] As an alternative implementation, a ventilation channel is provided between the baffle plate and the cooling tower shaft.

[0026] As an alternative implementation, the design method of the cooling tower windbreak device further includes adjusting the configuration scale of the cooling tower body according to the design of the windbreak plate and the supporting structure; specifically including:

[0027] Based on the installation positions of the baffle plates and supporting structures, the distance between the baffle plates and the cooling tower shaft, and the distance between the baffle plates, the cooling tower outlet water temperature under a given wind speed and prevailing wind direction is obtained through numerical simulation calculation.

[0028] Based on a given wind speed and its corresponding cooling tower outlet water temperature, an empirical formula is obtained through fitting.

[0029] Based on empirical formulas and any wind speed, the approximate outlet water temperature at any wind speed is obtained.

[0030] A preset water temperature threshold is used to determine whether the approximate outlet water temperature meets the threshold requirement at any wind speed, thereby adjusting the configuration scale of the cooling tower.

[0031] In a second aspect, the present invention provides a cooling tower windbreak device, comprising: a windbreak plate and a support structure disposed between the windbreak plates; the windbreak plate is disposed in the air inlet area inside the cooling tower body, and the windbreak plates are arranged radially outward from the outer wall of the central vertical shaft inside the cooling tower, wherein the distance between the windbreak plate and the vertical shaft of the cooling tower, and the distance between the windbreak plates are determined by the design method described in the first aspect.

[0032] Thirdly, the present invention provides a cooling tower, comprising: a cooling tower body and the cooling tower windbreak device described in the second aspect.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] This invention proposes a design method for a cooling tower wind baffle, a cooling tower wind baffle, and a cooling tower. Based on the mechanism of natural wind's influence on the thermal performance of the cooling tower, discontinuous wind baffles are set in the air inlet area according to a certain pattern to redistribute the natural wind in the air inlet area of ​​the cooling tower, adjust the air flow field state in the air inlet area, increase the resistance of natural wind passing through the air inlet area, avoid through drafts, and make the flow field distribution in the packing area more uniform under natural wind, which facilitates the performance of the cooling tower's thermal performance, improves the cooling capacity of the cooling tower under natural wind conditions, and reduces the impact of natural wind on the thermal performance of the cooling tower.

[0035] This invention proposes a design method for a cooling tower windbreak device, a cooling tower windbreak device, and a cooling tower. A ventilation channel is provided between the windbreak plate and the cooling tower shaft. At the same time, the design of the windbreak plate divides the air inlet area of ​​the cooling tower into different areas. Natural air is introduced into other areas through the ventilation channel, ensuring the connectivity and uniformity of the flow field between the areas. While reducing the incoming wind pressure, it also improves the uniformity of the wind speed distribution at the bottom of the packing, which is beneficial to the thermal performance of the cooling tower.

[0036] The present invention proposes a design method for a cooling tower windbreak device, a cooling tower windbreak device, and a cooling tower. Through the design of the ventilation channel, it avoids the situation where the pressure rises sharply in the upwind area of ​​the air inlet area when the natural wind speed is high, which may even cause the packing to be overturned; it avoids the accumulation of natural wind in the air inlet area, thereby significantly reducing the wind load on the windbreak plate, reducing the civil engineering cost of the windbreak plate support structure, and reducing the project investment.

[0037] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0038] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0039] Figure 1 This is a flowchart illustrating the design method of the cooling tower windbreak device provided in Embodiment 1 of the present invention.

[0040] Figure 2 This is a schematic diagram of the cooling tower windbreak device provided in Embodiment 2 of the present invention. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0042] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0043] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0044] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0045] Example 1

[0046] This embodiment provides a design method for a cooling tower windbreak device to reduce the impact of natural wind on the thermal performance of the cooling tower, such as... Figure 1 As shown, it specifically includes:

[0047] Determine the configuration and scale of the cooling tower body;

[0048] The distance between the baffle plate and the cooling tower shaft is determined. The baffle plate is located in the air inlet area inside the cooling tower body. The distance is determined according to the natural wind speed, the prevailing wind direction and the configuration scale of the cooling tower body. The distance is optimized according to the stability of the packing under natural wind.

[0049] After optimizing the spacing between the baffle plate and the cooling tower shaft, the spacing between the baffle plates is determined based on the wind load distribution of the baffle plates, so as to set up a support structure between the baffle plates.

[0050] In this embodiment, the required cooling water volume and the configuration scale of the cooling tower body are determined based on the hot end load and meteorological conditions.

[0051] As an alternative implementation method, the configuration scale of the cooling tower body can be determined using cooling tower thermal performance calculation software.

[0052] In this embodiment, the process of determining the distance between the baffle plate and the cooling tower shaft includes:

[0053] The windbreak panels are arranged in a continuous manner;

[0054] The distance between the pre-set windbreak plate and the cooling tower shaft is used as a basis. Based on the natural wind speed, the prevailing summer wind direction, and the configuration scale of the cooling tower, the stability of the packing material is analyzed by numerical simulation.

[0055] Specifically, calculate the wind speed V at the bottom cross-section of the packing:

[0056]

[0057] A p =A x q 2 +A y q+A z

[0058] M = M x q 2 +M y q+M z

[0059] In the formula, Δp is the pressure drop (Pa), and q is the spray density (t / (m³)). 2 ·h)), V is the wind speed (m / s), and γ is the specific gravity of air (N / m³). 3 ), A x A y A z M x M y M z This is the experimental constant for the packing material.

[0060] The pressure loss coefficient k can be obtained from the above three equations:

[0061]

[0062]

[0063] In the formula, H f The height is the filler height, and → indicates the upward direction of the wind speed.

[0064] From this, the lifting force F of the wind on the packing at the wind speed V at the packing cross section can be obtained. The lifting force F is compared with the self-weight G of the water-spreading packing. The stability coefficient is η = F / G. If η is greater than 1, that is, F is greater than G, then it is unstable, otherwise it is relatively safe.

[0065] If the packing material is stable, reduce the distance between the baffle plate and the cooling tower shaft, and repeat the numerical simulation calculation; if the packing material is unstable, increase the distance between the baffle plate and the cooling tower shaft, and repeat the numerical simulation calculation; until the packing material stability judgment result is reversed, take the distance before the reversal as the final determined distance between the baffle plate and the cooling tower shaft.

[0066] As an alternative implementation method, the distance between the baffle plate and the cooling tower shaft can be reduced or increased by 0.1m, 0.2m, 0.3m or other distances each time, and is not limited here.

[0067] In this embodiment, the height of the windbreak plate extends to the top of the water distribution tank.

[0068] In this embodiment, the wind baffles are not continuous, and a support structure is provided between them. Under the final determined distance between the wind baffles and the cooling tower shaft, the wind load distribution of the wind baffles is analyzed to determine the distance between them. Specifically, this includes:

[0069] Based on the natural wind speed, the prevailing summer wind direction, and the configuration and scale of the cooling tower, numerical simulation optimization calculations were used to obtain the wind pressure on the surface of the baffle plate under the combined effects of natural wind passing through the rain zone and the cooling tower's exhaust force. The wind pressure load acting on the baffle plate was obtained based on the wind pressure and the corresponding area of ​​the baffle plate. Based on the location of the wind pressure load's application point and the magnitude of the force, the corresponding shear force and bending moment for each segment were calculated. Specifically:

[0070] The shear force on any segment is F i =P i A i ;

[0071] The shear force on any segment in the lower part is the sum of the shear forces on all segments in the upper part.

[0072] The bending moment on any segment of the lower part is

[0073] Among them, P i For any segment, A i Let L be the area of ​​any segment. i This represents the distance from each segment to the ground.

[0074] Therefore, after obtaining the shear force and bending moment of each segment, the structural dimensions and reinforcement are calculated according to the calculation of the shear capacity of the inclined section and the calculation of the bending capacity of the normal section in the "Code for Design of Concrete" (GB50010-2010).

[0075] As an alternative implementation, the wind load is equal to the product of the wind pressure and the windward area.

[0076] In this embodiment, the width of the support structure is equal to the distance between the windbreak panels.

[0077] In this embodiment, a ventilation channel is provided between the baffle plate and the cooling tower shaft. Simultaneously, the design of the baffle plate divides the cooling tower's air inlet area into different zones. The ventilation channel guides natural wind to other zones, ensuring the connectivity and uniformity of the flow field between zones. This reduces the incoming wind pressure while improving the uniformity of wind speed distribution at the bottom of the packing material, which is beneficial for the cooling tower's thermal performance. It also prevents a sharp increase in pressure in the upwind area of ​​the air inlet area when the natural wind speed is high, which could even cause the packing material to overturn. Furthermore, it avoids the accumulation of natural wind in the air inlet area, thereby significantly reducing the wind load on the baffle plate, reducing the civil engineering costs of the baffle plate support structure, and lowering project investment.

[0078] This embodiment is based on the mechanism of natural wind's influence on the thermal performance of cooling towers. Discontinuous baffles are set in the air inlet area according to a certain pattern to redistribute the natural wind in the air inlet area of ​​the cooling tower, adjust the air flow field state in the air inlet area, increase the resistance when natural wind passes through the air inlet area, avoid through drafts, make the flow field distribution in the packing area more uniform under natural wind, facilitate the performance of the cooling tower's thermal performance, improve the cooling capacity of the cooling tower under natural wind conditions, and reduce the impact of natural wind on the thermal performance of the cooling tower.

[0079] In this embodiment, the design method further includes optimizing the configuration scale of the cooling tower body based on the design of the windbreak and support structure; specifically including:

[0080] Based on the installation positions of the baffle plates and supporting structures, the distance between the baffle plates and the cooling tower shaft, and the distance between the baffle plates, the thermal performance of the cooling tower under the current cooling tower configuration scale is analyzed through three-dimensional numerical simulation calculations under a given wind speed and the prevailing summer wind direction, and the cooling tower outlet water temperature under a given wind speed is obtained.

[0081] Based on a given wind speed and its corresponding cooling tower outlet water temperature, an empirical formula is obtained through fitting.

[0082] Based on empirical formulas and any wind speed, the approximate outlet water temperature can be obtained.

[0083] A preset water temperature threshold is used to determine whether the approximate outlet water temperature meets the water temperature threshold requirement under any wind speed.

[0084] If the approximate outlet water temperature is lower than the water temperature threshold, then the size of the cooling tower is reduced according to a certain rule, and all the above calculations are repeated.

[0085] If the approximate outlet water temperature is higher than the water temperature threshold, then the size of the cooling tower is increased according to a certain rule, and all the above calculations are repeated.

[0086] The specific adjustment method is to adjust the area of ​​the cooling tower according to the ratio of the specific value below or above the threshold to the design temperature difference between the inlet and outlet water of the cooling tower; for example, by increasing the area of ​​the cooling tower, and finally determine the configuration scale of the cooling tower body after adjustment.

[0087] Example 2

[0088] This embodiment provides a cooling tower wind baffle device. Based on the mechanism of natural wind affecting the thermal performance of the cooling tower, according to the design method described in Embodiment 1, a wind baffle is set in the air inlet area inside the cooling tower body to form a wind-blocking and flow passage.

[0089] like Figure 2 As shown, it specifically includes: a baffle plate and a supporting structure. The baffle plate is located in the air inlet area inside the cooling tower body. The baffle plate is arranged radially outward from the outer wall of the central vertical shaft inside the cooling tower. The distance between the baffle plate and the vertical shaft of the cooling tower, as well as the distance between the baffle plates, is determined by the design method described in Example 1.

[0090] The design method of the cooling tower windbreak device is applicable to thermal power generation, nuclear power, metallurgy, and chemical industries. It addresses the development of a device to reduce the impact of natural wind on the thermal performance of cooling towers when using natural draft cooling towers as cooling equipment. This fundamentally avoids through drafts in the cooling tower inlet area and prevents the risk of packing material overturning due to airflow accumulation in the central area of ​​the cooling tower. Simultaneously, the formation of airflow ventilation channels improves the uniformity of the flow field distribution in the inlet area, facilitating the optimal performance of the cooling tower's thermal performance. Furthermore, it reduces the size of the windbreak support structure, thereby reducing concrete usage and investment.

[0091] Example 3

[0092] This embodiment provides a cooling tower, including: a cooling tower body and the cooling tower windbreak device described in Embodiment 2.

[0093] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A design method for a cooling tower windbreak device, characterized in that, include: Determine the configuration and scale of the cooling tower body; The distance between the baffle plate and the cooling tower shaft is determined. The baffle plate is located in the air inlet area inside the cooling tower body. The distance is determined according to the natural wind speed, the prevailing wind direction and the configuration scale of the cooling tower body. The distance is optimized according to the stability of the packing under natural wind. After optimizing the spacing between the baffle plate and the cooling tower shaft, the spacing between the baffle plates is determined according to the wind load distribution of the baffle plates, so as to set up a support structure between the baffle plates. The process of determining the spacing between windbreaks includes: After optimizing the distance between the baffle plate and the cooling tower shaft, the wind pressure on the surface of the baffle plate is obtained through numerical simulation based on the natural wind speed, the prevailing wind direction in summer and the configuration scale of the cooling tower body. The wind load force acting on the baffle plate is obtained based on the wind pressure and the windward area of ​​the baffle plate. The distance between the baffle plates is obtained based on the location of the wind load force and the magnitude of the force. The width of the support structure is equal to the distance between the windbreak panels.

2. The design method of the cooling tower windbreak device as described in claim 1, characterized in that, The process of determining the distance between the baffle plate and the cooling tower shaft includes: Assuming the windbreak panels are arranged continuously; The distance between the baffle plate and the cooling tower shaft is preset. At this distance, the stability of the packing is determined by numerical simulation calculation based on the natural wind speed, the prevailing summer wind direction and the configuration scale of the cooling tower body. The distance between the baffle plate and the cooling tower shaft is reduced or increased based on the judgment result.

3. The design method of the cooling tower windbreak device as described in claim 2, characterized in that, If the packing material is stable at the current distance between the baffle plate and the cooling tower shaft, then reduce the distance between the baffle plate and the cooling tower shaft, and repeat the numerical simulation calculation until the packing material stability judgment result is reversed. If the packing is unstable at the current distance between the baffle plate and the cooling tower shaft, increase the distance between the baffle plate and the cooling tower shaft, and repeat the numerical simulation calculation until the packing stability judgment result is reversed. The spacing before the reversal is taken as the final determined spacing between the baffle plate and the cooling tower shaft.

4. The design method of the cooling tower windbreak device as described in claim 1, characterized in that, The height of the baffle plate extends to the top of the cooling tower water distribution tank.

5. The design method of the cooling tower windbreak device as described in claim 1, characterized in that, A ventilation channel is provided between the windbreak plate and the cooling tower shaft.

6. The design method of the cooling tower windbreak device as described in claim 1, characterized in that, The design method for the cooling tower windbreak device also includes adjusting the configuration scale of the cooling tower body based on the design of the windbreak plate and supporting structure; specifically including: Based on the installation positions of the baffle plates and supporting structures, the distance between the baffle plates and the cooling tower shaft, and the distance between the baffle plates, the cooling tower outlet water temperature under a given wind speed and prevailing wind direction is obtained through numerical simulation calculation. Based on a given wind speed and its corresponding cooling tower outlet water temperature, an empirical formula is obtained through fitting. Based on empirical formulas and any wind speed, the corresponding outlet water temperature at any wind speed can be obtained; A preset water temperature threshold is used to determine whether the outlet water temperature meets the threshold requirement at any wind speed, thereby adjusting the configuration scale of the cooling tower.

7. A cooling tower windbreak device, characterized in that, include: The wind baffle and the supporting structure between the wind baffles; the wind baffle is located in the air inlet area inside the cooling tower body, and the wind baffle is arranged radially outward from the outer wall of the central vertical shaft inside the cooling tower. The distance between the wind baffle and the vertical shaft of the cooling tower, and the distance between the wind baffles are determined by the design method described in any one of claims 1-6.

8. A cooling tower, characterized in that, include: The cooling tower body and the cooling tower windproof device as described in claim 7.

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