Real-time simulation method of thermal fluid medium based on Modelica

Abstract

An embodiment of the present invention discloses a real-time method for thermal fluid medium simulation based on Modelica, which relates to simulation technology. The method includes: running a Modelica-based original component model in a simulation machine environment; if the single-step solution time of the original component model is longer than a preset machine physical interaction time, determining a custom medium template corresponding to a target original fluid medium model among all original fluid medium models; calling the custom medium template to generate a new fluid medium model, and generating a new component model based on the new fluid medium model; wherein the computational complexity of any custom function is less than that of the corresponding original function, and / or the number of custom functions in the custom medium template is less than the number of functions in the corresponding original medium template. This embodiment improves the computational efficiency of component models and thermal system models.

Description

Technical Field

[0001] The embodiments of the present invention relate to simulation technology, and in particular to a real-time method for simulating thermal fluid media based on Modelica. Background Art

[0002] The development of complex thermal-fluid systems involves extensive experimental research. To avoid experimental non-reproducibility and save costs, real-time digital models can be linked to physical systems to shorten the development cycle. For example, Modelica can be used to build and simulate medium models. Because thermal fluids are slow-reacting systems, real-time simulation of complex thermal-fluid systems is particularly challenging, often resulting in timeouts and large step-size computational divergence.

[0003] Traditionally, the real-time simulation approach for thermal fluid system models involves using Modelica-based models to reduce the number of system components while preserving the original medium model. This reduces the number of equations and improves computational efficiency. However, thermal fluid systems often take the form of pipe networks, which have diverse components. If this approach were to be applied uniformly with fewer components, the numerical accuracy of the system model would be lost, making it difficult for the model to provide guidance for practical applications. Summary of the Invention

[0004] The embodiment of the present invention provides a real-time method for thermal fluid medium simulation based on Modelica, so as to improve the computational efficiency within the component model and make the entire system model meet the timeliness requirements without reducing any components.

[0005] In a first aspect, an embodiment of the present invention provides a real-time method for thermal fluid medium simulation based on Modelica, comprising:

[0006] Running a Modelica-based primitive component model in a simulation environment, wherein the primitive component model includes at least one primitive fluid medium model, each of the primitive fluid medium models is constructed using a corresponding primitive medium template, and each of the primitive medium templates includes information of at least one primitive function;

[0007] If the single-step solution time of the original component model is longer than the preset machine physical interaction time, determining a custom medium template corresponding to a target original fluid medium model among all original fluid medium models, wherein the custom medium template includes information of at least one custom function;

[0008] Calling the custom medium template to generate a new fluid medium model, and generating a new component model according to the new fluid medium model;

[0009] The computational complexity of any custom function is smaller than that of the corresponding original function, and / or the number of custom functions in the custom media template is smaller than the number of functions in the corresponding original media template.

[0010] In a second aspect, an embodiment of the present invention further provides an electronic device, comprising:

[0011] one or more processors;

[0012] a memory for storing one or more programs,

[0013] When the one or more programs are executed by the one or more processors, the one or more processors implement the real-time method for thermal fluid medium simulation based on Modelica as described in any embodiment.

[0014] In a third aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the real-time method for thermal fluid medium simulation based on Modelica as described in any embodiment.

[0015] In an embodiment of the present invention, when the original component model based on Modelica does not meet the timeliness requirements, a custom medium template is called to replace the original medium template. By reducing the computational complexity and / or the number of functions in any function in the medium template, the computational complexity of the fluid medium model is reduced, so that the calculation of the new component model meets the timeliness requirements. Without reducing any component model, the computational efficiency of the entire system model is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a flow chart of a real-time method for thermal fluid medium simulation based on Modelica provided by an embodiment of the present invention;

[0018] Figure 2 It is a structural diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0022] The embodiment of the present invention provides a real-time simulation method for thermal fluid medium based on Modelica, which is applicable to the case of real-time simulation of thermal system in Modelica simulation environment. This embodiment is executed by electronic equipment. The flow chart of the method is as follows Figure 1 As shown, the method provided in this embodiment specifically includes:

[0023] S110. Run the original component model based on Modelica in the simulation machine environment.

[0024] Modelica simulation software is used to simulate thermal systems. The simulation software includes component models for simulating thermal system components. In this embodiment, this component model is referred to as the original component model. This step runs the original component model in a simulator environment to measure the single-step solution time of the original component model. The single-step solution time refers to the time required for a simulation model to converge within a single time step. This time is determined by deploying the simulation model in a simulator environment and testing it.

[0025] Specifically, the original component model includes at least one original fluid medium model, each of the original fluid medium models is constructed using a corresponding original medium template, and each of the original medium templates includes information of at least one original function.

[0026] It should be noted that the original functions in the original medium template are all empty functions. They only have variable declarations for the function but no specific variable values. Therefore, the original medium template cannot be run. If specific variable values are substituted into the original medium template, the original fluid medium model is constructed.

[0027] When running, the original fluid medium model is used to simulate a specific thermal fluid medium. Each thermal fluid medium corresponds to a corresponding original fluid medium model. Because a thermal system component includes at least one thermal fluid medium, the original component model includes at least one original fluid medium model.

[0028] S120. If the single-step solution time of the original component model is longer than the preset machine physical interaction time, determine a custom medium template corresponding to the target original fluid medium model in all original fluid medium models, each of the custom medium templates including information of at least one custom function.

[0029] The machine physical interaction duration refers to the duration for a simulation model to interact with simulation data externally through electronic devices deployed in the simulation machine environment. It can be pre-set in the simulation machine environment according to actual simulation requirements.

[0030] This step determines whether the original component model meets the timeliness requirements by comparing the preset machine physical interaction time with the single-step solution time calculated by running the original component model. If the single-step solution time of the original component model is longer than the preset machine physical interaction time, it is considered that the original component model has not completed the convergence calculation within the set external interaction time, resulting in a timeout. At this time, first, from all the original fluid medium models included in the original component model, the original fluid medium model that causes the timeout (called the target original fluid medium model) is screened out; then the custom medium template corresponding to the target original fluid medium model is determined.

[0031] Customized media templates are used to construct new fluid media models, replacing the original media templates. This shortens the single-step solution time for component models and ensures that the new component models meet timeliness requirements. Customized media templates are similar to original media templates and include information about at least one custom function.

[0032] Optionally, if the single-step solution time of the original component model is longer than the preset machine physical interaction time, determining the custom medium template corresponding to the target original fluid medium model in all original fluid medium models includes: if the single-step solution time of the original component model is longer than the preset machine physical interaction time, determining abnormal data by analyzing the simulation results; locating the target original function according to the abnormal data, and determining the target original fluid medium model according to the target original function.

[0033] By analyzing the abnormal data in the simulation results, the target original fluid medium model can be located. Specifically, each type of data in the simulation results corresponds to a primitive function. The primitive function corresponding to the abnormal data is the target primitive function, and the fluid medium model including the target primitive function is the target fluid medium model.

[0034] Optionally, abnormal data includes: data with divergent change trends, data that does not satisfy physical laws, or data that directly reports errors in simulation software; the determination of abnormal data by analyzing the simulation results includes: if the change trend of a data in the simulation results diverges or does not satisfy physical laws, determining the data as abnormal data; and / or, if the simulation results report an error for a data, determining the data as abnormal data.

[0035] S130: Call the custom medium template to generate a new fluid medium model, and generate a new component model according to the new fluid medium model.

[0036] In order to ensure that the single-step solution time of the new component model is less than the single-step solution time of the original component model, the called custom template meets at least one of the following conditions: (1) the computational amount of any custom function is less than the computational amount of the corresponding original function; (2) the number of custom functions in the custom medium template is less than the number of functions in the corresponding original medium template.

[0037] Optionally, each of the custom media templates includes at least one declared variable of a custom function; calling the corresponding custom media template to generate a new fluid medium model includes: calling the corresponding custom media template; calling the corresponding entity function according to the declared variables in the custom media template to generate a new fluid medium model.

[0038] Similar to the original media template, the custom functions in a custom media template are empty functions, containing only variable declarations but no specific values. When a custom media template is called, the corresponding entity function is called based on the declared variables in the template. The specific variable values are substituted into the entity function, generating a new fluid media model. When run, this new fluid media model is used to simulate the specific medium using the new calculation method.

[0039] The technical effect of this embodiment is: when the original component model does not meet the timeliness requirements, this embodiment calls a custom media template to replace the original media template, and reduces the calculation amount of the fluid media model by reducing the calculation amount and / or the number of functions of any function in the media template, so that the calculation of the new component model meets the timeliness requirements, and improves the calculation efficiency of the entire system model without reducing any component model.

[0040] Based on the above and following embodiments, optionally, after generating a new component model according to the new fluid medium model, the method further includes:

[0041] S210, running the new component model in a simulation machine environment;

[0042] S220: If the single-step solution time of the new component model is less than or equal to the preset machine physical interaction time, the real-time requirement is met; if the single-step solution time of the new component model is greater than the preset machine physical interaction time, a new custom medium template corresponding to the target fluid medium model in all new fluid medium models is determined; the new custom medium template includes information about at least one new custom function;

[0043] S230: Call the corresponding new custom medium template to generate a new fluid medium model, and generate a new component model according to the new fluid medium model.

[0044] The computational complexity of any new custom function is smaller than that of the corresponding custom function, and / or the number of new custom functions in any new custom media template is smaller than the number of custom functions in the corresponding custom media template.

[0045] The component model update of this embodiment is an iterative process. If the single-step solution time of the new model after one update can meet the real-time requirements, the update is completed; if the single-step solution time of the new model still cannot meet the real-time requirements, the update is continued using the same method.

[0046] Specifically, in each update, all fluid medium models included in the component model obtained in the last update (which may have been updated, may not have been updated, or may have been updated multiple times) are used as new fluid medium models, and a new target fluid medium model is screened out from all the new fluid medium models, and a new custom medium template corresponding to the new target fluid medium model is determined (which may have been updated, may not have been updated, or may have been updated multiple times); the new custom medium template is called to generate a new fluid medium model, and the component model obtained in this update is generated based on the new fluid medium model.

[0047] Based on the above and following embodiments, this embodiment further refines the process of constructing a custom media template. Optionally, before running the original Modelica-based component model in a simulation environment, the process further includes: constructing a custom function such that the difference between the physical property data calculated by the custom function and the actual physical property data meets accuracy requirements; and constructing a custom media template based on the custom function.

[0048] A custom media template includes at least one custom function. Therefore, when constructing a custom media template, the first step is to create a custom function. Each custom function is used to calculate a physical property of the corresponding medium. After the custom function is constructed, its accuracy is verified to maintain the simulation accuracy of the original system model. In this embodiment, actual physical property data is used as the verification standard, and the difference between the physical property data calculated by the custom function and the actual physical property data is compared. If the difference is within the allowable accuracy deviation range, the constructed custom function meets the accuracy requirements. The custom function that meets the accuracy requirements is then called to construct the custom media template.

[0049] Optionally, constructing the custom function includes: constructing a physical property parameter solving function using a polynomial fitting method; or constructing a physical property parameter solving function using a table interpolation method. There are many ways to construct a custom function. This embodiment uses the polynomial fitting method and the table interpolation method to construct the custom function.

[0050] Specifically, taking the function for solving the viscosity parameter of the medium as an example, the following two construction methods are adopted:

[0051] Method 1: Use the polynomial fitting method to convert the following polynomial equation into a Modelica function:

[0052]

[0053] Where Y represents the viscosity parameter, T represents the temperature, and A, B, C, and D represent fitting coefficients, which can be set as constants. This method supports custom expansion of polynomials, resulting in more scalable custom functions.

[0054] Method 2: Use a table interpolation method. Enter the viscosity parameters of the fluid medium at multiple values of a certain variable into the Modelica interpolation table. Then, interpolation is used to calculate the viscosity parameters corresponding to other values of the variable. For example, by entering the following table into the Modelica interpolation table, the viscosity coefficient of hydrogen at all temperatures can be interpolated.

[0055] Table 1 Viscosity coefficient of hydrogen at various temperatures

[0056]

[0057] Compared with the original function, the functions constructed using these two methods use fewer calculation equations and have a simpler construction method. While ensuring the calculation accuracy, they simplify the fluid medium model and improve the calculation efficiency.

[0058] Optionally, the constructing of the custom function includes: retaining the core equations in the original function and simplifying the equations for enhancing the result performance.

[0059] The primitive function includes core equations and equations that enhance the performance of the results. These equations include auxiliary solution equations, robustness equations (such as maximization, minimization, and smoothing equations), and experimental parameter equations. Therefore, the primitive function is computationally intensive, and some data is difficult to obtain. For example, some experimental parameters are obtained from NASA experiments.

[0060] This embodiment retains the core equations in the original function and simplifies only those equations that enhance the performance of the result. This also reduces the computational complexity of the function. For example, equations with experimental parameters can be removed; or equations with minimal impact on the parameters being solved can be removed. Alternatively, if a calculation yields superior model performance, the variable values of certain equations from that calculation can be recorded and directly substituted into these equations in subsequent calculations.

[0061] Based on the above and following embodiments, optionally, constructing a custom medium template according to the custom function includes: determining the type of the original fluid medium model in the original component model to be simulated; using the type of the original fluid medium model as the type of the custom medium template to be constructed; selecting the required custom function according to the type of the custom medium template to be constructed, and constructing the corresponding type of custom medium template according to the selected custom function.

[0062] In Modelica simulation software, the type of the original medium template corresponds to the type of fluid medium, and the same type of medium corresponds to the same original medium template. Fluid medium types include: single-phase fluid medium, two-phase fluid medium, and mixture fluid medium, etc. Correspondingly, the types of custom medium templates include: pure substance medium template, phase-changing medium template, and mixture medium template. The type of the custom medium template is the same as the original medium template. After a custom medium template is constructed, it can be called in new fluid medium models that belong to the same fluid medium type as the custom medium template. Therefore, this embodiment constructs custom medium templates and custom functions based on the type of medium template, which can not only improve the versatility of the custom medium template but also reduce the difficulty of construction.

[0063] Specifically, when building a custom media template, first determine the type of the custom media template. The type of the original fluid media model determines the type of custom media template to be built. Then, select the desired custom function based on the determined type. Fluids of the same type require the same physical properties to be calculated, so the desired custom function is selected based on the desired properties. Finally, the custom media template of that type is built based on the selected custom function.

[0064] Figure 2 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention is shown in FIG. Figure 2 As shown, the device includes a processor 20, a memory 21, an input device 22 and an output device 23; the number of processors 20 in the device can be one or more. Figure 2 In the embodiment, a processor 20 is used as an example; the processor 20, the memory 21, the input device 22 and the output device 23 in the device can be connected by a bus or other means. Figure 2 The bus connection is taken as an example.

[0065] Memory 21, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the Modelica-based real-time thermal fluid simulation method in the embodiments of the present invention. Processor 20 executes the software programs, instructions, and modules stored in memory 21 to execute various functional applications and data processing of the device, thereby implementing the aforementioned Modelica-based real-time thermal fluid simulation method.

[0066] The memory 21 may primarily include a program storage area and a data storage area. The program storage area may store an operating system and at least one application required for a function; the data storage area may store data created based on the use of the terminal, etc. Furthermore, the memory 21 may include high-speed random access memory and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other non-volatile solid-state memory device. In some instances, the memory 21 may further include a memory remotely located relative to the processor 20, and these remote memories may be connected to the device via a network. Examples of the aforementioned networks include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0067] The input device 22 may be used to receive input digital or character information and generate key signal input related to user settings and function control of the device. The output device 23 may include a display device such as a display screen.

[0068] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the program is executed by a processor, the real-time method for thermal fluid medium simulation based on Modelica of any embodiment is implemented.

[0069] The computer storage medium of the embodiment of the present invention can adopt any combination of one or more computer-readable media. Computer-readable media can be computer-readable signal media or computer-readable storage media. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or components, or any combination thereof. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by an instruction execution system, device or device or used in combination with it.

[0070] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0071] Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0072] Computer program code for performing the operations of the present invention may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages such as Java, Smalltalk, C++, and conventional procedural programming languages such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a stand-alone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A real-time method for thermal fluid medium simulation based on Modelica, characterized in that: include: Running a Modelica-based primitive component model in a simulation environment, wherein the primitive component model includes at least one primitive fluid medium model, each of the primitive fluid medium models is constructed using a corresponding primitive medium template, and each of the primitive medium templates includes information of at least one primitive function; If the single-step solution time of the original component model is longer than the preset machine physical interaction time, determining a custom medium template corresponding to a target original fluid medium model among all original fluid medium models, wherein the custom medium template includes information of at least one custom function; Calling the custom medium template to generate a new fluid medium model, and generating a new component model according to the new fluid medium model; The computational complexity of any custom function is smaller than that of the corresponding original function, and / or the number of custom functions in the custom media template is smaller than the number of functions in the corresponding original media template; Before running the original Modelica-based component model in the simulator environment, it also includes: Constructing a custom function so that the difference between the physical property data calculated by the custom function and the actual physical property data meets the accuracy requirement; A custom media template is constructed according to the custom function.

2. The method according to claim 1, characterized in that The construction of the custom function includes: Use polynomial fitting method to construct physical property parameter solving function; or, The table interpolation method is used to construct the physical property parameter solution function.

3. The method according to claim 1, characterized in that The step of constructing a custom media template according to the custom function includes: Determining the type of the original fluid medium model in the original component model to be simulated; Using the type of the original fluid medium model as the type of the custom medium template to be constructed; Select the required custom function according to the type of custom media template to be built, and build the corresponding type of custom media template based on the selected custom function.

4. The method according to claim 1, wherein The construction of the custom function includes: The core equations in the original function are retained, and the equations are simplified to enhance the performance of the result.

5. The method according to any one of claims 1 to 4, characterized in that If the single-step solution time of the original component model is longer than the preset machine physical interaction time, determining a custom medium template corresponding to a target original fluid medium model in all original fluid medium models includes: If the single-step solution time of the original component model is longer than the preset machine physical interaction time, abnormal data is determined by analyzing the simulation results; A target primitive function is located according to the abnormal data, and a target primitive fluid medium model is determined according to the target primitive function.

6. The method according to claim 5, characterized in that The analysis of the simulation results to determine abnormal data includes: If the change trend of a data in the simulation result diverges or does not satisfy the physical law, the data is determined to be abnormal data; and / or, If the simulation result indicates an error for a data, the data is determined to be abnormal data.

7. The method according to claim 1, characterized in that After generating a new component model according to the new fluid medium model, the method further includes: Running the new component model in a simulator environment; If the single-step solution time of the new component model is less than or equal to the preset machine physical interaction time, the real-time requirement is met; If the single-step solution time of the new component model is longer than the preset machine physical interaction time, determining a new custom medium template corresponding to the new target fluid medium model in all new fluid medium models; the new custom medium template includes information of at least one new custom function; Calling the new custom medium template to generate a new fluid medium model, and generating a new component model according to the new fluid medium model; The computational complexity of any new custom function is smaller than that of the corresponding custom function, and / or the number of new custom functions in the new custom media template is smaller than the number of custom functions in the corresponding custom media template.

8. An electronic device, characterized in that: include: one or more processors; a memory for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors implement the real-time method for thermal fluid medium simulation based on Modelica as described in any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the real-time method for thermal fluid medium simulation based on Modelica as described in any one of claims 1 to 7 is implemented.

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