Calculation Method, Calculation Device and Readable Medium for Mass Evaporation Rate in Boiling Environment

Abstract

The present invention provides a method, a computing device and a readable medium for calculating the mass evaporation rate in a boiling environment. The method for calculating the mass evaporation rate includes: dividing nodes of a pressurized water reactor coolant system; for each node, determining whether the fouling thickness of the current node is greater than a critical value. If so, the current node is a fouling surface, and the mass evaporation rate of the node is calculated based on a porous sediment boiling module. If not, the current node is a clean cladding surface, and the mass evaporation rate of the node is calculated based on a boiling heat flux and mass evaporation module. The present invention separately considers clean and fouled cladding surfaces, establishes a set of mass evaporation rate calculation formulas, and calculates the mass evaporation rate of each node in the reactor core and steam generator in detail according to user input information. The calculated mass evaporation rate is more accurate and conforms to the actual scenario.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of nuclear reactors, and particularly relates to a method, a device and a readable medium for calculating the mass evaporation rate in a boiling environment. Background Art

[0002] During the operation of a reactor, corrosion products (such as nickel and iron) on the pipes of the pressurized water reactor coolant system in a pressurized water reactor nuclear power plant will be released into the coolant and deposited on the upper part of the high heat flux fuel assembly where subcooled nucleate boiling occurs to form dirt. Boron and lithium hydroxide accumulate in the pore-like gaps of the dirt. When the boron accumulates to a certain extent, it will precipitate onto the dirt, which will cause the power of the upper part of the fuel assembly to decrease. As a result, the power peak will shift downward, that is, crud-induced power shift (CIPS) occurs. If the dirt deposition at a local position is thick, the coolant will not be able to flow through the dirt and cool the surface of the fuel cladding, which will cause the temperature of the fuel cladding to be too high. If the fuel cladding is at a high temperature for a long time, it will accelerate the corrosion and failure of the fuel cladding, resulting in crud-induced localized corrosion (CILC).

[0003] CIPS and CILC will affect the safety and economy of reactor operation. The risk assessment of dirt in the reactor core is one of the important issues that future nuclear safety will focus on. The mass evaporation rate refers to the mass evaporated per unit time per unit area. The accumulation of dirt will reduce the heat transfer efficiency, thereby reducing the mass evaporation rate. The mass evaporation rate is one of the important indicators for evaluating the dirt risk in the reactor core. Therefore, it is necessary to establish a method for calculating the mass evaporation rate for dirt risk analysis to evaluate the risks of CIPS and CILC. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method, a device and a readable medium for calculating the mass evaporation rate in a boiling environment, and to solve the current lack of a method for calculating the mass evaporation rate for dirt risk analysis.

[0005] To solve the above technical problem, the present invention provides a method for calculating the mass evaporation rate in a boiling environment, including: dividing nodes of the pressurized water reactor coolant system; for each node, determining whether the dirt thickness of the current node is greater than the critical value. If so, the current node is the dirt surface, and the mass evaporation rate of the node is calculated based on the porous deposit boiling module. If not, the current node is the clean cladding surface, and the mass evaporation rate of the node is calculated based on the boiling heat flux and mass evaporation module.

[0006] Optionally, calculating the mass evaporation rate of the node based on the porous sediment boiling module includes: dividing grid nodes sequentially from the fouling surface to the wall surface; setting the interior of the fouling as a capillary porous structure and setting the parameter boundary values on the fouling surface; constructing the energy equation and heat transfer equation of the fouling, and inputting the parameter boundary values on the fouling surface into the energy equation and the heat transfer equation to calculate the mass evaporation rate of each grid node.

[0007] Optionally, the parameter boundary values on the fouling surface include the temperature of the fouling surface and the mass evaporation rate gradient of the fouling surface.

[0008] Optionally, calculating the mass evaporation rate of each grid node includes: calculating the mass evaporation rate of the fouling surface based on the heat flux transferred by conduction through the fouling surface and the heat flux of the wall surface; calculating the temperature gradient of each grid node according to the energy equation, and calculating the temperature of each grid node according to the temperature of the fouling surface and the temperature gradient; calculating the mass evaporation rate gradient of each grid node according to the heat transfer equation and the temperature of each grid node; calculating the mass evaporation rate of each grid node according to the mass evaporation rate of the fouling surface, the mass evaporation rate gradient of the fouling surface, and the mass evaporation rate gradient of each grid node.

[0009] Optionally, the mass evaporation rate of the fouling surface is calculated by the following formula:

[0010]

[0011] where is the enthalpy value of the vapor phase on the fouling surface, is the enthalpy value of the liquid phase on the fouling surface, is the heat flux transferred by conduction through the fouling surface, is the heat flux of the wall surface, and G(1) is the mass evaporation rate of the fouling surface.

[0012] Optionally, the energy equation is:

[0013]

[0014] where is the heat flux transferred by conduction through the (n + 1)-th grid node, is the thermal conductivity of the fouling, is the temperature gradient of the (n + 1)-th grid node.

[0015] Optionally, the heat transfer equation is:

[0016]

[0017] where is the volume heat transfer coefficient of the phase change, is the saturation temperature of the liquid inside the fouling, is the temperature of the grid node, is the latent heat of vaporization, is the mass evaporation rate gradient.

[0018] Optionally, calculating the mass evaporation rate of the node based on the boiling heat flux and the mass evaporation module includes: calculating the wall temperature considering only forced convection heat transfer and the wall temperature at the boiling onset point; determining whether the wall temperature considering only forced convection heat transfer is greater than the wall temperature at the boiling onset point, and if so, calculating the heat flux density component through the subcooled boiling equation; calculating the mass evaporation rate according to the heat flux density component and the latent heat of vaporization.

[0019] Optionally, the wall temperature considering only forced convection heat transfer is calculated by the following formula:

[0020]

[0021] where, is the wall temperature considering only forced convection heat transfer, is the fluid temperature, is the heat transfer coefficient of forced convection heat transfer, and q is the heat flux density.

[0022] Optionally, the wall temperature at the boiling onset point is calculated by the following formula:

[0023]

[0024] where, is the wall temperature at the boiling onset point, is the fluid temperature, is the heat flux density component at the boiling onset point, is the heat transfer coefficient at the boiling onset point.

[0025] Optionally, the subcooled boiling equation is:

[0026]

[0027] where q is the heat flux density, is the saturated boiling heat flux density component, is the heat flux density component at the boiling onset point, is the forced convection heat flux density component.

[0028] Optionally, the mass evaporation rate is calculated by the following formula:

[0029]

[0030] where, is the mass evaporation rate, is the latent heat of vaporization.

[0031] Optionally, it further includes: if the wall temperature considering only forced convection heat transfer is less than or equal to the wall temperature at the onset of boiling, the mass evaporation rate is zero.

[0032] To solve the above technical problems, the present invention provides a computing device, including: at least one processor; and at least one memory storing instructions thereon, which when executed by the at least one processor alone or jointly, cause the computing device to execute the method as described above.

[0033] To solve the above technical problems, the present invention provides a computer-readable medium storing instructions thereon, which when executed by at least one processor of a computing device alone or jointly, cause the computing device to execute the method as described above.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The method for calculating the mass evaporation rate of the boiling environment, the computing device and the readable medium of the present invention respectively consider the clean and fouled cladding surfaces, establish a set of mass evaporation rate calculation formulas, and calculate the mass evaporation rate of each node in the core and the steam generator in detail according to the user input information. The calculated mass evaporation rate is more accurate and conforms to the actual scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The inclusion of the drawings is to provide a further understanding of the present application. They are incorporated and constitute a part of the present application. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0037] Figure 1 is a flowchart of a method for calculating the mass evaporation rate of a boiling environment according to an embodiment of the present disclosure.

[0038] Figure 2 is Figure 1 a flowchart of an embodiment of step S3 in

[0039] Figure 3 is a schematic diagram of the division of fouling grid nodes according to an embodiment of the present disclosure.

[0040] Figure 4 is a schematic diagram of a capillary porous structure according to an embodiment of the present disclosure.

[0041] Figure 5 is Figure 1 a flowchart of an embodiment of step S4 in

[0042] Figure 6 is a system block diagram of a computing device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] To more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some examples or embodiments of the present application. For those of ordinary skill in the art, without creative efforts, the present application can also be applied to other similar scenarios based on these drawings. Unless obvious from the language context or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0044] The present invention provides a method for calculating the mass evaporation rate in a boiling environment. This method separately considers the clean and fouled cladding surfaces, establishes a set of mass evaporation rate calculation formulas, and calculates the mass evaporation rate of each node in the core and steam generator in detail according to the user input information, for carrying out CIPS and CILC risk analyses.

[0045] Figure 1 is a flowchart of the method for calculating the mass evaporation rate in a boiling environment according to an embodiment of the present disclosure. As Figure 1 shown, the method 100 for calculating the mass evaporation rate in a boiling environment includes:

[0046] Step S1: Divide the nodes of the pressurized water reactor coolant system.

[0047] In the nuclear power plant system, the reactor coolant system is also called the primary loop system. The coolant system consists of reactor coolant pumps, reactors, steam generators, and corresponding pipelines. For the reactor coolant system, model calculation nodes are divided for the core and steam generator according to the calculation requirements.

[0048] Step S2: For each node, determine whether the fouling thickness of the current node is greater than the critical value. If so, go to step S3; if not, go to step S4.

[0049] Among them, the critical value can be set as needed, and the present application does not limit this.

[0050] Step S3: The current node is a fouled surface, and the mass evaporation rate of the node is calculated based on the porous deposit boiling module.

[0051] Taking the critical value of 500 nm as an example, determine whether the fouling thickness of the current node is greater than 500 nm. If it is greater, then the current node is a fouled surface, and the mass evaporation rate of the node is calculated based on the porous deposit boiling module.

[0052] Figure 2 is Figure 1 a flowchart of an embodiment of step S3 in Figure 2 shown, step S3 includes:

[0053] Step S31: Divide grid nodes successively from the fouling surface towards the wall surface.

[0054] Figure 3 It is a schematic diagram of fouling grid node division according to an embodiment of the present disclosure. As Figure 3 shown, the grid is evenly divided according to the given fouling thickness δ, and the grid size is dx. Nodes are successively divided from the fouling surface (close to the fluid side) towards the wall surface, and are respectively denoted as x(1), x(2), …, x(n), x(n + 1). x(n) represents the nth fouling layer. In particular, x(1) represents the first fouling layer, also known as the fouling surface. Among them is the heat flux of the wall surface, which is transferred in the fluid direction, is the heat flux of the fluid.

[0055] Step S32: Set the interior of the fouling as a capillary porous structure and set the parameter boundary values of the fouling surface.

[0056] The present disclosure sets the interior of the fouling as a capillary porous structure. Figure 4 It is a schematic diagram of the capillary porous structure according to an embodiment of the present disclosure. As Figure 4 shown, there is a group of interconnected pores in the porous body of this structure. These pores or porous bodies 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.

[0057] Parameter boundary values refer to the boundaries of the effective range of input parameters and the values near them. 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 and 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 often occur near the boundaries of the input range rather than in the middle. Optionally, the parameter boundary values of the fouling surface include but are not limited to the temperature of the fouling surface 、the critical pore radius 、the critical pore radius gradient 、the mass evaporation rate gradient .

[0058] Step S33: Construct the energy equation and heat transfer equation of the fouling, and input the parameter boundary values of the fouling surface into the energy equation and heat transfer equation to calculate the mass evaporation rate of each grid node.

[0059] Optionally, calculating the mass evaporation rate of each grid node includes:

[0060] Step S331: Calculate the mass evaporation rate of the fouling surface based on the heat flux transferred by heat conduction through the fouling surface and the heat flux of the wall surface.

[0061] Mass evaporation rate of the fouling surface Obtained based on "the heat flux transferred by heat conduction through the fouling surface must be equivalent to the heat flux of the wall surface ", and their mutual relationship is as shown in Equation as follows.

[0062] (1)

[0063] In the formula: —Enthalpy value of the vapor phase on the fouling surface, unit is J / kg, where v represents the vapor phase;

[0064] —Enthalpy value of the liquid phase on the fouling surface, unit is J / kg, where l represents the liquid phase;

[0065] is the heat flux transferred by heat conduction through the fouling surface, unit is W / m 2 .

[0066] Step S332: Calculate the temperature gradient of each grid node according to the energy equation, and calculate the temperature of each grid node based on the temperature of the fouling surface and the temperature gradient;

[0067] This application believes that for the steady-state situation, the energy transferred out of the fouling layer by heat conduction is equal to the net energy transferred into the fouling layer by the convection of the liquid and vapor. The relationship of its energy conservation equation is as shown. Combining with Fourier's law, as shown in the relationship as follows:

[0068] (2)

[0069] In the formula: —Heat flux under the heat conduction of the (n + 1)-th layer, unit is W / m 2 ;

[0070] is the heat flux under the heat conduction of the n-th layer, unit is W / m 2 ;

[0071] is the mass evaporation rate of the (n + 1)-th layer, unit is kg / m 2 ·s;

[0072] is the mass evaporation rate of the n-th layer, unit is kg / m 2 ·s;

[0073] is the enthalpy value of the vapor phase on the fouling surface, is the enthalpy value of the liquid phase on the fouling surface.

[0074] (3)

[0075] (4)

[0076] In the formula: k is the thermal conductivity of the (n + 1)-th layer, and the subscripts crud, l, v, s represent the fouling layer, the liquid phase in the fouling layer, the vapor phase in the fouling layer, and the solid phase in the fouling layer respectively.

[0077] —is the porosity of the (n + 1)-th layer;

[0078] —is the proportion of the liquid phase in the (n + 1)-th layer in the fouling layer;

[0079] is the temperature gradient of the (n + 1)-th layer.

[0080] When the temperature and the temperature gradient of the fouling surface are known, and are input into the formula , the temperature of the second layer is obtained. According to and , the temperature of the third layer can be calculated, and so on, the temperature of the (n + 1)-th layer can be calculated.

[0081] Step S333: Calculate the mass evaporation rate gradient of each grid node according to the heat transfer equation and the temperature of each grid node;

[0082] The equation for heat transfer between phases in the voids is as follows:

[0083] (5)

[0084] Among them, is the volumetric heat transfer coefficient of phase change, is the saturation temperature of the liquid inside the fouling, is the temperature of the grid node, is the latent heat of vaporization, is the mass evaporation rate gradient.

[0085] Step S334: Calculate the mass evaporation rate of each grid node according to the mass evaporation rate on the fouling surface, the mass evaporation rate gradient on the fouling surface, and the mass evaporation rate gradient of each grid node.

[0086] According to the surface mass evaporation rate , the mass evaporation rate gradient of the fouled surface 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 the mass evaporation rate gradient are input = , and the output ; then, based on the mass evaporation rate and the calculated mass evaporation rate gradient , is calculated, and so on, to obtain the mass evaporation rate of the n+1 layer.

[0087] When the solution of this relational expression (5) converges, it is judged whether the position of dry evaporation is reached. If so, the calculation ends.

[0088] Step S4: The current node is a clean cladding surface, and the mass evaporation rate of the node is calculated based on the boiling heat flux and mass evaporation module.

[0089] Continuing to take the critical value of 500 nm as an example, it is judged whether the fouling thickness of the current node is greater than 500 nm. If it is less than or equal to 500 nm, the current node is a clean cladding surface. The mass evaporation rate of the node is calculated based on the boiling heat flux and mass evaporation module.

[0090] Figure 5 Yes Figure 1 is a flowchart of an embodiment of step S4 in Figure 4 . As

[0091] shown, step S4 includes:

[0092] Step S41: Calculate the wall temperature considering only forced convection heat transfer.

[0093] (6)

[0094] where is the wall temperature considering only forced convection heat transfer, is the fluid temperature, is the forced convection heat transfer coefficient, and q is the heat flux density.

[0095] Step S42: Calculate the wall temperature at the boiling onset point.

[0096] (7)

[0097] where is the wall temperature at the boiling onset point, is the fluid temperature, is the heat flux density component at the boiling onset point. is the heat transfer coefficient at the boiling onset point.

[0098] Step S43: Determine whether the wall temperature considering only forced convection heat transfer is greater than the wall temperature at the boiling onset point. If it is, proceed to step S44; if not, proceed to step S46.

[0099] Step S44: Calculate the heat flux density component through the subcooled boiling equation.

[0100] (8)

[0101] where q is the heat flux density, is the saturated boiling heat flux density component, is the heat flux density component at the boiling onset point, is the forced convection heat flux density component.

[0102] Step S45: Calculate the mass evaporation rate based on the heat flux density component and the latent heat of vaporization.

[0103] (9)

[0104] where, is the mass evaporation rate, is the latent heat of vaporization.

[0105] Step S46: The mass evaporation rate is zero.

[0106] That is, .

[0107] This application also includes a computing device, including a memory and a processor. Among them, the memory is used to store instructions executable by the processor; the processor is used to execute the instructions to implement the mass evaporation rate calculation method for the boiling environment described above.

[0108] Figure 6 is the system block diagram of the computing device according to an embodiment of the present disclosure. Refer to Figure 6As shown, the computing device 600 may include an internal communication bus 601, a processor 602, a read-only memory (ROM) 603, a random access memory (RAM) 604, and a communication port 605. When the application is on a personal computer, the computing device 600 may further include a hard disk 606. The internal communication bus 601 may enable data communication among the components of the computing device 600. The processor 602 may make judgments and issue prompts. In some embodiments, the processor 602 may be composed of one or more processors. The communication port 605 may enable data communication between the computing device 600 and the outside. In some embodiments, the computing device 600 may send and receive information and data from a network through the communication port 605. The computing device 600 may further include different forms of program storage units and data storage units, such as the hard disk 606, the read-only memory (ROM) 603, and the random access memory (RAM) 604, which can store various data files used for computer processing and / or communication, as well as possible program instructions executed by the processor 602. The processor executes these instructions to implement the main part of the method. The result processed by the processor is transmitted to the user device through the communication port and displayed on the user interface.

[0109] The above operation method may be implemented as a computer program, stored in the hard disk 606, and loaded into the processor 602 for execution to implement the mass evaporation rate calculation method for the boiling environment of the present application.

[0110] The present application further includes a computer-readable medium storing computer program code, which implements the mass evaporation rate calculation method for the boiling environment described above when executed by a processor.

[0111] When the mass evaporation rate calculation method for the boiling environment is implemented as a computer program, it may also be stored in a computer-readable storage medium as an article of manufacture. For example, the 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 discs (CDs), digital versatile discs (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.

[0112] Flowcharts are used in this application to illustrate the operations performed by the systems according to the embodiments of this application. It should be understood that the operations described above or below do not necessarily have to be executed precisely in sequence. Instead, various steps can be executed in reverse order or simultaneously. Also, one or more other operations can be added to these processes, or one or more steps can be removed from these processes.

[0113] The basic concepts have been described above. Obviously, for those skilled in the art, the above invention disclosure is only an example and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0114] Meanwhile, this application uses specific terms to describe the embodiments of this application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0115] As shown in this application, unless the context clearly indicates an exception, words such as "a", "an", "one", and / or "the" are not specifically singular and can also include the plural. Generally speaking, the terms "comprising" and "including" 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.

[0116] Unless otherwise specifically stated, the relative arrangements of the components and steps, numerical expressions, and values set forth in these embodiments do not limit the scope of this application. At the same time, it should be understood that for the sake of convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be interpreted as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments can have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0117] Some aspects of the present application can be executed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above-mentioned hardware or software can all be referred to as "data block", "module", "engine", "unit", "component" or "system". The processor can 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, aspects of the present application may be embodied as a computer product located in one or more computer-readable media, which includes computer-readable program code. For example, the computer-readable media may include, but is not limited to, magnetic storage devices (such as hard disks, floppy disks, magnetic tapes...), optical discs (such as compact discs CD, digital versatile discs DVD...), smart cards, and flash memory devices (such as cards, sticks, key drives...).

[0118] The computer-readable media may contain a propagated data signal that contains computer program code, for example, on a baseband or as part of a carrier wave. The propagated signal may have various forms of representation, including electromagnetic form, optical form, etc., or a suitable combination of forms. The computer-readable media can be any computer-readable media other than computer-readable storage media, which can be connected to an instruction execution system, apparatus, or device to achieve communication, propagation, or transmission for use of the program. The program code located on the computer-readable media can be propagated through any suitable media, including radio, cable, fiber optic cable, radio frequency signal, or similar media, or any combination of the above media.

[0119] Similarly, it should be noted that, in order to simplify the description of the present application disclosure and thus help the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of the present application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the object of the present application are more than the features mentioned. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above.

[0120] In some embodiments, numbers are used to describe components and the quantity of attributes. It should be understood that such numbers used in the description of embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicate that the stated number allows a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification are approximate values, and these approximate values may vary according to the characteristics required by individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the method of retaining the general number of digits. Although the numerical ranges and parameters used in some embodiments of the present application to confirm the breadth of their scope are approximate values, in specific embodiments, such numerical settings are as precise as possible within the feasible range.

[0121] Although the present application has been described with reference to the current specific embodiments, those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present application, and various equivalent changes or substitutions can 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 scope of the spirit of the present application, they will fall within the scope of the present application.

Claims

1. A method for calculating the mass evaporation rate of a boiling environment, characterized in that: include: Node division of the PWR coolant system; For each node, determine whether the dirt thickness of the current node is greater than a critical value. If yes, the current node is a dirty surface, and the mass evaporation rate of the node is calculated based on the porous sediment boiling module. If no, the current node is a clean cladding surface, and the mass evaporation rate of the node is calculated based on the boiling heat flow and mass evaporation module. Among them, calculating the mass evaporation rate of the node based on the porous sediment boiling module includes: dividing the grid nodes 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 the energy equation and heat transfer equation of the dirt, and inputting the parameter boundary value of the dirt surface into the energy equation and the heat transfer equation to calculate the mass evaporation rate of each grid node.

2. The mass evaporation rate calculation method according to claim 1, characterized in that: The parameter boundary values ​​of the fouling surface include the temperature of the fouling surface and the mass evaporation rate gradient of the fouling surface.

3. The mass evaporation rate calculation method according to claim 2, characterized in that: Calculating the mass evaporation rate for each grid node involves: The mass evaporation rate of the dirt surface is calculated based on the heat flux transferred by heat conduction on the dirt surface and the heat flux on the wall; Calculate the temperature gradient of each grid node according to the energy equation, and calculate the temperature of each grid node according to the temperature of the fouling surface and the temperature gradient; Calculate the mass evaporation rate gradient of each grid node according to the heat transfer equation and the temperature of each grid node; The mass evaporation rate of each grid node is calculated according to the mass evaporation rate of the dirt surface, the mass evaporation rate gradient of the dirt surface and the mass evaporation rate gradient of each grid node.

4. The mass evaporation rate calculation method according to claim 2, characterized in that: The mass evaporation rate of the dirt surface is calculated by the following formula: in, is the vapor phase enthalpy of the dirt surface, is the liquid phase enthalpy of the dirt surface, is the heat flow transferred by heat conduction on the dirt surface, is the heat flux on the wall, and G(1) is the mass evaporation rate of the dirt surface.

5. The mass evaporation rate calculation method according to claim 3, characterized in that: The energy equation is: in, is the heat flux transferred by heat conduction at the n+1th grid node, is the thermal conductivity of the dirt, is the temperature gradient of the n+1th grid node.

6. The mass evaporation rate calculation method according to claim 3, characterized in that: The 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 grid node, is the latent heat of vaporization, is the mass evaporation rate gradient.

7. The mass evaporation rate calculation method according to claim 1, characterized in that: Calculating the mass evaporation rate of the node based on the boiling heat flux and mass evaporation module includes: The calculation only considers the wall temperature of forced convection heat transfer and the wall temperature at the boiling start point; Determine whether the wall temperature considering only forced convection heat transfer is greater than the wall temperature at the boiling starting point, and if so, calculate the heat flux density component by the subcooled boiling equation; The mass evaporation rate is calculated based on the heat flux density component and the latent heat of vaporization.

8. The mass evaporation rate calculation method according to claim 7, characterized in that: The wall temperature considering only forced convection heat transfer is calculated by the following formula: in, is the wall temperature considering only forced convection heat transfer, is the fluid temperature, is the forced convection heat transfer coefficient, and q is the heat flux density.

9. The mass evaporation rate calculation method according to claim 7, characterized in that: The boiling starting point wall temperature is calculated by the following formula: in, is the wall temperature at the boiling starting point, is the fluid temperature, is the heat flux component at the boiling starting point, is the heat transfer coefficient at the boiling onset.

10. The mass evaporation rate calculation method according to claim 7, characterized in that: The subcooled boiling equation is: Where q is the heat flux, is the saturated boiling heat flux component, is the heat flux component at the boiling starting point, is the forced convection heat flux component, and n is the preset weight value.

11. The mass evaporation rate calculation method according to claim 10, characterized in that: The mass evaporation rate is calculated by the following formula: in, is the mass evaporation rate, is the latent heat of vaporization.

12. The mass evaporation rate calculation method according to claim 7, characterized in that: Also includes: If the wall temperature considering only forced convection heat transfer is less than or equal to the wall temperature at the boiling starting point, the mass evaporation rate is zero.

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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