Dirt layer drying rate calculation method, calculation device and computer readable medium

Abstract

The invention provides a dirt layer drying rate calculation method, a dirt layer drying rate calculation device and a computer readable medium. The problem that an existing dirt layer drying rate calculation method is not accurate is solved. The dirt layer drying rate calculation method comprises the following steps: sequentially dividing dirt layers from a dirt surface to a wall surface; setting the interior of the dirt as a capillary porous body structure, and setting parameter boundary values of the surface of the dirt; constructing a group of relational expression combinations for flow heat transfer parameter calculation, and calculating flow heat transfer parameters of each dirt layer according to the relational expression combinations and the parameter boundary values of the dirt surfaces; judging whether the current dirt layer is in a dry-out position or not according to the flow heat transfer parameters, if yes, obtaining the thickness of the current dirt layer, and calculating the dry-out rate of the dirt layer according to the thickness of the current dirt layer and the total thickness of the dirt layer.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of nuclear reactors, and in particular to a method for calculating a burnout rate of a dirt layer, a calculation device and a computer-readable medium. Background Art

[0002] The corrosion products (also called fouling) released by the primary loop system of a pressurized water reactor will be deposited on the surface of the fuel cladding. A large amount of fouling deposition can not only cause Crud Induced Power Shift (CIPS), but also cause the local temperature of the fuel cladding surface to rise, thereby accelerating the oxidation of the cladding, and in severe cases, leading to corrosion failure of the fuel cladding. Crud-Induced Localized Corrosion (CILC) of the fuel cladding is one of the important reasons for the failure of fuel rods.

[0003] The burnout rate of the fouling layer is an important indicator for assessing the CILC risk in the risk analysis of reactor core fouling. The burnout rate of the fouling layer refers to the ratio of the thickness of the burnout part of the fouling to the total thickness of the fouling. Therefore, it is urgent to provide a method for calculating the burnout rate of the fouling layer required for fouling risk analysis. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for calculating the burnout rate of a dirt layer, a calculation device and a computer-readable medium, so as to solve the problem that the existing method for calculating the burnout rate of a dirt layer is inaccurate.

[0005] To solve the above technical problems, the present invention provides a method for calculating the burnout rate of a dirt layer, comprising: dividing the dirt layer in sequence from the dirt surface to the wall surface; setting the inside of the dirt to a capillary porous structure, and setting the parameter boundary value of the dirt surface; constructing a set of relationship formula combinations for calculating flow heat transfer parameters, and calculating the flow heat transfer parameters of each dirt layer according to the relationship formula combinations and the parameter boundary value of the dirt surface; judging whether the current dirt layer is in a burnout position according to the flow heat transfer parameters, and if so, obtaining the thickness of the current dirt layer, and calculating the burnout rate of the dirt layer according to the thickness of the current dirt layer and the total thickness of the dirt layer.

[0006] Optionally, the flow heat transfer parameters include mass evaporation rate, temperature and critical pore radius, and the combination of relationship equations includes: momentum conservation equation, energy conservation equation and interphase heat transfer equation.

[0007] Optionally, the momentum conservation equation is:

[0008]

[0009] in, is the surface tension of the liquid, is the contact angle, R* is the critical pore radius, P is the pressure, and the subscripts l and v represent the liquid phase and the vapor phase, respectively. is the grid size.

[0010] Optionally, the energy conservation equation is:

[0011]

[0012] in, is the heat flow under the heat conduction of the n+1th layer, is the heat flow under the heat conduction of the nth layer, is the mass evaporation rate of the n+1th layer, is the mass evaporation rate of the nth layer, is the vapor phase enthalpy of the dirt surface, is the liquid phase enthalpy of the dirt surface.

[0013] Optionally, the temperature of each fouling layer is calculated by the following formula:

[0014]

[0015] in, is the thermal conductivity of the dirt layer, is the temperature of the dirt layer, is the grid size.

[0016] Optionally, the thermal conductivity of the fouling layer is calculated by the following formula:

[0017]

[0018] in, is the porosity of the n+1th layer, is the ratio of the liquid phase in the n+1th layer to the dirt layer, k is the thermal conductivity, and the subscripts l, v, and s represent the liquid phase in the dirt layer, the vapor phase in the dirt layer, and the solid phase in the dirt layer, respectively.

[0019] Alternatively, based on Darcy's law for porous media, the proportion of the liquid phase in the fouling layer A variable value.

[0020] Optionally, the interphase heat transfer equation is:

[0021]

[0022] in, is the volume heat transfer coefficient of phase change, is the saturation temperature of the liquid inside the dirt, is the temperature of the dirt layer, is the latent heat of vaporization, is the mass evaporation rate, is the grid size.

[0023] Optionally, when the mass evaporation rate of the dirt layer is lower than a first threshold and the temperature of the dirt layer is higher than a second threshold, it is determined that the dirt layer is in a burnt-dry position.

[0024] Optionally, it also includes: in the process of calculating the flow heat transfer parameters, judging the convergence and rationality of the calculation results according to physical laws to save the number of iterations in the calculation process.

[0025] Optionally, the method further includes: dynamically adjusting the grid size during the calculation of the flow heat transfer parameters.

[0026] Optionally, the parameter boundary values ​​of the fouling surface include: temperature of the fouling surface, critical pore radius, critical pore radius gradient and mass evaporation rate gradient.

[0027] To solve the above technical problems, the present invention provides a computing device, comprising: at least one processor; and at least one memory on which instructions are stored, and when the instructions are executed by the at least one processor individually or collectively, the computing device executes the method as described above.

[0028] To solve the above technical problem, the present invention provides a computer-readable medium, on which instructions are stored. When the instructions are executed individually or collectively by at least one processor of a computing device, the computing device executes the above method.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The present invention provides a method for analyzing the burnout rate of a fouling layer required for fouling risk analysis. The method divides the fouling layer from the fouling surface to the wall surface in sequence, considers that the inside of the fouling is a capillary porous structure, and considers the capillary action in the pores, assumes the parameter boundary value of the fouling surface, solves the energy conservation equation, momentum conservation equation and phase heat transfer equation in sequence, and judges the convergence and rationality of the calculation results according to the physical laws, and finally obtains the burnout rate of the fouling layer, making the calculation results more accurate. The burnout rate of the fouling layer calculated by this method is an important indicator for evaluating the risk of local cladding corrosion (CILC) in the risk analysis of reactor core fouling. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the present application. They are included and constitute a part of the present application. The accompanying drawings illustrate embodiments of the present application and together with the present specification serve to explain the principles of the present application. In the accompanying drawings:

[0032] Figure 1 It is a flow chart of a method for calculating the burn-off rate of a dirt layer according to an embodiment of the present disclosure.

[0033] Figure 2 Schematic diagram of dirt layer division according to an embodiment of the present disclosure.

[0034] Figure 3 Schematic diagram of a capillary porous body structure according to an embodiment of the present disclosure.

[0035] Figure 4 yes Figure 1 Flow chart of an embodiment of step S3 in FIG.

[0036] Figure 5 is a system block diagram of a computing device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. Unless it is obvious from the language environment or otherwise explained, the same reference numerals in the figures represent the same structure or operation.

[0038] The present invention provides a method for analyzing the burnout rate of a fouling layer required for fouling risk analysis. The method divides the fouling into grids, assumes the parameter boundary values ​​of the fouling surface, solves the energy conservation equation, momentum conservation equation and interphase heat transfer equation in sequence, and judges the convergence and rationality of the calculation results according to physical laws, and finally obtains the burnout rate of the fouling layer. The burnout rate of the fouling layer calculated by this method is an important indicator for evaluating the risk of local cladding corrosion (CILC) in the risk analysis of reactor core fouling.

[0039] Figure 1 FIG. 1 is a flow chart of a method for calculating the burnout rate of a dirt layer according to an embodiment of the present disclosure. Figure 1 As shown, the method 100 for calculating the burning-out rate of the dirt layer includes the following steps:

[0040] Step S1: Divide the dirt layers from the dirt surface to the wall surface in sequence.

[0041] Figure 2 Schematic diagram of dirt layer division according to an embodiment of the present disclosure. Figure 2 As shown, the grid is evenly divided according to the given dirt thickness δ, and the grid size is dx. The dirt layers are divided from the dirt surface (close to the fluid side) to the wall, and are recorded as x(1), x(2), ..., x(n), x(n+1) respectively. x(n) represents the nth dirt layer. In particular, x(1) represents the first dirt layer, also known as the dirt surface. The heat flux of the wall surface is transferred in the direction of the fluid. is the heat flux of the fluid.

[0042] Step S2: Set the inside of the fouling to be a capillary porous structure and set the parameter boundary values on the fouling surface.

[0043] The present disclosure sets the inside of the fouling to be a capillary porous structure. Figure 3 is a schematic diagram of the capillary porous structure according to an embodiment of the present disclosure. As Figure 3 shown, there is a group of interconnected pores in the porous body of this structure. These pores or the porous body can be divided into clusters of vertical pores and interconnected side pores. Assume that the larger vertical pores (r > critical effective radius R*) are filled with steam, and the smaller pores (r < R*) are filled with liquid. For the side pores with a critical effective radius of R*, a dynamic equilibrium state is maintained between the liquid phase and the steam.

[0044] The parameter boundary value refers to the boundary of the effective range of the input parameter and the values near it. These values usually include the minimum value, the maximum value of the parameter, and the adjacent values of these values. For example, if the value range of a parameter is [1, 100], then the minimum value is 1, the maximum value is 100. Then the effective boundary values are 1 and 100. The invalid boundary values are 0 and 101. The adjacent values are 2 and 99. Boundary value analysis is based on the assumption that instances tend to occur near the boundary of the input range rather than in the middle. Optionally, the parameter boundary values on the fouling surface include but are not limited to the temperature of the fouling surface 、critical pore radius 、critical pore radius gradient 、mass evaporation rate gradient .

[0045] Surface mass evaporation rate is obtained according to "the heat flux on the fouling surface must be equivalent to the heat flux on the wall surface ", and their mutual relationship is as shown in Equation .

[0046] (1)

[0047] In the formula: —Vapor phase enthalpy value on the fouling surface, unit is J / kg, where v represents the vapor phase;

[0048] —Liquid phase enthalpy value on the fouling surface, unit is J / kg, where l represents the liquid phase;

[0049] —Heat flux transferred by heat conduction, unit is W / m 2 .

[0050] Step S3: construct a set of relational expressions for calculating flow heat transfer parameters, and calculate the flow heat transfer parameters of each fouling layer according to the relational expressions and the parameter boundary values ​​of the fouling surface.

[0051] The combination of relational expressions used for calculating flow heat transfer parameters includes but is not limited to the energy conservation equation, the momentum conservation equation, and the phase heat transfer equation. Optionally, calculating the flow heat transfer parameters of each fouling layer includes inputting the parameter boundary value of the fouling surface into the combination of relational expressions used for calculating flow heat transfer parameters, and recursively calculating the flow heat transfer parameters of each fouling layer.

[0052] Optionally, flow heat transfer parameters include, but are not limited to, mass evaporation rate, temperature, and critical pore radius.

[0053] Figure 4 yes Figure 1 Flow chart of step S3 in an embodiment. Figure 4 As shown, step S3 includes:

[0054] Step S31: construct an energy conservation equation, and calculate the temperature of the n+1 layer according to the energy conservation equation.

[0055] This method assumes that for steady-state conditions, the energy transferred out of the fouling layer by heat conduction is equal to the net energy transferred into the fouling layer by convection of liquid and steam. The energy conservation equation is expressed as As shown. Combined with Fourier's law, as shown in the relation As shown, the n+1 layer fouling temperature can be obtained.

[0056] (2)

[0057] Where: —Heat flow under the heat conduction of the n+1th layer, in W / m 2 ;

[0058] is the heat flux under the heat conduction of the nth layer, in W / m 2 ;

[0059] is the mass evaporation rate of the n+1th layer, in kg / m 2 ·s;

[0060] is the mass evaporation rate of the nth layer, in kg / m 2 ·s;

[0061] is the vapor phase enthalpy of the dirt surface, is the liquid phase enthalpy of the dirt surface.

[0062] (3)

[0063] (4)

[0064] Where: k is the thermal conductivity of the n+1th layer, and the subscripts crud, l, v, and s represent the dirt layer, the liquid phase in the dirt layer, the vapor phase in the dirt layer, and the solid phase in the dirt layer, respectively.

[0065] —porosity of the n+1th layer;

[0066] —The proportion of the n+1th liquid phase in the dirt layer.

[0067] Optionally, before step S31, the method further includes: adjusting the temperature of the dirt surface Enter formula (3) to calculate the heat flow on the dirt surface , determine the heat flow on the dirt surface Is the deviation from the actual measured heat flow greater than a preset threshold? If so, adjust the temperature of the fouling surface. The value of .

[0068] Step S32: construct a momentum conservation equation, and calculate the critical pore radius of the n+1 layer according to the momentum conservation equation.

[0069] This method takes into account the fraction of the liquid phase in the fouling layer based on Darcy's Law for porous media. Variable, add the space acceleration phase to the momentum conservation equation, the relationship is as follows and Darcy's law is a basic law describing the flow of fluid in porous media, proposed by French engineer Henry Darcy in 1856. Darcy's law states that the flow rate of a fluid in a porous medium is proportional to the hydraulic gradient, and the proportionality coefficient is the permeability coefficient.

[0070] (5)

[0071] (6)

[0072] Where: —pressure, in Pa, with subscripts l and v representing the liquid phase and vapor phase, respectively;

[0073] —Density, in kg / m 3 ;

[0074] —Flow rate, in m / s;

[0075] —Viscosity, unit is N·s / m 2 ;

[0076] —Permeability, in m 2 .

[0077] The difference in pressure gradient between the vapor and liquid phases is shown in the relation As shown, combined with the kinetic conservation equation, the critical pore radius gradient of the n+1 layer can be obtained .

[0078] (7)

[0079] Where: —Surface tension of liquid, in N / m;

[0080] —Contact angle, in degrees.

[0081] R*—critical pore radius.

[0082] Optionally, before step S32, the method further includes: calculating the critical pore radius of the n+1 layer and judging its rationality. , critical pore radius gradient Enter the formula = , and obtain the critical pore radius , and determine whether it is within a given pore radius range If not within the range, adjust the initial parameters: critical pore radius , critical pore radius gradient The value of .

[0083] Optionally, after step S32, the method further includes: judging whether the momentum conservation equation converges based on the Newton iteration method, and if not, returning to the step: calculating the critical pore radius of the n+1 layer and judging the rationality. When performing iterative calculations, the present disclosure adopts the Newton iteration method, and in fact, different iterative convergence algorithms can also be used without affecting the calculation results.

[0084] Optionally, after step S32, the method further includes: determining the critical pore radius gradient Is it positive? If negative, adjust the initial parameters: critical pore radius , critical pore radius gradient The value of .

[0085] Step S33: constructing an interphase heat transfer equation, and calculating the mass evaporation rate of the n+1 layer according to the interphase heat transfer equation.

[0086] The equation for heat transfer between phases in the gap is as follows: As shown, combined with the momentum conservation equation, the mass evaporation rate gradient of the n+1 layer can be obtained.

[0087] (8)

[0088] Where: —Volume heat transfer coefficient of phase change, unit is W / m 3 K;

[0089] —Saturation temperature of the liquid inside the dirt, in K;

[0090] is the temperature of the dirt layer, in K;

[0091] —Latent heat of vaporization, in J / kg.

[0092] Evaporation rate according to surface mass and the mass evaporation rate gradient of the n+1 layer The mass evaporation rate of the n+1 layer can be calculated. For example, the surface mass evaporation rate and mass evaporation rate gradient enter = , output ; Then according to the mass evaporation rate and the calculated mass evaporation rate gradient Calculate , and so on, we get the mass evaporation rate .

[0093] Optionally, before step S33, the method further includes: setting an initial value of the mass evaporation rate gradient , and based on this value and the surface mass evaporation rate Calculate the mass evaporation rate , and determine whether it is within the preset range. If not, adjust the mass evaporation rate gradient The value of .

[0094] Optionally, after step S33, the method further includes: judging whether the interphase heat transfer equation converges based on the Newton iteration method, and if not, returning to step: setting the initial value of the mass evaporation rate gradient of the n+1 layer.

[0095] Step S4: determine whether the current dirt layer is at a burn-out position according to the flow heat transfer parameters. If so, obtain the thickness of the current dirt layer, and calculate the burn-out rate of the dirt layer according to the thickness of the current dirt layer and the total thickness of the dirt layer.

[0096] The accumulation of dirt will reduce the heat transfer efficiency, thereby reducing the evaporation rate. Optionally, when the mass evaporation rate of the dirt layer is lower than a first threshold and the temperature of the dirt layer is higher than a second threshold, the dirt layer is judged to be a burnt-out position. The burnt-out rate of the dirt layer is calculated according to equation (9).

[0097] (9)

[0098] Where: —The thickness of the current dirt layer, in m;

[0099] —Total thickness of the dirt layer, in m.

[0100] The method for calculating the burning-dryness rate of the dirt layer of the present invention has the following advantages:

[0101] 1. The present invention provides a method and system for analyzing the burnout rate of a dirt layer required for fouling risk analysis, and constructs a set of relationship combinations for calculating the burnout rate of the dirt layer on the surface of the reactor core fuel rod. The temperature, mass evaporation rate and other parameters of each dirt layer are calculated in detail according to the fouling characteristic parameters and fluid conditions, and then the burnout rate of the dirt layer is obtained, which is helpful for conducting local cladding corrosion analysis caused by fouling.

[0102] 2. In the present invention, by setting a reasonable analysis process and combining physical laws, setting rationality judgment at appropriate positions in the analysis method process, the number of iterations in the calculation process can be saved and more accurate and reasonable calculation results can be obtained.

[0103] 3. In the present invention, the capillary porous structure inside the dirt is considered, and the capillary action in the pores is considered, so that the calculation results are closer to reality.

[0104] 4. In the present invention, the dirt is divided into fine grids, and the grid size is dynamically adjusted in the calculation process to make the calculation results more accurate.

[0105] Flowcharts are used in the present application to illustrate the operations performed by the system according to the embodiments of the present application. It should be understood that the preceding or following operations are not necessarily performed accurately in order. On the contrary, various steps may be processed in reverse order or simultaneously. At the same time, other operations may be added to these processes, or one or more operations may be removed from these processes.

[0106] The present application also includes a computing device, including a memory and a processor, wherein the memory is used to store instructions executable by the processor; and the processor is used to execute the instructions to implement the above-mentioned method for calculating the burn-off rate of the dirt layer.

[0107] Figure 5 is a system block diagram of a computing device according to an embodiment of the present disclosure. Figure 5As shown, the computing device 500 may include an internal communication bus 501, a processor 502, a read-only memory (ROM) 503, a random access memory (RAM) 504, and a communication port 505. When applied to a personal computer, the computing device 500 may also include a hard disk 506. The internal communication bus 501 can realize data communication between the components of the computing device 500. The processor 502 can make judgments and issue prompts. In some embodiments, the processor 502 can be composed of one or more processors. The communication port 505 can realize data communication between the computing device 500 and the outside. In some embodiments, the computing device 500 can send and receive information and data from the network through the communication port 505. The computing device 500 may also include different forms of program storage units and data storage units, such as a hard disk 506, a read-only memory (ROM) 503 and a random access memory (RAM) 504, which can store various data files used for computer processing and / or communication, and possible program instructions executed by the processor 502. The processor executes these instructions to implement the main part of the method. The processing result of the processor is transmitted to the user device through the communication port and displayed on the user interface.

[0108] The above-mentioned operation method can be implemented as a computer program, stored in the hard disk 506, and loaded into the processor 502 for execution, so as to implement the method for calculating the burn-off rate of the dirt layer of the present application.

[0109] The present application also includes a computer-readable medium storing a computer program code, which, when executed by a processor, implements the above-mentioned method for calculating the burn-off rate of the dirt layer.

[0110] When the method for calculating the burn-off rate of the dirt layer is implemented as a computer program, it can also be stored in a computer-readable storage medium as a product. For example, a computer-readable storage medium may include, but is not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs)), smart cards, and flash memory devices (e.g., electrically erasable programmable read-only memories (EPROMs), cards, sticks, key drives). In addition, the various storage media described herein can represent one or more devices and / or other machine-readable media for storing information. The term "machine-readable medium" may include, but is not limited to, wireless channels and various other media (and / or storage media) that can store, contain and / or carry code and / or instructions and / or data.

[0111] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only used as an example and does not constitute a limitation of the present application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements and amendments to the present application. Such modifications, improvements and amendments are suggested in the present application, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of the present application.

[0112] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0113] Some aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor may be one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. In addition, various aspects of the present application may be represented as computer products located in one or more computer-readable media, which include computer-readable program codes. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes ...), optical disks (e.g., compact disks CDs, digital versatile disks DVDs ...), smart cards, and flash memory devices (e.g., cards, sticks, key drives ...).

[0114] A computer-readable medium may include a propagated data signal containing computer program code, such as in baseband or as part of a carrier wave. The propagated signal may have a variety of manifestations, including electromagnetic, optical, etc., or a suitable combination. A computer-readable medium may be any computer-readable medium other than a computer-readable storage medium, which may be connected to an instruction execution system, device or apparatus to communicate, propagate or transmit a program for use. The program code on the computer-readable medium may be propagated via any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above mediums.

[0115] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the subject of the present application requires more features than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0116] As shown in this application, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0117] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to actual proportional relationships. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0118] In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used for the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the numbers are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are approximate values, which can be changed according to the required characteristics of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the method of general digit retention. Although the numerical domains and parameters used to confirm the breadth of the range in some embodiments of the present application are approximate values, in specific embodiments, the setting of such numerical values ​​is as accurate as possible within the feasible range.

[0119] Although the present application has been described with reference to the current specific embodiments, ordinary technicians in this technical field should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present application, they will fall within the scope of the present application.

Claims

1. A method for calculating the burnout rate of a dirt layer, characterized in that: include: Dirt layers are divided sequentially from the dirt surface to the wall surface; Set the dirt interior to a capillary porous structure and set the parameter boundary value of the dirt surface; Constructing a set of relational expressions for calculating flow heat transfer parameters, and calculating the flow heat transfer parameters of each fouling layer according to the relational expressions and the parameter boundary values ​​of the fouling surface; It is determined whether the current dirt layer is at a burn-out position according to the flow heat transfer parameters. If so, the thickness of the current dirt layer is obtained, and the burn-out rate of the dirt layer is calculated according to the thickness of the current dirt layer and the total thickness of the dirt layer.

2. The method for calculating the burnout rate of the dirt layer according to claim 1, characterized in that: The flow heat transfer parameters include mass evaporation rate, temperature and critical pore radius, and the relationship combination includes: momentum conservation equation, energy conservation equation and interphase heat transfer equation.

3. The method for calculating the burnout rate of the dirt layer according to claim 2, characterized in that: The momentum conservation equation is: in, is the surface tension of the liquid, is the contact angle, R* is the critical pore radius, P is the pressure, the subscripts l and v represent the liquid phase and vapor phase respectively, and x is the thickness parameter of the fouling layer.

4. The method for calculating the burnout rate of the dirt layer according to claim 2, characterized in that: The energy conservation equation is: in, is the heat flow under the heat conduction of the n+1th layer, is the heat flow under the heat conduction of the nth layer, is the mass evaporation rate of the n+1th layer, is the mass evaporation rate of the nth layer, is the vapor phase enthalpy of the dirt surface, is the liquid phase enthalpy of the dirt surface, is the difference between the liquid phase enthalpy of the dirt surface at the n+1th layer and the vapor phase enthalpy of the dirt surface, It is the difference between the liquid phase enthalpy of the dirt surface in the nth layer and the vapor phase enthalpy of the dirt surface.

5. The method for calculating the burnout rate of the dirt layer according to claim 4, characterized in that: The temperature of each dirt layer is calculated by the following formula: in, is the thermal conductivity of the dirt layer, is the temperature of the dirt layer, and x is the thickness parameter of the dirt layer.

6. The method for calculating the burnout rate of the dirt layer according to claim 5, characterized in that: The thermal conductivity of the dirt layer is calculated by the following formula: in, is the porosity of the n+1th layer, is the ratio of the liquid phase in the n+1th layer to the dirt layer, k is the thermal conductivity, and the subscripts l, v, and s represent the liquid phase in the dirt layer, the vapor phase in the dirt layer, and the solid phase in the dirt layer, respectively.

7. The method for calculating the burnout rate of the dirt layer according to claim 6, characterized in that: Based on Darcy's law for porous media, the proportion of the liquid phase in the fouling layer A variable value.

8. The method for calculating the burnout rate of the dirt layer according to claim 2, characterized in that: The interphase heat transfer equation is: in, is the volume heat transfer coefficient of phase change, is the saturation temperature of the liquid inside the dirt, is the temperature of the dirt layer, is the latent heat of vaporization, is the mass evaporation rate, and x is the thickness parameter of the dirt layer.

9. The method for calculating the burnout rate of the dirt layer according to claim 2, characterized in that: When the mass evaporation rate of the dirt layer is lower than a first threshold and the temperature of the dirt layer is higher than a second threshold, it is determined that the dirt layer is in a burnt-dry position.

10. The method for calculating the burnout rate of the dirt layer according to claim 1, characterized in that: Also includes: In the process of calculating the flow heat transfer parameters, the convergence and rationality of the calculation results are judged according to physical laws to save the number of iterations in the calculation process.

11. The method for calculating the burnout rate of the dirt layer according to claim 1, characterized in that: Also includes: In the process of calculating the flow heat transfer parameters, the grid size is dynamically adjusted.

12. The method for calculating the burn-off rate of a dirt layer according to any one of claims 1 to 11, characterized in that: The parameter boundary values ​​of the fouling surface include: the temperature of the fouling surface, the critical pore radius, the critical pore radius gradient and the mass evaporation rate gradient.

13. A computing device, characterized in that: include: at least one processor; as well as At least one memory having instructions stored thereon, wherein when the instructions are executed individually or collectively by the at least one processor, the computing device executes the method as claimed in any one of claims 1 to 12.

14. A computer readable medium, characterized in that The computer-readable medium stores instructions, which, when executed individually or collectively by at least one processor of a computing device, cause the computing device to execute the method as claimed in any one of claims 1 to 12.

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