In precise fuel circuit systems, the filtration of particulate impurities seriously affects the efficiency and service life of various components. For filtration process intensification of high-pressure fuel laser per...
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In precise fuel circuit systems, the filtration of particulate impurities seriously affects the efficiency and service life of various components. For filtration process intensification of high-pressure fuel laser perforated filters, the two-phase flow characteristics in filters is studied. The size, position and number of filtration holes are taken as optimization variables, and take the filtration efficiency and flow pressure drop as optimizationobjectives. Computational fluid dynamics (CFD) is used to simulate the two-phase motion of continuous phase and discrete particles in a periodic unit. Artificial neural networks (ANN) are utilized for objectives prediction, and the NSGA-II genetic algorithm is employed for multi-objective optimization, resulting in the Pareto front solution set. Furtherly, the reasonable solution is selected by introducing TOPSIS to ensure that two optimization indexes are relatively smaller and balanced. The optimized filter element scheme allows the filter to have a pressure drop of less than 3.2 MPa under high pressure and a filtration efficiency of over 80% for spherical particle impurities with a diameter of 5 μm or more.
Ultra-high performance concrete(UHPC)has gained a lot of attention lately because of its remarkable properties,even if its high cost and high carbon emissions run counter to the current development *** lower the cost ...
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Ultra-high performance concrete(UHPC)has gained a lot of attention lately because of its remarkable properties,even if its high cost and high carbon emissions run counter to the current development *** lower the cost and carbon emissions of UHPC,this study develops a multi-objective optimization framework that combines the non-dominated sorting genetic algorithm and 6 different machine learning methods to handle this *** key features of UHPC are filtered using the recursive feature elimination approach,and Bayesian optimization and random grid search are employed to optimize the hyperparameters of the machine learning prediction *** optimal mix ratios of UHPC are found by applying the multi-objective algorithm non-dominated sorting genetic algorithm-Ⅲ and multiobjective evolutionary algorithm based on adaptive geometric *** results are evaluated by technique for order preference by similarity to ideal solution and validated by *** outcomes demonstrate that the compressive strength and slump flow of UHPC are correctly predicted by the machine learning *** multiobjectiveoptimization produces Pareto fronts,which illustrate the trade-off between the mix’s compressive strength,slump flow,cost,and environmental sustainability as well as the wide variety of possible *** research contributes to the development of cost-effective and environmentally sustainable UHPC,and aids in robust,intelligent,and sustainable building practices.
The cascaded multi-layer packed bed thermal energy storage (TES) unit with varying fill ratios is proposed to enhance its thermal performance. A concentric dispersion model for simulating thermal fluid heat transfer i...
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The cascaded multi-layer packed bed thermal energy storage (TES) unit with varying fill ratios is proposed to enhance its thermal performance. A concentric dispersion model for simulating thermal fluid heat transfer is developed and experimentally validated. Based on this, four designs are explored to examine the effect of the filling ratio of phase change materials with different melting points on the thermal performance of the packed bed TES system, including that of balanced-layer, top-heavy-layer, middle-heavy-layer and bottom-heavy-layer. The multi-factor and multi-objective optimization is conducted by response surface and factor analysis methods. Differs from the previous studies that only designed several configurations with different phase change material filling ratios, the present sudy focuses on the interaction between the filling ratio and the thermal performances, as well as the optimal filling ratio of each layer to achieve the best thermal performance. The results show that the bottom-heavy-layer has the shortest charging time of 950 min and the highest energy utilization of 61.72 %, while the top-heavy-layer has the highest charging exergy efficiency of 84.7 % and the largest TES capacity of 96.88 MWh. As for the multi-objective optimization, the optimized value of comprehensive evaluation indicator F is 1.7112, and the corresponding charging time, energy utilization, TES capacity, and charging exergy efficiency is 778 min, 0.62, 99.76 MWh, and 0.83, respectively. This research establishes a foundation for the advanced optimization of phase change material filling ratios and comprehensive system-level evaluation.
The axial field flux-switching magnetic gear composite machine (AFFSMGCM) is a new type of magnetic field modulation machine with a dual-rotor. Due to the complicated structure of the AFFSMGCM and the nonlinear charac...
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The axial field flux-switching magnetic gear composite machine (AFFSMGCM) is a new type of magnetic field modulation machine with a dual-rotor. Due to the complicated structure of the AFFSMGCM and the nonlinear characteristic of dual magnetic fields coupling, a divided-layer varying-network magnetic circuit (VNMC) method is developed to optimize the machine to obtain a high calculation accuracy and reduce operation time. First, an accurate VNMC model is established according to the magnetic field distribution of an AFFSMGCM. The magnetic field coupling of the rotor and stator permanent magnets (PMs) is performed by the rotary magnetic modulation ring (RMMR). Thus, the magnetic circuit of the RMMR is divided into two layers to reduce the influence of magnetic saturation and leakage flux on the calculation accuracy of the permeances. Then the particle swarm optimization (PSO) method is used to achieve multi-objective optimization of the AFFSMGCM based on the divided-layer VNMC for achieving a large torque, low torque ripple and high efficiency. Next, a multi-physics field coupling analysis is carried out to verify the optimized AFFSMGCM. Finally, a prototype is built and experiments are carried out to validate the AFFSMGCM.
Based on the industrial production data, the simulation of the separation process of a 2 million tons/year FCC unit including the fractionation and the absorption-stabilization systems were conducted on Aspen Plus sof...
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Based on the industrial production data, the simulation of the separation process of a 2 million tons/year FCC unit including the fractionation and the absorption-stabilization systems were conducted on Aspen Plus software. To optimize the operation process, multi-objective optimization was performed integrating the Aspen Plus platform and MATLAB environment utilizing the improved non-dominated sorting genetic algorithm (NSGA-II). The established multi-objective optimization model was used for the operating variable screening, the genetic algebra selection and the optimal solution determination. During the optimization, the total yield of LPG and stable gasoline was aimed as the first optimizationobjective while the energy consumption of the whole system as the second objective. Five expressions were applied as the constraint functions and nine operating variables were conducted as the decision variables. The results showed that the performances of FCC separation system have been greatly improved after optimization. Some optimization strategies are advised for the whole system. The total yield of LPG and stabilized gasoline increases by 2. 44 %, and the energy consumption of the separation system decreases by 41. 79 %. In addition, the CO2 emission is reduced by 23.59 t/h and the total annual cost (TAC) is reduced by $0.89 million/year. It has been revealed that the multi-objective optimization method based on NSGA-II algorithm is useful for the guidance of the optimization of industrial petrochemical process.
In this paper, we utilize an active intelligent reflecting surface (IRS) to assist wireless systems with multiple functionalities, including multi-group (MG) multicast (MC) transmission, integrated sensing and communi...
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In this paper, we utilize an active intelligent reflecting surface (IRS) to assist wireless systems with multiple functionalities, including multi-group (MG) multicast (MC) transmission, integrated sensing and communication (ISAC) and wireless energy harvesting. Specifically, a multi-antenna base station (BS) simultaneously transmits communication signals to MG MC users and sensing signals towards targets, while other users can harvest energy from the received radio frequency signals. We formulate the joint design of the BS transmit precoders (TPs) and the IRS reflection coefficients (RCs) as multi-objective optimization problems (MOOPs) in which the objective functions of the sum rate maximization (SRM) and sum harvested energy maximization (SHEM) are considered under the constraints of transmit power at the BS, amplitude and power amplifications at the active IRS, minimum achievable rate of communication users (CUs), minimum harvested energy of energy harvesting users (EHUs), and beamforming pattern similarity for sensing. To tackle the nonconvexity characteristics of the formulated design problems, we leverage alternating optimization (AO) frameworks to decompose the original problems into subproblems. In the subproblems, we seek appropriate surrogate functions by following majorization-minimization (MaMi) techniques to convert the subproblems into convex ones. Then, iterative algorithms are developed to obtain the optimal BS TPs and IRS RCs. The numerical simulations are carried out to validate the effectiveness of the proposed methods. The numerical results also reveal useful insights in the tradeoffs between the performance metrics and demonstrate the superior performance of systems with an active IRS in comparison with those without an IRS or with a passive IRS.
Equations of state using the Statistical Associating Fluid Theory (SAFT EoS) have found tremendous success in the thermodynamic modeling of ionic liquids (ILs) and mixtures. Traditionally, SAFT EoS parameters are fit ...
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Equations of state using the Statistical Associating Fluid Theory (SAFT EoS) have found tremendous success in the thermodynamic modeling of ionic liquids (ILs) and mixtures. Traditionally, SAFT EoS parameters are fit to pure component pressure-volume-temperature (PVT) (density) data and vapor pressure data. We have recently combined the PC-SAFT EoS with entropy scaling theory to correlate and predict the viscosity of ILs and IL mixtures. We found that the PC-SAFT EoS parameters for ionic liquids regressed to PVT data can sometimes lead to relatively large deviations in the viscosity correlations, especially at high pressure. Here, we investigate the effect of including viscosity data along with PVT data for the PC-SAFT parameter regression of two series of 1-nalkyl-3-methyl imidazolium ionic liquids ([CnMIm][Tf2N] and [CnMIm][BF4]). From analyzing the Pareto fronts, the inclusion of viscosity data to PVT data for PC-SAFT parameters resulted in only a small loss in accuracy for the density, but with much improved viscosity correlations through entropy scaling. We found that the parameter sets obtained from density and viscosity data regression are less prone to numerical pitfalls, i.e. fictitious SAFT critical points, than the parameter sets obtained from PVT data alone. In addition, the predicted (kij=0) phase equilibrium (VLE) of ionic liquids and mixtures with CO2, CH4, and water were equal to, if not better than the predictions using PVT data alone. Overall, the use of pure PVT and viscosity data in the parameterization of PCSAFT yields a more widely applicable prediction method for both thermodynamic and transport properties.
Minimizing the maximum revisit time of satellite constellations is crucial for the rapid detection of changes, especially in disaster, defense and intelligence contexts. This study aims to design a Walker Delta satell...
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Minimizing the maximum revisit time of satellite constellations is crucial for the rapid detection of changes, especially in disaster, defense and intelligence contexts. This study aims to design a Walker Delta satellite constellation to cover T & uuml;rkiye's geography, collecting data with short revisit times and low costs. A Matlab script was created to calculate the maximum revisit time parametrically in the Systems Tool Kit software by configuring satellite constellation configurations, and this script was integrated into the ModeFrontier software to create an optimization loop using the multi-objective Genetic Algorithm method. The optimization has four objectives: minimizing the number of satellites, the number of orbital planes, the vertical half-angle of the sensor, and the maximum revisit time. As a result of the study, it was concluded that to achieve a maximum revisit time of fewer than 120 minutes in the region where data is to be collected, there should be a minimum of 33 satellites, at least 11 orbital planes, and a minimum vertical half-angle of 15 degrees for the sensor. A satellite constellation configuration was chosen from the optimized Paretooptimal solution set, meeting cost and revisit time criteria.
Identifying the most optimal slat shape significantly influences the performance of louver systems in terms of daylighting, glare control, and energy consumption. This is particularly crucial in climates with high lev...
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Identifying the most optimal slat shape significantly influences the performance of louver systems in terms of daylighting, glare control, and energy consumption. This is particularly crucial in climates with high levels of solar irradiance, where thermal gain and daylight illumination highly affect buildings and occupants. This study aims to identify the optimal slat shapes for various profile types-flat, single-curvature, and double-curvature-that simultaneously reduce annual energy consumption and enhance annual daylighting and visual comfort performance in fully glazed office buildings. This goal is achieved by employing a multi-objective optimization (MOO) algorithm, NSGA-II, applied to a control-point-based algorithm designed to generate diverse slat shapes for each profile type. The main objective functions include the maximization of spatial useful daylight illuminance (sUDI) and spatial glare autonomy (sGA), as well as the minimization of energy use intensity (EUI). The MOO process results in a diverse set of Pareto optimal slat shapes for each profile type, which are subsequently ranked by a fitness function. Findings suggest that the Pareto optimal solutions within each type significantly improve the overall performance of the space compared to the base case. Specifically, among these solutions, flat profiles with the highest fitness scores enhance daylighting levels of the space to a greater extent (9.028% to 14.583%) compared to single (-2.778% to 12.5%) and double-curvature profiles (-5.556% to 9.722%) with the highest scores. Regarding glare, double-curvature profiles with the highest fitness scores provide a more visually comfortable environment for users by improving the sGA value by 19.879% to 33.247% compared to the base case. However, those with a concave-convex shape produce excessive illumination in the perimeter zone, whereas those with a convex-concave shape present challenges in providing sufficient daylight in the rear zone of the space. Ad
Cryocooler-based zero boil-off schemes are promising for long-term storage of cryogenic propellants. To date, no studies have addressed the fluid-thermal coupling between key components of the zero boil-off system, as...
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Cryocooler-based zero boil-off schemes are promising for long-term storage of cryogenic propellants. To date, no studies have addressed the fluid-thermal coupling between key components of the zero boil-off system, as well as the trade-offs among the cooling power, insulation performance and energy utilization efficiency. To predict and optimize the performance of a cryocooler-based zero-boil-off system, a systemic model integrating theoretical calculations and computational fluid dynamics was developed. Additionally, a multi-objective optimization method was designed based on a modified hyperplane generation approach and a self-adaptive crossover operator. The accuracy of the model was validated using the results of liquid nitrogen experiments from the literature. On the same computation platform, the proposed optimization method demonstrated superior capabilities in avoiding local optima and accelerating convergence compared with the original Non-dominated Sorting Genetic Algorithm-III: the temperature uniformity of the cold shield improved by at least 10.44 %, and the time cost was reduced by 32.25 %. In addition, conflicts were identified among the cooling power, temperature uniformity of the cold shield, and parasitic heat leakage, whereas the temperature uniformity showed a positive correlation with heat leakage through multilayer insulation. These findings provide guidelines for the multi-objective design of cryogenic propellant storage systems for future space missions.
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