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design and optimization of a 500 kW multi-cylinder double-acting free piston stirling engine for deep-sea nuclear power system

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PROGRESS IN NUCLEAR ENERGY 2025年 180卷

作者： Guo, Siyi Lan, Yongqi Li, Gen South China Univ Technol Sch Elect Power Engn Guangzhou 510641 Peoples R China

Given the increasing demand for deep-sea exploration, nuclear power system is attracting great interest for electricity supply due to its long-time operation with one refuelling. Double-acting free piston Stirling engine (DAFPSE) is a promising energy conversion system for nuclear power considering its long operation life, low vibration and little maintenance. However, the research on the DAFPSE design and optimization for deep-sea nuclear power system is scarce, which requires high volumetric power density. In this study, a practical isothermal model for designing multi-cylinder DAFPSE was established with the validation against the experiment. Also, the influences of structure parameters, operating parameters and heat exchanger parameters on the DAFPSE performance were investigated. The results indicated that the maximum deviation between the calculation and the experimental result was 8.75%. The compression ratio had significant influence on power density but less influence on efficiency. Specifically, the power density increased by 109.8% and the efficiency decreased by 11.7% respectively when the compression ratio changed from 1.5 to 2. As the engine frequency increased, power density first increased and then decreased, and the maximum power density of 10.71 MW m- 3 was obtained at the frequency of 21 Hz. With the increase of regenerator porosity, the engine efficiency and power density had similar change trends, which showed that the maximum efficiency of 36.6% and the maximum power density of 10.35 MW m-3 were achieved at the regenerator porosity of 0.8 and 0.9, respectively. The engine efficiency and power density had linear variations with both the hot end temperature and the inlet temperature of cooling water. After the sensitivity investigation of the design parameters, multi-objective optimizations were performed for the structures with different cylinders. The four-cylinder DAFPSE obtained better overall engine performance, in which the optimal scheme w

关键词： Double-acting Free piston stirling engine design and optimization Deep-sea nuclear power

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design and optimization of a solar-driven methane dry reforming reactor by developing an optical-thermal-chemical model

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CHEMICAL ENGINEERING JOURNAL 2024年 483卷

作者： Zhang, Weichen Li, Qing Qiu, Yu Cent South Univ Sch Energy Sci & Engn Changsha 410083 Hunan Peoples R China

The reactor plays a crucial role in solar-driven methane dry reforming. To improve the reactor performance, a cavity reactor with a hemispherical porous absorber and a secondary concentrator was designed and optimized by developing an optical-thermal-chemical coupled model. Using this model, the effects of different pore parameters on the reactor performance were firstly investigated, finding that porosity and pore size significantly influence the distributions of solar energy and temperature but mildly influence the reforming performance. Considering the optical-chemical efficiency as the optimization objective, the reactor with the porosity of 0.85 and the pore size of 1 mm was suggested as the optimal design. Then, the influences of the CO2:CH4 feed molar ratio, incident power, and the inlet volumetric flow rate were analyzed, revealing that they dramatically influence the reactor performance in complex ways. To make a compromise between the optical-chemical efficiency and carbon deposition, the operating condition with the CO2:CH4 feed molar ratio of 1:1, the inlet volumetric flow rate of 0.6 L & sdot;s- 1, and the incident power of 3 kW was selected as the optimal one. Finally, the performance of the optimal reactor was evaluated at the optimal condition, finding it can achieve quite high methane conversion ratio, optical-chemical efficiency, and optical-thermal efficiency of 36.71 %, 30.88 %, and 59.05 %, respectively. Results from present work can provide valuable insights for the design and optimization of solar reactors.

关键词： Methane dry reforming Solar -driven cavity reactor Optical -thermal -chemical model design and optimization Optical -chemical efficiency

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design and optimization of a body weight support system for lower-limb rehabilitation robots considering vibration characteristics

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STRUCTURAL AND MULTIDISCIPLINARY optimization 2023年第12期66卷 1-21页

作者： Li, Shuoyu Huang, Shuangyuan Huang, Li Shen, Hongyi Liu, Youwei Xie, Longhan South China Univ Technol Shien Ming Wu Sch Intelligent Engn Guangzhou 511442 Peoples R China Sun Yat Sem Univ Lingnan Hosp Affiliated Hosp 3 Guangzhou 510000 Peoples R China

The structural characteristics of a Body Weight Support System (BWSS) significantly influence the rehabilitation effect and control system of a lower-limb robot. This study considers vibration characteristics to design and optimize a BWSS. First, the design principles of the BWSS are formulated, and the force of the system during the rehabilitation training process is analyzed. Second, the BWSS optimization model is established by considering the vibration characteristics, including the design object, selected materials, design variables, optimization objective functions and constraints in static and dynamic analyses. Third, a hybrid multi-objective optimization method combining the finite element method, Kriging metamodel and Multi-Objective Genetic Algorithm (MOGA) is proposed. After performing optimization, the Kriging metamodel is discussed, and the final design parameters of a single-arm support structure are obtained by the MOGA. Finally, different MOGA parameters and the screening algorithm are compared and analyzed. Simultaneously, the experimental vibration acceleration data and the shock data of the actual original rehabilitation robot are compared with the numerical results of the optimized design. The numerical results indicate that the proposed hybrid multi-objective optimization method is reliable in terms of designing the BWSS, and the vibration characteristics of the designed BWSS are improved over those of the actual original BWSS.

关键词： Rehabilitation robot Body weight support system design and optimization Multi-objective optimization algorithm Kriging metamodel Vibration characteristics

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design and optimization of Heat Exchangers Using Large Language Models 4

Design and Optimization of Heat Exchangers Using Large Langu...

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4th International Workshop on Knowledge-Infused Learning, KiL 2024

作者： Mishra, Sandeep Jadhav, Vishal Karande, Shirish Runkana, Venkataramana Tata Research Development and Design Centre Maharashtra Pune India

Heat exchangers (HEs) are essential in process industries for efficient thermal energy transfer. Their design and optimization are crucial for improving energy efficiency, reducing costs, and ensuring reliable system performance. However, these tasks are complex due to varying fluid properties, phase changes, and fouling. This study proposes the HxLLM framework, utilizing Large Language Models (LLMs) to aid in the design and optimization of HEs. The framework identifies the mathematical model for heat transfer in HEs, followed by retrieval-augmented generation (RAG) based code generation and correction. In this study, a repository was created by extracting mathematical models from relevant literature along with common errors observed in such tasks. These repositories, combined with carefully crafted prompts, were used to extract the mathematical model and generate the corresponding code within this framework. We observed that LLMs can effectively identify and generate initial code for mathematical models, though first responses often needed corrections. The RAG approach for code correction significantly enhanced code accuracy. This study demonstrates that LLMs, with a RAG framework, can automate and improve the design and optimization process of HEs, offering a promising tool for engineers and researchers to achieve better efficiency and cost-effectiveness. © 2024 Copyright for this paper by its authors.

关键词： design and optimization Heat Exchangers Large Language Models Retrieval Augmented Generation

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design and optimization of JO-IEX process for highly efficient quaternary separation of 5′-ribonucleotides

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AICHE JOURNAL 2022年第6期68卷 e17592-e17592页

作者： Dai, Kun Jiao, Pengfei Peng, Xiaoqiang Kou, Jingwei Yang, Pengpeng Zhuang, Wei Ying, Hanjie Wu, Jinglan Nanjing Tech Univ Coll Biotechnol & Pharmaceut Engn Natl Engn Tech Res Ctr Biotechnol Nanjing Peoples R China Nanyang Normal Univ Coll Life Sci & Agr Engn Nanyang 473061 Peoples R China

The developed JO-IEX technology was applied to continuously separate four 5'-ribonucleotides here. The unit contained seven columns with three separation steps, among which three columns were for the quaternary separation and the others for regeneration of resins. The operating conditions, that is, the critical flow rates in three separation steps were preliminarily designed according to the equilibrium theory and optimized by a three-dimensional theoretical separation region approach. The feasibility of the JO-IEX process and the separation performances were validated by four runs using the actual 5'-ribonucleotides' enzymatic hydrolysate as feed solutions. The purities and yields of 5'-ribonucleotides could reach above 97%. The productivity was enhanced to be 0.91 g/(kg h), and the desorbent consumption was reduced to be 1.01 L/g, compared to those of 0.70 g/(kg h) and 1.75 L/g in the fixed-bed process. The technology proposed could be a potential technique in the continuous multicomponent ion-exchange separation process.

关键词： 5 '-ribonucleotides design and optimization JO-IEX technology quaternary separation three-dimensional theoretical separation region approach

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Neural Network aided PMSM multi-objective design and optimization for more-electric aircraft applications

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Chinese Journal of Aeronautics 2022年第10期35卷 233-246页

作者： Yuan GAO Tao YANG Serhiy BOZHKO Pat WHEELER Tomislav DRAGICEVIC Chris GERADA Power Electronics Machines and Control GroupUniversity of NottinghamNottingham NG72RDUK Department of Electrical Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark

This study uses the Neural Network(NN)technique to optimize design of surfacemounted Permanent Magnet Synchronous Motors(PMSMs)for More-Electric Aircraft(MEA)*** key role of NN is to provide dedicated correction factors for the analytical PMSM mass and loss estimation within the entire design *** on that,a globally optimal design can be quickly *** the analytical estimation with Finite-Element Analysis(FEA)is the main research target of training the *** analytical formulae serve as the basis of this study,but they are prone to loss accuracy(especially for a large design space)due to their assumptions and *** the help of the trained NNs,the analytical motor model can give an estimation as accurate as the FEA but with super less time during the optimization *** Average Correction Factor(ACF)approach is regarded as the comparison method to demonstrate the excellent performance of the proposed NN ***,a NN aided three-stage-sevenstep optimization methodology is ***,a Pole-10-Slot-12 PMSM case study is given to demonstrate the feasibility and gain of the NN aided multi-objective optimization *** this case,the NN aided analytical model can generate one motor design in 0.04 s while it takes more than 1 min for the used FEA model.

关键词： design and optimization Loss estimation Mean Length per Turn(MLT) More-Electric Aircraft(MEA) Neural Network(NN) Permanent Magnet Synchronous Motor(PMSM)

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A Brief Survey on Randomizer design and optimization for Efficient Stochastic Computing 8

A Brief Survey on Randomizer Design and Optimization for Eff...

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8th IEEE International Test Conference in Asia (ITC-Asia)

作者： Thong, Kuncai Wang, Jiangyuan Chen, Lu Wang, Peng You, Zixuan Zhangl, Yuan Zhang, Jiliang Hunan Univ Coll Integrated Circuits Coll Semicond Changsha Peoples R China Hunan Univ Sch Phys & Elect Changsha Peoples R China

ISBN: (纸本)9798331540340;9798331540333

Stochastic computing (SC) is a promising computing paradigm for circuit design in the post-Moore era. It encodes data through stochastic bit streams (SBSs) and employs a randomizer to generate them, where the randomizer converts binary-encoded variables into stochastic formats and can optionally provide some SBSs of constant values. Owing to this, the randomizer generally plays a critical role in determining the accuracy of SC circuits and occupies a significant portion of their hardware cost. Therefore, it is crucial to apply proper randomizers to enhance the overall performance and efficiency of SC circuits. However, recent SC circuit designs often suffer from complex randomizers to ensure high accuracy. To address this issue, several efficient designs and optimization methods of randomizers have been proposed. In this paper, we review the common designs, the optimization methods, and the efficient application of randomizers, while discussing current challenges and future directions. By providing a brief overview, this survey underscores the critical role of randomizer design and optimization for efficient SC.

关键词： Stochastic computing Randomizer design and optimization

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design and optimization of the four-stage recuperative coiled tube-in-tube heat exchanger for a 1.8 K hybrid cryocooler

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CRYOGENICS 2022年 126卷

作者： Zhao, Bangjian Zhang, Tao Tan, Jun Zhao, Yongjiang Xue, Renjun Tan, Han Wu, Shiguang Zhai, Yujia Dang, Haizheng Chinese Acad Sci Shanghai Inst Tech Phys State Key Lab Infrared Phys 500 Yutian Rd Shanghai 200083 Peoples R China Shanghai Res Ctr Quantum Sci Shanghai 201315 Peoples R China Univ Chinese Acad Sci 19A Yuquan Rd Beijing 100049 Peoples R China Shanghai Boreas Cryogen Co Ltd Shanghai 201802 Peoples R China

The recuperative coiled tube-in-tube heat exchanger (RCTTHE) is a key component of the hybrid cryocooler formed by a four-stage Stirling-type pulse tube cryocooler and a JT cooler, and its heat exchanger effectiveness and pressure drop of low-pressure side play an important role in enhancing the overall performance of the hybrid cryocooler. This paper develops a finite difference model to systematically investigate the four-stage RCTTHE. The flow and heat transfer characteristics in the temperature range of 4-300 K under different dimensional and operating parameters are investigated in detail. The heat exchanger effectiveness and pressure drop of the low-pressure side are optimized to meet the requirements of the 1.8 K hybrid cryocooler with He-4 as the only working medium. The experimental investigations of the hybrid cryocooler based on the optimized four-stage RCTTHE are conducted. Satisfactory agreements are observed between the theoretical and experimental data, and thus verify the proposed model. The experimental results show that the pressure drop of the low-pressure side of the RCTTHE reaches a considerably low value of 518 Pa and an effectiveness of higher than 97.1 % is achieved for the four-stage RCTTHE, both of which make a significant contribution to the hybrid cryocooler in achieving 1.8 K.

关键词： Recuperative coiled tube-in-tube heat exchanger 4-300 K design and optimization Heat exchanger effectiveness Pressure drop 1.8 K hybrid cryocooler

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design and optimization of rudder bulb based on CFD and genetic algorithm

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OCEAN ENGINEERING 2022年 265卷

作者： Wang, Xiaolong Zou, Zaojian Fan, Tao Xia, Li Liu, Weidong Jiangnan Shipyard Grp Co Ltd Shanghai Peoples R China Shanghai Jiao Tong Univ Sch Naval Architecture Ocean & Civil Engn Shanghai Peoples R China China Dev Bank Financial Leasing Co Ltd Shenzhen Peoples R China

With the mandatory implementation of Energy Efficiency design Index (EEDI), higher requirements are put forward on the energy-saving capacity of ships. The fact that 15-30% propulsion energy is lost in the wake inspires people to exploit the measures for improving energy-saving capacity of ships to meet the EEDI re-quirements by recovering the lost energy, such as through rudder bulb. Thus, the design and optimization of rudder bulb appears to be particularly important. This paper aims to propose a design and optimization framework for rudder bulb to find a high-performance energy-saving device suitable for the propulsion system of a ship. A Computational Fluid Dynamics (CFD) method is applied to predict the hydrodynamic performance of the propulsion system with rudder bulbs, and validation and gird uncertainty analysis are conducted for simu-lation of propeller open-water test. Then, a design of Experiment (DOE) method is used to conduct sensitivity analysis of design variables, and a Genetic Algorithm (GA) approach is adopted in search of the optimal design of rudder bulb. The results of the propulsion system with different rudder bulbs are presented and analysed. It shows that a 3.66% increase in efficiency is achieved by the optimal rudder bulb design via GA approach.

关键词： Rudder bulb design and optimization Computational fluid dynamics design of experiment Genetic algorithm

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design and optimization of a large-scale permanent magnet synchronous generator

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SCIENTIA IRANICA 2022年第1期29卷 217-229页

作者： Alemi-Rostami, M. Rezazadeh, G. Alipour-Sarabi, R. Tahami, F. Minist Sci Res & Technol Aerosp Res Inst Dept Elect Engn Tehran Iran Sharif Univ Technol Dept Elect Engn Tehran Iran

Direct-drive permanent magnet synchronous generators enjoy numerous advantages including improved reliability, low maintenance, long life, and developed performance characteristics. In recent years, many researchers have worked on these generators to enhance their performance, especially for the wind turbine application. The focus of this paper is on the development of a step-by-step method for the design of a permanent magnet synchronous generator. Then, the winding function method is used to model the generator and calculate its output characteristics analytically. The analytical results of the designed generator are validated using Finite Element Analysis (FEA) and it is demonstrated that the obtained results from both methods are in great agreement with the experimental measurements of the Northern Power direct-drive generator. The sensitivity analysis and optimization procedure based on genetic algorithm are employed to design an optimum generator. The optimization goal is obtaining higher efficiency and power factor with lower voltage regulation and required permanent magnet volume compared to the initial design. In addition, the calculation of the voltage Total Harmonic Distortion (THD) is presented and the optimum skew angle for the optimum generator is computed to reduce the voltage THD. (C) 2022 Sharif University of Technology. All rights reserved.

关键词： Direct-drive permanent magnet synchronous generator design and optimization Winding function method Performance calculation Voltage THD calculation Optimum skew angle

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