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Numerical simulation of swirling flow effect on the first stage vane film cooling distribution

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International Journal of Modeling, Simulation, and Scientific Computing 2016年第3期7卷 319-337页

作者： Hong Yin electric power Research Institute of Guangdong power Grid corporation Guangzhou Guangdong ProvinceP.R.China

In advanced gas turbine technology,lean premixed combustion is an effective strategy to reduce peak temperature and thus,NOX *** swirler is adopted to establish recirculation flow zone,enhancing mixing and stabilizing the ***,the swirling flow is dominant in the combustor flow field and has impact on the *** paper mainly investigates the swirling flow effect on the turbine first stage vane cooling system by conducting a group of numerical ***,the numerical methods of turbulence modeling using RANS and LES are *** computational model of one single swirl flow field is *** the RANS and LES results give reasonable recirculation zone *** comparing the velocity distribution,the RANS results generally match the experimental data but fail to at some local *** LES modeling gives better results and more detailed unsteady flow *** the second step,the RANS modeling is incorporated to investigate the vane film cooling performance under the swirling inflow boundary *** to the numerical results,the leading edge film cooling is largely altered by the swirling flow,especially for the swirl core-leading edge aligned *** to the pressure side,the suction side film cooling is more sensitive to the swirling ***,the film cooling jet is lifted and turned by the strong swirling flow.

关键词： Gas turbine swirling flow combustor simulator film cooling

Inspection-replacement policy of system under predictive maintenance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第3期8卷 495-500页

作者： LIU Bao-you FANG You-tong WEI Jin-xiang WANG Yong-liang Department of Mathematics and Physics Shijiazhuang Railway Institute Shijiazhuang 050043 China College of electrical Engineering Zhejiang University Hangzhou 310027 China Extrahigh Tension Transmittal and Transformation Company branch Hebei Electric Power Company Shijiazhuang 050051 China

In general, every system is in one of the three states： normal, abnormal, or failure state. When the system is diagnosed as abnormal state, it needs predictive maintenance, lfthe system fails, an identical new one will replace it. The predictive maintenance cannot make the system ＂as good as new＂. Under these assumptions, the reliability index and the inspection-replacement policy of a system were studied. The explicit expression of the reliability index and the average income rate （i.e., the long-run average income per unit time） are derived by using probability analysis and vector Markov process method. The criterion of feasibility for the optimal inspection-replacement policy under the maximum average income rate is obtained. The numerical example shows the optimal inspection-replacement policy can raise the average income rate when the optimal inspection-replacement policy is feasible.

关键词： lnspection-replacement policy. Inspection and diagnosis. Monotone stochastic process. Reliability index Vector Markov process method

Grid Side Distributed Energy Storage Cloud Group End Region Hierarchical Time-Sharing Configuration Algorithm Based onMulti-Scale and Multi Feature Convolution Neural Network

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Energy Engineering 2023年第5期120卷 1253-1269页

作者： Wen Long Bin Zhu Huaizheng Li Yan Zhu Zhiqiang Chen Gang Cheng State Grid Chongqing Shiqu electric power Supply branch Chongqing400000China

There is instability in the distributed energy storage cloud group end region on the power grid *** order to avoid large-scale fluctuating charging and discharging in the power grid environment and make the capacitor components showa continuous and stable charging and discharging state,a hierarchical time-sharing configuration algorithm of distributed energy storage cloud group end region on the power grid side based on multi-scale and multi feature convolution neural network is ***,a voltage stability analysis model based onmulti-scale and multi feature convolution neural network is constructed,and the multi-scale and multi feature convolution neural network is optimized based on Self-OrganizingMaps(SOM)algorithm to analyze the voltage stability of the cloud group end region of distributed energy storage on the grid side under the framework of *** to the optimal scheduling objectives and network size,the distributed robust optimal configuration control model is solved under the framework of coordinated optimal scheduling at multiple time scales;Finally,the time series characteristics of regional power grid load and distributed generation are *** to the regional hierarchical time-sharing configuration model of“cloud”,“group”and“end”layer,the grid side distributed energy storage cloud group end regional hierarchical time-sharing configuration algorithm is *** experimental results show that after applying this algorithm,the best grid side distributed energy storage configuration scheme can be determined,and the stability of grid side distributed energy storage cloud group end region layered timesharing configuration can be improved.

关键词： Multiscale and multi feature convolution neural network distributed energy storage at grid side cloud group end region layered time-sharing configuration algorithm

Inhibition roles of molybdate and borate on Q235 steel corrosion in resistance reducing agent

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Journal of Iron and Steel Research International 2023年第8期30卷 1477-1489页

作者： Yang Yang Hui Su Lan-lan Liu Song Xu Zhen Zhong Xiao-bao Zhou Tang-qing Wu School of Materials Science and Engineering Xiangtan UniversityXiangtan 411105HunanChina State Grid Hunan electric power Company Limited Transmission maintenance Changsha 410100HunanChina State Grid Hunan electric power Company Limited Research Institute Changsha 410007HunanChina

The effects of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7) on corrosion behavior of Q235 steel in resistance reducing agent(RRA)containing sodium bentonite were studied by mass loss,scanning electron microscopy and electrochemical *** results showed that both the independent and mixed additions of Na_(2)MoO_(4) and/or Na_(2)B_(4)O_(7),can reduce the corrosion rate of Q235 steel in RRA containing sodium *** the inhibition effect of Na_(2)MoO_(4) and/or Na_(2)B_(4)O_(7)increased with their dosage *** the same dosage,the inhibition efficiency of the mixed addition of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7),was higher than that of their independent *** passivation effect of Q235 steel was easy to obtain in the RRA with the mixed addition of Na_(2)MoO_(4) and Na_(2)B_(4)O_(7).The optimized inhibitor for the RRA containing sodium bentonite was the mixture of Na_(2)B_(4)O_(7) and Na_(2)MoO_(4) with a total concentration of 1.5 wt.%.Furthermore,the increase in corrosion potential E_(corr) and the decrease in corrosion current density i_(cor) in carbon steel were one of the important criteria for the formation of passivation film.

关键词： Q235 steel Resistance reducing agent Corrosion inhibitor Sodium bentonite Electrochemical impedance spectrum

Modeling of Large-Scale Hydrogen Storage System Considering Capacity Attenuation and Analysis of Its Efficiency Characteristics

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Energy Engineering 2024年第2期121卷 291-313页

作者： Junhui Li Haotian Zhang Cuiping Li Xingxu Zhu Ruitong Liu Fangwei Duan Yongming Peng Key Laboratory of Modern power System Simulation and Control&Renewable Energy Technology Ministry of Education(Northeast Electric Power University)Jilin132012China Ministry of Science and Technology Electric Power Research Institute of State Grid Liaoning Electric Power Co.Ltd.Shenyang110006China Northeast electric power Dispatching Control Center Northeast Branch of State Grid Corporation of ChinaShenyang110180China

In the existing power system with a large-scale hydrogen storage system,there are problems such as low efficiency of electric-hydrogen-electricity conversion and single modeling of the hydrogen storage *** order to improve the hydrogen utilization rate of hydrogen storage system in the process of participating in the power grid operation,and speed up the process of electric-hydrogen-electricity *** article provides a detailed introduction to the mathematical and electrical models of various components of the hydrogen storage unit,and also establishes a charging and discharging efficiency model that considers the temperature and internal gas partial pressure of the hydrogen storage *** models are of great significance for studying and optimizing gas storage *** these models,the performance of gas storage units can be better understood and *** studies are very helpful for improving energy storage efficiency and sustainable *** factors affecting the charge-discharge efficiency of hydrogen storage units are *** integrating the models of each unit and considering the capacity degradation of the hydrogen storage system,we can construct an efficiency model for a large hydrogen storage system and power conversion *** addition,the simulation models of the hydrogen production system and hydrogen consumption system were established in MATLAB/*** accuracy and effectiveness of the simulation model were proved by comparing the output voltage variation curve of the simulation with the polarization curve of the typical hydrogen production system and hydrogen consumption *** results show that the charge-discharge efficiency of the hydrogen storage unit increases with the increase of operating temperature,and H2 and O2 partial voltage have little influence on the charge-discharge *** the process of power conversion system converter rectification operation,its efficiency decreases wi

关键词： Hydrogen storage system simulation modeling electrolyzer fuel cell capacity loss

Review of Optical Character Recognition for power System Image Based on Artificial Intelligence Algorithm

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Energy Engineering 2023年第3期120卷 665-679页

作者： Xun Zhang Wanrong Bai Haoyang Cui Gansu electric power Research Institute of StateGrid corporation of China LanzhouChina College of Electronic and Information Engineering Shanghai University of Electric PowerShanghaiChina

Optical Character Recognition(OCR)refers to a technology that uses image processing technology and character recognition algorithms to identify characters on an *** paper is a deep study on the recognition effect of OCR based on Artificial Intelligence(AI)algorithms,in which the different AI algorithms for OCR analysis are classified and ***,the mechanisms and characteristics of artificial neural network-based OCR are ***,this paper explores machine learning-based OCR,and draws the conclusion that the algorithms available for this form of OCR are still in their infancy,with low generalization and fixed recognition errors,albeit with better recognition effect and higher recognition ***,this paper explores several of the latest algorithms such as deep learning and pattern recognition *** paper concludes that OCR requires algorithms with higher recognition accuracy.

关键词： Optical character recognition artificial intelligence power system image artificial neural network machine leaning deep learning

Accommodation of curtailed wind power by electric water heaters based on a new hybrid prediction approach

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Journal of Modern power Systems and Clean Energy 2019年第3期7卷 525-537页

作者： Yang YU Zengqiang MI Xiaoming ZHENG Da CHANG State Key Laboratory of Alternate electrical power System with Renewable Energy Sources North China Electric Power UniversityBaoding071003China hebei Key Laboratory of Distributed Energy Storage and Micro-grid North China Electric Power UniversityBaoding071003China

Wind power curtailment is of great importance with the increase of large-scale wind power connected to the grid. A new concept of redundant wind power accommodated by dispatching electric water heaters(EWHs) is developed in the paper. Precise predictions of wind power and EWHs load power are the basis for this work. A hybrid multi-kernel prediction approach integrating an adaptive fruit fly optimization algorithm(AFOA)and multi-kernel relevance vector machine(MKRVM) is proposed to deal with the sample distribution of multisource heterogeneous features uncovered by an energy entropy method, where AFOA is used to determine the kernel parameters in MKRVM adaptively and avoid the arbitrariness. For the large computation of the prediction approach, parallel computation based on the Hadoop cluster is used to accelerate the calculation. Then, an economic dispatching model for accommodating wind power is built taking into account the penalty of curtailed wind power and the operation cost of EWHs. The proposedscheme is implemented in an intelligent residential *** results show that the optimization performance of the hybrid prediction approach is superior to those of four usual optimization algorithms in this case. Regular or orderly scheduling of EWHs enables accommodation of superfluous wind power and reduces dispatch cost.

关键词： Wind power curtailment electric water heaters(EWH) Dispatching model Relevance vector machine Prediction model

Thermogram-based estimation of foot arterial blood flow using neural networks

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Applied Mathematics and Mechanics(English Edition) 2023年第2期44卷 325-344页

作者： Yueping WANG Lizhong MU Ying HE School of Energy and power Engineering Dalian University of TechnologyDalian 116023Liaoning ProvinceChina State power Investment corporation Northeast electric power Co. Ltd.Shenyang 110181China

The altered blood flow in the foot is an important indicator of early diabetic foot ***,it is challenging to measure the blood flow at the whole foot *** study presents an approach for estimating the foot arterial blood flow using the temperature distribution and an artificial neural *** quantify the relationship between the blood flow and the temperature distribution,a bioheat transfer model of a voxel-meshed foot tissue with discrete blood vessels is established based on the computed tomography(CT)sequential images and the anatomical information of the vascular *** our model,the heat transfer from blood vessels and tissue and the inter-domain heat exchange between them are considered thoroughly,and the computed temperatures are consistent with the experimental *** data are then used to train a neural network to determine the foot arterial blood *** trained network is able to estimate the objective blood flow for various degrees of stenosis in multiple blood vessels with an accuracy rate of more than 90%.Compared with the Pennes bioheat transfer equation,this model fully describes intra-and inter-domain heat transfer in blood vessels and tissue,closely approximating physiological *** introducing a vascular component to an inverse model,the blood flow itself,rather than blood perfusion,can be estimated,directly informing vascular health.

关键词： diabetic foot thermal analysis blood flow inverse method neural network

Influence of thermal ageing on high-field polarisation characteristics and conductivity behaviour of submarine polymeric cables insulation

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High Voltage 2023年第1期8卷 138-148页

作者： Xize Dai Jian Hao Gian Carlo Montanari Zheng Jian Ruijin Liao Xinlong Zheng State Key Laboratory of power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina Department of Energy Aalborg UniversityAalborgDenmark Center for Advanced power Systems Florida State UniversityTallahasseeFloridaUSA Shinan power Supply branch Company of State Grid Chongqing electric power Company NananChina Zhoushan power Supply branch Company of State Grid Zhejiang electric power Company ZhoushanChina

Diagnosing insulation intrinsic ageing is essential for preventing insulation failure of submarine cables,and in case of failure,helping in any decision about maintenance *** this study,a novel aged cable diagnosis approach based on high-voltage frequency domain spectroscopy(HV-FDS)with broader frequency width is proposed to analyse the high-field polarisation characteristics and conductivity behaviour of 500 kV submarine polymeric cables insulation,aiming to support the evaluation of overall insulation *** measurement principle of HV-FDS and relaxation mechanism are stated,and then focus is on studying the extent of change of polarisation and conduction properties of submarine cables insulation as a function of ageing stress and ***,the high-field polarisation characteristics and conductivity behaviour are discussed in-depth based on the carrier transport and trap ***,the novel diagnostic indicator based on the high-field characteristics is extracted to quantify the thermal ageing state of submarine cables *** show that the high-field polarisation characteristics and conductivity behaviour seem to become sensitive diagnostic quantities if measured at reasonably high voltage,which are able to reveal mechanisms associated with thermo-oxidative ageing as that generated in the testing procedure considered in this *** is considerably higher than that experienced in typical dielectric spectroscopy approaches.

关键词： behaviour insulation characteristics