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Comparing Simulation for Turbulent Dispersion and Coalescence of Droplets within a Spray with two Models Shaoyun Deng1, a 1Xinjiang Applicative Polytechnic, Kuitun, 833200, China anhrisydeng@163.com Keywords: Model, Simulate, Turbulent Dispersion, Coalescence, Spray.
The ultimate aim of this paper is to develop a validated CFD model to predict the extent of particle agglomeration within a spray dryer, and the flow patterns and drying of particles, and to use this predictive tool to design more efficient spray dryers that produce higher throughputs.
Methods It is the aim of the author to address this gap in fundamental understanding and to develop a Computational Fluid Dynamics (CFD) model to predict the turbulent dispersion and coalescence of droplets within a spray.
A commercially-available Computational Fluid Dynamic (CFD) program called ANSYS CFX4 is used to solve the equation sets for the Eulerian and Lagrangian approaches described above.
All subsequent simulations involving different droplet flows, gas flows or droplet size distributions adopt the same values for these parameters.

This paper analyzes the simulation results obtained by using FLUENT 6.1, simulation being carried out on supersonic inlet.
Overseas, the computation results from the CFD programs are usually compared with that from the experiment by various research institutions, so to confirm the accuracy of numerical methods and turbulence models [2].
Figure 3 illustrates the calculation domains used in the numerical simulation.
These two functions are employed by the two k- models in the simulation computation.
In this paper, commercial CFD program FLUENT was used and its prediction accuracy verified.

Simulation Grids.
The simulation grid is created using ANSYS ICEM CFD and it is shown in Fig. 2.
On the accuracy of CFD simulations of cross-ventilation flows for a generic isolated building: comparison of RANS, LES and experiments.
"PIV verification of greenhouse ventilation air flows to evaluate CFD accuracy."
"Cross-ventilation in a generic isolated building equipped with louvers: Wind-tunnel experiments and CFD simulations."

The full flow field model of a widely used multi-blade centrifugal was built, using the CFD method, the steady and unsteady numerical simulation of the inner flow in the fan at different working conditions are presented.
The numerical simulation results were validated by contrasting to the experiment results.
The quality of the grids is one of the key factors determining performance of numerical simulation [3].
In order to make sure the stability of the unsteady simulation, the steady numerical simulation is done at first based on the same mesh subdivision, after that, the results of the steady simulation are used as the beginning field to proceed with the whole passage unsteady simulation inside the multi-blade centrifugal fan.
Simulation results and analysis Comparison between simulation and experiment.

On the numerical simulation side, researchers focused on simulating the temperature, chemical species concentration, flow field and formation of NOx on the internal reactor by using CFD methods.
So results of numerical simulation are very similar and provide credible results with pulverized coal MILD combustion.
All the numerical simulations predict a cold zone correspondent to the lateral jet.
So EDC have advantages on numerical simulation of the combustible particle coal MILD combustion.
Influence of turbulence-chemical interaction on CFD pulverized coal MILD combustion modeling [J].

Guobiao Cai et al. [7] investigated an optimization approach using CFD for performance prediction and optimization of the nozzle shape.
It was shown that the proposed extension was capable to be implemented in commercial computational fluid dynamics (CFD) programs.
He successfully used the CFD software package Fluent with Reynolds-Averaged Navier-Stokes (RANS) equations for his investigation.
[9] Kercher, D.M., “A Film-Cooling CFD Bibliography: 1971-1996”, Int.
S., (2005) "The Modelling of Film Cooling - Part 11: Model for use in 3D CFD."

The paper is devoted to selection of a numerical approach for simulation of fluid flow in a torque flow pump of “Turo” type and its influence on simulation results.
At present numerical simulation of fluid flow in pumps is used with modern CFD-codes.
Numerical simulation allows costs decrease in dozen times.
However CFD-codes turbulence models and specified initial conditions, used for centrifugal pumps, don’t show adequate flow pattern for vortex pumps because of their flow structure differences.
Kochevsky, Possibilities for simulation of fluid flows using the modern CFD software tools, Ploiesti (Romania), (2005) 64-79

Therefore, this study is focused on developing an internal nozzle by analysed the characteristics of spray using ANSYS-CFX simulation with RNG k-epsilon turbulence model.
The simulation are based on plain nozzle design where the geometry and physical properties were carefully scale based on actual condition.
This study focused on investigating the internal nozzle geometries of the aerosol spray by conductly CFD modelling.
Numerical modelling The flow inside the nozzle geometry is investigated through numerical simulation based on Computational Fluid Dynamics (CFD).
The equations are solved using computer simulation software, ANSYS CFX (Version 14.0).

A three-dimensional CFD model is applied to simulate the flow patterns and particle concentrations in a street canyon under different aspect ratios and ground thermal conditions.
Numerical Simulation Procedure Computational Domains, Grids and Solution Method.
The resulting unstructured grid number of 2,700,000 is used for all the simulations.
The three-dimensional Navier - Stokes equations and the continuity equation are solved using the commercial CFD code Fluent 6.3.2.
Wong, et al.: Building Simulation Vol. 5 (2012), p. 359 [16] R.

Spalart-Allmaras turbulence model was used in the present simulation.To speed up the convergence, a full multigrid technique was applied.
Due to the limitation of the experiment conditions, test data is only available in a much narrower range compared to the CFD result.
The difference is maily due to volute isn't included in the simulation model and loss efficiency in volute is ignored.
Temperature distribution and pressure loading were obtained from steady CFD analysis by transferring the data from CFD domain to FEA domain.The results show that centrifugal force caused by turbine rotation had significant impact on wheel's natural frequency.
[7] Simulation of the Effects of Shock Wave Passing on a Turbine Rotor Blade[J].