A framework design method for system-level multi-energy flow integration and equipment-level structural optimization of new energy ships based on digital twins

Abstract

The present invention provides a system-level multi-energy flow integration and equipment-level structural optimization framework design method for new energy ships based on digital twins, which specifically includes the following steps: S1: system-level multi-energy fluid thermal energy flow network design, and various energy fluids involved in energy conversion in various equipment in the ship system are composed of system-level multi-energy fluid thermal energy flow network; S2: equipment-level thermal hydraulic structure simulation model construction, and the three-dimensional structure of each equipment in the ship system is established using numerical simulation software; S3: digital twin interactive data coupling and transmission between the two levels, and digital twin interactive data coupling and transmission are performed between the system-level multi-energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model. The present invention is helpful to deeply develop the energy-saving and emission-reduction potential of ship power conversion systems under large-scale nonlinearity, complex and diverse equipment, and interactive coupling of energy flows.

Description

Technical Field

[0001] The present invention relates to the field of design and manufacturing of intelligent new energy ship systems, and more specifically, to a system-level multi-energy flow integration and equipment-level structural optimization framework design method for new energy ships based on digital twins. Background Art

[0002] In recent years, the International Maritime Organization has formulated a series of ship energy conservation and emission reduction measures, from passive response to active prevention and control to encouraging innovation in power system design and construction technology. As a Category A member of the International Maritime Organization, how China can further develop new technologies for green ships and strengthen the strategic deployment of energy conservation and emission reduction for maritime ships has posed new challenges to the energy conservation research of modern ship power systems and equipment. Power conversion systems and related heat exchange equipment are an important part of the power core of 85% of the world's cargo transport ships. While providing energy and power for ships, they are also related to factors such as ship operation stability, safety, energy conservation, and economy. Therefore, how to study the multi-scale energy distribution, integrated simulation, and data interactive collaborative theory and technology of power systems and related equipment from a scientific perspective has become one of the key issues in promoting energy conservation and emission reduction of high-energy-consuming ship systems and equipment.

[0003] The power energy conversion system of modern large ships refers to the various energy flows such as propulsion, electricity, cold and heat energy, etc., as well as the various equipment and systems required to transport and store these energy flows, which usually include the ship's main power plant, power station, auxiliary boiler, refrigeration and air conditioning system, etc. In this large-scale, complex, and diversely equipment strongly coupled multi-scale system, there are many different types of energy fluids with different thermodynamic parameters acting as intermediate energy media. If the traditional independent flow energy integration form is used to simulate the system and related equipment, the calculation model will be too complicated, the intermediate unknown parameters will be doubled, the local optimal solution will increase, and the model will be difficult to converge. In addition, in the traditional simulation lumped parameter method, there is little interaction between the system and each equipment model or each is an isolated boundary condition, the simulation linkage is poor, and isolated subsystems are prone to appear, which has little guiding significance for the actual ship power conversion system. Digital twin technology is a digital mapping specifically for physical systems, equipment process parameters and structural parameters. After reception, it is reflected in the digital mirror of the processing simulation center. It is a digital expression of the real-world physical entity. After being processed in the simulation model, it provides feedback to the real individual through effective optimization design methods, so as to facilitate deeper thinking and management of the real world.

[0004] With the continuous expansion of the scope of application and the increasingly severe energy and environmental problems, traditional static isolated simulation can no longer solve the digital simulation problems in strongly coupled multi-scale systems with large scale, complex composition and diverse equipment, and cannot meet the urgent needs of modern ship power systems for more efficient, energy-saving and variable operating condition optimization design. Summary of the invention

[0005] In order to achieve energy flow matching and interactive coordination between the power system and the equipment level, the present invention specifically targets the simulation process of ship power systems and related equipment, and proposes a new energy ship system-level multi-energy flow integration and equipment-level structural optimization framework design method based on digital twins, which aims at how to build a system-level multi-energy flow heat exchange network to determine the interaction between the energy flows of each device; how to comprehensively consider the collaborative simulation method and data interaction at the multi-scale coupling level of the system and equipment level, and form a typical interactive collaborative simulation framework between the system and equipment level. The present invention helps to deeply develop the energy-saving and emission-reduction potential of ship power conversion systems under the conditions of large-scale nonlinearity, complex and diverse equipment, and interactive coupling of energy flows. It has important practical significance for realizing efficient energy integration of large-scale ship power systems and promoting energy conservation and consumption reduction and green development of my country's maritime shipbuilding industry.

[0006] The technical means adopted by the present invention are as follows:

[0007] A digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structural optimization framework design method specifically includes the following steps:

[0008] S1: System-level design of thermal energy flow networks for multiple energy fluids

[0009] The energy fluids involved in energy conversion in each device in the ship system are combined into a system-level multi-energy fluid thermal energy flow network. The system-level multi-energy fluid thermal energy flow network is used to determine the initial and final working conditions of the ship system and connect the energy fluids in each device in the ship system. The system-level multi-energy fluid thermal energy flow network design is completed through the one-dimensional distributed parameter method:

[0010] First, let all the cold fluids in the ship system be t C , all thermal fluids are T H , the inflow and outflow of the ship system are represented by superscripts in and out, respectively, the counts of hot fluid and cold fluid are represented by subscripts i and j, respectively, and the system-level multi-stream energy fluid thermal energy flow network is represented by the following formula:

[0011]

[0012] Among them, Q H and Q C Represents the external heat source and cold source, CP represents the specific heat capacity of the hot fluid, and cp represents the specific heat capacity of the cold fluid;

[0013] Then, the one-dimensional distribution parameter method is used to express the external process conditions of the above formula:

[0014]

[0015]

[0016]

[0017] Among them, AP is the closest position corresponding to the inlet and outlet temperatures of the cold and hot fluids in the system, the subscripts C and H correspond to the cold fluid and hot fluid respectively, and P in the above table represents the approximate point; △T min is the minimum average temperature difference; T p is the point where the inlet and outlet temperatures of the cold and hot fluids in the system are closest, and

[0018] S2: Construction of equipment-level thermal hydraulic structure simulation model

[0019] Use numerical simulation software to establish the three-dimensional structure of each device in the ship system, then divide the three-dimensional structure into grids, and finally, according to the known initial boundary conditions, calculate the energy conservation, momentum conservation, and mass conservation equations to obtain the description of the temperature field, pressure field, and velocity field inside each device in the ship system;

[0020] S3: Interactive data coupling transmission between two levels of digital twins

[0021] The digital twin interactive data coupling transmission is carried out between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model, so that data sharing is formed between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model, and the connection relationship between the system-level multi-stream energy fluid thermal energy flow network and each device in the equipment-level thermal hydraulic structure simulation model is virtualized to form a mapping relationship between the two levels of digital twins. The specific mapping relationship is expressed as:

[0022] f1(a1,b1,c1.....x1,y1,z1) e =f s+1 '

[0023] f s+1 '=f2(a'1,b'1,c'1....x'1,y'1,z'1) e+1 ......

[0025]

[0026] Among them, a, b, c...x, y, z represent the variable parameters of each equipment in the ship system, including the thermal properties of the fluid, temperature, pressure, specific volume and structural parameters; the subscript e represents the equipment-level thermal hydraulic structure simulation model, and s represents the system-level multi-stream energy fluid thermal energy flow network; firstly, the given parameters are introduced into the equipment-level thermal hydraulic structure simulation model to obtain the system-level multi-stream energy fluid thermal energy flow network result f s+1 , and then perform data interaction to change the system-level multi-stream energy fluid thermal energy flow network result to f s+1 ', and then feed back to the equipment-level thermal-hydraulic structure simulation model to regain the feedback of the parameters a1', b1', c1'...x1', y1', z1' of the equipment-level thermal-hydraulic structure simulation model, and use the feedback to continue to obtain the system-level multi-stream energy fluid thermal energy flow network results, and finally form an interactive system-level multi-stream energy fluid thermal energy flow network to the equipment-level thermal-hydraulic structure simulation model. Mapping.

[0027] Furthermore, the system-level multi-stream energy fluid thermal energy flow network includes the ship power system pipelines, the ship auxiliary system pipelines, the corresponding ship heat exchange equipment in the pipeline nodes, the boosting device, the steam equipment and the various energy fluids participating in energy conversion in the pipeline auxiliary equipment.

[0028] Furthermore, the ship's heat exchange equipment includes a cooler, a heater and a regenerator; the booster device includes a compressor and a working fluid pump; and the steam equipment includes an auxiliary boiler and a condenser.

[0029] Furthermore, the equipment-level thermal-hydraulic structure simulation model includes ship heat exchange equipment, booster equipment, steam equipment, pipelines, and pipeline auxiliary equipment.

[0030] Furthermore, it also includes:

[0031] S4: Collect data through the reserved interfaces of the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal-hydraulic structure simulation model respectively, match and verify the mapping between the interactive system-level multi-stream energy fluid thermal energy flow network formed in S3 and the equipment-level thermal-hydraulic structure simulation model with the data retrieved from the real ship navigation database and the full-task simulation experiment platform of the turbine system, and revise the mapping process according to the verification results to achieve synchronization with the actual ship operation requirements.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. Considering that the existing system simulation only starts from the design of a single device energy flow, but ignores the interaction between multiple energy flows, sacrificing its process conditions as a heat exchange network, the integrity and complexity of the ship power system simulation process, any change in the state of the device flow will cause changes in the overall configuration of the heat exchange network and the final simulation results. The digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structural optimization framework design method provided by the present invention, as far as the ship power system is concerned, the various flows involved in the energy flow conversion can be regarded as the heat exchange network of the energy exchange system, which not only connects and couples multiple single devices, but also has the characteristics of the overall heat exchange network and the corresponding process conditions. It is a ship power system simulation design method that is more in line with actual process conditions.

[0034] 2. Most traditional simulation methods use known or assumed conditions to separate the equipment level and the system level, so they cannot achieve dynamic data transmission and simulation calculation of time-varying working conditions; the design of efficient and energy-saving ship power auxiliary equipment is inseparable from accurate and reliable refined thermal and hydraulic three-dimensional simulation; and in order to meet the actual process conditions of the entire power system, it also depends on the organization and coordination of the energy flow of each device in the system heat exchange network. The two complement each other and cannot be neglected. Therefore, the new energy ship system-level multi-energy flow integration and equipment-level structural optimization framework design method based on digital twins provided by the present invention comprehensively considers the collaborative simulation method and data interaction at the multi-scale coupling level of the system and equipment level, forms a typical interactive collaborative simulation framework and analysis method between the system and equipment levels, and provides technical guidance for the digital simulation design of ship power systems with similar multi-scale coupling.

[0035] Based on the above reasons, the present invention can be widely promoted in the fields of ship multi-power systems and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative labor.

[0037] Figure 1 It is a schematic diagram of the principle of digital twin mapping between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal-hydraulic structure simulation model described in the present invention. DETAILED DESCRIPTION

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1 As shown, the present invention provides a new energy ship system-level multi-energy flow integration and equipment-level structure optimization framework design method based on digital twin, which specifically includes the following steps:

[0042] S1: System-level design of thermal energy flow networks for multiple energy fluids

[0043] The energy fluids involved in energy conversion in each device in the ship system are combined into a system-level multi-energy fluid thermal energy flow network. The system-level multi-energy fluid thermal energy flow network is used to determine the initial and final working conditions of the ship system and connect the energy fluids in each device in the ship system. The system-level multi-energy fluid thermal energy flow network design is completed through the one-dimensional distributed parameter method:

[0044] First, let all the cold fluids in the ship system be t C , all thermal fluids are T H , the inflow and outflow of the ship system are represented by superscripts in and out, respectively, the counts of hot fluid and cold fluid are represented by subscripts i and j, respectively, and the system-level multi-stream energy fluid thermal energy flow network is represented by the following formula:

[0045]

[0046] Among them, Q H and Q C Represents the external heat source and cold source, CP represents the specific heat capacity of the hot fluid, and cp represents the specific heat capacity of the cold fluid;

[0047] Then, the one-dimensional distribution parameter method is used to express the external process conditions of the above formula:

[0048]

[0049]

[0050]

[0051] Among them, AP is the closest position corresponding to the inlet and outlet temperatures of the cold and hot fluids in the system, the subscripts C and H correspond to the cold fluid and hot fluid respectively, and P in the above table represents the approach point, that is, the "narrow point"; △T min is the minimum average temperature difference; T p is the point where the inlet and outlet temperatures of the cold and hot fluids in the system are closest, and

[0052] S2: Construction of equipment-level thermal hydraulic structure simulation model

[0053] Use numerical simulation software (such as CFD) to establish the three-dimensional structure of each device in the ship system, then mesh the three-dimensional structure, and finally obtain the description of the temperature field, pressure field, and velocity field inside each device in the ship system by calculating the energy conservation, momentum conservation, and mass conservation equations based on the known initial boundary conditions;

[0054] The equipment-level thermal-hydraulic structure simulation model can be regarded as a non-uniformly distributed parameter subsystem containing different energy flow changes or an operational boundary condition at the end of the above system. Numerical simulation software (such as CFD) can be used to establish a three-dimensional structural model to solve the internal design problems of the equipment and obtain the temperature field, pressure field and velocity field description under the specific size of the equipment.

[0055] S3: Interactive data coupling transmission between two levels of digital twins

[0056] The digital twin interactive data coupling transmission is carried out between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model, so that data sharing is formed between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model, and the connection relationship between the system-level multi-stream energy fluid thermal energy flow network and each device in the equipment-level thermal hydraulic structure simulation model is virtualized to form a mapping relationship between the two levels of digital twins. The specific mapping relationship is expressed as:

[0057] f1(a1,b1,c1.....x1,y1,z1) e =f s+1 '

[0058] f s+1 '=f2(a'1,b'1,c'1....x'1,y'1,z'1) e+1 ......

[0060]

[0061] Among them, a, b, c...x, y, z represent the variable parameters of each equipment in the ship system, including the thermal properties of the fluid, temperature, pressure, specific volume and structural parameters; the subscript e represents the equipment-level thermal hydraulic structure simulation model, and s represents the system-level multi-stream energy fluid thermal energy flow network; firstly, the given parameters are introduced into the equipment-level thermal hydraulic structure simulation model to obtain the system-level multi-stream energy fluid thermal energy flow network result f s+1 , and then perform data interaction to change the system-level multi-stream energy fluid thermal energy flow network result to f s+1 ', and then feed back to the equipment-level thermal-hydraulic structure simulation model to re-obtain the parameters a1', b1', c1'...x1', y1', z1' feedback of the equipment-level thermal-hydraulic structure simulation model, and use the feedback to continue to obtain the system-level multi-stream energy fluid thermal energy flow network results, and finally form an interactive system-level multi-stream energy fluid thermal energy flow network to the equipment-level thermal-hydraulic structure simulation model. Mapping;

[0062] The mapping refers to the mathematical relationship between the various devices in the ship and the systems that communicate with these devices.

[0063] Figure 1 H1, H2, and H3 represent different hot energy fluids in the system, and there can be an infinite number of them according to the actual system analysis. C1, C2, and C3 represent different cold energy fluids in the system, and there can be an infinite number of them according to the actual system analysis. In the system-level multi-stream energy fluid thermal energy flow network, each intersection of hot and cold energy fluids is mapped to each device in the equipment-level thermal hydraulic structure simulation model. ● represents ship heat exchange equipment (such as coolers, heaters, regenerators, heat exchangers, etc.); ▲ represents boosting devices (such as compressors, working fluid pumps, etc.); ■ represents steam devices (such as steam boilers, condensers, etc.); ◆ represents related pipelines (such as secondary circuits, branch pipes, etc.); ★ represents other auxiliary equipment in the ship system.

[0064] Furthermore, the system-level multi-stream energy fluid thermal energy flow network includes the ship power system pipelines, the ship auxiliary system pipelines, the corresponding ship heat exchange equipment in the pipeline nodes, the boosting device, the steam equipment and the various energy fluids participating in energy conversion in the pipeline auxiliary equipment.

[0065] Furthermore, the ship's heat exchange equipment includes a cooler, a heater and a regenerator; the booster device includes a compressor and a working fluid pump; and the steam equipment includes an auxiliary boiler and a condenser.

[0066] Furthermore, the equipment-level thermal-hydraulic structure simulation model includes ship heat exchange equipment, booster equipment, steam equipment, pipelines, and pipeline auxiliary equipment.

[0067] Furthermore, it also includes: S4: collecting data respectively through the reserved interfaces of the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal-hydraulic structure simulation model, matching and verifying the mapping between the interactive system-level multi-stream energy fluid thermal energy flow network formed in S3 and the equipment-level thermal-hydraulic structure simulation model with the data retrieved from the real ship navigation database and the full-task simulation experimental platform of the turbine system, and revising the mapping process according to the verification results to achieve synchronization with the actual ship operation requirements.

[0068] By means of the digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structural optimization framework design method provided by the present invention, theoretical analysis, numerical simulation modeling, and verification and revision with the help of actual data are carried out, and finally a multi-scale collaborative simulation design strategy for the ship power conversion process at the system and equipment interaction level can be given.

[0069] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structural optimization framework design method, characterized in that: The specific steps include: S1: System-level design of thermal energy flow networks for multiple energy fluids The energy fluids involved in energy conversion in each device in the ship system are combined into a system-level multi-energy fluid thermal energy flow network. The system-level multi-energy fluid thermal energy flow network is used to determine the initial and final working conditions of the ship system and connect the energy fluids in each device in the ship system. The system-level multi-energy fluid thermal energy flow network design is completed through the one-dimensional distributed parameter method: First, let all the cold fluids in the ship system be t C , all thermal fluids are T H , the inflow and outflow of the ship system are represented by superscripts in and out, respectively, the counts of hot fluid and cold fluid are represented by subscripts i and j, respectively, and the system-level multi-stream energy fluid thermal energy flow network is represented by the following formula: Among them, Q H and Q C Represents the external heat source and cold source, CP represents the specific heat capacity of the hot fluid, and cp represents the specific heat capacity of the cold fluid; Then, the one-dimensional distribution parameter method is used to express the external process conditions of the above formula: Where AP is the closest position corresponding to the inlet and outlet temperatures of the cold and hot fluids in the system, the subscripts C and H correspond to the cold fluid and hot fluid respectively, and the superscript P represents the approximate point; △T min is the minimum average temperature difference; T p is the point where the inlet and outlet temperatures of the cold and hot fluids in the system are closest, and S2: Construction of equipment-level thermal hydraulic structure simulation model Use numerical simulation software to establish the three-dimensional structure of each device in the ship system, then divide the three-dimensional structure into grids, and finally, according to the known initial boundary conditions, calculate the energy conservation, momentum conservation, and mass conservation equations to obtain the description of the temperature field, pressure field, and velocity field inside each device in the ship system; S3: Interactive data coupling transmission between two levels of digital twins The digital twin interactive data coupling transmission is carried out between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model, so that data sharing is formed between the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal hydraulic structure simulation model, and the connection relationship between the system-level multi-stream energy fluid thermal energy flow network and each device in the equipment-level thermal hydraulic structure simulation model is virtualized to form a mapping relationship between the two levels of digital twins. The specific mapping relationship is expressed as: f1(a1,b1,c1.....x1,y1,z1) e =f s+1 ' f s+1 '=f2(a'1,b1',c'1.....x1',y1',z1') e+1 ...... Among them, a, b, c...x, y, z represent the variable parameters of each equipment in the ship system, including the thermal properties of the fluid, temperature, pressure, specific volume and structural parameters; the subscript e represents the equipment-level thermal hydraulic structure simulation model, and s represents the system-level multi-stream energy fluid thermal energy flow network; firstly, the given parameters are introduced into the equipment-level thermal hydraulic structure simulation model to obtain the system-level multi-stream energy fluid thermal energy flow network result f s+1 , and then perform data interaction to change the system-level multi-stream energy fluid thermal energy flow network result to f s+1 ', and then feed back to the equipment-level thermal-hydraulic structure simulation model to regain the feedback of the parameters a1', b1', c1'...x1', y1', z1' of the equipment-level thermal-hydraulic structure simulation model, and use the feedback to continue to obtain the system-level multi-stream energy fluid thermal energy flow network results, and finally form an interactive system-level multi-stream energy fluid thermal energy flow network to the equipment-level thermal-hydraulic structure simulation model. Mapping.

2. According to claim 1, the digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structure optimization framework design method is characterized in that: The system-level multi-stream energy fluid thermal energy flow network includes the ship power system pipelines, the ship auxiliary system pipelines, the corresponding ship heat exchange equipment in the pipeline nodes, the booster device, the steam equipment and the energy fluids involved in energy conversion in the pipeline auxiliary equipment.

3. The digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structure optimization framework design method according to claim 2 is characterized in that: Ship heat exchange equipment includes coolers, heaters and regenerators; boosting devices include compressors and working fluid pumps; steam equipment includes auxiliary boilers and condensers.

4. The digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structure optimization framework design method according to claim 1 is characterized in that: The equipment-level thermal-hydraulic structure simulation model includes ship heat exchange equipment, booster equipment, steam equipment, pipelines, and pipeline auxiliary equipment.

5. The digital twin-based new energy ship system-level multi-energy flow integration and equipment-level structure optimization framework design method according to claim 1 is characterized in that: Also includes: S4: Collect data through the reserved interfaces of the system-level multi-stream energy fluid thermal energy flow network and the equipment-level thermal-hydraulic structure simulation model respectively, match and verify the mapping between the interactive system-level multi-stream energy fluid thermal energy flow network formed in S3 and the equipment-level thermal-hydraulic structure simulation model with the data retrieved from the real ship navigation database and the full-task simulation experiment platform of the turbine system, and revise the mapping process according to the verification results to achieve synchronization with the actual ship operation requirements.

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