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SSRN 2024年

作者： Li, Yang Bai, Minli Zhou, Zhifu Wu, Wei-Tao Wei, Lei Hu, Chengzhi Liu, Xinyu Gao, Shuai Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116023 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China

Improving the poor performance of lithium-ion battery (LIB) in extreme temperatures is essential to promoting electric vehicles (EVs) into wider application. The most severe challenge for the existing battery thermal management systems (BTMSs) is to overcome the contradiction between excellent heat dissipation at high temperatures and effective insulation at low temperatures. Here, we propose a zero-energy nonlinear temperature control strategy based on thermal regulator. The designed thermal regulator based on shape memory alloy (SMA) can switch the heat flux on the battery surface according to its temperature without any power supply or logic control and provide the desirable thermal functions. This thermal regulator increases the battery capacity by 55.44% in the cold environment of -20℃ compared to the baseline BTMS with superior heat dissipation. Simultaneously, it can limit the battery peak temperature to near the FS49 boiling point (49℃) in the hot environment of 45℃ to ensure safety. Furthermore, we demonstrate that the thermal regulator enables thermal runaway to be effectively suppressed inside the battery, reducing the emission of combustible or toxic gases by 72.26%, which is reported for the first time. Finally, we simplify the design of the thermal regulator from the perspective of system integration and demonstrate the feasibility of the thermal regulator at the battery pack level. © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Adaptive Growing Randomized Neural Networks for Solving Partial Differential Equations

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arXiv 2024年

作者： Dang, Haoning Wang, Fei Jiang, Song School of Mathematics and Statistics Xi’an Jiaotong University Shaanxi Xi’an710049 China School of Mathematics and Statistics State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Institute of Applied Physics and Computational Mathematics Beijing100088 China

Randomized neural network (RNN) methods have been proposed for solving various partial differential equations (PDEs), demonstrating high accuracy and efficiency. However, initializing the fixed parameters remains a challenging issue. Additionally, RNNs often struggle to solve PDEs with sharp or discontinuous solutions. In this paper, we propose a novel approach called Adaptive Growing Randomized Neural Network (AG-RNN) to address these challenges. First, we establish a parameter initialization strategy based on frequency information to construct the initial RNN. After obtaining a numerical solution from this initial network, we use the residual as an error indicator. Based on the error indicator, we introduce growth strategies that expand the neural network, making it wider and deeper to improve the accuracy of the numerical solution. A key feature of AG-RNN is its adaptive strategy for determining the weights and biases of newly added neurons, enabling the network to expand in both width and depth without requiring additional training. Instead, all weights and biases are generated constructively, significantly enhancing the network’s approximation capabilities compared to conventional randomized neural network methods. In addition, a domain splitting strategy is introduced to handle the case of discontinuous solutions. Extensive numerical experiments are conducted to demonstrate the efficiency and accuracy of this innovative approach. Copyright © 2024, The Authors. All rights reserved.

关键词： Partial differential equations

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Model Predictive Control for Automatic Operation of Space Nuclear Reactors: Design, Simulation, and Performance Evaluation

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SSRN 2023年

作者： Fu, Jianghan Jin, Zhao Dai, Zhiwen Su, Guanghui Wang, Chenglong Tian, Wenxi Qiu, Suizheng Department of Nuclear Science and Technology State Key Lab. of Multiphase Flow in Power Engineering Shaanxi Key Lab. of Advanced Nuclear Energy and Technology Xi’an Jiaotong University Xi’an710049 China

Space nuclear reactors possess the inherent benefits of independence from solar energy and the capability to withstand intricate external circumstances. Consequently, the establishment of a dependable automatic control system assumes utmost significance. In this paper, a high-fidelity nonlinear space thermionic nuclear reactor system model is established. An automatic control system with a model predictive control (MPC) controller is designed based on the system. In the case of a nuclear power step response, the MPC controller achieves an overshoot of 0.07% and a settling time of 0.65s. For an electric power step response, the MPC controller yields an overshoot of 0.28% and a settling time of 36.6s. These control performances are better than those achieved by the PID controller. In power tracking control, the MPC controller demonstrates virtually error-free tracking performance. When external reactivity disturbances are introduced, the MPC controller swiftly compensates for the disturbances at the desired level. © 2023, The Authors. All rights reserved.

关键词： Model predictive control

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Thermal Management for the Prismatic Lithium-Ion Battery Pack by Immersion Cooling with Fluorinated Liquid

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SSRN 2024年

In this study, a novel FS49-based battery thermal management system (BTMS) was proposed and tested for cooling the prismatic lithium-ion battery (LIB) module. The boiling of dielectric refrigerant occurred at the battery surface, which provided strong and uniform cooling for each battery cell. The results show that the peak temperature difference of liquid immersion cooling (LIC) module during 1C rate discharging and charging was reduced by 91.3% and 94.44%, respectively, compared to the natural convection (NC) module. The reduction of temperature nonuniformity greatly reduced the state of charge (SOC) inhomogeneity of different cells within the module. Moreover, the energy density of LIC module can be optimized by reducing the cell spacing and liquid filling ratio. Comparing with 100% filling rate, the module maximum temperature corresponding to 25% filling rate (with wick) during 2C rate discharging is only increased by 1.6°C, however, the module peak temperature difference is reduced by 53.3%, and the energy density is increased by 13.14%. In addition, Equivalent circuit model (ECM) and volume of fluid (VOF) model were used to simulate the LIC module, and the numerical results are in good agreement with the experimental data. This study provides a systematic design plan and numerical method for the engineering application of LIC in the field of BTMS. © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

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Hydrothermal pretreatment of protein-rich substrate:Modified physicochemical properties and consequent responses in its anaerobic digestion

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Carbon Resources Conversion 2023年第1期6卷 1-10页

作者： Fa Qiao Guangyi Zhang Jie Fan Hang Zhang Bowen Shi Jiancheng Yang Jianling Zhang Zhennan Han Shenyang University of Chemical Technology Shenyang 110142Liaoning ProvinceChina School of Ecology and Environment Beijing Technology and Business UniversityBeijing 100048China State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Urban Construction Wuhan University of Science and TechnologyWuhan 430081Hubei ProvinceChina China Power Engineering Consulting Group Co. LtdBeijing 100120China

Wasted tofu rich in protein was subject to hydrothermal pretreatment(HTPT)under different conditions(at 120,140,160 and 180℃;for 0,30,60 and 90 min)followed by biochemical methane potential(BMP)tests,and 140℃and 0 min were found to be respectively the best temperature and duration for HTPT of tofu in terms of its biogas *** the under the optimal conditions(140℃,0 min)the accumulative methane yield reached up to 510.9 mL⋅(gVS)-1,which was 26.98%higher than that without HTPT(402.3 mL⋅(gVS)-1).The start-up process of continuous anerobic digestion(AD)of the tofu before and after hydrothermal treated(HT)at the optimal HTPT conditions(140℃,0 min)was examined,to investigate and compare how their consequent AD responded to *** was found that,for start-up of continuous AD,the HT tofu delivered more balanced nutrients and thus led to more stable AD and quicker biogas ***,HTPT generated products refractory to biodegradation,to slightly decrease the total biogas *** AD of HT tofu some weak ammonia-tolerant microbes,such as methylotrophic methanogens,survived and played indispensable *** of living microbial community structure indicated that,some hydrolytic acidification bacteria intolerant to ammonia nitrogen(such as Proteobacteria)were always active and appeared at high *** viable methylotrophic methanogens,*** M2,took obvious responsibilities in start-up of the AD for HT tofu.

关键词： Hydrothermal pretreatment(HTPT) Protein-rich substrate Anaerobic digestion(AD) Biogas Microbial community structure

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Synthesis of Co3o4@C/Ti3c2tx Mxene-Type Composites for Enhanced Electromagnetic Wave Absorption

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SSRN 2024年

作者： Hou, Yunxi Jia, Zhen Zheng, Hanli Hu, Zewei Shen, Lu Liu, Dongyu Li, Lu Liu, Shiwei Liu, Yue Yu, Shitao Key Laboratory of Multiphase Flow Reaction and Separation Engineering of Shandong Province State Key Laboratory Base of Eco-chemical Engineering College of Chemical Engineering Qingdao University of Science and Technology Qingdao266042 China A VIC Research Institute for Special Structures of Aeronautical Composites 19 Jiqi Road Jinan250000 China

Highly efficient microwave absorbing materials have attracted widespread attention due to the harmful effects of electromagnetic pollution on the human body and electronic equipment. In this paper, Co3O4@C composites with core-shell structure were prepared by hydrothermal method using a simple strategy, and then Ti3C2Tx was assembled with core-shell Co3O4@C by electrostatic self-assembly method, which resulted in the successful attachment of Co3O4@C to the lamellar structure of Ti3C2Tx and the formation of MXene-based composite wave-absorbing Co3O4@C/Ti3C2Tx material. The composites exhibit strong electromagnetic wave absorption when the mass ratio of Co3O4@C to Ti3C2Tx was 1:2, with a minimum reflection loss of -35.2 dB at a matched thickness of only 4.5 mm. Excellent electromagnetic wave absorption performance Co3O4@C/Ti3C2Tx composite material was mainly attributed to the synergistic effect of the multiple reflection absorption of the core-shell structure and the high conductivity and large specific surface area of MXene material. These results indicate that Co3O4@C/Ti3C2Tx composites were promising candidates for electromagnetic absorption and provide new ideas for the design of MXene-based magnetic absorption materials. © 2024, The Authors. All rights reserved.

关键词： Composite materials

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Thermodynamic Analysis of a Hybrid Energy System Coupling Solar Organic Rankine Cycle and Ground Source Heat Pump: Exploring Heat Cascade Utilization

SSRN

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SSRN 2023年

作者： Chen, Liangqi Yue, Huifeng Wang, Jiangfeng Lou, Juwei Wang, Shunsen Guo, Yumin Deng, Bohao Sun, Lu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China China United Northwest Institute for Engineering Design & Research Co. Ltd Xi’an710077 China School of Human Settlements and Civil Engineering Xi'an Jiaotong University Xi’an710049 China

The demand for efficient utilization of renewable energy is growing and the hybrid energy system driven by solar and geothermal energy is a significant way to achieve carbon neutrality. This paper presents a hybrid energy system coupling solar organic Rankine cycle (S-ORC) with ground source heat pump (GSHP) for heating and power supply to explore the heat cascade utilization. In the hybrid energy system, the ground heat exchanger (GHE) is shared by the S-ORC and GSHP systems and the waste heat from the condenser of S-ORC is recovered to enhance the coefficient of performance (COP) of GSHP. A mathematical model is optimized to analyze the parametric effects on thermodynamic performance. The results indicate that the COP of the hybrid energy system can be improved up to 6.5 which shows the obvious advantage compared to 2.8 of the stand-alone GSHP system. Furthermore, the hybrid energy system can obtain optimum exergy efficiency by matching ground source temperature and condensation temperature in the ORC unit. For a building of 3000m2 with heating and power supply, multi-objective optimization is carried out to obtain the optimal design performance that the net power output, thermal efficiency and exergy efficiency are 180.0kW, 27.5%, and 9.2% respectively. © 2023, The Authors. All rights reserved.

关键词： Geothermal heat pumps

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Preparation and Application of Red Mud-Based Zero-Valent Iron Heterogeneous Fenton Catalyst: A New Idea for Red Mud Recycling

SSRN

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SSRN 2022年

作者： Li, Hang Shi, Bofang Fu, Xiaojie Zhang, Haowen Yang, Honghui Xi’an Key Laboratory of Sustainable Energy Materials Chemistry School of Chemistry Xi'an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China

As an abundant hazardous waste, red mud needs a simple and effective mean of resource utilization. Herein, a novel zero-valent iron heterogeneous Fenton catalyst RMB-900 was synthesized by pyrolysis (900°C) using red mud and straw with a facile solvent-free carbothermal redox approach. X-ray diffraction analysis showed that Fe2O3 in the red mud was reduced to Fe0. Characterization data showed that RMB-900 was a zero-valent iron loaded porous material. Under the conditions of 2.86 mM H2O2, 100 mg/L acid red G, and 1 g/L RMB-900, 98% of acid red G was removed within 10 min, the reaction rate constant is 6.7 folds higher than that of commercial zero-valent iron. The RMB-900/H2O2 system also showed good degradability to antibiotics (Sulfamethoxazole, Ibuprofen and Carbamazepine). H2O2 is mainly catalysed by Fe0 in RMB-900 to generate •OH for ARG degradation. RMB-900 still showed excellent catalytic performance after standing for four months and after being reused nine times. This study not only prepared a catalyst with low cost, high stability, and great potential for wastewater treatment through a simple and green solvent-free method, but also provided a research basis for further exploration of red mud-based catalysts. © 2022, The Authors. All rights reserved.

关键词： Wastewater treatment

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Parametric Investigation of Multi-Pulsed Cryogen Spray Cooling for Skin Protection During Hyperthermal Laser Lipolysis Through in Vitro Experiment and Numerical Simulation

SSRN

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SSRN 2022年

作者： Xin, Hui Yu, Fangbo Deng, Chenggang Chen, Ming Li, Dong Chen, Bin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi'An710049 China School of Mechanical Engineering Ningxia University Ningxia Yinchuan750021 China

Laser lipolysis is now a commonly accepted modality to remove fat. Transcutaneous hyperthermal laser lipolysis has attracted researchers’ interest because of its advantages of non-invasive nature and high efficiency. Owing to the competitional absorption of laser energy between skin and adipose tissue, it is necessary to develop efficient skin cooling technology to protect epidermis and dermis from thermal damage. In vitro laser experiment was carried out using streaky pork which has similar optical and thermal properties with human adipose tissue. Temperature changes of pigskin epidermis under 1210nm laser irradiation with different power (6W~12W) and irradiation duration (3s~13s) were obtained by infrared thermal imager. The experimental results showed that the epidermis temperature will exceed the safety threshold of 47°C when laser power is equal to 6W and irradiation duration longer than 5s, or laser power is equal or larger than 9W and irradiation duration equal or longer than 3s. To protect skin from thermal injury, multi-pulsed cryogen spraying cooling (MP-CSC) by using R134a was introduced. Numerical simulation was conducted to match cooling and laser parameters by simplifying skin tissue to a multi-layered model. It is suggested that hyperthermal laser lipolysis with power of 6W/9W and irradiation duration of 7s can be realized, accompanied by MP-CSC with pulse duration of 10ms, pulse delay of 2000ms and pulse number of 5. © 2022, The Authors. All rights reserved.

关键词： Cooling

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Effect of 2,5-dimethylfuran addition on ignition delay times of n-heptane at high temperatures

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Frontiers in Energy 2019年第3期13卷 464-473页

作者： Zhenhua GAO Erjiang HU Zhaohua XU Geyuan YIN Zuohua HUANG State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

The shock tube autoignition of 2,5-dimethylfuran (DMF)/n-heptane blends (DMF)/n-100%, by mole fraction) with equivalence ratios of 0.5, 1.0, and 2.0 over the temperature range of 1200-1800 K and pressures of 2.0 atm and 10.0 atm were investigated. A detailed blend chemical kinetic model resulting from the merging of validated kinetic models for the components of the fuel blends was developed. The experimental observations indicate that the ignition delay times nonlinearly increase with an increase in the DMF addition level. Chemical kinetic analysis including radical pool analysis and flux analysis were conducted to explain the DMF addition effects. The kinetic analysis shows that at lower DMF blending levels, the two fuels have negligible impacts on the consumption pathways of each *** the DMF addition increases to relatively higher levels, the consumption path of n-heptane is significantly changed due to the competition of small radicals, which primarily leads to the nonlinear increase in the ignition delay times of DMF/n-heptane blends.

关键词： ignition delay time shock tube kinetic model 2,5-dimethylfuran (DMF) n-heptane

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