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Li Q.,Tsinghua University | Zuo Z.,China Power Complete Equipment Co. | Hu Y.,Tsinghua University | Liang G.,Tsinghua University
Journal of Aerospace Engineering | Year: 2017

The structural behavior during the first reservoir-filling phase is significant for evaluating a super high arch dam's safety. This paper presents an in situ monitoring network of the Xiluodu Dam in Yunnan, China, including a deformation monitoring system using geodetic and nongeodetic monitoring. The system also includes a refined thermal monitoring system based on a slab-level active cooling system. The thermal-structural decoupling numerical analysis method for a dam-water-foundation system is presented in this study with considerations of viscoelasticity material properties and internal/external thermal loads. The structural behavior of the Xiluodu Dam during the first reservoir-filling phase is analyzed using the smart monitoring system with combination of the in situ monitoring technique and the numerical simulation method. The in situ monitoring result can provide intuitional instructions of the structural behavior, showing a positive correlation between the dam deformation and the reservoir water level. The monitoring results are also used as the verification reference of the numerical model. The distribution characteristics of the displacement and stress of the dam subjected to load cases such as nonimpounding, impounding process, and the normal operating water level are discussed and predicted. © 2016 American Society of Civil Engineers.

Hu Y.,Tsinghua University | Liang G.,Tsinghua University | Li Q.,Tsinghua University | Zuo Z.,Tsinghua University | Zuo Z.,China Power Complete Equipment Co.
Advances in Structural Engineering | Year: 2017

Knowledge of the concrete temperature of a dam is necessary for the implementation of improved construction methodologies. A monitoring-mining-modeling system is proposed in this article to study the thermal state of a super high arch dam in China. The monitoring-mining-modeling system includes an in situ monitoring network setup, data mining methods, and numerical finite element analysis. Two engineering cases are surveyed in detail using monitoring-mining-modeling system. The first case is the long-term temperature rise phenomenon, whose cause is determined from the data mining result, and the numerical modeling of the external boundary condition is improved using the result. The modeling result then shows that the effect of the TRP is also a dangerous factor for the deformation and stress state of the dam. The second case is the performance of cooling pipes. The energy absorption capability of the cooling pipes is revealed by the data mining result, as well as the performance difference between high-density polyethylene and iron pipes. The numerical modeling result shows good agreement with the monitored result, which demonstrates the closed-loop validity of the monitoring-mining-modeling system. © The Author(s) 2016.

Li Y.,China Power Complete Equipment Co. | Ren X.-D.,Hong Kong University of Science and Technology
Applied Thermal Engineering | Year: 2016

Energy and environment issue set utilizing low-grade heat noticed. Organic Rankine Cycle (ORC) has been demonstrated to be a promising technology to recover waste heat. As a critical component of ORC system, the turbine selection has an enormous influence on the system performance. This paper carries out a study on the thermodynamic analysis of ORC system and the aerodynamic design of an organic radial turbine. The system performance is evaluated with various working fluids. The aerodynamic design of the organic radial-inflow turbine is focused due to the high molecule weight and the low sound speed of the organic working fluid. An aerodynamic and profile design system is developed. A radial-inflow turbine with R123 as the working fluid is designed and the numerical analysis is conducted. The simulation results indicate that the shock wave caused by the high expansion ratio in the nozzle is well controlled. Compared with the one-dimensional design results, the performance of the radial-inflow turbine in this paper reaches the design requirements. © 2015 Elsevier Ltd. All rights reserved.

Wang H.,Yanshan University | Liang J.-X.,Yunnan Power Grid Beijing New Energy Technology Research and Development Center | Hu J.-L.,China Power Complete Equipment Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

Doubly-fed wind power generator (DFIG) type is the mainstream model of the wind turbine at home and abroad at present. To study the impact on reliability and stability of power system with large-scale wind power grid, it must have accurate model and parameters of wind turbine. Therefore, this paper studies the model parameter identification method of doubly-fed wind power generator. First, in the Matlab/Simulink environment, it sets up a simulation model for the wind turbine grid-connected and gets the measured data. Afterwards, by using the generator αβ coordinate system (mathematical) model, it analyzes the identifiability to illustrate the convergence for the proposed model, and then through the analysis of the mathematical model, gets an expression of stator self-induction and the mutual inductance. Finally, the rotor initial phase angle θ0, stator self inductance, mutual inductance, and mutual inductance between rotor and stator can be identified by using genetic algorithm with identification strategy step by step. It provides reliable theory for the study of large-scale wind power grid.

Deng H.,North China Electrical Power University | Bai Y.,North China Electrical Power University | Li X.,North China Electrical Power University | Dang W.,China Guodian Corporation | Li X.,China Power Complete Equipment CO.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2015

The down-flow unit tube is a key component of air cooled heat exchanger (ACHE) in power plant. The study on the heat and mass transfer mechanism inside the unit tube is very important for heat-transfer efficiency optimization and safe operation of ACHE. In this paper, considering the geometry characteristics of tube, a 3D mathematical model was constructed to simulate the condensation of steam on the internal wall of unit tube. The temperature of tube wall was assumed to be unknown and an iterative algorithm was developed to evaluate this temperature. The numerical solution of steam condensate rate was compared with design value, and simultaneously, numerical solution of heat transfer coefficient was compared with Nusselt empirical formula value to verify the model validation. Further analysis on the model numerical solution shows that the partial differential equations of condensate film thickness can accurately describe the film characteristic which varies with geometry structure and declination of the tube. And the predicted value of vapour-liquid separation location agrees well with ACHE experimental operation. However, the numerical solution of the condensate sub-cooling temperature doesn't agree with actual measurement value very well. The result of this study is of great significance for optimization design of down-flow unit tubes, and also, it is meaningful for antifreezing protect of ACHE in winter. © 2015 Chin. Soc. for Elec. Eng.

Bai Y.,North China Electrical Power University | Deng H.,North China Electrical Power University | Li X.,China Power Complete Equipment CO. | Zhang D.,Beijing GDZS control technology CO.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2016

The single-row flat wave finned tube is widely applied as the unit tube by the direct air cooled condenser in power plants. Caused by the complicated body geometry in fin side, the vapour condensation involving phase transition, and the heat transfer from vapour zone to air zone conjugating on several interfaces, using computational fluid dynamics (CFD) method to simulate the heat transfer in both the vapour channel and the cooling air channel simultaneously, many challenges are encountered. A mathematical model to simulate the condensation of water vapour was developed counting the interfacial shear stress, the heat balance conditions on the interfacial boundaries of the conjugate heat were presented as well as the method to calculate the conjugate heat. The numerical simulation for the full-size finned tube was carefully separated to 282 CFD modules which share same boundaries each other. Based on the 282 CFD modules, the asynchronous strategy to calculate the conjugate heat of the finned tube in overall scale was successfully carried out. The results from the CFD simulations agree very well with the experimental results, which validates the proposed condensation model, also show the great potential of the asynchronous CFD approach as an effective tool for the full-size finned tube to predict the heat transfer in both sides. Based on the CFD results, the characteristics of flow field was also investigated in terms of both the cooling air and the vapour. © 2016 Chin. Soc. for Elec. Eng.

Liu G.,Tsinghua University | Li Q.,Tsinghua University | Msekh M.A.,University of Babylon | Zuo Z.,Tsinghua University | Zuo Z.,China Power Complete Equipment Co.
Computational Materials Science | Year: 2016

The phase-field model for fractures regularizes crack diffusion using a length-scale parameter. The displacement fields and the phase-field in a coupled system can be solved as either fully coupled "monolithic" or sequentially coupled "staggered" fields. In this paper, we employ the commercial finite-element software Abaqus to solve the monolithic and staggered phase-field models using a user-defined element (UEL) and user-defined material (UMAT/VUMAT) subroutines in two- and three-dimensions for quasi-static and dynamic fractures. We present the implementation procedures for both strategies, and make a detailed comparison using different applications. By comparing the phase-field model as a diffusive crack model and the extended finite-element method (XFEM) as a discrete crack model, we obtain good agreement. We investigate the influence of the model-regularization parameter based on experimental results. We adopt the thread-parallel execution and mutexes of Abaqus solvers. © 2016 Elsevier B.V. All rights reserved.

Yan Z.,China Power Complete Equipment Co.
Gaoya Dianqi/High Voltage Apparatus | Year: 2015

The larger the capacity of a generating unit is, the greater the electromagnetic force on the enclosure type isolated-phase bus becomes in short circuit fault condition. In the related national and industrial standards with enclosure type isolated-phase bus, the requirements for axial welding are unclear. In this paper, a force analysis of the enclosure type isolated-phase bus in short circuit condition is conducted for a 1250 MWe nuclear power project, and some suggestions are provide for axial welding requirements of large capacity enclosure type isolated-phase bus. ©, 2015, Xi'an High Voltage Apparatus Research Institute. All right reserved.

Gao Y.-J.,China Power Complete Equipment Co.
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2011

This paper introduces the design parameters of the passive residual heat removal heat exchanger for American advanced passive pressurized water reactor (AP1000), describes the fabrication process for the head, tubesheet, heat exchange tube, corrugated plate and support frame assembly of the heat exchanger, mainly in terms of material, forging, welding, and heat treatment, and also analyzes the crucial steps for the support frame assembling, tubesheet plate welding, tube penetration welding of C tube bundle, closure/head welding, heat treatment, hydraulic (pressure) test, and etc. in the process of heat exchanger assembling.

Liu G.,Tsinghua University | Li Q.,Tsinghua University | Zuo Z.,Tsinghua University | Zuo Z.,China Power Complete Equipment Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2016

A staggered updated method for a phase field model was implemented in the commercial finite element software ABAQUS through UMAT and VUMAT subroutines. In order to verify the reliability of the algorithm, crack propagation in modes I and II under quasi-static and dynamic loads was calculated. All the results are generally consistent with the testing results in the existed references. In addition, simulations for wing cracks and curved surface cracks were also carried out. The results show that the main reason of dynamic crack branching is the high elastic strain energy stored in solids. The algorithm of phase field model is effective to simulate crack initiation, intersection, bifurcation and propagation in three-dimensional space, and can be executed conveniently in commercial FEM software. © 2016, Science Press. All right reserved.

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