A method and device for simulating infrared characteristics of a ship exhaust device, and equipment

Abstract

The application discloses a simulation method for infrared characteristics of a ship exhaust device, which can improve the operation speed of infrared radiation data simulation results, greatly reduce the time complexity, and gradually refine through layer-by-layer approximation, improve the detection efficiency, solve the problems of large computer memory consumption, high computer overhead, precision reduction after model simplification, and calculation error caused by the difference in order of magnitude in the process of mapping the flow field parameters to the infrared grid.

Description

Technical Field

[0001] This application relates to the field of simulation technology, for example to a method, apparatus, and equipment for simulating the infrared characteristics of a ship's exhaust system. Background Technology

[0002] Numerical calculation of infrared radiation characteristics involves theories and techniques from multiple disciplines, including computational fluid dynamics, computational heat transfer, computational radiometry, and computer graphics. It primarily addresses the problem of radiant energy transmission in three-dimensional space. Commonly used methods such as the discrete transfer method and the finite volume method require solving the angle coefficients between micro-elements of a high-temperature solid wall and a large set of effective radiation matrix equations. This leads to high memory consumption and computational overhead for infrared radiation calculations of complex structures like targets. Currently, this can generally be addressed by simplifying the target model and reducing the number of micro-elements, but this results in a decrease in computational accuracy, making it difficult to find a good compromise. Secondly, since the calculation of high-temperature exhaust gas and jet radiation from ship exhaust systems requires parameters such as the temperature, pressure, and concentration of the gas components as input, accurate flow field calculations are necessary beforehand. Flow field calculations require mesh generation. When using the discrete transfer method or the finite volume method for radiation calculations, a secondary mesh generation of the target is also required. Generally, the number of infrared meshes is two orders of magnitude lower than that of the flow field meshes. This difference in magnitude introduces computational errors during the mapping of flow field parameters to the infrared mesh.

[0003] The current simulation methods for the infrared characteristics of exhaust systems involve the following steps: 1. Meshing the 3D model of the exhaust system and plume flow field, and assigning temperature values ​​to the meshes; 2. When using the discrete transfer method and finite volume method for radiation calculation, a secondary meshing of the target is required, generally with the number of infrared meshes being two orders of magnitude lower than that of the flow field mesh; 3. Calculating the infrared radiation and secondary radiation characteristics of the exhaust system and exhaust plume using the discrete transfer method and finite volume method by solving the angle coefficients between the micro-elements of the high-temperature solid wall and the large effective radiation matrix equations; 4. Reflecting the atmospheric transmission characteristics of the ship's exhaust system's infrared radiation by calculating atmospheric transmittance parameters. However, current methods such as the discrete transfer method and finite volume method suffer from problems when dealing with complex structural targets, including high computer memory consumption, high computer overhead, decreased accuracy after model simplification, and computational errors introduced by the order-of-magnitude difference in mapping flow field parameters to the infrared mesh. Summary of the Invention

[0004] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0005] This disclosure provides a method, apparatus, and equipment for simulating the infrared characteristics of a ship's exhaust system. This method improves the speed of producing infrared radiation data simulation results, significantly reduces time complexity, and improves detection efficiency through layer-by-layer approximation and gradual refinement. It also addresses issues such as high computer memory consumption, high computer overhead, decreased accuracy after model simplification, and computational errors introduced by the order-of-magnitude difference in mapping flow field parameters to the infrared grid.

[0006] In some embodiments, a method for simulating the infrared characteristics of a ship's exhaust system includes:

[0007] Obtain a three-dimensional model of the exhaust system of the target ship and the plume flow field of the exhaust system;

[0008] Based on the temperature field distribution of the exhaust device, the three-dimensional model is meshed to obtain multiple model meshes, and the infrared radiation data of each model mesh is determined.

[0009] For each model mesh, generate the corresponding hierarchical bounding box; calculate the infrared ray path of the corresponding hierarchical bounding box.

[0010] The infrared ray path of the background region is determined based on the infrared ray paths of the bounding boxes corresponding to all model meshes.

[0011] Based on the infrared radiation data of each model grid and the infrared light path of the background region, the simulation results of the infrared radiation data of the exhaust device of the target ship are generated.

[0012] In some embodiments, a ship exhaust system infrared characteristic simulation device includes:

[0013] The acquisition unit is used to acquire a three-dimensional model of the exhaust device of the target ship and the plume flow field of the exhaust device.

[0014] The meshing unit is used to mesh the three-dimensional model according to the temperature field distribution of the exhaust device to obtain multiple model meshes, and to determine the infrared radiation data of each model mesh.

[0015] The computing unit is used to generate the hierarchical bounding box corresponding to each model mesh; and to calculate the infrared ray path of the hierarchical bounding box corresponding to the model mesh.

[0016] The unit is used to determine the infrared ray path of the background region based on the infrared ray path of the bounding box corresponding to all model meshes.

[0017] The simulation unit is used to generate simulation results of the infrared radiation data of the exhaust device of the target ship based on the infrared radiation data of each model grid and the infrared light path of the background area.

[0018] In some embodiments, a ship exhaust device infrared characteristic simulation device includes a processor and a memory storing program instructions, characterized in that the processor is configured to execute the ship exhaust device infrared characteristic simulation method as described above when executing the program instructions.

[0019] In some embodiments, a device includes an infrared characteristic simulation device for ship exhaust systems as described above.

[0020] The infrared characteristic simulation method, apparatus, and equipment for ship exhaust devices provided in this disclosure can achieve the following technical effects: This application acquires a three-dimensional model of the exhaust device of the target ship and the plume flow field of the exhaust device; based on the temperature field distribution of the exhaust device, the three-dimensional model is meshed to obtain multiple model meshes, and the infrared radiation data of each model mesh is determined; for each model mesh, a corresponding hierarchical bounding box is generated; the infrared ray path of the hierarchical bounding box corresponding to the model mesh is calculated; based on the infrared ray paths of the hierarchical bounding boxes corresponding to all model meshes, the infrared ray path of the background region is determined; based on the infrared radiation data of each model mesh and the infrared ray path of the background region, the infrared radiation data simulation result of the exhaust device of the target ship is generated. As can be seen, this application utilizes the temperature field distribution of the exhaust device to mesh the three-dimensional model to obtain multiple model meshes. Furthermore, it uses the infrared radiation data of each model mesh and the infrared light path of the background region to generate the infrared radiation data simulation results of the exhaust device of the target ship. This improves the running speed of the infrared radiation data simulation results production, greatly reduces the time complexity, and improves detection efficiency through layer-by-layer approximation and gradual refinement. It also solves the problems of high computer memory consumption, high computer overhead, decreased accuracy after model simplification, and calculation errors introduced by the order of magnitude difference in the process of mapping flow field parameters to the infrared mesh.

[0021] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0023] Figure 1This is a flowchart illustrating a method for simulating the infrared characteristics of a ship exhaust system according to an embodiment of this disclosure.

[0024] Figure 2 This is a flowchart illustrating a method for simulating the infrared characteristics of a ship exhaust system according to an embodiment of this disclosure.

[0025] Figure 3 This is a flowchart illustrating a method for simulating the infrared characteristics of a ship exhaust system according to an embodiment of this disclosure.

[0026] Figure 4 This is a flowchart illustrating a method for simulating the infrared characteristics of a ship exhaust system according to an embodiment of this disclosure.

[0027] Figure 5 This is a schematic diagram of an infrared characteristic simulation device for a ship exhaust system provided in an embodiment of this disclosure. Detailed Implementation

[0028] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0029] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0030] Unless otherwise stated, the term "multiple" means two or more.

[0031] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0032] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0033] Combination Figure 1 As shown, this disclosure provides a method for simulating the infrared characteristics of a ship's exhaust system, including:

[0034] S101: Obtain a three-dimensional model of the exhaust system of the target ship and the plume flow field of the exhaust system.

[0035] In this embodiment, the exhaust system of the target ship is first obtained. Then, a three-dimensional model of the exhaust system's plume flow field can be obtained by modeling the exhaust system. During the construction of this three-dimensional model, the geometric modeling and structure of the target entity (i.e., the three-dimensional model of the exhaust system's plume flow field) can be simplified. Specifically, while ensuring the accuracy of the temperature field and the calculation of its distribution characteristics, the target geometry is approximated and simplified, adhering to certain simplification principles. The simplified geometry is made as close as possible to the target prototype, forming a guiding method for simplifying the exhaust system's geometry. For example, in the treatment of curved surfaces, planes with similar angles can be used to replace complex curved surfaces; small and unimportant structures are ignored; and the structural features of internal heat sources are regularized. In principle, the simplified infrared characteristics of the exhaust system should be as consistent as possible with the actual infrared characteristics.

[0036] S102: Based on the temperature field distribution of the exhaust device, the three-dimensional model is meshed to obtain multiple model meshes, and the infrared radiation data of each model mesh is determined.

[0037] In this embodiment, the temperature field distribution of the exhaust device can be obtained. Then, based on the temperature field distribution of the exhaust device, the three-dimensional model can be meshed to obtain multiple model meshes, and the infrared radiation data of each model mesh can be determined. Specifically, this may include the following steps:

[0038] S102a: Based on the temperature field distribution of the exhaust device, the three-dimensional model is divided into the target core region and the outer flow domain;

[0039] S102b: For the target core region, the target core region is divided based on a preset first-size tetrahedral mesh to obtain multiple model meshes corresponding to the target core region; among the multiple model meshes corresponding to the target core region, the target model mesh whose temperature and pressure data changes satisfy a first preset condition is determined; the target model mesh that satisfies the first preset condition is subjected to local mesh densification processing to obtain a first target model network.

[0040] S102c: For the outer basin, the outer basin is subdivided based on a preset second-size tetrahedral mesh to obtain multiple model meshes corresponding to the outer basin; for each model mesh corresponding to the outer basin, the model mesh is locally adjusted according to the distance of the model mesh from the target core region to obtain a second target model mesh; wherein, the size of the preset second-size tetrahedral mesh is larger than the size of the preset first-size tetrahedral mesh;

[0041] S102d: Merge the first target model mesh and the second target model mesh to obtain multiple merged model meshes; and, for each of the multiple merged model meshes, perform mesh transient temperature calculation to obtain mesh transient temperature data corresponding to the model mesh, and determine the infrared radiation data of the model mesh based on the mesh transient temperature data corresponding to the model mesh.

[0042] The step of merging the first target model mesh and the second target model mesh to obtain multiple merged model meshes includes: determining the location of the interface between the target core region and the outer basin; merging the first target model mesh and the second target model mesh located at the interface to obtain the merged model meshes.

[0043] Specifically, the step of calculating the transient temperature of each model mesh in the merged plurality of model meshes to obtain the transient temperature data of that model mesh includes:

[0044] For each of the merged model meshes, the transient temperature of the mesh is calculated using Fluent software to obtain the transient temperature data of the mesh corresponding to that model mesh.

[0045] It is understandable that, in this embodiment, the mesh generation method for the target entity's geometric model can be simplified to establish the target finite element model. The mesh generation of the exhaust device target requires manual intervention and judgment based on the temperature field distribution of the exhaust device; the mesh generation density is directly proportional to the temperature field gradient. To minimize the number of computer calculations while ensuring computational accuracy, the following mesh generation method is adopted for the ship's exhaust device: ① The core region of the target is meshed with smaller tetrahedral meshes. Based on the actual physical process of the target operation, the mesh is locally refined in locations with drastic changes in temperature and pressure data to avoid divergence during numerical solution. During mesh generation, different mesh sizes are set according to the structural dimensions; larger mesh sizes are used for larger structural dimensions, and smaller mesh sizes are used for smaller structural dimensions. ② The outer flow domain is meshed with larger tetrahedral meshes. Since the outer flow domain is large, a large global mesh size is first set, and then the mesh nodes are locally adjusted, gradually refining the mesh from the far field to the core region with a smooth transition. ③ The core region mesh and the outer flow domain mesh are merged; at the interface, the mesh nodes are merged. After meshing, Fluent software was used to calculate the transient temperature field of the 3D model. It should be noted that the mesh size differs for different regions, including the exhaust port initiation point and the core and non-core regions defined by temperature.

[0046] S103: For each model mesh, generate the corresponding hierarchical bounding box; calculate the infrared ray path of the corresponding hierarchical bounding box.

[0047] For each model mesh, the model mesh is broken down into multiple basic geometric elements, and a bounding box corresponding to each basic geometric element is generated. According to a preset merging strategy, the bounding boxes corresponding to all basic geometric elements of the model network are merged to obtain the hierarchical bounding boxes corresponding to the model network. Specifically, as follows... Figure 2As shown, in the scene, both the target and background models can be represented using polygon meshes. A hierarchical bounding box (BVH) acceleration structure is adopted to improve the efficiency of ray tracing. This project will construct the hierarchical bounding box tree from bottom to top. Each node in the hierarchical bounding box tree is a bounding box. The root node stores the entire collision detection participant, while the leaf nodes store the geometric elements that make up that participant. First, a bounding box is created for each basic geometric element of the collision detection participant, serving as a leaf node. Then, the leaf nodes are merged pairwise according to a certain strategy, and the merged bounding box is constructed as the parent node of the two leaf nodes, until the entire collision detection participant is completed. For example, the nearest neighbor merging strategy can be used. The process is as follows: During ray tracing, according to the hierarchical bounding box tree, starting from the root node, the intersection points of the ray and the bounding box are detected sequentially, and so on, until the leaf node is found, obtaining the interaction polygon, as shown in the figure. After testing, the computational efficiency of calculating the infrared radiation of the background model using the hierarchical bounding box acceleration structure is nearly 20 times higher than that of calculating without any acceleration structure method.

[0048] Furthermore, the gas transparent boundary elements of the hierarchical bounding box corresponding to the model mesh are extracted; based on the gas transparent boundary elements of the hierarchical bounding box corresponding to the model mesh, a surface mesh model corresponding to the model mesh is constructed; based on the surface mesh model corresponding to the model mesh, the hierarchical bounding box corresponding to the surface mesh model is determined; based on the acceleration structure of the hierarchical bounding box corresponding to the surface mesh model, the intersection point of the light rays with the model mesh is determined; based on the intersection point, the infrared light path of the hierarchical bounding box corresponding to the model mesh is determined. Figure 3 As shown, a volume mesh ray tracing algorithm based on spatial topology information can determine the infrared ray path of the hierarchical bounding box corresponding to the model mesh. Infrared targets often contain infrared reactive gases diffused in space (such as exhaust devices with plumes), requiring representation using volume meshes. When ray tracing is needed within a volume mesh, utilizing the inherent spatial topology information of the volume mesh can significantly improve ray tracing efficiency. Before ray tracing, all gas transparent boundary elements of the volume mesh are extracted to construct a surface mesh model, forming a BVH (Browser-Video-Hovered) model. Then, the aforementioned BVH acceleration structure is used to solve for the intersection points between the ray and the volume mesh surface elements. If an intersection point exists, the ray enters the volume element pointed to by that boundary surface element. Based on the type of volume element, the algorithm searches for boundary surface elements intersecting with the ray among all the surface elements constituting that volume element. At this point, the ray exits from that surface element and enters the volume element whose normal direction is opposite to that surface element. This process is repeated until the ray reaches the receiving surface element or encounters an occluding surface element, completing the ray tracing within the target volume mesh.

[0049] S104: Determine the infrared ray path of the background region based on the infrared ray paths of the bounding boxes corresponding to all model meshes.

[0050] Specifically, the periodic symmetry property of Fourier transform can be used to perform coordinate transformation on the infrared light paths of the hierarchical bounding boxes corresponding to all model meshes to determine the infrared light paths of the background region; wherein, the intersection of the infrared light paths of the hierarchical bounding boxes corresponding to all model meshes and the background region is within the background region.

[0051] The specific algorithm flow is as follows Figure 4 As shown, assuming the background region is the sea surface, a finite wave mesh is used to represent the infinitely large sea surface when calculating sea surface radiation. When the light rays exceed the proxy mesh region, the periodic symmetry property of the Fourier transform is used to perform coordinate transformation on the light rays, ensuring that the intersection points of the rays always remain within the proxy sea surface region. Since the wave mesh approximates a plane, this property of the sea surface mesh can be utilized to design an efficient tracking algorithm without using acceleration structures such as BVH. This algorithm can be called the Ocean Adaptive Stepped Ray Tracing Algorithm.

[0052] S105: Based on the infrared radiation data of each model grid and the infrared light path of the background area, generate the infrared radiation data simulation results of the exhaust device of the target ship.

[0053] In this embodiment, based on the atmospheric attenuation equation, the infrared radiation data of the background region is determined according to the infrared radiation data of each model grid and the infrared light path of the background region; and the infrared radiation data simulation results of the exhaust device of the target ship are generated according to the infrared radiation data of each model grid and the infrared radiation data of the background region.

[0054] Specifically, in complex scenes, the root node contains multiple types of models. Since different model categories need to be set at the root node, it facilitates ray recognition of the model mesh category and the use of different ray tracing algorithms. The scene does not directly store model data; instead, bounding boxes are used to represent the model's pose and position within the scene, and the model data is stored in model containers. This setup has two advantages: ① Before ray tracing, the bounding boxes of each model are intersected. Only when a ray intersects with a bounding box is the next tracing calculation performed, thus reducing a large number of invalid intersection calculations; ② Using multiple bounding boxes to represent the same model in the scene means that when multiple repetitive models appear in the scene, only the memory consumption of one model is required.

[0055] In complex ocean scenes, with the ocean surface as the background, by controlling the interactive ray tracing across the exhaust device target, the wave surface mesh, and the sky, the radiation effects of the exhaust gas passing through the exhaust device can be calculated. The exhaust gas exerts both a radiation attenuation mechanism and a radiation gain effect on the background radiation. It can be seen that the attenuation mechanism plays a dominant role because the radiation spectrum of the sky largely overlaps with the absorption spectrum of the exhaust gas; while the radiation spectrum of the ocean background has a low overlap with the absorption spectrum of the exhaust gas, making the radiation gain effect dominant. Furthermore, through a coupled ray tracing mechanism, the reflection of the target on the water surface can also be calculated.

[0056] In other words, using the basic principles of infrared radiation, the portion of infrared radiation emitted from the sky and sea surface (i.e., the background area) reflected by the exhaust device is calculated, while the atmospheric attenuation equation is used to calculate the attenuation of infrared radiation along its path. The advantage is that the calculations only need to be performed within a single box, and then the values ​​for each box are linearly added together.

[0057] As can be seen, the simulation method, apparatus, and equipment for the infrared characteristics of ship exhaust devices provided in this disclosure can achieve the following technical effects: This application obtains a three-dimensional model of the exhaust device of the target ship and the plume flow field of the exhaust device; based on the temperature field distribution of the exhaust device, the three-dimensional model is meshed to obtain multiple model meshes, and the infrared radiation data of each model mesh is determined; for each model mesh, a hierarchical bounding box corresponding to the model mesh is generated; the infrared ray path of the hierarchical bounding box corresponding to the model mesh is calculated; based on the infrared ray paths of the hierarchical bounding boxes corresponding to all model meshes, the infrared ray path of the background region is determined; based on the infrared radiation data of each model mesh and the infrared ray path of the background region, the infrared radiation data simulation result of the exhaust device of the target ship is generated. As can be seen, this application utilizes the temperature field distribution of the exhaust device to mesh the three-dimensional model to obtain multiple model meshes. Furthermore, it uses the infrared radiation data of each model mesh and the infrared light path of the background region to generate the infrared radiation data simulation results of the exhaust device of the target ship. This improves the running speed of the infrared radiation data simulation results production, greatly reduces the time complexity, and improves detection efficiency through layer-by-layer approximation and gradual refinement. It also solves the problems of high computer memory consumption, high computer overhead, decreased accuracy after model simplification, and calculation errors introduced by the order of magnitude difference in the process of mapping flow field parameters to the infrared mesh.

[0058] In other words, this application improves the running speed and significantly reduces the time complexity by adopting simplified target entity geometric modeling and structure, simplified target entity geometric model meshing methods, and using a target-sea surface background coupled infrared radiation calculation method that combines surface mesh model ray tracing acceleration, volume mesh ray tracing algorithm based on spatial topology information, ocean adaptive stepping ray tracing algorithm, and target coupling ray tracing algorithm for complex scenes. Furthermore, the application employs a layer-by-layer approximation and progressive refinement approach, resulting in a significant improvement in detection efficiency. It also addresses the problems of high computer memory consumption, high computer overhead, decreased accuracy after model simplification, and computational errors introduced by the order-of-magnitude difference in mapping flow field parameters to the infrared mesh.

[0059] This disclosure provides an infrared characteristic simulation device for ship exhaust systems, the device comprising:

[0060] The acquisition unit is used to acquire a three-dimensional model of the exhaust device of the target ship and the plume flow field of the exhaust device.

[0061] The meshing unit is used to mesh the three-dimensional model according to the temperature field distribution of the exhaust device to obtain multiple model meshes, and to determine the infrared radiation data of each model mesh.

[0062] The computing unit is used to generate the hierarchical bounding box corresponding to each model mesh; and to calculate the infrared ray path of the hierarchical bounding box corresponding to the model mesh.

[0063] The unit is used to determine the infrared ray path of the background region based on the infrared ray path of the bounding box corresponding to all model meshes.

[0064] The simulation unit is used to generate simulation results of the infrared radiation data of the exhaust device of the target ship based on the infrared radiation data of each model grid and the infrared light path of the background area.

[0065] Optionally, the partitioning unit is used for:

[0066] Based on the temperature field distribution of the exhaust device, the three-dimensional model is divided into the target core region and the outer flow domain;

[0067] For the target core region, the target core region is divided based on a preset first-size tetrahedral mesh to obtain multiple model meshes corresponding to the target core region; among the multiple model meshes corresponding to the target core region, the target model mesh whose temperature and pressure data changes satisfy a first preset condition is determined; the target model mesh that satisfies the first preset condition is subjected to local mesh densification processing to obtain a first target model network;

[0068] For the outer basin, the outer basin is divided based on a preset second-size tetrahedral mesh to obtain multiple model meshes corresponding to the outer basin; for each model mesh corresponding to the outer basin, the model mesh is locally adjusted according to the distance of the model mesh from the target core region to obtain a second target model mesh; wherein, the size of the preset second-size tetrahedral mesh is larger than the size of the preset first-size tetrahedral mesh;

[0069] The first target model mesh and the second target model mesh are merged to obtain multiple merged model meshes; and for each of the multiple merged model meshes, the transient temperature of the mesh is calculated to obtain the transient temperature data of the mesh corresponding to the model mesh, and the infrared radiation data of the model mesh is determined based on the transient temperature data of the mesh corresponding to the model mesh.

[0070] Optionally, the partitioning unit is used for:

[0071] Determine the location of the interface between the target core region and the outer basin; merge the first target model mesh and the second target model mesh located at the interface to obtain the merged model mesh.

[0072] Optionally, the partitioning unit is used for:

[0073] For each of the merged model meshes, the transient temperature of the mesh is calculated using Fluent software to obtain the transient temperature data of the mesh corresponding to that model mesh.

[0074] Optionally, the computing unit is used for:

[0075] For each model mesh, the model mesh is broken down into multiple basic geometric elements, and a bounding box corresponding to each basic geometric element is generated. According to a preset merging strategy, the bounding boxes corresponding to all basic geometric elements of the model network are merged to obtain the hierarchical bounding box corresponding to the model network.

[0076] Optionally, the computing unit is used for:

[0077] Extract the gas transparent boundary surface elements of the hierarchical bounding box corresponding to the model mesh;

[0078] Based on the gas transparent boundary surface elements of the hierarchical bounding box corresponding to the model mesh, construct the surface mesh model corresponding to the model mesh.

[0079] Based on the surface mesh model corresponding to the model mesh, determine the hierarchical bounding box corresponding to the surface mesh model;

[0080] Based on the acceleration structure of the hierarchical bounding box corresponding to the mesh model, determine the intersection point between the ray and the mesh model.

[0081] The infrared ray path of the hierarchical bounding box corresponding to the model mesh is determined based on the intersection point.

[0082] Optionally, the determining unit is used for:

[0083] By utilizing the periodic symmetry property of Fourier transform, the infrared light paths of the bounding boxes corresponding to all model meshes are transformed to determine the infrared light paths of the background region; wherein, the intersection of the infrared light paths of the bounding boxes corresponding to all model meshes and the background region is within the background region.

[0084] Optionally, the simulation unit is used for:

[0085] Based on the atmospheric attenuation equation, the infrared radiation data of the background region is determined according to the infrared radiation data of each model grid and the infrared ray path of the background region.

[0086] Based on the infrared radiation data of each model grid and the infrared radiation data of the background region, the infrared radiation data simulation results of the exhaust device of the target ship are generated.

[0087] Combination Figure 5 As shown, this disclosure provides an infrared characteristic simulation device for a ship's exhaust system, including a processor 100 and a memory 101 storing program instructions. Optionally, the device may further include a communication interface 102 and a bus 103. The processor 100, communication interface 102, and memory 101 can communicate with each other via the bus 103. The communication interface 102 can be used for information transmission. The processor 100 can call the program instructions in the memory 101 to execute the infrared characteristic simulation method for a ship's exhaust system described in the above embodiment.

[0088] Furthermore, the program instructions in the aforementioned memory 101 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0089] The memory 101, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 100 executes functional applications and data processing by running the program instructions / modules stored in the memory 101, thereby realizing the infrared characteristic simulation method of ship exhaust device in the above embodiments.

[0090] The memory 101 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 101 may include high-speed random access memory and may also include non-volatile memory.

[0091] This disclosure provides an apparatus that includes the aforementioned infrared characteristic simulation device for ship exhaust systems.

[0092] This disclosure provides a computer-readable storage medium storing computer-executable instructions configured to execute the above-described method for simulating the infrared characteristics of a ship exhaust system.

[0093] This disclosure provides a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions, which, when executed by a computer, cause the computer to perform the above-described method for simulating the infrared characteristics of a ship exhaust device.

[0094] The aforementioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0095] The technical solutions of this disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of this disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and other media capable of storing program code; it can also be a transient storage medium.

[0096] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0097] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0098] The methods and products disclosed in the embodiments herein (including but not limited to devices and equipment) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0099] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A method for simulating the infrared characteristics of a ship's exhaust system, characterized in that, include: Obtain a three-dimensional model of the exhaust system of the target ship and the plume flow field of the exhaust system; Based on the temperature field distribution of the exhaust device, the three-dimensional model is meshed to obtain multiple model meshes, and the infrared radiation data of each model mesh is determined. For each model mesh, generate the corresponding hierarchical bounding box; calculate the infrared ray path of the corresponding hierarchical bounding box. The infrared ray path of the background region is determined based on the infrared ray paths of the bounding boxes corresponding to all model meshes. Based on the infrared radiation data of each model grid and the infrared light path of the background region, the simulation results of the infrared radiation data of the exhaust device of the target ship are generated. The step of meshing the three-dimensional model based on the temperature field distribution of the exhaust device to obtain multiple model meshes, and determining the infrared radiation data of each model mesh, includes: Based on the temperature field distribution of the exhaust device, the three-dimensional model is divided into the target core region and the outer flow domain; For the target core region, the target core region is divided based on a preset first-size tetrahedral mesh to obtain multiple model meshes corresponding to the target core region; among the multiple model meshes corresponding to the target core region, the target model mesh whose temperature and pressure data changes satisfy a first preset condition is determined; the target model mesh that satisfies the first preset condition is subjected to local mesh densification processing to obtain a first target model network; For the outer basin, the outer basin is divided based on a preset second-size tetrahedral mesh to obtain multiple model meshes corresponding to the outer basin; for each model mesh corresponding to the outer basin, the model mesh is locally adjusted according to the distance of the model mesh from the target core region to obtain a second target model mesh; wherein, the size of the preset second-size tetrahedral mesh is larger than the size of the preset first-size tetrahedral mesh; The first target model mesh and the second target model mesh are merged to obtain multiple merged model meshes; and for each of the multiple merged model meshes, the transient temperature of the mesh is calculated to obtain the transient temperature data of the mesh corresponding to the model mesh, and the infrared radiation data of the model mesh is determined based on the transient temperature data of the mesh corresponding to the model mesh.

2. The method according to claim 1, characterized in that, The step of merging the first target model mesh and the second target model mesh to obtain multiple merged model meshes includes: Determine the location of the interface between the target core region and the outer basin; merge the first target model mesh and the second target model mesh located at the interface location to obtain the merged model mesh.

3. The method according to claim 1, characterized in that, The step involves calculating the transient temperature of each model mesh in the merged set of multiple model meshes to obtain the transient temperature data corresponding to that model mesh, including: For each of the merged model meshes, the transient temperature of the mesh is calculated using Fluent software to obtain the transient temperature data of the mesh corresponding to that model mesh.

4. The method according to claim 1, characterized in that, The step of generating a hierarchical bounding box for each model mesh includes: For each model mesh, the model mesh is broken down into multiple basic geometric elements, and a bounding box corresponding to each basic geometric element is generated. According to a preset merging strategy, the bounding boxes corresponding to all basic geometric elements of the model network are merged to obtain the hierarchical bounding box corresponding to the model network.

5. The method according to claim 1, characterized in that, The calculation of the infrared ray path of the hierarchical bounding box corresponding to the model mesh includes: Extract the gas transparent boundary surface elements of the hierarchical bounding box corresponding to the model mesh; Based on the gas transparent boundary surface elements of the hierarchical bounding box corresponding to the model mesh, construct the surface mesh model corresponding to the model mesh. Based on the surface mesh model corresponding to the model mesh, determine the hierarchical bounding box corresponding to the surface mesh model; Based on the acceleration structure of the hierarchical bounding box corresponding to the mesh model, determine the intersection point between the ray and the mesh model. The infrared ray path of the hierarchical bounding box corresponding to the model mesh is determined based on the intersection point.

6. The method according to claim 1, characterized in that, The step of determining the infrared ray path of the background region based on the infrared ray paths of the hierarchical bounding boxes corresponding to all model meshes includes: By utilizing the periodic symmetry property of Fourier transform, the infrared light paths of the bounding boxes corresponding to all model meshes are transformed to determine the infrared light paths of the background region; wherein, the intersection of the infrared light paths of the bounding boxes corresponding to all model meshes and the background region is within the background region.

7. The method according to claim 1, characterized in that, The process of generating the infrared radiation data simulation results of the target ship's exhaust device based on the infrared radiation data of each model grid and the infrared ray path of the background region includes: Based on the atmospheric attenuation equation, the infrared radiation data of the background region is determined according to the infrared radiation data of each model grid and the infrared ray path of the background region. Based on the infrared radiation data of each model grid and the infrared radiation data of the background region, the infrared radiation data simulation results of the exhaust device of the target ship are generated.

8. A simulation device for the infrared characteristics of a ship's exhaust system, characterized in that, include: The acquisition unit is used to acquire a three-dimensional model of the exhaust device of the target ship and the plume flow field of the exhaust device. The meshing unit is used to mesh the three-dimensional model according to the temperature field distribution of the exhaust device to obtain multiple model meshes, and to determine the infrared radiation data of each model mesh. The step of meshing the three-dimensional model to obtain multiple model meshes based on the temperature field distribution of the exhaust device, and determining the infrared radiation data of each model mesh, includes: dividing the three-dimensional model into a target core region and an outer flow domain based on the temperature field distribution of the exhaust device; for the target core region, meshing the target core region based on a preset first-size tetrahedral mesh to obtain multiple model meshes corresponding to the target core region; among the multiple model meshes corresponding to the target core region, determining the target model meshes whose temperature and pressure data changes satisfy a first preset condition; performing local mesh refinement processing on the target model meshes that satisfy the first preset condition to obtain a first target model network; for the outer flow domain, meshing the target model meshes based on a preset second-size tetrahedral mesh... The outer basin is divided into multiple model grids corresponding to the outer basin. For each model grid corresponding to the outer basin, the model grid is locally adjusted according to the distance of the model grid from the target core region to obtain a second target model grid. The size of the preset second-size tetrahedral grid is larger than the size of the preset first-size tetrahedral grid. The first target model grid and the second target model grid are merged to obtain multiple merged model grids. For each model grid in the multiple merged model grids, the transient temperature of the grid is calculated to obtain the transient temperature data of the grid corresponding to the model grid, and the infrared radiation data of the model grid is determined based on the transient temperature data of the grid corresponding to the model grid. The computing unit is used to generate the hierarchical bounding box corresponding to each model mesh; and to calculate the infrared ray path of the hierarchical bounding box corresponding to the model mesh. The unit is used to determine the infrared ray path of the background region based on the infrared ray path of the bounding box corresponding to all model meshes. The simulation unit is used to generate simulation results of the infrared radiation data of the exhaust device of the target ship based on the infrared radiation data of each model grid and the infrared light path of the background area.

9. A simulation device for the infrared characteristics of a ship's exhaust system, characterized in that, The device includes a processor and a memory storing program instructions, characterized in that the processor is configured to execute, when executing the program instructions, the infrared characteristic simulation method for ship exhaust devices as described in any one of claims 1 to 7.

10. A device, characterized in that, Including the infrared characteristic simulation device for ship exhaust systems as described in claim 9.

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