Optimization Design Of System Research Articles

Analysis of electromechanical coupling modal and dynamic response characteristics of permanent magnet gear transmission system considering variable load condition

In order to study the influence of electromagnetic (EM) effect and load change on the modal characteristics and dynamic response of gear transmission system driven by permanent magnet synchronous motor (PMSM), a electromechanical coupling dynamic model is established. The composite air gap permeability coefficient is introduced, and the formula of permanent magnet flux linkage under the influence of space harmonic and cogging effect is derived. The variation laws of gear meshing stiffness and bearing support stiffness under the influence of load change are simulated and analyzed. The natural frequency and vibration modal under different load, flux linkage and PI controller gain are revealed. On this basis, the influence of EM effect and load change on the resonance domain is analyzed through frequency sweep analysis and time domain simulation. Results indicate that the 1st order natural frequency and resonance amplitude will increase with the load, and the influence of PMSM EM excitation will gradually dominate. The increase of the flux linkage and speed loop controller gain Kpω will reduce the 1st order natural frequency. When Kpω =123, a new mode appears, and there is a modal transition between the new mode and mode 1 when Kpω =161. The research results can provide theoretical guidance for improving the transmission performance and structure optimization design of the permanent magnet gear transmission system.

A Three-State Space Modeling Method for Aircraft System Reliability Design

Reliability is an inherent attribute of a system through optimal system design. However, during the aircraft system development process, the reliability evaluation and system function design efforts are often disconnected, leading to a divide between reliability experts and system designers in their work schedule. This disconnect results in an inefficient aircraft system reliability optimization process, known as the “two-skin” phenomenon. To address this issue, a three-state space model is proposed. Firstly, an analysis was conducted on the relationship between the system function architecture developed by the system designers and the reliability evaluation performed by the reliability experts. Secondly, based on the principle of function flow, the state of failure was categorized into “physical failure” and “non-physical failure”. Additionally, a new state of “function loss” was introduced as the third state for the system, in addition to the traditional states of “normal” and “faulty”. Thirdly, through the state of “Function loss”, an effective integration of system fault modes and function modes was achieved, leading to an optimized system reliability model. A three-state space modeling method was then developed by transforming the system function architecture into a system reliability model. Finally, this new model was applied to an aircraft’s rudder and fly-by-wire control system. The results demonstrate that the function architecture at the design stage of the system can be accurately transformed into the new three-state space model. The structure aligns closely with the function architecture and can be effectively utilized in quantitative system reliability calculations. In this way, the process of ensuring system reliability can be seamlessly integrated into the system optimization design process. This integration alleviates the issue of disjointed work between reliability experts and system designers, leading to a more streamlined and efficient aircraft system optimization process.

Whether the off-design characteristics of equipment should be considered in integrated energy system optimization design models – A case study

The operational performance of integrated energy systems (IESs) varies with their configuration. The equipment model directly influences the capacity configuration of IESs. The conventional static model assumes that equipment efficiency is constant, ignoring its off-design characteristics. For this reason, this paper establishes a dynamic model considering the off-design characteristics of the equipment. Based on the dynamic and static models, bi-level optimization models with the minimum total cost as the optimization objective are established to optimize the configuration of IESs, and the optimization results are System 1 and System 2, respectively. Then, the operational performance of the two systems under the dynamic optimal scheduling model is compared. The results demonstrate that the capacity of the absorption chiller (ABC), combined heating and power (CHP) unit in System 1 are larger than in System 2 owing to the difference in equipment models, whereas the capacity of ground source heat pumps (GSHPs) shows the opposite trend. The larger capacity of the GSHP increases the grid power consumption of System 2 but also reduces its operating efficiency. The greater operation energy consumption and grid power consumption make the operating cost, carbon tax, and total cost of System 2 under the design condition higher than that of System 1, with an increased rate of 1.38%, 3.47%, and 1.14%, respectively. As with the design condition, the carbon tax, operating cost, and total cost of System 2 are higher than those of System 1 under both summer and winter operating conditions, particularly under summer operating conditions, where the carbon tax, operating cost, and total cost increase by 2.27%, 1.24%, and 0.88% respectively. Even if the energy price changes, the carbon tax, operating cost and total cost of System 2 in a typical year are still greater than those of System 1. Therefore, it is necessary to consider the off-design characteristics of equipment in the bi-level optimization design model.

Optimization design of a two-stage multidirectional vibration isolation system for large airborne equipment

Purpose Improvement and optimization design of a two-stage vibration isolation system proposed in this paper are conducted to ensure the device of electronic work effective.Design/methodology/approach The proposed two-stage vibration isolation system of airborne equipment is optimized and parameterized based on multi-objective genetic algorithm.Findings The results show that compared with initial two-stage vibration isolation system, the angular vibration of the two-stage vibration isolation system becomes 3.55 × 10-4 rad, which decreases by 89%. The linear isolation effect is improved by at least 67.7%.Originality/value The optimized two-stage vibration isolation system effectively improves the vibration reduction effect, the resonance peak is obviously improved and the reliability of the mounting bracket and the shock absorber is highly improved, which provides an analysis method for two-stage airborne equipment isolation design under complex dynamic environment.

Fast and Accurate Computation of Wireless Power Transfer System Optimal Design Using Particle Swarm Optimization Method

Fast and Accurate Computation of Wireless Power Transfer System Optimal Design Using Particle Swarm Optimization Method

Hybrid solar energy systems with hydrogen and electrical energy storage for a single house and a midrise apartment in North America

Allowing deeper penetration of renewable energy technologies through the adaptation of hybrid systems is unanimously considered critical for decarbonizing the building sector. The objective of this research is to analyze and contrast different renewable energy systems utilizing PV panels, an electrolyzer, and a fuel cell (FC) in a single-house and a midrise apartment located in North America. The study uses HOMER software to simulate and optimize three types of systems: PV/battery bank, PV/hydrogen, and PV/battery bank/hydrogen. The findings indicate that larger batteries can be utilized in place of the electrolyzer and fuel cell, but they incur a higher net present cost (NPC) due to their expensive initial investment. Therefore, a combination of PV arrays, hydrogen, and smaller battery banks can significantly reduce the net present cost of the system while also achieving efficient performance. After conducting an economic analysis of various setups for a single house, the research indicates that a configuration of 522 kW photovoltaic (PV) panels, 150 kW electrolyzer, 20 kW fuel cell, 200 kg hydrogen tank, 18.6 kW converter, and 159 batteries offers the most favorable results in Toronto, Canada. This configuration achieves lower NPC and levelized cost of energy (COE) than the PV/hydrogen system. In addition, according to the optimum design of the hydrogen system for the midrise apartment, the PV/battery bank/hydrogen configuration has a lower NPC and COE than the PV/hydrogen system, which shows that adding the battery to the system lowers the cost and offer short and long-term energy storage. The optimum design was then verified by implementing a sensitivity analysis to evaluate different solar radiation, electric load, derating factor and tilt angle of the PV array.

On the Innovation, Design, Construction, and Experiments of OMEGA-Based SSPS Prototype: The Sun-Chasing Project

This study systematically introduces the development of the world’s first full-link and full-system ground demonstration and verification system for the OMEGA space solar power satellite (SSPS). First, the OMEGA 2.0 innovation design was proposed. Second, field-coupling theoretical models of sunlight concentration, photoelectric conversion, and transmitting antennas were established, and a systematic optimization design method was proposed. Third, a beam waveform optimization methodology considering both a high beam collection efficiency and a circular stepped beam shape was proposed. Fourth, a control strategy was developed to control the condenser pointing toward the sun while maintaining the transmitting antenna toward the rectenna. Fifth, a high-efficiency heat radiator design method based on bionics and topology optimization was proposed. Sixth, a method for improving the rectenna array’s reception, rectification, and direct current (DC) power synthesis efficiencies is presented. Seventh, high-precision measurement technology for high-accuracy beam-pointing control was developed. Eighth, a smart mechanical structure was designed and developed. Finally, the developed SSPS ground demonstration and verification system has the capacity for sun tracking, a high concentration ratio, photoelectric conversion, microwave conversion and emission, microwave reception, and rectification, and thus satisfactory results were obtained.

Incidence of wind spectrum and turbulence intensity on the design of mooring systems for floating offshore wind turbines

The paper focuses on the incidence of wind spectrum and turbulence intensity on the design of stationkeeping systems for Floating Offshore Wind Turbines. After a brief review about the employed nonlinear time-domain hydrodynamic model, some basics about the Ultimate and Fatigue Limit State design conditions of the mooring system are provided. Subsequently, the two wind spectra, employed in the numerical simulations, are briefly introduced. The former is the NPD wind spectrum, generally applied for the design of mooring systems for typical offshore structures, employed in the oil and gas sector. The latter is the Kaimal wind spectrum, generally employed for the design of offshore wind turbines in conjunction with different turbulence models, depending on the operative scenario. The numerical investigation is performed considering the DeepCwind platform, equipped with the 5 MW NREL wind turbine, as reference support structure, deployed in the North Sea area. Three different water depths, from 200 up to 400 m, are considered. It is verified that both the wind spectrum and turbulence model play a fundamental role not only for the optimum design of the stationkeeping system, but also for the proper selection of the line scope, as well as of the leading usage factors.

Quasi-zero stiffness interval optimization design and dynamics analysis of a new bi-directional horizontal isolation system

The quasi-Zero Stiffness (QZS) isolation system is a typical nonlinear isolation system, which has high static stiffness characteristics to improve the bearing capacity and deformation resistance, and its low dynamic stiffness characteristics can reduce the inherent frequency of the system to realize a wider vibration isolation frequency band, so it has a more excellent low-frequency vibration isolation performance compared with the linear system. In this paper, a horizontal QZS isolator is constructed based on a pre-compressed oblique spring system, and two sets of the horizontal QZS isolators are mechanically assembled to work together to achieve a bi-directional horizontal QZS isolation system. Considering that the construction of two sets of horizontal vibration isolators is approximately the same, we focus on one of the isolators for the static analysis and derive the parameter conditions to be satisfied for achieving quasi-zero stiffness characteristics. We considered the effect of each adjustable parameter of the horizontal vibration isolator on the mechanical performance of the QZS system, and sought to optimize the QZS interval to improve the vibration isolation performance. A comparative study of the dynamical properties between the QZS system with ordinary and optimized parameters, as well as the equivalent linear system, is further carried out by means of nonlinear approximate analysis. Finally, the dynamic characteristics of the bi-directional horizontal QZS system and the equivalent linear system are compared by shaker tests on the prototype device, which proved the excellent vibration isolation performance of the proposed QZS isolation system.

Performance optimization design of wide-body aircraft pressure refueling system

In order to reduce the wide body aircraft refueling process time-cost and improve the airport operation efficiency, pressure refueling system design strategy was innovated. The shutoff valves’ operation sequence in refueling process was optimized. The diameter of the orifices on the pressure refueling system fuel line was designed. Pressure refueling performance was simulated and analyzed at different scenarios. The results show that it can improve the pressure refueling system performance at different scenarios by optimizing the pressure refueling process strategy design including optimizing the fuel line orifice design and optimizing the wing tank inner side shut-off valve operation sequence.

Thermal Performance Analysis and Multi-Factor Optimization of Middle–Deep Coaxial Borehole Heat Exchanger System for Low-Carbon Building Heating

Ground-source heat pumps with deep borehole heat exchangers can fully utilize deep geothermal energy, effectively reducing the consumption of non-renewable energy for building air conditioning and achieving energy conservation and emissions reduction goals. However, the middle–deep coaxial borehole heat exchange (MDBHE) development is insufficient, and there is currently a lack of definitive guidelines for system optimal design and operation. This paper firstly establishes an effective and efficient system model and examines nine important parameters related to the design and operation of the MDBHE using a single-factor analysis. Thereafter, we compare and analyze the impact of different parameters through an orthogonal experimentation method. The findings reveal that the three most significant factors are borehole depth, inlet temperature, and mass flow rate, in descending order of importance. In addition, in terms of operation mode, this paper makes a comparative analysis of the operation of the MDBHE in variable flow mode and constant flow mode. The results showed that the average energy consumption of the pump in the variable flow mode decreased by 9.6%, and the surrounding ground temperature recovered at a faster rate.

A quasi-2D thermodynamic model for performance analysis and optimization of liquid hydrogen storage system with multilayer insulation and vapor-cooled shield

Liquid hydrogen (LH2) holds great potential in both aerospace and civil markets due to its high energy density. However, on account of the low boiling point and latent heat of vaporization of LH2, the high performance insulation storage system is the key to its efficient storage. One of the most efficient insulation methods for a LH2 storage system is considered to be Variable Density Multilayer Insulation (VDMLI) coupled with Vapor-Cooled Shield (VCS). This study establishes a quasi-two-dimensional (quasi-2D) thermodynamic model of liquid hydrogen storage system with VDMLI and VCS. The quasi-2D model incorporates the temperature gradient of VCS and its impact on VDMLI. The model can reveal the two-dimensional temperature and heat distribution in insulation systems, predict heat leakage and evaporation rate, and can be utilized for optimizing the design of the VCS structure. Using a NASA's tank as an example, the analysis conducted with the model indicates that the presence of VCS reduces the average temperature gradient of the inner VDMLI. The upper half of the tank exhibits a significantly smaller temperature gradient compared to the lower half, resulting in lower heat leakage. This effect becomes more pronounced as the VCS moves outward of the tank. Additionally, the VCS absorbs more heat in the inlet section than that in the outlet section, and this disparity becomes increasingly significant as the VCS moves outward of the tank. The model can also be employed to optimize the position of the VCS, resulting in a 69.73 % reduction in daily evaporation rate compared to NASA's original design. Lastly, a graphical method for the quick design of VCS structure is proposed which is based on calculated data for daily evaporation rate and apparent thermal conductivity. This method enables the retrieval of the corresponding apparent thermal conductivity based on the desired evaporation rate, facilitates the rapid determination of the range of VCS position, and allows for the quick prediction of the evaporation rate based on the VCS position. In conclusion, this research presents a new approach for the performance analysis and optimization design of liquid hydrogen storage system with VDMLI and VCS.

Concurrent topology optimization of shells with pattern-guided infills for intuitive design and additive manufacturing

This paper introduces a systematic design optimization approach for shells with pattern-guided infills, aiming to address both intuitive design requirements and considerations for additive manufacturing. The approach utilizes a density-based topology optimization method and assigns two sets of design variables to distinctly define the base, coating, and infill structures. By evolving the solid shells and enriched infills concurrently, the design optimization process ensures a cohesive integration of both components. To guide the infill design towards matching the geometrical features of a predefined pattern, a geometrical constraint is imposed on the infill field. Enhanced by an updated and approximate volume constraint, the infill materials with prescribed appearance performances are accordingly distributed in the base region. The simultaneous optimization of shell geometry and infill layout is then performed within the framework of minimum compliance topology optimization. A range of numerical results illustrate the effectiveness and robustness of the proposed approach. The topology optimized results demonstrate that a given pattern can directly control the design features of the infill in a visually explicit manner and the shell-infill composites ensure convenient manufacturability.

Test and Evaluation Analysis of Thermal Balance of Advanced Fuel Cell Vehicle Models

The thermal balance of fuel cell passenger vehicles needs to solve the problem of heat dissipation and integration, which is the key to solve the vehicle performance for high-power fuel cell systems. In this paper, international advanced fuel cell passenger vehicles are selected to evaluate and analyze the thermal balance capability. By comparing the existing thermal balance test and evaluation methods, a test method aiming at the unique characteristics of fuel cell vehicles is proposed, including the test condition of the maximum output power of fuel cell stacks. Two fuel cell passenger cars were evaluated respectively, and the results showed that both models could quickly balance the temperature under the condition of high-speed climbing, and the key was to control the inlet and outlet water temperature of the fuel cell pile. The test method proposed in this paper has important reference value for the optimization design of thermal management system of fuel cell vehicles.

Design of subsurface drainage network with minimum overall cost using Lagrange multiplier optimization

AbstractSubsurface drainage is effective for not only controlling groundwater levels in agricultural lands but also alleviating soil salinity localized at the root zone, especially for arid and semi‐arid agro‐ecosystems. In this research, an optimization model that minimizes the overall costs of subsurface drainage systems subjected to design constraints was formulated. The Lagrange multiplier method for optimization was utilized to derive a general differential equation for obtaining the most economical design of the subsurface drainage system. Design charts for the minimum cost of the subsurface drainage network ($ ha−1) for lateral diameters (dL) of 2.5, 5, 7.5, 10 and 12.5 cm; hydraulic conductivities (K) of 0.5, 1, 2, 3 and 4 m day−1; different lateral lengths (LL) of 100, 150, 200, 250, and 300 m; a constant collector length (LC) of 1000 m (assuming laterals join the collector from both sides); drainage recharge (q) values of 1, 2, 3, 4 and 5 mm day−1; and excavation depths of 1.5 and 2.0 m were developed. The minimum computed subsurface drainage network (SSDN) costs observed at a lateral length (LL) of 300 m were 205, 246, 288, 331 and 374 ($ ha−1) for lateral diameters of 2.5, 5, 7.5, 10 and 12.5 cm, respectively, corresponding to lateral spacing of 175, 176, 177, 178 and 179 m. The suggested charts for the optimum design of a subsurface drainage system have lower overall costs than using conventional design approaches for pipelines and tube wells. The results will support solutions for designers to implement subsurface drainage systems with less and more affordable expenses in the old lands of the Nile delta of Egypt and other regions with similar agrosystems. Quality control during construction is very necessary for guaranteeing the effective and sustainable performance of subsurface drainage systems for many years.

Capacity Optimization Design of Hybrid Energy Power Generation System

Capacity Optimization Design of Hybrid Energy Power Generation System

Optimizing Security Systems with an Optimum Design of a Hybrid Renewable Energy System

Security systems play a crucial role in protecting individuals and assets within diverse infrastructures, including seaports. The uninterrupted operation of these systems heavily relies on a continuous power supply, as any disruptions can lead to severe consequences. Therefore, security systems are classified as critical loads requiring uninterrupted power availability. This study focuses on the investigation of an optimal hybrid energy system (HES) to ensure a reliable power supply for security systems in two seaports located in Turkiye. Through the utilization of the HOMER software, optimization analyses were conducted, considering both conventional sources such as grid-generator or grid-generator-battery configurations, as well as off-grid and on-grid HES solutions integrating photovoltaic (PV) and wind turbine technologies. The findings reveal that on-grid HES solutions incorporating PV and wind technologies offer a more cost-effective and dependable energy supply for security systems in seaports, surpassing traditional alternatives. This study represents a significant contribution to the existing literature, as it presents the first comprehensive optimization study on the design of HES for security systems. The outcomes serve as a valuable reference for future research endeavors in this field.

Numerical investigation on vortex cooling flow and heat transfer characteristics for gas turbine blade with variable coolant chamber cross-sectional shapes

In this paper, according to the actual size of gas turbine blade interior space, eight vortex cooling models with different cross-sectional shapes of coolant chambers are established. Rectangular, Circle, Trapezoidal up, Trapezoidal down, Ellipse up, Ellipse down, Sine up and Sine down are the eight coolant chamber shapes. Functions of variable coolant chamber structures on vortex cooling flow and heat exchange characteristics are numerically analyzed by verifying the Standard k- ω turbulence model and conducting grid independence analysis. Research results show that the heat exchange ability of Sine up coolant chamber is the best compared with the other coolant chambers. The cool air enters the vortex chamber at a faster speed and impacts on the target surface to form a high-pressure area and a low-temperature swirl. The more the cool air moves downstream, the greater the turbulent kinetic energy becomes, which is more conducive to the heat transfer. Therefore, Sine up coolant chambers have the highest thermal performance factor. Due to the low drag coefficient and high target surface average Nusselt number of Ellipse up, its thermal exchange performance is second only to that of Sine up. Circle coolant chamber will not bring favorable factors to engineering application because of the slowest flow speed and the worst heat exchange capacity. For Trapezoidal up and Trapezoidal down, the flow velocity, pressure distribution, turbulent kinetic energy intensity and heat transfer uniformity are almost the same as Rectangle coolant chamber. The models of Ellipse down and Sine down coolant chambers exhibit less turbulent kinetic energy strength to heat transfer and higher temperature in the vortex chamber, and it is not suggested for cooling system optimal design.

Multi-objective optimization design of a grid-connected hybrid hydro-photovoltaic system considering power transmission capacity

The first step in creating a hybrid system that incorporates the adjustable hydropower station is selecting an appropriate scale of new energy. This study proposed a methodology for optimized design an on-grid hydro-photovoltaic (PV) system considering power transmission capacity. The concepts of short-term joint hydro-PV operation were first given. The on-grid hybrid hydro-PV system's two evaluation indicators were then proposed, integrating double carbon targets and new energy power curtailments. Then, an optimization design model was established with maximum carbon emission reductions and minimum PV power curtailments. Finally, the methodologies were applied to a case study in northwest China to test its rationality. Results manifested that (1) PV power curtailments increase with carbon emission reductions under the given PV size and runoffs, and the optimized PV size was 200 MW; (2) the utilization rate of the newly add transmission channel generally decreases gradually with an increase in power transmission capacity expansion, and the optimum power transmission capacity expansion was 10 MW with the maximum utilization rate of 12.36%; (3) the hydro-PV joint production was impacted by both the characteristics of PV output and runoff. Thus, this study helps to the joint development of flexible hydropower stations and volatile new energy sources.

Optimization Design and Experimental Study of Cooling System in a High Voltage Induction Motor after Power Density Upgrade

Background: In order to upgrade a motor based on the YXKK450-2 for high power density with high efficiency, low energy consumption, and low weight with the same volume, its power is increased from the original 900 kW to 1250 kW. To ensure good ventilation and heat dissipation characteristics, it is necessary to redesign the ventilation and cooling system of the entire machine. Methods: Based on the finite volume method, a physical model of the entire flow field of the motor's inner and outer air passages was established. The internal and external cooling systems of the motor were simulated, and the fluid flow law of the cooling system was realized. By extracting the pressure difference between the inlet and outlet of the cooler and the circulating cooling air velocity in the inner air passage, the boundary conditions for calculating the flowheat coupling field were determined. The temperature rise trend and overall temperature distribution were obtained. Results: The results of the test resistance method were in good agreement with the numerical simulation test results, The temperature rise error was 4%, and the wind speed value error was 2.7%, all within allowable limits (<s5%), verifying the accuracy and effectiveness of the calculation method. Conclusion: An accurate prediction of motor temperature rise, fluid flow law, and temperature distribution is achieved.