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Experimental Study on the Propagation Mechanism of Acetylene-Air Detonation Waves in a Unilaterally Intermittently Constrained Channel

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SSRN 2024年

作者： Gai, Jingchun Qiu, Hua Xiong, Cha Zhao, Minghao He, Xinlu Yang, Zhan Feng, Zhiyuan Cehn, Xitao Huang, Zuohua School of Power and Energy Northwestern Polytechnical University Xi’an710072 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

This study experimentally explores the propagation mechanisms of acetylene/air detonation waves within a channel intermittently constrained on one side, utilizing soot foil and high-speed schlieren photography to capture the cellular structure and shock-flame evolution. The experiments revealed that the detonation waves traverse the semi-enclosed channel with various discrete wall configurations on the side in four distinct propagation modes: (I) periodic detonation failure and re-initiation;(II) single extinction and re-initiation;(III) localized extinction and (IV) non-extinction. Mode I occurs exclusively when the open area ratio exceeds 0.85, while detonation tends to favour Mode II when the gaps between discrete walls exceed three times the cell size;otherwise, it tends towards Modes III and IV. The re-initiation mechanism of detonation involves curvature shocks inducing local explosions of reactive mixtures through multiple Mach reflections off the discrete walls. The self-sustained propagation mechanism of the detonation wave is maintained by the interaction of strong transverse shocks reflected from discrete walls with the inherent transverse waves within the detonation structure, sustaining the instability of the cellular detonation. © 2024, The Authors. All rights reserved.

关键词： Detonation

Co-Optimization for Distributed Multi-Energy System Based on Multi-Objective Robust Stackelberg Game: Energy Management and Multi-Energy Pricing

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SSRN 2024年

作者： Ren, Xiaoxiao Wang, Jinshi Yang, Sifan Zhao, Quanbin Jia, Yifan Ou, Kejie Hu, Guangtao Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China School of Energy Engineering Yulin University Yulin719000 China

To achieve low-carbon operation of distributed multi-energy system (DMES) and enhance its activity in the energy market, this paper proposes a novel multi-objective Stackelberg game model. The DMES operator (DMEO) acts as the leader, guiding users' behavior through DMES optimal scheduling and multi-energy pricing. The optimization objectives include maximizing DMEO revenues, minimizing DMES primary energy consumption and carbon emissions. The users act as followers, adjusting energy demand based on upper-level energy pricing with the objective of maximizing consumption surplus. To achieve the low-carbon and flexible operation of DMES, carbon trading and demand response mechanisms are introduced. The upper-level model is solved using the non-dominated sorting genetic algorithm III (NSGA-III), while the lower-level model is solved by the Gurobi solver. Furthermore, a robust optimization model with adjustable robust measure is established to mitigate the impact of renewable energy uncertainty. Finally, the validity of the proposed model is verified by a data center in Qinghai. Compared with traditional Stackelberg game model, the proposed model reduces DMEO revenue by 0.63% but decreases carbon emissions by 1.64% and energy consumption by 1.59%. Under this optimization framework, the energy efficiency and exergy efficiency of DMES are 0.798 and 0.535, and the share of renewable energy is 34.6%. Besides, increasing renewable energy uncertainty leads to lower DMEO revenue, higher carbon emissions and energy consumption, while significantly reducing energy efficiency and exergy efficiency. The proposed multi-objective Stackelberg game model may provide some references for multi-stage energy system optimization. © 2024, The Authors. All rights reserved.

关键词： Energy utilization

An Innovative Damping Random Walk Algorithm with Compulsive Evolution for the Synthesis of Heat Exchanger Networks

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SSRN 2024年

作者： Huang, Xiaohuang Liu, Weiwei Xu, Yue Xiao, Yuan Duan, Huanhuan Cui, Guomin Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China

The development of heat exchanger networks is considered a hot research topic within the chemical processing sector. In this regard, the proper design of heat exchanger networks significantly improves energy efficiency, reduces costs, and decreases carbon footprints. However, the design of optimal heat exchanger networks is often a challenge, primarily because the problem is characterized by nonlinear, nonconvex, and discontinuous attributes. Moreover, it is coupled with the prevalence of numerous local optima in the solution space. At a certain level of the optimization problem, the process becomes trapped in local extremes. Thus, the process will not be able to advance further, leading to a stagnation in the optimization. This study introduces an innovative damping Random Walk Algorithm with Compulsive Evolution (damping RWCE). The proposed method is an extension of the stochastic RWCE algorithm, which has received a lot of attention recently. The presented damping RWCE algorithm incorporates a damping coefficient to temper the acceptance of optimal solutions. This slows the rate of structural changes without undue interference. The added value of this approach lies in its thorough examination of both discrete and continuous variables, which, in turn, decreases the probability of neglecting potential solutions. This method successfully navigates out of local optima, increasing the likelihood of identifying the global optimum. To implement and evaluate the proposed method, three types of damping coefficients are defined. The method effectiveness is then validated, considering three case scenarios. The results demonstrated that the optimal total annual costs obtained in this study are more favorable compared to the optimal results listed in the literatures. © 2024, The Authors. All rights reserved.

关键词： Damping

Data-Driven Surrogate Model for the Dynamic Characteristics of Supercritical Units

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Data-Driven Surrogate Model for the Dynamic Characteristics ...

power System and New Energy Technology Innovation Forum (NPSIF), Boao New power System International Forum -

作者： Shuai Dong An Zheng Junyao Jiang Wei Gao Ming Liu HUANENG YIMIN COAL-POWER CO. LTD. Hulunbuir China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China

ISBN: (数字)9798331504557

ISBN: (纸本)9798331504564

Coal-fired power generation units are characterized by large inertia, strong coupling, and high delay, making dynamic characteristic modeling inherently complex and computationally intensive. To address this, this paper utilizes GSE software to explore the dynamic characteristics of supercritical units. Data-driven approaches are then employed to develop surrogate model for these dynamics, comparing neural networks and support vector regression methods in the process. The study indicates that the surrogate model achieves a relative prediction error of less than 1% for live steam temperature, reheater steam outlet temperature, and power output. For live steam pressure and reheater steam outlet pressure, the model maintains a relative error within 10%.

关键词： Support vector machines Technological innovation Temperature Accuracy Computational modeling power system dynamics Neural networks Predictive models Vectors Load modeling

A Preliminary Study on the Blistering Behavior of Dispersion Plate-Type Fuel Assembly

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SSRN 2024年

作者： Yu, Songjiao Zhang, Kui Yang, Yiming Liu, Yumin Tian, Wenxi Qiu, Suizheng School of Nuclear Science and Technology Shanxi Key Laboratory of Advanced Nuclear Energy and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The dispersion plate fuel assembly, owing to its favorable characteristics of low temperature gradient, high stability, and excellent thermal conductivity, has become a focal point in the research of novel high-performance fuel elements. However, the current literature lacks a comprehensive understanding of the fuel plate's performance, particularly with regard to the bubbling phenomenon in the fuel plate cladding. In this study, we have implemented a fission gas release model, building upon previous analyses of fuel plate performance under steady-state operation. By comparing our calculation results with the Forsberg-Massih model, we find a close correspondence in trends, thereby validating the accuracy of our computational approach. Furthermore, we utilize the upgraded FROBA-PLATEs code to predict the blistering behavior of fuel plates under specific quasi-steady-state conditions. Our results demonstrate that the occurrence position and threshold temperature of blistering in the fuel assembly can be precisely predicted using this approach. © 2024, The Authors. All rights reserved.

关键词： Fission products

A Novel Multi-Objective Stackelberg Game Model for Multi-Energy Dynamic Pricing and Flexible Scheduling in Distributed Multi-Energy System

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SSRN 2024年

In the face of global energy and environmental challenges, distributed multi-energy system (DMES) offers a promising solution. To optimize resource allocation and promote energy market development, this paper proposes a novel multi-energy management and pricing framework based on multi-objective Stackelberg game. The DMES operator (DMEO) acts as the leader by optimizing DMES scheduling and pricing to guide user behavior towards revenue, energy consumption, and carbon emissions goals. Users adjust energy demand based on energy pricing to maximize consumption surplus. To achieve the low-carbon and flexible operation of DMES, carbon trading and demand response mechanisms are introduced. The model is solved using NSGA-III and Gurobi solver, with a robust optimization model with adjustable robust measure is established to address renewable energy uncertainty. The validity of the proposed model is verified by a data center in Qinghai. Compared with traditional Stackelberg game model, the proposed model reduces carbon emissions by 1.64% and energy consumption by 1.59%. Under this optimization framework, the exergy efficiency and energy efficiency of DMES are 0.535 and 0.798, and the share of renewable energy is 34.6%. Increased renewable energy uncertainty leads to lower DMEO revenue, higher carbon emissions and energy consumption, while significantly reducing energy and exergy efficiency. © 2024, The Authors. All rights reserved.

关键词： Energy utilization

Wall temperature calculation and safety analysis for the water wall of 660 MW ultra-supercritical circulating fluidized bed boiler 13

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Wall temperature calculation and safety analysis for the wat...

13th International Conference on Fluidized Bed Technology, CFB 2021

作者： Yang, Dong Liang, Ziyu Dong, Le Zhou, Xihong Li, Juan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

ISBN: (纸本)9781771368506

Temperature safety analysis was conducted on the smooth tube of the supercritical circulating fluidized bed boiler through experiments, numerical simulation, and hydrodynamic calculation. The numerical simulation results of the inner wall temperature were compared with the results of the experiments and hydrodynamic calculation. Experimental results showed that heat transfer enhancement occurred near a pseudocritical point. Non-uniform circumferential heating weakened the buoyancy effect, which could effectively delay or prevent the occurrence of heat transfer deterioration, and the circumferential distribution of the wall temperature and heat flux was parabolic. The simulated results of the inner wall temperature were in satisfactory agreement with the experimental results. Furthermore, the inner wall temperature values of the hydrodynamic calculation were lower than the experimental values. These findings indicated that the temperature experimental results obtained by non-uniform circumferential heating were conservative. © 2021 CFB 2021 - Proceedings of the 13th International Conference on Fluidized Bed Technology. All rights reserved.

关键词： Heat flux

Heat transfer behaviors of some supercritical fluids: A review

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Chinese Journal of Aeronautics 2022年第1期35卷 290-306页

作者： Gongnan XIE Xiaoxiao XU Xianliang LEI Zhouhang LI Yong LI Bengt SUNDEN School of Marine Science and Technology Northwestern Poly technical UniversityXi'an 710072China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing UniversityChongqing 400044China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and TechnologyKunming 650093China School of Mechanical Engineering Northwestern Polyteclwical UniversityXi'an 710072China Department of Energy Sciences Lund UniversitySE-22100 LundSweden

Supercritical fluids(e.g.,hydrocarbon fuels,water,carbon dioxide,and organic working medium,etc)have been recognized as working media to improve thermal efficiencies in power cycles and energy conversion,and have been used or selected as the working fluids in engineering fields such as aerospace,nuclear power,solar energy,refrigeration,geothermal energy,chemical technology,and so *** better understand the interesting characteristic or abnormal behaviors of supercritical fluids,most valuable research works(including experimental results and numerical studies)from domestic and abroad have been *** such,this paper presents a comprehensive review on heat transfer behaviors of some supercritical fluids in engineering *** review focuses on recently available articles published mainly from 2016 up to the present *** common problems(i.e.,heat transfer enhancement and heat transfer deterioration particularly for the supercritical hydrocarbon fuels)in the supercritical field are summarized and some perspectives on future prospects are also included.

关键词： Heat transfer behavior Supercritical fluids Thermo-physical property Turbulence model Working condition

Study on Variable Condition of Large Temperature Differential Heating System With Integrated Ejector Heat Pump

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Kung Cheng Je Wu Li Hsueh Pao/Journal of engineering Thermophysics 2022年第4期43卷 863-869页

作者： Wang, Li-Yuan Liu, Ji-Ping Fu, Yue Liu, Ming Yan, Jun-Jie Key Laboratory of Heat Flow Science and Engineering of Ministry of Education Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

In the case of increasing urban heating demand, reducing the return water temperature of primary heating network can improve the heating capacity and utilize and recycle low-temperature waste heat resources. The ejector heat pump can use the high temperature heat source of the primary heat network to reduce the temperature of the return water, it has the advantages of simple structure, stable and reliable operation. In this paper, a model of ejector heat pump system is established to study the variable operating conditions of ejector heat pump system under central heating regulation. The results show that the ejector heat pump can effectively reduce the primary heat network return water temperature, and the primary network return water temperature can be reduced by 22 degree centigrade under the same primary network water supply temperature. With the increase of water supply temperature of primary network, the temperature of primary network return water, COP of the heat pump system and ejector ejection ratio increase gradually, the exergy efficiency decreases gradually. In the process of heating regulation, with the increases of outdoor temperature, the primary network return water temperature increases continuously, and the exergy efficiency decreases gradually;However, when the outdoor temperature is lower than the local design temperature, the ejector ejection ratio and the COP of the heat pump system decrease sharply. © 2022, Science Press. All right reserved.

关键词： Water temperature