Stress calculation method for heat absorber tube panel of tower type solar power station

Abstract

The invention discloses a stress calculation method for a heat absorber tube panel of a tower type solar power station, and relates to the technical field of solar photo-thermal power generation. In order to overcome the defects that in the prior art, heat absorber tube panel stress analysis and calculation efficiency is low, modeling and calculation processes are complex, and all-working-condition rapid coverage calculation and structure rapid optimization design are difficult to achieve, the technical scheme provided by the invention is that a stress calculation method for a tower type solar power station heat absorber tube panel is provided. Comprising the following steps: establishing a simplified model of the heat absorber tube panel in stress analysis software; importing a temperature boundary condition to generate a thermal model; setting multiple working conditions and an external load, and performing stress calculation; and classifying and judging stress results according to standards. The method is suitable for structural strength evaluation and multi-working-condition stress rapid calculation work of a heat absorber tube panel in a tower type solar thermal power generation system.

Description

Technical Field

[0001] The present invention relates to the technical field of solar thermal power generation, and in particular to a stress calculation method for a heat absorber tube panel of a tower-type solar power station. Background Art

[0002] With the proposed goals of achieving carbon peak and carbon neutrality, clean energy technologies are rapidly developing. The widespread access of unstable energy sources like photovoltaics and wind power to the power grid has brought challenges in peak regulation and stable operation. Solar thermal power generation has become a hot topic in research and application in recent years due to its advantages, including high controllability, built-in heat storage systems, and stable output similar to conventional thermal power. Tower-type solar thermal power generation systems, among others, are becoming the mainstream form of solar thermal power generation due to their high heat collection efficiency, strong power generation capacity, and suitability for large-scale centralized energy supply.

[0003] In tower-type solar thermal power generation systems, the absorber tube panel is the core heat exchange component. Installed at the top of the high-altitude absorber tower, it receives sunlight reflected by a concentrator, converts it into high-temperature heat, and transfers it to a working fluid (such as molten salt), ultimately driving the power generation system. Due to its high location, high operating temperatures, and complex structure, its stress distribution directly affects the safety and reliability of the equipment.

[0004] To ensure the structural safety of absorber tube panels, finite element simulation software (such as ANSYS) is currently widely used to perform thermomechanical coupling analysis. For example, existing techniques disclose a stress simulation method using 3D modeling and multi-condition loading to iteratively solve various boundary conditions, such as thermal and wind loads. While these methods offer high accuracy, in actual engineering, they suffer from complex modeling, time-consuming meshing, long solution times, and high computational resource consumption. This makes effective calculation and feedback difficult to achieve within the project cycle, especially when analyzing multiple operating conditions.

[0005] Furthermore, traditional methods typically rely on detailed three-dimensional models, which leads to a strong reliance on modeling accuracy and boundary condition settings, and requires high levels of experience and software proficiency from engineering designers. This not only increases project implementation costs but also hinders the large-scale deployment and rapid iterative optimization of solar thermal power generation technology.

[0006] In summary, the existing technology has the defects of low efficiency of heat absorber tube panel stress analysis calculation, complex modeling and calculation process, and difficulty in achieving rapid coverage calculation of all working conditions and rapid structural optimization design. Summary of the Invention

[0007] In order to solve the defects in the prior art, such as low efficiency of heat absorber tube panel stress analysis calculation, complex modeling and calculation process, and difficulty in achieving rapid coverage calculation of all working conditions and rapid structural optimization design, the present invention provides the following technical solutions: A stress calculation method for a heat absorber tube panel of a tower-type solar power station includes: Steps to create a simplified model of the absorber tube panel in stress analysis software; Steps to import temperature boundary conditions to generate thermal model; Steps for setting up multiple load cases and external loads and performing stress calculations; Steps for classifying and judging stress results according to standards.

[0008] Furthermore, a preferred embodiment is provided, wherein the simplified model is specifically: The absorber tube panel is optimized as a row of parallel pipe models. It is assumed that the circumferential temperature of the absorber tube is uniform, and the temperature change distribution is set only along the axial direction.

[0009] Furthermore, a preferred embodiment is provided, wherein the temperature boundary conditions are imported into each node of the simplified model from temperature field data of a third-party thermal analysis software by linear interpolation.

[0010] Furthermore, a preferred embodiment is provided, wherein the multiple operating conditions include a cold state, a preheating state, a preheating and salting state, a normal operating state, a maximum temperature state, and a salt discharge state.

[0011] Furthermore, a preferred embodiment is provided, wherein the external loads include earthquake loads, wind loads, and deflection loads caused by the heat absorption tower structure.

[0012] Furthermore, a preferred embodiment is provided, wherein the stress calculation includes solving axial stress, shear stress and circumferential stress, and completing stress conversion based on material properties and geometric parameters.

[0013] Based on the same inventive concept, the present invention also provides a stress calculation device for a tower-type solar power station absorber tube panel, comprising: A module for building a simplified model of the absorber tube panel in stress analysis software; A module for importing temperature boundary conditions to generate thermal models; A module for setting multiple load conditions and external loads and performing stress calculations; A module that classifies and judges stress results according to standards.

[0014] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computer program. When the computer program is read by a computer, the computer executes the method described above.

[0015] Based on the same inventive concept, the present invention also provides a computer, comprising a processor and a storage medium. When the processor reads the computer program stored in the storage medium, the computer executes the method described above.

[0016] Based on the same inventive concept, the present invention also provides a computer program product, which is a computer program. When the computer program is executed, the method described above is implemented.

[0017] Compared with the prior art, the technical solution provided by the present invention is beneficial in that: This solution effectively reduces model complexity by modeling the absorber tube panels in CAESAR II stress analysis software, simplifying them into rows of parallel pipes. By ignoring circumferential temperature differences in the absorber tubes and considering only the axial temperature gradient, the modeling process is more efficient and simplified. Compared to the traditional ANSYS approach of 3D modeling, meshing, and thermomechanical coupling, this approach not only significantly shortens model construction time but also allows for more flexible switching between multiple operating conditions, facilitating rapid iteration and parameter adjustment.

[0018] This solution utilizes linear interpolation to import temperature boundary conditions obtained from third-party software into the stress model, improving data integration efficiency and thermal field mapping accuracy. This method avoids the errors that can be introduced by manually setting the temperature field in traditional finite element simulations, achieving highly accurate restoration of the thermal boundary. Compared to existing methods that manually adjust temperature boundaries or set local thermal loads, interpolation allows for precise adaptation of temperature data to the structural model, improving the physical consistency of the temperature input.

[0019] In terms of operating condition handling, this solution comprehensively covers six actual operating conditions: cold state, preheating state, preheating salting state, normal operation state, maximum temperature state, and salt discharge state. It also incorporates earthquake, wind, and tower deflection loads based on the geological information of the project site. This method ensures that stress calculation results are more closely aligned with actual operating conditions, enhancing the model's adaptability and robustness. Compared to traditional finite element calculations that only model and analyze a subset of limit states or a single operating condition, this method achieves a full lifecycle stress assessment for the entire operating cycle, significantly improving the completeness of the safety design.

[0020] By adhering to the ASME-B31.1 "Power Piping" standard, primary, secondary, and accidental stresses are categorized and solved for each operating condition, making the results auditable, traceable, and comparable. This approach standardizes complex stress analysis and avoids calculation errors or misjudgment caused by different analysts using different judgment methods. Compared to traditional finite element analysis results that require secondary processing and manual judgment, this method can more clearly compare and evaluate whether the absorber tube panel structure meets design specifications, improving the reliability of the analysis results and engineering guidance.

[0021] In summary, this solution adopts efficient and engineering-based processing methods in many aspects, including model simplification, thermal boundary data import, multi-condition modeling, and standardized stress determination. This greatly improves the efficiency, accuracy, and adaptability of stress analysis, and provides solid technical support for the optimized design and safety assessment of the absorber tube panel structure in tower-type solar thermal power generation systems.

[0022] It is suitable for structural strength assessment and rapid stress calculation of multiple working conditions of absorber tube panels in tower solar thermal power generation systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the calculation process of the method; Figure 2 is the tube panel stress model diagram; Figure 3 Schematic diagram of stress distribution in the bent pipe structure. DETAILED DESCRIPTION

[0024] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically: Embodiment 1: This embodiment provides a stress calculation method for a tower-type solar power station absorber tube panel, including: Steps to create a simplified model of the absorber tube panel in stress analysis software; Steps to import temperature boundary conditions to generate thermal model; Steps for setting up multiple load cases and external loads and performing stress calculations; Steps for classifying and judging stress results according to standards.

[0025] Furthermore, a preferred embodiment is provided, wherein the simplified model is specifically: The absorber tube panel is optimized as a row of parallel pipe models. It is assumed that the circumferential temperature of the absorber tube is uniform, and the temperature change distribution is set only along the axial direction.

[0026] The temperature boundary conditions are imported into each node of the simplified model from the temperature field data of the third-party thermal analysis software by linear interpolation.

[0027] The multiple operating conditions include a cold state, a preheating state, a preheating salting state, a normal operating state, a maximum temperature state and a salt discharge state.

[0028] The external loads include earthquake loads, wind loads and deflection loads caused by the heat absorption tower structure.

[0029] The stress calculation includes solving axial stress, shear stress and circumferential stress, and completing stress conversion based on material properties and geometric parameters.

[0030] Implementation Method 2: This implementation method further describes the technical solution provided in Implementation Method 1. Specifically: A stress analysis method based on CAESAR II software features efficient modeling, accurate data input, multi-state coverage, and standardized evaluation. The following describes the method in steps, combined with the implementation steps of the present invention: Step 1: Construct the absorber tube panel stress model This step was completed in CAESAR II stress analysis software. Based on the structural characteristics of the absorber tube panel, the panel was first simplified into a model of parallel rows of pipes. The geometric connections between the pipe components, including the absorber tubes, headers, and their supporting structures, were established. This simplified modeling approach assumes a uniform circumferential temperature for all absorber tubes, retaining only the temperature variations along the tube height. This model accurately reflects the axial thermal stress distribution characteristics of the absorber tube panel while significantly reducing modeling complexity and computational resource consumption.

[0031] Step 2: Import temperature boundary conditions This step builds on the geometric structural model established in the first step. Based on this foundation, temperature field data from the receiver's operating conditions, obtained from thermal analysis software (such as Fluent or COMSOL), is mapped to the nodes of the pipeline model via linear interpolation. This ensures that the corresponding pipe segment at each height point has thermal boundary conditions consistent with actual operation. This seamlessly couples the structural thermal analysis model with the calculated thermal field data, providing the foundational input for subsequent thermal stress analysis.

[0032] Step 3: Set operating conditions and external loads After the temperature field input is completed, the operating conditions faced by the absorber tube panel need to be fully modeled. The present invention takes into account six typical operating states of the absorber system: cold state, preheating state, preheating salt state, normal operating state, maximum temperature state and salt discharge state. For each state, the corresponding temperature field, internal pressure parameters, structural boundary conditions, etc. are set respectively. At the same time, the seismic load model is introduced according to the geological data of the project site, and the wind load and tower yaw load are considered in combination with the tower structure, so that the model calculation is closer to the actual operating environment. The operating condition combination generated in this step will be used as the input condition for subsequent stress calculations.

[0033] Step 4: Perform stress analysis calculations Based on the modeled pipeline structure and complete operating condition settings, the CAESAR II software solver module is used to perform stress calculations. This method separately calculates the axial, shear, and circumferential stresses under continuous operating conditions, as well as the stress responses under thermal expansion conditions and accidental conditions (such as earthquakes and wind loads). The software automatically solves for mechanical parameters such as bending moment, torque, internal pressure, and axial force on the heat absorption tube cross section. Stress conversion is performed using material properties and geometric parameters to determine the stress distribution at each node and in key areas.

[0034] Step 5: Determine whether the stress meets the standard requirements The calculated stress results are classified and determined according to the US ASME-B31.1 "Power Piping" standard. Stresses under continuous operating conditions are classified as primary stresses and must meet the basic allowable stress limits set by the standard. Stress caused by thermal expansion is considered secondary stress and must be verified using the stress intensification factor and cyclic stress reduction factor. Stress generated under accidental operating conditions requires adjustment of the accidental factor to ensure a safety margin in the structure even under extreme circumstances. This standardized determination method effectively identifies potential stress concentrations and overload risk points within the structure.

[0035] Step 6: Output stress assessment report and optimization suggestions Combined with stress analysis results, a detailed assessment report is generated, including stress values ​​at key nodes under various conditions, comparisons with standards, and areas where stress exceeds standards. If stress exceeds limits, the model's flexibility allows for rapid adjustments to panel structural parameters, material grades, or layouts, and repeated calculations until all indicators meet safety design requirements. This provides data support for the safe operation and engineering optimization of the receiver system.

[0036] In summary, this implementation plan constitutes a complete, feasible and engineering-applicable method for rapid calculation of absorber tube panel stress through five organically connected steps: structural modeling, thermal boundary introduction, operating condition setting, stress analysis and standard verification. It has significant advantages such as strong versatility, high computational efficiency and adaptability to a wide range of operating conditions.

[0037] Implementation Method 3: Combination Figure 1-3 This embodiment is explained. This embodiment further describes the technical solution provided above in detail through specific examples. Specifically, in order to overcome the shortcomings of the existing technology and address the deficiencies in the stress calculation of the absorber tube panel of the existing tower solar power station, the present invention proposes to use CAESARⅡ software to simplify the heat absorbing tubes, headers, etc. of the tube panel into a two-dimensional model, which greatly reduces the amount of calculation and can realize rapid calculation of the tube panel. Without considering the time-consuming modeling, the calculation of a single working condition only takes a few minutes, which greatly reduces the calculation time and can realize calculation covering all working conditions.

[0038] A stress calculation method for a tower-type solar power station absorber tube panel is provided, and the specific steps are as follows: Step 1: Model the absorber tube panel in CAESAR II stress analysis software. The calculation standard follows ASME-B31.1 "Power Piping". The absorber tube panel is optimized into a row of parallel pipe models. By default, the circumferential temperature of the absorber tube is the same, and the axial temperature varies along the height of the absorber tube panel. Step 2: Import the temperature boundary conditions calculated by the third-party software into the tube panel stress calculation model using the linear interpolation method; Step 3: The absorber tube panel will operate in the following six states: cold, preheat, preheating and salting, normal operation, maximum temperature, and salt discharge. Edit the absorber tube panel model calculation conditions under the six operating conditions, adding seismic loads and wind loads based on the project's geological conditions, and adding yaw loads based on the absorber tower's condition. After editing the working conditions in CAESAR II stress calculation software, calculate the detailed stress values ​​using the following formula: Axial stress

[0039] shear stress

[0040] Circumferential stress

[0041] in: -Bending moment acting on the cross section of the heat absorber tube in N·m; Z-section coefficient in m³; -Internal force N acting on the cross section of the heat absorber tube; - cross-sectional area of ​​the heat absorption tube wall in m2; P-design pressure in MPa; D0-outer diameter of the heat absorption tube in m; t-heat absorption tube wall thickness in m; -Torque acting on the absorber cross section in N·m.

[0042] In the ASME-B31.1 "Power Piping" standard, the primary stress corresponds to the stress under continuous working conditions in the stress calculation software, and its calculated value should meet the following requirements ; Secondary stress corresponds to the stress under thermal expansion conditions in the stress calculation software, and its calculated value should meet the following requirements

[0043] Accidental stress corresponds to the stress under accidental working conditions in the stress calculation software, and its calculated value should meet the following requirements ; Where: P, D, Z, t are the same as above; -The resultant moment N·m generated by the weight and other continuous loads on the cross section of the absorber tube; -Basic allowable stress of the material at the maximum temperature MPa; - stress intensification factor; -The resultant moment N·m generated by the secondary load on the cross section of the heat absorber tube; -Cyclic stress range reduction factor; - Allowable stress of the heat absorption tube at ambient temperature MPa; - The resultant moment N·m generated by the accidental load on the cross section of the heat absorber tube; -Occasional load factor.

[0044] Based on the stress characteristics of the pressure pipeline structure, the pipeline stress caused by the circumferential temperature deviation of the heat absorption pipe is not considered in the above stress calculation process.

[0045] The absorber tube panel model is optimized into a parallel pipe model to increase calculation speed and facilitate model improvement. It is more convenient to calculate the constraints and bending structure of the absorber tube panel. The maximum allowable temperature deviation of the tubes connected to the absorber tube panel and the overall maximum temperature deviation of the two adjacent absorber tube panels can also be checked. This provides calculation data support for the safe and reliable operation of the absorber system and improves the performance and safety of the tower solar power station.

[0046] The above further describes the technical solution provided by the present invention in detail through several specific embodiments in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific embodiments described above are not intended to limit the present invention. Any reasonable modification and improvement of the present invention, combination of embodiments and equivalent replacement based on the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A stress calculation method for a tower solar power station absorber tube panel, characterized in that: include: Steps to create a simplified model of the absorber tube panel in stress analysis software; Steps to import temperature boundary conditions to generate thermal model; Steps for setting up multiple load cases and external loads and performing stress calculations; Steps for classifying and judging stress results according to standards.

2. The stress calculation method for a tower solar power station absorber tube panel according to claim 1, characterized in that: The simplified model is specifically: The absorber tube panel is optimized as a row of parallel pipe models. It is assumed that the circumferential temperature of the absorber tube is uniform, and the temperature change distribution is set only along the axial direction.

3. The stress calculation method for a tower solar power station absorber tube panel according to claim 1, characterized in that: The temperature boundary conditions are imported into each node of the simplified model from the temperature field data of the third-party thermal analysis software by linear interpolation.

4. The stress calculation method for a tower solar power station absorber tube panel according to claim 1, characterized in that: The multiple operating conditions include a cold state, a preheating state, a preheating salting state, a normal operating state, a maximum temperature state and a salt discharge state.

5. The stress calculation method for a tower solar power station absorber tube panel according to claim 1, characterized in that: The external loads include earthquake loads, wind loads and deflection loads caused by the heat absorption tower structure.

6. The stress calculation method for a tower solar power station absorber tube panel according to claim 1, characterized in that: The stress calculation includes solving axial stress, shear stress and circumferential stress, and completing stress conversion based on material properties and geometric parameters.

7. A stress calculation device for a heat absorber tube panel of a tower solar power station, characterized in that: include: A module for building a simplified model of the absorber tube panel in stress analysis software; A module for importing temperature boundary conditions to generate thermal models; A module for setting multiple load conditions and external loads and performing stress calculations; A module that classifies and judges stress results according to standards.

8. A computer storage medium for storing a computer program, characterized in that When the computer program is read by a computer, the computer executes the method according to claim 1 .

9. A computer comprising a processor and a storage medium, characterized in that When the processor reads the computer program stored in the storage medium, the computer executes the method according to claim 1 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method according to claim 1 is implemented.

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