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Novel Distance Protection Based on distributed parameter model for Long-Distance Transmission Lines

IEEE TRANSACTIONS ON POWER DELIVERY 2013年第4期28卷 2116-2123页

作者： Song, Guobing Chu, Xu Gao, Shuping Kang, Xiaoning Jiao, Zaibin Suonan, Jiale Xi An Jiao Tong Univ Dept Elect Engn Xian 710049 Shaanxi Peoples R China Xian Univ Sci & Technol Sch Elect & Control Engn Xian 710054 Shaanxi Peoples R China

Traditional distance protections mainly use a lumped parameter model and perform poorly under high-resistance ground fault and/or for long-distance transmission line. In order to overcome the defects, this paper presents a new distance protection method, which is developed based on the distributed-parameter transmission-line model and can distinguish internal faults from external faults based on the trend of the voltage distribution in the neighborhood of the setting point of protection. The criterion of this new distance protection is also put forward. The effectiveness of the proposed method and the error involved are discussed in detail. This new distance protection is simple in principle and easy to implement. In addition, without having to calculate the voltage distribution along the entire line, this algorithm has low computational complexity. In particular, the proposed distance protection still operates correctly under high-transition-resistance faults. Both simulations in distributed parameter transmission-line models and 750-kV power-line field data have demonstrated validity and feasibility of the proposed protection method.

关键词： Distance protection distributed parameter model transition resistance voltage distribution

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Identifyability measures to select the parameters to be estimated in a solid-state fermentation distributed parameter model

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BIOTECHNOLOGY PROGRESS 2016年第4期32卷 905-917页

作者： da Silveira, Christian L. Mazutti, Marcio A. Salau, Nina P. G. Univ Fed Santa Maria Dept Chem Engn Santa Maria RS Brazil

Process modeling can lead to of advantages such as helping in process control, reducing process costs and product quality improvement. This work proposes a solid-state fermentation distributed parameter model composed by seven differential equations with seventeen parameters to represent the process. Also, parameters estimation with a parameters identifyability analysis (PIA) is performed to build an accurate model with optimum parameters. Statistical tests were made to verify the model accuracy with the estimated parameters considering different assumptions. The results have shown that the model assuming substrate inhibition better represents the process. It was also shown that eight from the seventeen original model parameters were nonidentifiable and better results were obtained with the removal of these parameters from the estimation procedure. Therefore, PIA can be useful to estimation procedure, since it may reduce the number of parameters that can be evaluated. Further, PIA improved the model results, showing to be an important procedure to be taken. (c) 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:905-917, 2016

关键词： solid-state fermentation bioreactor distributed parameter model parameters identifyability analysis and estimation optimization

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Analysis of herbicide biosorption by means of a phenomenological mathematical distributed parameter model

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ENVIRONMENTAL TECHNOLOGY 2022年第13期43卷 1953-1960页

作者： Wernke, Gessica Triques, Carina Contini Suzaki, Pedro Yahico Ramos Fagundes-Klen, Marcia Regina Bergamasco, Rosangela Univ Estadual Maringa Dept Chem Engn Maringa PR Brazil State Univ Western Parana Dept Chem Engn Toledo PR Brazil Univ Tecnol Fed Parana UTFPR Campus Dois VizinhosEstr Boa Esperanca BR-85660000 Dois Vizinhos PR Brazil

A distributed parameter model and two lumped parameter models were used in order to find the rate-limiting step in the adsorption process of a herbicide (Diuron) by Moringa oleifera husks, a possible low-cost adsorbent. For that, four kinetics assays, differentiated by the initial Diuron concentration, were performed. Langmuir isotherm well represented the equilibrium data and through this evaluation, Moringa husks proved to be a potential adsorbent for Diuron removal from water. The internal mass transfer resistance, analysed as a distributed parameter model, was found to better represent the experimental data. This fact enabled the simulation of the process according to the variation of time and space, which contributed to the better understanding of the adsorption process.

关键词： Biosorption Moringa husks Diuron herbicide phenomenological mathematical modelling distributed parameter model

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A general distributed parameter model for ground heat exchangers with arbitrary shape and type of heat sources

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ENERGY CONVERSION AND MANAGEMENT 2018年 164卷 667-679页

作者： You, Tian Wang, Baolong Li, Xianting Shi, Wenxing Yang, Hongxing Tsinghua Univ Beijing Key Lab Indoor Air Qual Evaluat & Control Sch Architecture Dept Bldg Sci Beijing Peoples R China Hong Kong Polytech Univ Renewable Energy Res Grp Hong Kong Hong Kong Peoples R China

The heat and mass transfer simulation model of a ground heat exchanger (GHE) directly affects the design and operation performance of a ground-coupled heat pump system. The GHE models based on the response function (like the Green function and g-function) can achieve a fast calculation speed. However, the heat sources in these models are limited to points or whole boreholes, leading to low calculation accuracy in heat transfer during a short time period and limitation to a certain GHE. A general distributed parameter model for a ground heat exchanger (RF model) is proposed based on the principle of response factors in this paper. A sandbox experimental platform is then built to test the temperatures of typical points in the double-layered soil and to validate the RF model. After that, the calculation of the RF model is simplified by determining suitable positions for the soil boundaries and the numbers of sub pipes and sub soil boundaries. Finally, the RF model is applied in different scenarios to demonstrate its characteristics. The results show that: (1) the RF model is suitable for different kinds of GHEs with arbitrary shape and type of heat sources releasing heat in arbitrary time steps;(2) the RF model has only 0.01 degrees C and 0.23 degrees C temperature response errors compared to those from numerical solutions and experiments, respectively;(3) the general RF model has similar accuracy to the numerical solution in calculating the distributed temperatures of the borehole and pipes, heat transfer in the short term, and heat transfer of borehole groups and the energy pile.

关键词： Ground-coupled heat pump Ground heat exchanger distributed parameter model Response factor Simulation

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Higher mode effects in frame pin-supported wall structure by using a distributed parameter model

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EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS 2016年第14期45卷 2371-2387页

作者： Wu, Shoujun Pan, Peng Zhang, Dongbin Tsinghua Univ Dept Civil Engn Beijing 100084 Peoples R China Tsinghua Univ Dept Civil Engn Key Lab Civil Engn Safety & Durabil China Educ Minist Beijing 100084 Peoples R China

Frame pin-supported wall structure is a kind of rocking structure, which releases constraints at the bottom of the wall. The wall is affiliated to the frame and can rotate around the hinge. Previous studies have investigated seismic performance (such as deformation pattern and plastic hinge distribution) of frame pin-supported wall structure. Strength demand of this system was investigated through static pushover analysis. However, dynamic characteristics, especially higher mode effects, remain to be quantified. As demonstrated in several researches, higher mode effects have non-negligible effects on seismic response. For this purpose, a distributed model for analyzing higher mode effects in frame pin-supported wall structure was proposed, where the pin-supported wall and the frame were simplified as a bending beam and a shear beam, respectively. The model was solved by differential equations derived from equilibrium and compatibility. Displacement and inner force distribution of frame pin-supported wall structure in higher modes were quantified according to the model. Influence of critical parameters, such as wall stiffness and structure period, was assessed on higher mode effects. It was demonstrated that response in higher modes cannot be neglected in the design of frame pin-supported wall structure. Capacity design based on the fundamental mode is not conservative, especially in the wall. Furthermore, pin-supported walls tend to force the frame to vibrate in the rocking mode and suppress higher mode effects in the frame. Copyright (c) 2016 John Wiley & Sons, Ltd.

关键词： frame pin-supported wall structure distributed parameter model higher mode effects parameter study

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A distributed parameter model of a frame pin-supported wall structure

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EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS 2015年第10期44卷 1643-1659页

作者： Pan, Peng Wu, Shoujun Nie, Xin Tsinghua Univ Dept Civil Engn China Educ Minist Key Lab Civil Engn Safety & Durabil Beijing 100084 Peoples R China Tsinghua Univ Dept Civil Engn Beijing 100084 Peoples R China

Many reinforced-concrete frames collapse via a soft-story mechanism during severe earthquakes. Such collapses are mainly attributed to concentrated deformation in a soft story. Deformation control is thus important in preventing collapse. The frame pin-supported wall structure is a type of rocking structure that releases constraints at the bottom of the wall. Previous research has obtained good results for the deformation control of this type of structure. However, the interior forces and strength demands of the pin-supported wall have not been systematically explored. In this paper, a distributed parameter model is developed to investigate the strength demand of the wall in a frame pin-supported wall structure. In the model, the pin-supported wall is simplified as a bending beam and the frame is simplified as a shear beam. The two beams are joined by distributed shear connectors, so that the shear force can be transferred at any location on the interface. The model can be solved using differential equations based on equilibrium and compatibility. The accuracy of the model is verified using SAP2000 (Computers and Structures Inc., Berkeley, CA, USA). Displacement distribution of the structure and distributions of the moment and shear force within the pin-supported wall are obtained for two typical external force profiles. It is found that the pin-supported wall can effectively reduce the drift concentration factor. Distributions of the displacement, moment, and shear force are closely correlated with the relative stiffness of the wall and frame. Finally, recommendations on the stiffness and strength of a pin-supported wall are made. Copyright (c) 2015 John Wiley & Sons, Ltd.

关键词： frame pin-supported wall structure distributed parameter model strength demand stiffness demand

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Study on multi-stream plate fin heat exchanger coupled with ortho-para hydrogen conversion based on distributed parameter model

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2023年第85期48卷 33315-33334页

作者： Li, Ke Li, Chaolong Wen, Jian Chen, Qiang Li, Yanzhong Xi An Jiao Tong Univ Sch Energy & Power Engn Dept Refrigerat & Cryogen Engn Xian 710049 Peoples R China State Key Lab Space Cryogen Propellant Technol Beijing 100028 Peoples R China

The distributed parameter model is used to simulate full domain of multi-stream CFPFHE (catalyst filled plate fin heat exchanger). The heat transfer due to the extended catalyst surface area, the ortho-para hydrogen conversion heat and the flow resistance in porous catalyst are integrated in the model. The results show that increasing the mass flow of fluid channel filled with catalyst not only decreases HEPUP (heat exchange amount per unit pump power), but also weakens efficiency of o-p conversion. For example, when the mass flow of fluid A (in which catalyst is filled) increases from 0.06 kg/s to 0.084 kg/s, the pump power increases by 34.6%, and the HEPUP and the average outlet para-hydrogen decreases by 30.9% and 7.0% respectively. In addition, A deviation parameter f is defined to quali-tatively describe the degree of inlet maldistribution. Although no catalyst filled in fluid C channel, the effect of fC on the outlet para-hydrogen mass fraction is obvious. With fC increasing from 0 to 1.5, the outlet para-hydrogen mass fraction in the layer numbered by 42 (middle layer of fluid A) increases by 6.8%, decreases by 11.9% and 11.9% respectively, in the layer numbered by 6 (upmost layer of fluid A) and 76 (downmost layer of fluid A). The increase of inlet maldistribution of fluid C prevents the potential of catalyst filled in up and down layers of fluid A from being fully utilized.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Catalyst filled plate fin heat exchanger distributed parameter model Ortho-para hydrogen conversion Inlet flow maldistribution Thermodynamic performance

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Application of distributed parameter model in thermal management of microchannel loop heat pipe

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APPLIED THERMAL ENGINEERING 2023年第1期234卷

作者： Sheng, Lisha Tian, Zhizheng Xu, Peng Han, Chaoling Chen, Zhenqian Southeast Univ Sch Energy & Environm Nanjing Peoples R China Minist Educ Key Lab Energy Thermal Convers & Control Nanjing Peoples R China Nanjing Tech Univ Coll Emergency Management Nanjing Peoples R China Jiangsu Prov Key Lab Solar Energy Sci & Technol Nanjing Peoples R China

Microchannel loop heat pipe (MCLHP) possesses the superiority of compact structure and energy saving, which are preferred in the thermal management of data centers and charging piles. In this study, the three-dimensional distributed parameter model combined with an experimental system was presented to investigate the effect of filling ratio, height difference, heat exchanger structure and operating parameters on the thermal transfer performance of the MCLHP system. Specially, pump auxiliary MCLHP was proposed to improve the heat transfer capacity. Simulations combined the distributed parameter model with the response surface methodology showed that the largest heat transfer capacity was 1.402 kW with a filling ratio of 79.7%. Although changing the structural parameters would improve the heat transfer capacity, it would compensate with increased space structure and air resistance. The proposed pump auxiliary MCLHP system could operate stably with the heat transfer capacity of up to 4 kW, which presented a potential application in high heat flux cooling such as charging piles and data centers.

关键词： Microchannel loop heat pipe distributed parameter model Thermal management Heat transfer performance Circulating pump

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Sound generation by unsteady flow ejecting from the vibrating glottis based on a distributed parameter model of the vocal cords

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ACOUSTICAL SCIENCE AND TECHNOLOGY 2007年第6期28卷 392-402页

作者： Nomura, Hideyuki Funada, Tetsuo Kanazawa Univ Div Elect Engn & Comp Sci Kakuma Machi Kanazawa Ishikawa 9201192 Japan

The purpose of the present paper is to clarify the effects of unsteady glottal flow on phonation. We perform numerical experiments with respect to vocal cord vibrations in order to verify the validity of the proposed model for a glottal sound source. In addition, the prediction of pressure waves induced by unsteady glottal jets is attempted. Good agreement between the numerical results and the measured data of the properties of the glottal source indicates that the proposed model is a good tool for the analysis of speech production. Simulated pulsatile glottal jets show the generation of high-frequency noises in a pressure wave at the glottis and the unsteady and asymmetric motion of vortices. These vortices cause amplitude fluctuations in the pressure wave downstream near the glottis, although pressure waves far from the glottis are not greatly affected. In conclusion, the unsteady glottal flow affects only the area near the glottis and does not greatly affect speech waves radiating from the mouth.

关键词： Glottal sound source distributed parameter model Unsteady glottal flow Amplitude fluctuation

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distributed parameter model and experimental investigation of galloping piezoelectric energy harvester

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MECHANICS OF ADVANCED MATERIALS AND STRUCTURES 2024年第27期31卷 8878-8886页

作者： Zheng, Shu Dou, Yaping Ren, Huiru Song, Rujun Zhuang, Xuye Sui, Wentao Shandong Univ Technol Sch Mech Engn Dept Elect Informat Zibo Peoples R China Shandong Univ Technol Sch Mech Engn Zibo Peoples R China

A galloping-based piezoelectric energy harvester has been proposed to generate power for wireless sensors using low-speed airflow. The utilization rate of wind energy is improved by optimizing the geometric parameters of the bluff body. The energy collection system's distributed parameter mathematical model is established by integrating the electromechanical model and aerodynamic model. To verify the model, a wind tunnel test is carried out. A parametric analysis is conducted to investigate the effects of external resistance, wind speed, and bluff body shape on power. When the wind speed is 5.2 m/s and the resistance is 150 k omega, the power is 3.72 mW.

关键词： Piezoelectric energy harvester galloping distributed parameter model wind energy

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