An air-cooled island anti-freezing area identification method and system

Abstract

An air-cooled island anti-freezing area identification method and system provided by the present invention, the method comprising: obtaining air-cooled island characteristic parameters; establishing an air-cooled island model according to the air-cooled island characteristic parameters; calculating the heat dissipation of each air-cooled unit of the air-cooled island based on the air-cooled island model; comparing the heat dissipation of each air-cooled unit of the air-cooled island with a preset anti-freezing heat quantity to identify the air-cooled island anti-freezing area. By numerically calculating the heat dissipation of each air-cooled unit and comparing the actual heat dissipation of the air-cooled unit with the minimum anti-freezing quantity, the areas where many air-cooled units are prone to freezing under different environmental conditions of the air-cooled island are identified, assisting in operation to adjust operation parameters and engineering transformation to meet the engineering requirements.

Description

Technical Field

[0001] The present invention relates to the field of the operation safety of air-cooled units, and particularly to a method and system for identifying anti-freezing areas of an air-cooled island. Background Art

[0002] The development of power plant air-cooling technology has provided an effective solution to the problem of more coal and less water in the northern regions of China. Compared with the traditional cold-end water cooling tower technology, the direct air-cooling technology shows outstanding water-saving advantages. The direct air-cooling technology has been widely applied in the northern regions of China and is very suitable for coal-fired power plants, circulating fluidized bed power plants, and solar thermal power plants. However, the air-cooled finned tube bundles are exposed to the environment and are vulnerable to environmental impacts. In particular, the low temperature in winter may cause the steam or condensate in the finned tubes to freeze, resulting in the freezing and cracking of the finned tube bundles, seriously affecting the operation safety of the units. The air-cooled island contains numerous air-cooling units (for example, in a 600MW-class unit, a single unit contains at least 56 air-cooling units). Under different wind directions and wind speeds, the heat dissipation of each unit is different, and the possibility of freezing is also different. Therefore, it is necessary to identify the areas where numerous air-cooling units in the air-cooled island are prone to freezing under different environmental conditions, and adjust the operation parameters and carry out engineering modifications. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that it is difficult to identify the areas where the air-cooling units in the air-cooled island are prone to freezing under different environmental conditions, and thus provide a method and system for identifying anti-freezing areas of the air-cooled island.

[0004] In a first aspect, an embodiment of the present invention provides a method for identifying anti-freezing areas of an air-cooled island, including: obtaining the characteristic parameters of the air-cooled island; establishing an air-cooled island model according to the characteristic parameters of the air-cooled island; calculating the heat dissipation of each air-cooling unit of the air-cooled island based on the air-cooled island model; comparing the heat dissipation of each air-cooling unit of the air-cooled island with a preset anti-freezing heat quantity to identify the anti-freezing areas of the air-cooled island.

[0005] Optionally, the calculating the heat dissipation of each air-cooling unit of the air-cooled island based on the air-cooled island model includes: dividing each air-cooling unit of the air-cooled island radiator into several domains based on the air-cooled island model; calculating the heat dissipation of each region according to the steam temperature at the inlet of the radiator, the environmental temperature, and the heat transfer efficiency of the radiator; and summing the heat dissipation of each region under each air-cooling unit to obtain the heat dissipation of each air-cooling unit of the air-cooled island.

[0006] Optionally, the comparing the heat dissipation of each air-cooling unit of the air-cooled island with a preset anti-freezing heat quantity to identify the anti-freezing areas of the air-cooled island includes: making a difference comparison between the heat dissipation of each air-cooling unit of the air-cooled island and the preset anti-freezing heat quantity; performing a division calculation on the result after the difference is made with the preset anti-freezing heat quantity to obtain a warning coefficient; and identifying the anti-freezing areas of the air-cooled island according to the relationship between the warning coefficient and a preset threshold.

[0007] Optionally, the heat dissipation of each area of the air-cooled island is calculated by the following formula:

[0008] q macro = σ(mc p )(T vapor - T a1 )

[0009] where T vapor is the steam temperature at the inlet of the radiator, T a1 is the ambient temperature, σ is the heat transfer efficiency of the radiator, m represents the air mass flow rate, and C p is the specific heat capacity of air.

[0010] Optionally, the heat dissipation of each air-cooled unit is calculated by the following formula:

[0011] Q = Σq macro .

[0012] Optionally, the warning coefficient is calculated by the following formula:

[0013] ф = (Q - Q safe ) / Q safe

[0014] where Q safe is the preset anti-freezing heat.

[0015] Optionally, the characteristics parameters of the air-cooled island include the characteristics of the air-cooled fan and the characteristics of the air-cooled finned tube.

[0016] In a second aspect, an embodiment of the present invention provides an air-cooled island anti-freezing area identification system, including: an acquisition module for acquiring the characteristics parameters of the air-cooled island; a construction module for establishing an air-cooled island model according to the characteristics parameters of the air-cooled island; a calculation module for calculating the heat dissipation of each air-cooled unit of the air-cooled island based on the air-cooled island model; and an identification module for comparing the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat to identify the anti-freezing area of the air-cooled island.

[0017] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores computer instructions, and the computer instructions are used to cause the computer to execute the air-cooled island anti-freezing area identification method described in the first aspect of the embodiments of the present invention.

[0018] In a fourth aspect, an embodiment of the present invention provides a computer device, including: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the air-cooled island anti-freezing area identification method described in the first aspect of the embodiments of the present invention by executing the computer instructions.

[0019] The technical solution of the present invention has the following advantages:

[0020] A method for identifying the anti-freezing area of an air-cooled island provided by the present invention includes: obtaining the characteristic parameters of the air-cooled island; establishing an air-cooled island model according to the characteristic parameters of the air-cooled island; calculating the heat dissipation of each air-cooled unit of the air-cooled island based on the air-cooled island model; comparing the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat to identify the anti-freezing area of the air-cooled island. By numerical calculation, the heat dissipation of each air-cooled unit is obtained, and the actual heat dissipation of the air-cooled unit is compared with the minimum anti-freezing amount to identify the areas where many air-cooled units are prone to freezing under different environmental conditions, assisting the operation in adjusting the operation parameters and engineering transformation to meet the engineering requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 It is a flowchart of a specific example of the method for identifying the anti-freezing area of the air-cooled island in the embodiment of the present invention;

[0023] Figure 2 It is a schematic diagram of the boundary conditions and calculation area division in the embodiment of the present invention;

[0024] Figure 3 It is a principle block diagram of a specific example of the system for the method for identifying the anti-freezing area of the air-cooled island in the embodiment of the present invention;

[0025] Figure 4 It is a composition diagram of a specific example of the computer device provided in the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] An air-cooled island anti-freezing area identification method is provided in an embodiment of the present invention, as Figure 1 shown, including the following steps:

[0031] Step S1: Obtain the air-cooled island characteristic parameters.

[0032] In a specific embodiment, the air-cooled island characteristic parameters need to be obtained through on-site measurement, edited as a custom function, and used as the boundary of fluid dynamics calculation. It mainly includes: the characteristics of the air-cooled fan and the characteristics of the air-cooled finned tube.

[0033] Among them, the characteristics of the air-cooled fan are as follows:

[0034] The fan physical model in FLUENT software is an infinitely thin plane. When the air flow passes through this plane, a pressure jump occurs. The pressure jump value is expressed as a polynomial function of the velocity:

[0035]

[0036] where f n represents the polynomial coefficient, and v represents the average velocity of the mass flow rate of the fan plane. According to the actual operating performance curve of the air-cooled fan, the polynomial coefficient f n is obtained from the fitting equation.

[0037] The circumferential and radial velocity components of the fan are defined as a function of the radial distance as follows:

[0038]

[0039]

[0040] where r is the radial distance, and f θn , f rn represent polynomial coefficients, both of which can be obtained through fan performance tests.

[0041] Among them, the characteristics of the air-cooled finned tubes are as follows:

[0042] The finned tube bundle is equivalent to the Radiator model in Fluent, and the resistance of the finned tubes

[0043]

[0044] Among them, the resistance coefficient can be fitted as a polynomial function and obtained through experimental measurement methods. Adjust the fan frequency f = 10, 20, 30, 40, 50 Hz to change the oncoming air velocity. Connect one end of the micro-pressure gauge to the fan outlet and the other end to the finned tube outlet to obtain the resistance of the finned tubes (where the resistance of the finned tubes includes the fan bridge, the inlet resistance of the finned tubes, the resistance of the finned tubes, and the outlet resistance of the finned tubes), thereby obtaining the resistance coefficient.

[0045]

[0046] In the formula: k L —— resistance coefficient; ρ—— density, kg / m 3 ; u—— air velocity, m / s; a i —— constant coefficient.

[0047] For a certain unit, for example, k L = 69.89 - 40.33v + 12.72v 2 - 2.06v 3 + 0.16v 4 - 0.0051v 5 .

[0048] The corresponding relationship between the heat transfer coefficient of the air-cooled finned tube bundle and the oncoming air velocity is obtained through actual measurement: where a and b are constants

[0049] K = av b

[0050] For a certain unit, for example

[0051] K = 28.2v 0.45

[0052] The heat transfer efficiency of the air-cooled radiator can be obtained:

[0053]

[0054] Where A represents the heat dissipation area, a constant;

[0055] m represents the air mass flow rate, which is uniquely determined by the oncoming wind speed and air density.

[0056] C p is the specific heat capacity of air and can be regarded as a constant.

[0057] Edit custom functions for the heat transfer characteristics, resistance characteristics, and fan characteristics of the air-cooled finned tube as the boundary conditions for numerical calculation.

[0058] Step S2: Establish an air-cooled island model based on the air-cooled island characteristic parameters.

[0059] In a specific embodiment, the physical model includes a fan, an air-cooled island, a windbreak wall, a windproof net, the buildings around the air-cooled island, etc. Model it according to the proportion, and the overall calculation area is not less than 1000m×1000m×1000m.

[0060] Use the software Fluent based on the finite volume method to perform numerical simulation calculations. For the air turbulent flow in the model, the Realizable k-epsilon turbulence model is used to describe it in this embodiment; the second-order upwind difference scheme is used to discretize the momentum equation, energy equation, turbulent kinetic energy equation, and turbulent kinetic energy dissipation equation, and the improved pressure-velocity coupling SIMPLEC algorithm is used for the algorithm. During the calculation process, the residual convergence criterion of the energy equation is set to 1×10 -6 , and the residual convergence criterion of the remaining parameters is set to 1×10 -3 .

[0061] The outer flow far-field space is simplified to a cube. According to the wind direction, a certain plane can be set as the pressure inlet, and the static pressure, wind speed, and wind temperature are set. The other five planes are the pressure outlet boundaries and the ground. The internal buildings and the windbreak wall are all defaulted to adiabatic wall surfaces, and the boiler building is simulated in the form of a constant heat flux for the heat dissipation of the boiler to the environment. The schematic diagram of the boundary conditions and the calculation area division is as shown in Figure 2 . Among them, the velocity inlet is the wind direction.

[0062] Step S3: Based on the air-cooled island model, calculate the heat dissipation of each air-cooled unit of the air-cooled island.

[0063] In a specific embodiment, the heat dissipation of each air-cooled unit of the air-cooled island is calculated through the following steps:

[0064] Step S31: Based on the air-cooled island model, divide each air-cooled unit of the air-cooled island radiator into several domains.

[0065] Step S32: Calculate the heat dissipation of each area according to the inlet steam temperature of the radiator, the ambient temperature and the heat transfer efficiency of the radiator.

[0066] Step S33: Sum up the heat dissipation of each area under each air-cooled unit to obtain the heat dissipation of each air-cooled unit in the air-cooled island.

[0067] In the embodiment of the present invention, based on the air-cooled island model, using a simple efficiency model, after dividing the grid, the radiator is divided into several domains, and each domain includes several grids. The heat dissipation q of each area macro = σ(mc p )(T vapor - T a1 ).

[0068] Among them, T vapor is the inlet steam temperature of the radiator, and T a1 is the ambient temperature.

[0069] Then the total heat dissipation Q of each air-cooled unit = Σq macro .

[0070] Step S4: Compare the heat dissipation of each air-cooled unit in the air-cooled island with the preset anti-freezing heat to identify the anti-freezing area of the air-cooled island.

[0071] In a specific embodiment, the anti-freezing area of the air-cooled island is identified in the following manner:

[0072] Step S41: Make a difference comparison between the heat dissipation of each air-cooled unit in the air-cooled island and the preset anti-freezing heat.

[0073] Step S42: Perform a division calculation on the result after the difference with the preset anti-freezing heat to obtain a warning coefficient.

[0074] Step S43: Identify the anti-freezing area of the air-cooled island according to the relationship between the warning coefficient and the preset threshold.

[0075] In the embodiment of the present invention, the preset anti-freezing heat is the minimum anti-freezing amount Q safe . The minimum anti-freezing amount Q safe is determined according to the operating conditions. The preset threshold is 0. Compare the actual heat dissipation of the unit with the minimum anti-freezing amount Q safe to obtain a warning coefficient ф = (Q - Q safe ) / Q safe .

[0076] Specifically, when the warning coefficient ф ≥ 0, it is determined that this air-cooled unit is an easily frozen area. When the warning coefficient ф < 0, it is determined that this air-cooled unit is a normal operation area.

[0077] Furthermore, a warning coefficient distribution map is drawn according to the relationship between the warning coefficient ф and the preset threshold, so that the operators can more intuitively identify the anti-freezing areas of the air-cooled island, and assist the operators in adjusting the operating parameters and engineering transformation.

[0078] A method for identifying the anti-freezing area of an air-cooled island provided by the present invention includes: obtaining the characteristic parameters of the air-cooled island; establishing an air-cooled island model according to the characteristic parameters of the air-cooled island; calculating the heat dissipation of each air-cooled unit of the air-cooled island based on the air-cooled island model; comparing the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat to identify the anti-freezing area of the air-cooled island. By numerical calculation, the heat dissipation of each air-cooled unit is obtained, and the actual heat dissipation of the air-cooled unit is compared with the minimum anti-freezing amount to identify the areas where many air-cooled units are prone to freezing under different environmental conditions, assisting the operation in adjusting the operating parameters and engineering transformation to meet the engineering requirements.

[0079] For example, the warning coefficient distribution map of an air-cooled island of a certain unit is obtained through calculation:

[0080] Table 1 Percentage of heat dissipation exceeding the warning line of each cooling triangle under the east wind in winter and 30% electric load (unit: %)

[0081]

[0082] Table 2 Percentage of heat dissipation exceeding the warning line of each cooling triangle under the north wind in winter and 30% electric load (unit: %)

[0083]

[0084]

[0085] The embodiment of the present invention also provides an anti-freezing area identification system for an air-cooled island, as Figure 3 shown, including:

[0086] An acquisition module 1 for acquiring the characteristic parameters of the air-cooled island. For the detailed content, refer to the relevant description of step S1 in the above embodiment, and it will not be repeated here.

[0087] A construction module 2 for establishing an air-cooled island model according to the characteristic parameters of the air-cooled island. For the detailed content, refer to the relevant description of step S2 in the above embodiment, and it will not be repeated here.

[0088] A calculation module 3 for calculating the heat dissipation of each air-cooled unit of the air-cooled island based on the air-cooled island model. For the detailed content, refer to the relevant description of step S3 in the above embodiment, and it will not be repeated here.

[0089] An identification module 4 for comparing the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat to identify the anti-freezing area of the air-cooled island. For the detailed content, refer to the relevant description of step S4 in the above embodiment, and it will not be repeated here.

[0090] An embodiment of the present invention further provides a computer device. As Figure 4 shown, the device terminal may include a processor 61 and a memory 62. The processor 61 and the memory 62 may be connected through a bus or other means. Figure 4 Here, the case of connection through a bus is taken as an example.

[0091] The processor 61 may be a central processing unit (CPU). The processor 61 may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. chips, or a combination of the above types of chips.

[0092] The memory 62, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the corresponding program instructions / modules in the embodiments of the present invention. The processor 61 executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions, and modules stored in the memory 62, that is, to implement the air-cooled island anti-freezing area recognition method in the above method embodiments.

[0093] The memory 62 may include a program storage area and a data storage area. Among them, the program storage area may store an operating system and application programs required for at least one function; the data storage area may store data created by the processor 61, etc. In addition, the memory 62 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage devices. In some embodiments, the memory 62 may optionally include a memory remotely set relative to the processor 61, and these remote memories may be connected to the processor 61 through a network. Examples of the above networks include, but are not limited to, the Internet, enterprise intranets, local area networks, mobile communication networks, and combinations thereof.

[0094] One or more modules are stored in the memory 62 and, when executed by the processor 61, execute the air-cooled island anti-freezing area recognition method in the embodiments.

[0095] Specific details of the above computer device can be understood by referring to the corresponding related descriptions and effects in the embodiments, and will not be elaborated here.

[0096] Those skilled in the art can understand that to implement all or part of the processes in the above-described embodiment methods, it can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above-described method embodiments. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), a random access memory (RAM), a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD), etc.; the storage medium can also include a combination of the above-mentioned types of memories.

[0097] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for identifying the anti-freezing area of an air-cooled island, characterized in that including: Obtain the characteristic parameters of the air-cooled island; Establish an air-cooled island model according to the characteristic parameters of the air-cooled island; Based on the air-cooled island model, calculate the heat dissipation of each air-cooled unit of the air-cooled island; Compare the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat quantity to identify the anti-freezing area of the air-cooled island; The calculating, based on the air-cooled island model, the heat dissipation of each air-cooled unit of the air-cooled island includes: Based on the air-cooled island model, divide each air-cooled unit of the air-cooled island radiator into several domains; Calculate the heat dissipation of each area according to the steam inlet temperature of the radiator, the ambient temperature and the heat transfer efficiency of the radiator; Sum up the heat dissipation of each area under each air-cooled unit to obtain the heat dissipation of each air-cooled unit of the air-cooled island; Calculate the heat dissipation of each area of the air-cooled island through the following formula: q macro = σ(mc p )(T vapor - T a1 ) Among them, T vapor is the inlet steam temperature of the radiator, T a1 is the ambient temperature, σ is the heat transfer efficiency of the radiator, m represents the air mass flow rate, and C p is the specific heat capacity of air.

2. The method for identifying the anti-freezing area of the air-cooled island according to claim 1, wherein The comparing the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat quantity to identify the anti-freezing area of the air-cooled island includes: Make a difference comparison between the heat dissipation of each air-cooled unit of the air-cooled island and the preset anti-freezing heat quantity; Perform a division calculation on the result after the difference is made with the preset anti-freezing heat quantity to obtain a warning coefficient; Identify the anti-freezing area of the air-cooled island according to the relationship between the warning coefficient and the preset threshold.

3. The method for identifying the anti-freezing area of the air-cooled island according to claim 1, wherein, Calculate the heat dissipation of each air-cooled unit through the following formula: Q = Σq macro .

4. The method for identifying the anti-freezing area of the air-cooled island according to claim 2, wherein Calculate the warning coefficient through the following formula: φ=(Q - Q safe ) / Q safe Among them, Q safe is the preset anti-freezing heat quantity.

5. The method for identifying the anti-freezing area of the air-cooled island according to claim 1, wherein The characteristic parameters of the air-cooled island include the characteristics of the air-cooled fan and the characteristics of the air-cooled finned tube.

6. An air-cooled island anti-freezing area identification system, characterized in that, including: An obtaining module, configured to obtain the characteristic parameters of the air-cooled island; A constructing module, configured to establish an air-cooled island model according to the characteristic parameters of the air-cooled island; A calculating module, configured to calculate the heat dissipation of each air-cooled unit of the air-cooled island based on the air-cooled island model; An identifying module, configured to compare the heat dissipation of each air-cooled unit of the air-cooled island with the preset anti-freezing heat quantity to identify the anti-freezing area of the air-cooled island; The calculating, based on the air-cooled island model, the heat dissipation of each air-cooled unit of the air-cooled island includes: Based on the air-cooled island model, divide each air-cooled unit of the air-cooled island radiator into several domains; Calculate the heat dissipation of each area according to the steam inlet temperature of the radiator, the ambient temperature and the heat transfer efficiency of the radiator; Sum up the heat dissipation of each area under each air-cooled unit to obtain the heat dissipation of each air-cooled unit of the air-cooled island; Calculate the heat dissipation of each area of the air-cooled island through the following formula: q macro = σ(mc p )(T vapor - T a1 ) Among them, T vapor is the inlet steam temperature of the radiator, T a1 is the ambient temperature, σ is the heat transfer efficiency of the radiator, m represents the air mass flow rate, and C p is the specific heat capacity of air.

7. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions, and the computer instructions are used to cause the computer to execute the air-cooled island anti-freezing area identification method according to any one of claims 1-5.

8. A computer device, characterized in that, including: A memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to execute the air-cooled island anti-freezing area identification method according to any one of claims 1-5.

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