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Based on CFX numerical simulation of Francis turbine runner Fang Hed Xinyu University of Mechanical Engineering, Xinyu 338004, China a514149150@qq.com Key words: turbine runner; CFX; numerical simulation; hydraulic vibration Abstract.
From the source of hydraulic vibration, Focus on numerical analysis, numerical simulation for the cutting thickness of the runner blade.
Finally, the runner blade is thin 0.5cm can obtain numerical performance is good numerical simulation results Analysis and simulation results of velocity distribution.
Based on CFX technology based on activity of the guide vane and the runner of turbine internal flow state for three dimensional flow field numerical simulation, Focusing on turbine runner blade thickness thinner after 0.5 cm and three dimensional flow field numerical calculation, simulation and analysis on the energy distribution.
Liu: Analysis of the internal flow in Francis turbine runner CFD (MS., XiHua University, China 2006)

Introduction In recent years, with the fast development of computer technology and the improvement on the theory of turbulent numerical simulation, numerical simulation has gradually taken the place of physical experiments.
Currently the numerical simulation methods which are implemented on the computer provide overall process in simulating the model of the Francis turbine as well as the prototype so as to provide accurate results for the numerical analysis and model the situation of the flow field in 3 dimensions [1].
Before a numerical simulation experiment is carried out on a Francis turbine, a 3D solid model of the Francis turbine must be built.
The quality of the solid 3D model influences the result of the numerical simulation experiment directly.
Using the 3D numerical model which was built by Pro/E to carry out numerical simulative experiments can save time and money, and also can embody design requests better, meet the requirements of further hydraulic analysis and provide a reliable foundation for the future CFD calculation and performance prediction.

The Simulation of the Circumfluence and Inhomogeneous Flow Field in Pulsing Electro-Floatation Deng Xiaogang 1, a, Zhou Xiong 1 ,b 1 Department of Machinery Engineering, Chongqing University of Science and Technology， Chongqing , 401331，P.R.China a yxydxg2002@sina.com, b cq_mecc@yahoo.com.cn Keywords: Pulsing Electro-Floatation ；Inhomogeneous Flow Field ；Circumfluence Abstract.
Chen Wen[3] pointed out the method of image analysis for bubbles velocity field in bubbles-liquid two phase flow based the theory of fluid dynamics and Computational fluid mechanics (CFD) . 1, The theory of Pulsing Electro-floatation (PEF) Based the principle of electrolysis of water by direct current, small and uniform micro-bubbles could be obtained using method of Electro-floatation(EF).
Thus, the equations of conservation of mass, momentum, kinetic energy of turbulence k, and dissipation rate ε could be calculated: (6) In Eq. 6，p is the pressure that is same of all the phase; g is the acceleration of gravity ; denotes a source of corresponding property due to the presence of the dispersed phase; The other parameters are constants: ,. 3, The Numerical Simulation of PEF inhomogeneous flow field In accordance with the sizes of the PEF experimental device, the simulation model of PEF inhomogeneous flow field is designed shown in Fig. 2.
The unsteady state pressure-based solver, mixture multiphase flow model and K-εturbulence model are called in the simulation.
A multiphase CFD model of DAF Process[J]，Wat．Sci．Tech，2001，43(8):153-157 [3] Cheng Wen, Song Ce.

This paper presents for the results of such fully coupled simulations.
In this study, commercial software CFDACE was adopted for the simulation.
Table 1 Material properties used in the micropump simulation.
In addition, the simulation can be extended to three dimensions, allowing the analysis of three dimensional flows.
Chen: Proceedings of SPIE Mechatronics, MEMS and Smart Materials (ChongQing, CHINA, September 20-23, 2005)Vol. 6040, P.60400U [6] CFD Research Corporation: CFD-ACE Theory Manual Ver.4.0 (Huntsville, AL 1998)

Turbulent Model In this paper, Menter F.’s SST k-omega turbulent model was used for the numerical simulation[4].
Therefore, SST k-omega model is suitable for the CFD simulation of bluff body with flow separation phenomenon, and then it is suitable for the CFD simulation of the heavy-duty commercial truck.
Numerical Simulation Mesh of Flow Field.
A hybrid of prism and polyhedron mesh was used for the numerical simulation in this research, and the mesh around the body and bridges is refined.
Gu: A Study on the Numerical Simulation of Car Aerodynamic Characteristics Under Crosswind Conditions.

Moreover, based on solving fluid rigid motion equation, turbine self-starting transient numerical simulation is carried out by using CFX CEL language.
What’s more, CFX CEL language is wrote to realize the turbine transient startup state simulation.
As for transient simulation, referring to two peak (10°and 110°) and two valley (50°and 70°) value of CFX simulation in Fig.4, the turbine self-starting performance at different azimuth angles is obtained as shown in Fig.6.It’s obtained that the final angular velocity is stable around 5rad/s at the azimuth angle of 10°, 50°and 70°, and self-starting time at the azimuth angle of 10° is the shortest.
References [1] L.Zhi-Chuan,Z.Liang,Vertical axis trend turbine numerical simulation research, Acta Energiae Solaris Sinica.Vol.32,No.9(2011) 1321-2-1326
[2] W.Shi-Peng,Numerical simulation of wave impact on the trend, PhD Thesis.Dalian: Dalian University of Technology,2007

On that basis, a new blade shape called as combined blade for Guiding VAWT was proposed and numerical investigation was complemented on its aerodynamic performance by CFD (Computational Fluid Dynamics) technique.
CFD (Computational Fluid Dynamics) technique is introduced to numerically investigate the aerodynamic performance of this Guiding VAWT with combined blade.
NUMERICAL MODEL The Guiding VAWT proposed in this paper is essentially a two dimensional structure, so the two dimensional domain for CFD simulation is chosen.
The grids for this CFD calculation is unstructured mesh inside the VAWT while in the extension domain, structure meshes are adopted to reduce the total grid number.
Followings are the prescribed boundary conditions: Inlet: Uniform velocity of the coming flow; Outlet: Ambient pressure of atmosphere; Walls: No-Slip conditions; The whole CFD calculations are complemented by commercial CFD software Fluent and the mesh generation is by its component -GAMBIT.

Using a T-Junction, Brown [17] ran several simulations to study swirling and uniform inlet flow conditions.
References [1] Kannojiya V, Kumar S, Kanwar M, Mohapatra S K. (2016) Simulation of erosion wear in slurry pipe line using CFD.
[2] Banakermani M R, Naderan H, Saffar-Avval M. (2018) An investigation of erosion prediction for 15 to 90 elbows by numerical simulation of gas-solid flow.
[5] Athulya A S, Cherian R M. (2016) CFD modelling of multiphase flow through T junction.
[13] Duarte C A, de Souza F J. (2017) Innovative pipe wall design to mitigate elbow erosion: A CFD analysis.

In fact, the three most important mechanics contributions in the past three decades are fracture mechanics, finite element method and computational fluid mechanics (CFD).
CFD took a quantum leap since the introduction of high-speed computers and fast parallel processors.
More importantly, the finite element method has become a common tool used for the modeling and simulation of solid, fluids, combustion, electric magnetic, and even other physical phenomenon as long they can be described within the context of a set of differential equations.
CFD methodology and algorithm has not only become the corner stone to the design and understanding of aerodynamic systems but also been extended for seeking solutions in the electric-magnetic regime.
CFD was developed under similar circumstances.

Fire simulation with the use of SS-A The case study is based on the initiation of a fire on the mezzanine floor of the building, in the meeting room of the Academy of Romanian Scientists (presented in Fig. 4).
This time was determined using a numerical simulation, a smoke detector being modelled in the burning area, placed 5 cm below the ceiling and in the center of the room and the necessary time to trigger it was measured.
For the SS-B, the numerical simulation of fire development, Fire Dynamics Simulator (named FDS) is used and for the SS-E, the numerical simulation of human evacuation in case of fire, Fire Dynamics Simulator with Evacuation (named FDS+Evac) is used.
Presentation of the FDS software FDS is a software that is based on Computation Fluid Dynamics (CFD) models for numerical simulation of fire development.
The main properties of agents used in the numerical simulation are presented in Table 3: Table 3.