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Optimization of Heliostat Fields Using Advanced Particle Swarm Optimization (APSO) 4

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Optimization of Heliostat Fields Using Advanced Particle Swa...

4th IEEE International Conference on Renewable Energy and power engineering, REPE 2021

作者： Rizvi, Arslan A. Yang, Dong Khan, Talha Ali Xi'An Jiaotong University State Key Laboratory of Multiphase Flow in Power Engineering Xi'an710049 China University of Europe for Applied Sciences Department of Data Science Potsdam Germany

ISBN: (纸本)9781665443715

Optical losses account for 40% of all the losses in a central receiver system. These optical losses occur due to factors like shading, blocking, atmospheric attenuation, spillage, cosine loss, and mirror reflectivity. These factors are collectively represented using a single factor known as optical efficiency. There exists a tradeoff among these factors. The unavoidable optical loss can be minimized by optimizing the positions of heliostats in a strategic manner. An advanced particle swarm algorithm is used to optimize the position of heliostats around a dense radial staggered field. An efficiency map of the heliostat field is generated. Using instantaneous optical efficiency as an objective function, a single objective optimization is performed using 30 particles and 2 dimensions (each dimension representing an optimization variable). The results highlight the areas in the heliostat field with the highest losses associated with different components of optical efficiency and their solution. The instantaneous efficiency increases by 1.5% after optimization. © 2021 IEEE.

关键词： Particle swarm optimization (PSO)

Hydrodynamic Characteristics Prediction Models for Water-Cooled Wall Under Different Loads Based on Artificial Neural Network

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SSRN 2024年

作者： Yang, Jiahui Zhang, Yong Li, Ruiyu Han, Lei Yue, Yang Wang, Jin Deng, 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 Yantai Longyuan Power Technology Co. Ltd Yantai264000 China Shunde Institute of Inspection Guangdong Institute of Special Equipment Inspection and Research Foshan528300 China

Real-time monitoring of hydrodynamic characteristics in water-cooled wall is crucial for boiler safety. Comprehensive numerical simulations are employed in this study to determine the heat flux distribution on the water-cooled wall across 38 different operating conditions. The heat flux results are applied to calculate hydrodynamic characteristics. Subsequently, the hydrodynamic characteristics results, along with the corresponding operating parameters, form the dataset for the Artificial Neural Network (ANN) models. The proposed methodology generates high-quality datasets, with a maximum root mean square error (RMSE) of only 6.8 K when comparing the results of working fluid temperature to the measured values. Two dataset partitioning methods are compared. Compared with random partitioning (control group), Considering each working condition as a whole during dataset partitioning (experimental group) reduces the average RMSE of predicted results in the test set by 47.6%, along with a 31.8% decrease in average number of neurons. The developed models exhibit excellent agreement with four working conditions in the test set, both in trends and absolute values, with acceptable error ranges. On the validation and test sets, the maximum RMSEs between the predicted and calculated values for flow rate, pressure, temperature and enthalpy are 0.033 kg s-1, 0.49 MPa, 5.7 K and 89.5 kJ kg-1, respectively, underscoring the reliability and practicality of the predictive models. © 2024, The Authors. All rights reserved.

关键词： Hydrodynamics

Life-Cycle-Based Multi-Objective Optimal Design and Analysis of Distributed Multi-Energy Systems for Data Centers

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SSRN 2023年

作者： Ren, Xiaoxiao Han, Zijun Ma, Jinpeng Xue, Kai Chong, Daotong Wang, Jinshi Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'An710049 China China Energy Construction Group Shaanxi Electric Power Design Institute Co. Ltd Xi’an710043 China

The widespread deployment of data centers has contributed to a dramatic increase in energy consumption and carbon emissions. To solve this problem, this study proposes a distributed multi-energy system (DMES) driven by solar, wind, geothermal and natural gas and its life-cycle-based multi-objective optimization model considered energy, economy and environment. This model employs an improved multi-objective grasshopper optimization algorithm (IMOGOA) based on the population variation mechanism and a novel operation strategy depending on load characteristics. On this basis, the effects of carbon tax, life span and indoor temperature set-point determined by improved predicted mean vote (PMV) on the system are further explored. Case studies are conducted on a practical data center in Qinghai, China. The results show that the IMOGOA is more suitable for the optimization of DMES than the commonly used algorithms. Besides, the supply of cooling, heating and electricity can meet the needs of the data center, and more than 30% of electricity is generated from renewable sources. Finally, the carbon tax, life span and indoor temperature set-points affect the optimization of the system. The methodology and results can be expected to be of great technical interest for the energy supply systems of data centers. © 2023, The Authors. All rights reserved.

关键词： Life cycle

Experimental Study and Theoretical Development of Liquid Entrainment in T-Junction with Double Inlets and Single Inlet of Gas Phase

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SSRN 2023年

作者： Li, Kepiao Shi, Yanggen Zhang, Kui Tian, Wenxi Qiu, Suizheng State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Nuclear Science and Technology Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi'an Jiaotong University Xi’an710049 China

The liquid phase entrainment through vertical-up branch had been analyzed through scaled and full size of experiment since ADS-4 (the fourth-stage Automatic Depressurization System) valve adopted in advanced PWR (Pressurized Water Reactor). Most of the existed studies focus on the single inlet of gas whereas steam may flow from two sides of the T-junction during the blowdown of primary system. Hence the experimental study on liquid entrainment with double end inlets are carried out. The data on the onset of entrainment (OLE) turns out that double end inlets show small difference with single inlet, whereas the entrainment rate research have great difference with single inlet and there is more than 50% error between the data and existing theoretical models. According to the visible flow phenomenon and flow instability, a new entrainment rate model was proposed which can well predict the double-end inlets and single-inlet entrainment phenomenon with the error within ±20%. © 2023, The Authors. All rights reserved.

关键词： Pressurized water reactors

Study on the Flame Structure and flow Field of Hydrogen-Enriched Combustion in Array Micro-Tube

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SSRN 2024年

作者： Tian, Liang Feng, Wenbin Han, Xiao Liu, Yuzhi Liu, Hongfang Cai, Xiao School of Energy and Environmental Engineering Hebei University of Technology Tianjin300401 China National Key Laboratory of Science and Technology on Aero-Engine Aero thermodynamics Research Institute of Aero-Engine Collaborative Innovation Center for Advanced Aero-Engine Beihang University Beijing100191 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China

Addressing climate change and reducing greenhouse gas emissions are critical priorities. Utilizing hydrogen-rich methane or pure hydrogen as fuels within gas turbines, facilitated by array micro-tube premixed combustion technology, is anticipated to markedly accelerate the decarbonization process of the energy sector. In this study, the flame structure of the array micro-tube premixed burner under various fuel compositions was examined using OH-Planar Laser-Induced Fluorescence (OH-PLIF) and Particle Image Velocimetry (PIV) measurement techniques. The effects of the equivalence ratio (φ) and the hydrogen power ratio (HPR) on the characteristics of the flame front, including its curvature, density, volume, and the associated flow field properties, were discussed. As φ and HPR increase, the wrinkled structure of the flame front is significantly enhanced, with a more pronounced effect on smaller scales. This enhancement leads to the separation of the unburned pockets from the main flame. Concurrently, both the flame length and flame area decrease with the augmentation of φ and HPR, indicating a more concentrated combustion process and increased combustion intensity under hydrogen-enriched and pure hydrogen conditions. The study also observed a slight increase in both the negative and positive curvatures of the flame front, with a more notable increase in negative curvature. The increased negative curvature results in an elevated degree of wrinkling and a higher value of Σ (flame surface density), reaching a maximum of 0.876 mm-1 under the conditions where φ is 0.8 and (mean progress variable) is 0.5, resulting in the smallest observed flame volume of 100.6 mm3. Upon coupling the flame with the flow field, it was discovered that the exit flow field of the array micro-tube exhibits symmetry and a characteristic conical flame shape. The burning velocity of the side flame brushes increases, and the velocity peak shifts upstream. The above findings confirms that the additio

关键词： flow fields

A Dynamic Plunger Lift Model for Shale Gas Wells

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Fluid Dynamics & Materials Processing 2023年第7期19卷 1735-1751页

作者： Shiyu Miao Xiao Liu Xiaoya Feng Haowen Shi Wei Luo Peng Liu Petroleum Engineering Institute of Yangtze University Wuhan430100China Laboratory of Multiphase Pipe Flow Gas Lift Innovation CenterChina National Petroleum Corp.Yangtze UniversityWuhan430100China Key Laboratory of Drilling and Production Engineering for Oil and Gas Wuhan430100China Sichuan Shale Gas Exploration and Development Limited Liability Company Chengdu640000China Sichuan Changning Gas Development Company PetroChina Southwest Oil&Gas Field CompanyChengdu610051China Oil and Gas Technology Research Institute of Changqing Oilfield Company PetroChinaXi’an710018China

At present,the optimization of the plunger mechanism is shale gas wells is mostly based on empirical methods,which lack a relevant rationale and often are not able to deal with the quick variations experienced by the production parameters of shale gas wells in comparison to conventional gas *** order to mitigate this issue,in the present work,a model is proposed to loosely couple the dynamics of gas inflow into shale gas wells with the dynamics of the liquid *** from the flow law that accounts for the four stages of movement of the plunger,a dynamic model of the plunger lift based on the real wellbore trajectory is *** model is then tested against 5 example wells,and it is shown that the accuracy level is higher than 90%.The well‘switch’,optimized on the basis of simulations based on such a model,is tested through on-site *** is shown that,compared with the original switch configuration,the average production of the sample well can be increased by about 15%.

关键词： Shale gas well complex and more complex well bore structure plunger lift loose coupling simulation model

Experiments and Predictions for Severe Slugging of Gas-Liquid Two-Phase flows in a Long-Distance Pipeline-Riser System

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SSRN 2023年

作者： Chang, Yingjie Xu, Qiang Zou, Suifeng Zhao, Xiangyuan Wu, Quanhong Wang, Yechun Thévenin, Dominique Guo, Liejin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Laboratory of Fluid Dynamics and Technical Flows Otto-von-Guericke-Universität Magdeburg Magdeburg39106 Germany

Experiments concerning the flow regimes observed in gas-liquid two-phase flows in a long pipeline-riser system have been carried out and are analyzed in this paper. The test loop with 0.075 m inner diameter consists of a 314 m horizontal pipeline, followed by a 25 m downward-inclined pipe, and finally a 21.5 m riser pipe. An industrial-scale global flow regime map is derived from differential pressure measurements in the riser. Electrical capacitance volume tomography installed in the horizontal section was used to reconstruct the phase interface in order to calculate the average gas void fraction (GVF). An appropriate model for this system is selected by comparing the experimental GVF with different, widely used models. The occurrence of a severe slugging flow (SS) can be well predicted using the model involving additional corrections (taking into account pipeline length, accurate GVF results, and gas density). This study supports the development of a suitable SS prediction model enabling safe design, operation, and control of practical systems. © 2023, The Authors. All rights reserved.

关键词： Pipelines

Optimization of Single-Hole Fender Design for Offshore Wind Turbine Foundation Under Ship Collision

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SSRN 2023年

作者： Wang, Yujin Li, Chun Yue, Minnan Liu, Qingsong Sun, Kang Yue, Xinzhi Han, Zhiwei School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering Shanghai China Shanghai Electric Wind Power Group Co. Ltd. Shanghai200233 China

This paper proposes a new design of protective fender for offshore wind turbine foundations based on nonlinear dynamics theory. The traditional anti-collision design for marine engineering platforms is not well-suited to wind turbine foundations, so the study uses the internal dynamics method and LS-DYNA to simulate the collision between a tripod foundation fender and a ship. The study analyzes impact force, energy absorption, stress, strain, and acceleration of the wind turbine tower top using finite element simulations under 19 relative hole angles. Results indicate that the optimal anti-collision protection is achieved with a hole angle of 20°. The study also examines the dynamic response and acceleration of the fender under different hole outer diameters of 0.5 m, 0.6 m, and 0.7 m and finds that the fender with a 0.7 m outer diameter exhibits the best anti-collision characteristics. The study utilizes a Kriging approximation model and a multi-objective genetic optimization algorithm to optimize the single-hole fender's design for minimum collision force and maximum energy absorption. The optimal parameter configuration has an inner hole diameter size of 0.658 m and a relative angle of 0.22°, achieving the best fender collision resistance ability. © 2023, The Authors. All rights reserved.

关键词： Offshore wind turbines

Experimental Study on Deliquification with Atomizing Nozzle in Gas Well

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Experimental Study on Deliquification with Atomizing Nozzle ...

2020 International Conference on Green Energy, Environment and Sustainable Development, GEESD 2020

作者： Gao, Yutang Li, Xiaobai Chang, Peng Liu, Lei State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Shaanxi710049 China

Gas is a clean energy resource in comparison with oil and coal. Liquid-loading problem is frequently encountered in the process of gas production. It would directly cause the production of gas wells decreasing, even off production. A number of deliquification techniques have been suggested for solving this kind of problem, but the available techniques are not yet widely applicable. Based on the analysis, the method of deliquification with atomizing nozzle in gas wells was put forward. The test bench was designed for studying the atomization of nozzles and the liquid entrainment of gas flow. The size distribution of atomized droplets was measured by Malvern laser grain size analyzer. The Sauter mean diameters of atomized droplets were analysed under different two-phase flow conditions. The results indicate that the designed nozzles have good atomization performances and show potential application for reducing liquid loading in gas wells. © Published under licence by IOP Publishing Ltd.

关键词： Two phase flow