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Optimal Simulation on the variable load for an Ultra-supercritical Boiler Lingda ZENG 1, a, Zhongguang FU 1 and Hancai ZENG 2 1Key Laboratory of Condition Monitoring and Control for Power Plant Equipment (North China Electric Power University),Ministry of Education, Beijing 102206, China; 2State Key Laboratory of Coal Combustion (Huazhong University of Science and Technology),Wuhan 430074,China; alingda-zeng@chdoc.com.cn Keywords: ultra-supercritical boiler; combustion; variable load; optimization; numerical simulation Abstract.
In this paper, 1000MW Ultra-Supercritical Boiler is as a prototype, meanwhile using CFD software Fluent for simulating the ultra supercritical and the opposed firing Fired Boiler variable load operating condition process in order to grasp the burning combustion characteristics of the boiler under changing conditions and provide the guidance information for adjusting and optimizing the buring process.
Calculation methods and boundary conditions The object for numerical simulation is a 1000MW ultra-supercritical boiler which take the method of opposed firing supercritical boiler transformer parameters and Π-type layout.Design and check the coal mixed with the coal of Jibei Mine and Yan Mine.
Figure 1 Furnace structure and grid Simulation results and analysis simulation results and analysis Figure 2 different load is along the average temperature of the furnace high, oxygen amount, CO and CO2 and NOx density distribution.

Numerical simulation methods Flow field and aerodynamic heating simulation.
All the simulation was calculated with CFD software FLUENT.
IR characteristic simulation method.
Simulation results The pressure field of missile surface was shown in Fig.3.
ACM Transactions on Modeling and Computer Simulation, 8 (1998) 3-30

During the search process, a computational fluid dynamics (CFD) based analytical model and microscopic traffic simulation VISSIM were applied to evaluate the performance of possible solutions.
Different simulation scenarios with varying AADT from 60,000 to 12,000 were tested.
Then, the microscopic traffic simulation VISSIM was implemented to validate the performance of the found solutions.
The simulation results showed very promising performance improvement, for example, 5% travel time reduction, 9% reduction in the percentage of vehicle with high collision risk and 11% emission reduction.
Compared with the other recent studies, the focus of this paper is on a real freeway stretch, other than simulation scenarios only.

The simulation is based on the Favre-averaged Navier-Stokes equations coupled with Wilcox’s turbulence model.
The numerical simulation is used to investigate in detail the flow physics for a range of the pressure ratio .
The purpose of the present work is a numerical simulation of the injection of the round sonic jet perpendicular to the supersonic flow in a channel and studied in detail vortices systems and flow physics at the moderate and high value of the pressure ratio.
The comparison highlights the qualitative agreement between the experiment and CFD.
The numerical simulation was applied to investigate in detail the flow physics for the range of the pressure ratio .

By combining CFD numerical simulation [2] technology and system identification principle, the method of least squares embed into Fluent [3] which get transfer function of wood drying kiln control system.
The input of the fuzzy controller are and , output are, , ： ,, (3) (4) Self-tuning process of the controller is shown in Fig.3: Fig.3 Flow chart of fuzzy self-tuning PID program Under unit step role, the simulation results of the fuzzy PID controller and traditional PID controller are shown in Fig.4, Fig.5 by MATLAB: 200 400 600 800 1000 1200 0 0.2 0.4 0.6 0.8 1 1.2 time(s) y Fig.4 Fuzzy-PID simulation curve 200 400 600 800 1000 1200 1400 1600 1800 2000 0.2 0.6 0.8 1 time(s) -0.2 0.4 0 Fig.5 Traditional PID simulation curve Simulation results show that the fuzzy PID control better than the traditional PID significantly in stability, speed, system overshoot.
Journal of North China Institute of Science and Technology.(2010),7 (2):59-63, In Chinese [2] Ruixue Zhang.The drying kiln wind speed testing and modeling and simulation based on the fluid dynamics.
Electronic Industry Press.(2010):33-50, In Chinese [5] YixingYang,DalianCui andAijunZhou.fuzzy adaptive PID controller and Simulink Simulation.

The flow driven by heat difference and buoyant force in such a cavity has been widely investigated by simulations or experiments.
Compared to conventional computational fluid dynamics (CFD) algorithm that solve the momentum and energy equations by finite volume method (FVM)[2] or arbitrary Lagrange equation (ALE), LBM uses a kinetic equation to solve the flow at microscopic level and conservative transport equation for macroscopic variables, which is time-cost saving and easy to parallelization[3].
In section 2, numerical method for the 2D differentially heated cavity simulation is described, including the governing equations and physical model.
Results for the simulations under different Rayleigh numbers from 103 to 106, and the aspect ratios range from 0.5 to 10 are obtained.
Table 1 Comparison of D2Q9 LBM simulations with Benchmark analysis Ra 103 104 105 106 CDA [1] 1.117 2.238 4.509 8.817 present 1.1313 2.2763 4.5641 8.8443 Fig. 2 presents the streamlines for and 106 of a standard square cavity.

Numerical Simulation of Flow Field of Metro Train Head Bin Yang1, a, Qinghong Sun2,b 1 College of Automobile and Traffic Engineering, Nanjing Forestry University, Nanjing, Jiangsu, 210037, China 2 Department of Mechanical Engineering, Southeast University, Nanjing, Jiangsu, 210096, China a yangb123@126.com, bsunqinghong@seu.edu.cn Keywords: Metro train, Numerical simulation, Flow field, Aerodynamic, Pneumatic idiosyncrasies, Pressure distribution Abstract.
In some countries such as Japan, French and Germany, wind tunnel model simulation trial and flow field numerical simulation calculation are taken into account during the development of high-speed metro train, at the same time, aerodynamic issues about steady state and unsteady state domino offects are also studied [1-3].
To eliminate influence on ground boundary layer during the period of wind tunnel trial and computer simulation, the paper introduces shifting floor (exert ground boundary a velocity, its value and direction are the same as entrance flow velocity) to eliminate the impact of ground [6-8]。
We must take train flow field CFD characteristics into account, train surface finite volume value is 0.075 m, bounding surface finite volume value is 0.5 m, entire body finite volume value is 1 m, there are three bounding layer gridding numbers and the thickness is 0.45 m, thereinto 0.45 means that the boundary layer height is 0.45 times as great as cliff surface gridding original size.
Fig.13 Train induced wind vertical component distritution along side plumb area in the direction of the metro train length Result Analysis Table 1 shows numerical simulation results of aerodynamic drag coefficient of different metro head schemes.

Numerical Simulation of Taylor Couette Flow in Bioreactor Li Yea, Zhengming Tong b,Jialei Lu, Kai Zhu, Chao Li School of Energy and Power Engingeering，University of Shanghai for Science and Techenology, Shanghai 200093，China asarah_shine@163.com, btzm1590041495@163.com Keywords: Taylor-Couette flow, Taylor vortex, bioreactor, numerical simulation.
Grids near boundary layers are treated by local grid refinement techniques in order to achieve better simulation results, and convergence is considered to be reached when residuals of each solved parameters descend in three order of magnitude and keep steady.
The growth process of Taylor vortexes along with the increasement of Re values illustrated in figure 2 is identical to that observed in experiment[8], and thus validity of the simulation model is confirmed.
Conclusions Taylor Couette flow in bioreactor at different Reynolds numbers are investigated using CFD numerical simulation technique.
Simulation results show that Taylor vortexes are generated and developed gradually along with the increasement of Reynolds numbers, and will fill the whole field when critical Re value is reached.

The algebraic equations are discretized by the finite volume method implemented by Fluent CFD software [1].
Computational domain The Gambit/Fluent simulation package was used to develop our numerical modeling.

Numerical simulation of the water transportation process in xylem is studied based on Ansys 12.0/fluent.
A 3-dimensional model for the flow field was then established, and the steady state flow was simulated with the computational fluid dynamics (CFD) software based on Navier-Stokes equations.
Simulation of 5 pits vessel element with different pits’ diameters.
Simulation of 10 pits vessel element.
Simulation of 20 pits vessel element.