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A Novel Demand Response-Based Distributed Multi-Energy System Optimal Operation Framework for Data Centers

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SSRN 2023年

作者： Ren, Xiaoxiao Wang, Jinshi Hu, Xiaoyang Sun, Zhiyong Zhao, Quanbin Chong, Daotong Xue, Kai 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 address the increasing energy demands in data centers, distributed multi-energy system (DMES) may provide an efficient solution to achieve clean and sustainable energy supply. The use of a DMES optimal scheduling approach with source-load interaction plays a crucial role in improving data center performance. In this study, A DMES coupled by photovoltaics, wind turbines, ground source heat pump, internal combustion engines, electric chillers, absorption chillers, and energy storage devices is proposed. Considering the flexibility of workload scheduling and the challenges of renewable energy consumption, an integrated demand response model is established that considers time-of-use pricing and renewable energy peak subsidies. Then, a clean and economical optimal operation model for DMES based on proposed demand response and carbon trading mechanisms is established. Finally, to enhance the robustness of scheduling, the impacts of uncertainties in renewable energy output and demand response on system operation are analyzed by combining the Monte Carlo method and the interval method. Case study results demonstrate that implementing the proposed demand response and carbon trading mechanism improves data center performance by reducing total costs by 1.85%, carbon emissions by 0.56%, electricity purchases by 2.93%, while increasing renewable energy utilization by 0.77%. Additionally, optimization considering multiple uncertainties, results in higher total costs and broader interval widths compared to single-factor uncertainty optimization, but reduces system operational risk. © 2023, The Authors. All rights reserved.

关键词： Energy utilization

Development and Validation of Fully-Coupled Subchannel Analysis Code for Lmr within the Moose Framework

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SSRN 2023年

作者： Zhu, Xinyang Chen, Ronghua Wang, Jinshun Niu, Yuhang Wu, Yingwei Zhang, Dalin Tian, Wenxi Qiu, Suizheng Su, Guanghui School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

As one of the Gen IV advanced reactors, liquid metal reactor(LMR) holds promising prospects for its high fuel efficiency and excellent inherent safety performance. Owing to its complex working conditions and ultra-high operating temperature, a thermal-hydraulic analysis of the reactor core is gradually playing a bigger role in recent years. Therefore, a subchannel code FLARE for LMRs is developed within the MOOSE ***, a hybrid discretization approach involving DG and FEM as well as the JFNK method are employed to solve the equations in a fully-coupled way. To validate the computational accuracy and convergence of FLARE code, comparisons between the calculation values of FLARE, those of other programs and the experimental data are performed using 7-pin, 19-pin and 37-pin assembly experiments. The computational results indicate a good agreement between FLARE, experimental values, and other programs. In conclusion, FLARE code possesses the capability to accurately analyze LMR core. © 2023, The Authors. All rights reserved.

关键词： Reactor cores

Chemical Kinetics Simulation on Nitrogen Migration Characteristics During Co-Combustion of Ammonia and Coal Under Deeply Fuel-Air Multistage Conditions

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SSRN 2024年

作者： Dai, Liangxu Wang, Chang'an Hou, Yujie Ma, Guowei Chen, Yongxu Hurera, Abu Zhou, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an710049 China China Energy Science and Technology Research Institute Co. Ltd. Nanjing210046 China

mmonia, a carbon-free fuel, is attracting an ever-increasing attention. Coal/ammonia co-combustion in coal-fired power plants is considered an effective and fast approach to achieving the global decarbonization goal. However, one bottleneck of the utilization of ammonia fuel is the possible increased NOx emissions. The supply strategy of ammonia can affect the reduction of NOx by NH3. Few studies have explored the influence of ratios of ammonia as a secondary fuel and the secondary air volume on NOx emissions, which could be effective methods to reduce pollution. In this work, a chemical kinetics model was established to study the NOx behaviors during coal/NH3 co-firing in deeply fuel-air multistage conditions. The effects of the ammonia distribution strategies such as the ratio of NH3 as a secondary fuel, the injection position of secondary fuel, and corresponding air distribution with different NH3 co-firing ratios (CR-NH3) on the ammonia reactivity for NOx-reduction were studied. The results show that ammonia should be used as a primary fuel entering the main combustion zone under small CR-NH3 conditions to mitigate the NOx emissions;otherwise, ammonia is inclined to be used as a secondary fuel entering the reduction zone under large CR-NH3 conditions. NOx generation is also found to primarily occur in the burnout zone in fuel-air multistage combustion. Thus, the burnout zone should be given priority to decrease the NOx emissions. With the delay of secondary fuel injection in the reduction zone, the escaping ammonia keeps increasing in the outlet of the reduction zone. Then it is completely burned in the burnout zone, which leads to an increase in NOx emissions. The volume flow rate of NOx shows a downward trend on the whole with the ratio of secondary air increased. The air distribution can alter the function of the reduction zone in both generating and eliminating NO. The findings can provide some guidance to effectively decrease NOx emissions in coal/NH3 co-fi

关键词： Coal

Thermal Characteristics and Structural Parameters Optimization of Apg/Cu/Pcm Integrated Architecture

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SSRN 2024年

作者： Su, Lizheng Zhang, Tianning Li, Xiaoyang Li, Dong Jiang, Xinyu Xie, Zhongnan Xi'an Electronic Engineering Research Institute Xi’an710100 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China State Key Laboratory of Nonferrous Metals and Processes GRINM Group Co. Ltd. Beijing100088 China

The challenges faced by radar seeker primarily stem from inadequate heat dissipation in chips and excessive weight. To address these issues, this study introduces a novel integrated phase-change heat sink architecture, composed of a copper alloy matrix, annealed pyrolytic graphite (APG), and phase-change materials (PCMs) serving as heat conduction reinforcements. The numerical analysis of the heat dissipation performance of this architecture is conducted using Fluent software. The study evaluates the impact of APG anisotropy, APG/Cu interface thermal resistance, APG thickness, and surface area on the heat conduction efficiency. Results demonstrate that APG facilitates a uniform in-plane temperature distribution, allowing PCMs to absorb heat more evenly. Consequently, APG proves effective in enhancing heat dissipation and safeguarding chips from high temperatures. In comparison to a pure copper component, the APG/Cu/PCM structure reduces chip temperature by a substantial 56.27%. Furthermore, increasing the surface area of APG generally contributes to an enhanced heat transfer capability of entire architecture. The paper presents a quantitative relationship between APG surface area and optimal thickness. Importantly, APG satisfies the lightweight requirement, further emphasizing its suitability for addressing the thermal challenges in radar seeker structures. © 2024, The Authors. All rights reserved.

关键词： Phase change materials

Numerical Investigation on Combustion Characteristics and NOx Emission of Double-Reheat Tower Boiler at Different Loads 9th

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Numerical Investigation on Combustion Characteristics and NO...

9th International Symposium on Coal Combustion, ISCC 2019

作者： Zhang, Yan Ma, Shihao Guo, Jin Li, Yuesheng Zhu, Zhengrong He, Jiaqi Deng, Lei Che, Defu State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Xi’an 710049 China Guangdong Institue of Special Equpiment and Research Foshan528251 China Guangdong Institue of Special Equipment Inspection and Research Shunde Institue of Inspection Foshan528300 China

ISBN: (纸本)9789811616563

In this study, a three-dimensional numerical investigation using a finite volume method is presented to obtain the velocity, temperature, and species distributions in a 660 MW double-reheat tower boiler fed with bituminous coal. The refined oxidation model of HCN and NO-char reaction model were used to substitute the default model by the user-defined functions (UDFs). The effects of different loads and excess air ratios on combustion characteristics and NOx emission were studied numerically. The results show that temperature distribution is more uneven at the upper part of the furnace and the NOx emission increases as the load decreases. The temperature distributions in the furnace have little differences under three different excess air ratios. That the oxygen concentration increases significantly as the increase of excess air ratios leads to an increase of NOx emission at the furnace outlet. The minimum NOx concentration at the furnace outlet, 308 ppm, appears under 100% THA with excess air ratio of 1.15. The simulation results in this study can provide reference for optimization of combustion characteristics in double-reheat tower boiler and illustrate a method to reduce NOx emission. © 2022, Tsinghua University Press.

关键词： Furnaces

A Three-Dimensional Curve Interface Reconstruction Algorithm for Two-Phase Fluid Flow

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SSRN 2024年

作者： Chen, Yujie Gong, Junhua Sun, Dongliang Han, Dongxu Wang, Peng Yu, Bo Tao, Wen-Quan School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing102617 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Key Laboratory of Thermo–Fluid Science and Engineering Ministry of Education School of Energy & Power Engineering Xi’an Jiaotong University Shaanxi 710049 China

The curve interface reconstruction algorithm has received significant attention in the context of two-dimensional two-phase flow. However, it remains absent in the three-dimensional scenario. This paper proposes a novel three-dimensional curve interface reconstruction (CIR) algorithm to address this challenge within structured meshes for the first time. Specifically, a portion of the spherical surface is employed to reconstruct the three-dimensional curve interface segment, with the radius and center coordinates determined by curvature and mass conservation constraints, respectively. To enhance curvature accuracy, a sphere-based iterative reconstruction (SIR) algorithm is proposed to calculate the reconstructed distance function (RDF) for the three-dimensional curve interface. Various tests involving the reconstruction and interface capture of spherical, ellipsoidal, and cubic objects demonstrate that the coupled SIR and CIR (SIR-CIR, simplified by SCIR) method achieves high accuracy, particularly with coarse mesh resolutions. Additionally, the SCIR method offers the advantages of straightforward implementation and coding for interface reconstruction in two-phase flow research. This advantage results in reduced computational costs compared to the coupled volume-of-fluid and level set (VOSET) method, which also utilizes an iterative method to solve RDF. © 2024, The Authors. All rights reserved.

关键词： Spheres

Development of a Two-Phase Flow Solver with Drift-Flux Model Based on Openfoam: Validation Against Single/Two-Phase and Boiling Flow

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SSRN 2024年

作者： Wu, Wenqiang Zhang, Dalin Huang, Tao Du, Peng Zhou, Lei Wang, Bo Deng, Jian Qiu, Zhifang Tian, Wenxi Qiu, Suizheng Su, Guanghui State Key Laboratory of Multiphase Flow in Power Engineering Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology School of Nuclear Science and Technology Xi’an Jiaotong University Shaanxi Xi’an710049 China Nuclear Power Institute of China 328 Changshun Avenue Chengdu610213 China

Based on the open-source platform OpenFOAM, this paper implements a two-phase flow solver for drift flux models with realistic closure relations. The solver inherits the numerical method from the OpenFOAM framework, adopts the PIMPLE algorithm, and follows its discrete and matrix-solving criteria, focusing on developing a two-phase flow model and constitutive models. The drift velocity model is based on Ishii and his collaborators’ work. The remaining models, such as wall friction, wall heat transfer, interfacial heat and mass transfer, are taken from TRACE Theory Manual. To fulfill the condition of conjugate heat transfer between fluid and solid, a virtual solid heat transfer function is developed under the premise of a single-domain solver. Extensive and successful validation has been conducted involving single-phase, two-phase, and boiling flow heat transfer phenomena by comparing with experimental data or typical system codes, and the two-phase flow solver's success has been demonstrated in several aspects. © 2024, The Authors. All rights reserved.

关键词： Two phase flow

P-Type Chemical Doping-Induced High Bipolar Electrical Conductivities in a Thermoelectric Donor–Acceptor Copolymer

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CCS Chemistry 2021年第10期3卷 2482-2493页

作者： Jing Wang Yizhuo Wang Qing Li Zhanchao Li Kuncai Li Hong Wang Frontier Institute of Science and Technology Xi’an Jiaotong UniversityXi’an 710054 State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710054

Typically,conducting polymers transfer either electrons or *** is rare to see high bipolar(p-and n-type)electrical conductivities within a single bulk doped organic polymer without the assistant of gate ***,we report that FeCl3-doped solutionprocessable D–A copolymer poly(2,5-bis(2-octyldo decyl)-3,6-di(thiophen-2-yl)diketopyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophen)(DPPTTT)could exhibit a high p-type electrical conductivity of 130.6 S/cm and a good n-type electrical conductivity of 14.2 S/cm by engineering the doping level.

关键词： polarity switching donor-acceptor copoly mer thermoelectric organic diode p-ty pe doping

Transient gas/liquid two-phase flow in a pipeline-riser system after the change of inlet flow rates

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multiphase Science and Technology 2020年第2期32卷 25-46页

作者： Zou, Suifeng Liu, Weizhi Xu, Qiang Xie, Xiangdong Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an China Wuhan Second Ship Design and Research Institute Wuhan China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Transient gas/liquid two-phase flow caused by the change of inlet gas and/or liquid flow rates was experimentally studied in a 380-meter-long pipeline-riser system with a vertical riser of 21.5 meters in height. Results showed that, for the transient processes with the same median flow rates, the rise of flow rates was likely to result in shorter duration time compared to the fall of flow rates. Apart from the manner of change, the duration time was also closely related to the flow mechanism, which varied with the global flow regime. As a consequence, the transient process lasted a longer time around the transition boundary of stable regime and the severe slugging regime;whereas, the transient process would be shorter if the regime was an irregular oscillation;and the longest transient process was found at very low gas and liquid flow rates. As for the prediction of duration time of both the entire transient process and the transition to undesirable flow regimes, the support vector machine turned out to be much more suitable than the log-linear regression. In addition, some similarities of pressure drop signals were found between the transition to unstable and irregular flow regimes and the steady state of these regimes. Since the method for fast recognition of a steady global flow regime has already been developed, it becomes possible to forecast the transition to these undesirable flow regimes through the modification of the recognition method. © 2020 Begell House Inc.. All rights reserved.

关键词： Flow rate