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Simulation on balde duct vortex in a Francis turbine runner based on S-A model Yongzhong Zeng1,a and Xiaobing Liu1,b 1School of Energy and Environment, Xihua University, Chengdu, 610039, China azyzzyzhome@163.com, bliuxb @mail.xhu.edu.cn Keywords: Spalart-Allmaras model, blade duct vortex, low specific speed, turbine Abstract.
Introduction With the rapid development of computational fluid dynamics (CFD), the using of turbulence theory to calculate the flow field in the turbine runner has become a powerful tool for the hydraulic design and performance analysis of the runner, and the calculation results have been approved by[1,2] .
Numerical Simulation of Vortex Flow in Draft Tube of Turbine 3.1 Geometric model and grid A Francis turbine with long and short blades and with the model of HLA542-LJ-130 was used for the calculation.
[2] YUAN Shouqi, HE Youshi, YUAN Jianping, et al., PIV measurements and numerical simulations of flow in centrifugal pump impellers with splitting vanes, Chinese Journal of Mechanical Engineering, 42(5) (2006), pp.60-63
Bui, A parallel finite-volume algorithm for large-eddy simulation of turbulent flows, Computer & Fluids; 2000, 29: 877-915

In study [25], the issue of dust accumulation on the filtering surface of a corrugated filter has been analyzed using a numerical simulation method.
In this study, the computational fluid dynamics (CFD) methods have not been applied.
Compared to CFD, empirical equations are simpler to use and require only a short calculation time.
J Mech Sci Technol. 35 (2021) 5007–5022. https://doi.org/10.1007/s12206-021-1019-9 [16] Cheng, K., Zhu, J., Qian, F., Cao, B., Lu, J., Han, Yu., CFD–DEM simulation of particle deposition characteristics of pleated air filter media based on porous media model.
Sādhanā. 48 (2023) 223. https://doi.org/10.1007/s12046-023-02206-z [20] Teng, G., Shi, G., Zhu, J., Qi, J., A numerical simulation method for pressure drop and normal air velocity of pleated filters during dust loading.

Using the FLUENT 6.3 CFD software，the RNG k-ε turbulence model and SI MPLE algorithm，the sewage treatment pool where a submersible mixer with two leaves was numerically simulated by describing the surface as wall，VOF model and rigid-lid assumption respectively.
The distribution graph of the three numerical simulation velocity is basically the same.
From the three numerical simulation, when z=-0.0375m, the velocity is accordant, shown as double hump shape.
Numerical Simulation of Three Dimensional Flow andIts Application in Hydraulic Engineering[D].
Numerical simulation of submersible mixer with three blades[J].

The FE simulation analysis results were verified correct.
Structural crashworthiness analysis by computer simulation can effectively improve the product reliability, reduce the development cost, and enhance the market competitiveness of the product.
So in early design, the simulation work can play a greater role.
According to the simulation results, we suggest that increasing support after screen, increasing fillet in stress concentration of the plastic casing, thickening rib and other measures can greatly reduce damage of the screen and rib Fig. 8 Schematic diagram of packaging materials unit deformation Compared With Experiment Results From the above simulation analysis results, main problems of integrated machine lie in the screen and plastic frame.
Overcoming of Barrier between CAD and CFD by Modif -ied Finite Volume Method [M], Proc. 1998 ASME Pressure Vessels and Piping Division.

,LTD) Keywords: Aerobic composting; Mechanical ventilation; Ammoniadistribution; Simulation and analysis Abstract.
Based on measured ventilation condition in thebuiltaerobic composting plant of large sludge treatment engineering,usingthe methord of CFD, four kinds of scheme for the new aerobic composting plantwere analysed,which contain two types of ventilation(natural air supply mechanical exhaust and mechanical air mechanical ventilation)and two kinds of supply air rates (4x105m3/h and 8x105m3/h).
The object of this simulation is incompressible fluent.The pollutant of this plant mainly contain ammonia,which is a kind of complex turbulent motion[9],and obey the above governing equation.In this article,indoorzeroequation model will be taken to solve the problem[10].
Fig.1 Theary of ventilation Simulation The size of exhaust outlet is 0.5m×0.3m,and the exhaust rate is 1280m3/h per vent.The plant have 2 doors,which size is 6.5m×6m,and have 56 windows,which size is 0.6m×1.8m.According to the theory of pollutant diffusion and the structure of the plant,this simulation complete 4 cases,which content the former case,as shown in Table.1.Multivariant simulations are compared to analysis the spead of ammonia in different ventilate conditions,which can offer the optimized case of air current composition.
[10] Spengler J D,ChenQ.Indoor air quality factors in designing a healthy building.Annual Review of Energy and the Environment,2000,25:567601 [11]Aoyongan,Wangli,Numerical Simulation of Pollutant Diffusion Law in Bathroom and Optimization of the Locations and Ways of Exhaust Outlet and Makeup Air[J].Journal of Shenyang Jianzhu University(Natural Science),2011,4:56-60

A Numerical Simulation of Parachute Opening Process Based on ALE Method Y.
Benny and Stein proposed the CFD/MSD (Mass Spring Damper) coupling model[2], which ignores the influence of fabric characteristics, and the research result had no test to verify.
Kim and Peskin[3] used Immersed Boundary (IB) method to simulate the three-dimensional parachute in finite mass situation, but this method is suitable for low Reynolds number simulation and has no structural results, such as fabric stress and so on.
Fig. 1 The finite element model In order to compare the simulation results with the experiment[9], the working conditions of calculation is shown in Table 1.
t=0 s t=0.48 s t=0.81 s t=0.99 s t=1.43 s t=2.23 s Fig.2 Calculation results Comparison of Experiment and Numerical Simulation.

Analysis on Numerical Simulation for Bionic Robot Fish Based on CATIA Dejian Li School of Mechanical Engineering, Baicheng Normal College, Baicheng137000, China bcldj @sohu.com Key Words: Bionic; Tuna; Computational Fluid Dynamics; CATIA Abstract: Based on the problem that there is a relatively small number of analog simulations on swimming of fish a in specific fluid conducted by science researchers, a simulated tuna model is established in this paper, in which CATIA is used to construct the streamline shape of simulated tuna and the method of computational fluid dynamics is utilized to simulate the swimming of tuna in marine environment.
Through several times of comparison and comprehensive consideration, tuna is selected as the object for shape simulation.
Simulation Analysis and Experimental Research on Movements of Biotic Fins[J].
CFD Simulation of Fish-like Body Moving in Viscous Liquid[J].Journal of Bionic Engineering,2006,3(3):147-153 [7] Wojciech Kowalczyk, Antonio Delgado.
Simulation of Fluid Flow in a Channel Induced by Three Types of Fin-Like Motion[J].

Ghodsipour and Sadrameli [11] made an analysis of a rotary air preheater for the flue gas heat recovery and good agreement has been obtained between the simulation results and experimental data.
In this simulation work, mixture multiphase flow model is applied to solve the flow process inside the heater, the continuity equation for the mixture is ∂(rm)∂t+∇×(rmvm)=0
CFD software is applied to simulate the heating process of the air by flue gas in this work.
Simulation results.
Deng, Numerical simulation research on mixing process of steam and crude oil, Energy Education Science and Technology Part A: Energy Science and Research. 32 (2014) 3125-3134.

The measured temperature values are compared with the results obtained from numerical simulation of the dynamic heat transport using non-stationary boundary conditions.
The value of heat flux determined by numerical simulation at the point between the columns is the same as the measured mean value of the local heat flux.
All results of simulation calculations have got sufficient accuracy.
Lausova, Experimental Measurement and Numerical Simulation of Dynamic Thermal Performance of External Timber Frame Wall.
Blejchar, M Bojko, M Kozubkova, CFD simulations of the effect of wind on the spontaneous heating of coal stockpiles, Fuel. 2014, vol. 118, pp. 107-112, ISSN 0016-2361, DOI: 10.1016/j.fuel.2013.10.064.

However, the simulation faces some difficulties.
Usually, the mishandling of grids will lead to the failure of simulation.
The computational accuracy of heat transfer in wall is of great importance to the precision of simulation.
The simulation result The first thermal boundary condition.
[2] Zhousan Cunshang:CFD and building environment design(China Architecture & Building Press, 2007)