Deposition of Small Particles From Turbulent Flows

2003 ◽  
Author(s):  
Z. Wu ◽  
J. B. Young
Keyword(s):  
Turbulent Flow ◽  
Turbulent Flows ◽  
Channel Flow ◽  
Gas Turbines ◽  
Particle Deposition ◽  
Numerical Study ◽  
Turbulent Channel Flow ◽  
Brownian Diffusion ◽  
Small Particles ◽  
Two Fluid

This paper deals with particle deposition onto solid walls from turbulent flows. The aim of the study is to model particle deposition in industrial flows, such as the one in gas turbines. The numerical study has been carried out with a two fluid approach. The possible contribution to the deposition from Brownian diffusion, turbulent diffusion and shear-induced lift force are considered in the study. Three types of turbulent two-phase flows have been studied: turbulent channel flow, turbulent flow in a bent duct and turbulent flow in a turbine blade cascade. In the turbulent channel flow case, the numerical results from a two-dimensional code show good agreement with numerical and experimental results from other resources. Deposition problem in a bent duct flow is introduced to study the effect of curvature. Finally, the deposition of small particles on a cascade of turbine blades is simulated. The results show that the current two fluid models are capable of predicting particle deposition rates in complex industrial flows.

Direct numerical simulation of turbulent channel flow up to

2015 ◽  
Vol 774 ◽  
pp. 395-415 ◽  
Author(s):  
Myoungkyu Lee ◽  
Robert D. Moser
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Channel Flow ◽  
Turbulent Channel Flow ◽  
Streamwise Velocity ◽  
Mean Velocity ◽  
Layer Structures ◽  
High Reynolds

A direct numerical simulation of incompressible channel flow at a friction Reynolds number ($\mathit{Re}_{{\it\tau}}$) of 5186 has been performed, and the flow exhibits a number of the characteristics of high-Reynolds-number wall-bounded turbulent flows. For example, a region where the mean velocity has a logarithmic variation is observed, with von Kármán constant ${\it\kappa}=0.384\pm 0.004$. There is also a logarithmic dependence of the variance of the spanwise velocity component, though not the streamwise component. A distinct separation of scales exists between the large outer-layer structures and small inner-layer structures. At intermediate distances from the wall, the one-dimensional spectrum of the streamwise velocity fluctuation in both the streamwise and spanwise directions exhibits $k^{-1}$ dependence over a short range in wavenumber $(k)$. Further, consistent with previous experimental observations, when these spectra are multiplied by $k$ (premultiplied spectra), they have a bimodal structure with local peaks located at wavenumbers on either side of the $k^{-1}$ range.

The Reynold’s Number Effect in High Swirling Flow in Unconfined Burner

2015 ◽  
Vol 72 (4) ◽  
Author(s):  
Norwazan A. R. ◽  
Mohammad Nazri Mohd. Jaafar
Keyword(s):  
Turbulent Flows ◽  
Gas Turbines ◽  
Swirling Flow ◽  
Numerical Study ◽  
Isothermal Condition ◽  
Navier Stokes ◽  
Reacting Flow ◽  
Ansys Fluent ◽  
Inlet Velocity ◽  
Burner Exit

The numerical simulations of swirling turbulent flows in isothermal condition in combustion chamber of burner were investigated. The aim is to characterize the main flow structures and turbulence in a combustor that is relevant to gas turbines. Isothermal flows with different inlet flow velocities were considered to demonstrate the effect of radial velocity. The inlet velocity, Uo is varied from 30 m/s to 60 m/s represent a high Reynolds number up to 3.00 X 105. The swirler was located at the upstream of combustor with the swirl number of 0.895. A numerical study of non-reacting flow in the burner region was performed using ANSYS Fluent. The Reynolds–Averaged Navier–Stokes (RANS) approach method was applied with the standard k-ɛ turbulence equations. The various velocity profiles were different after undergoing the different inlet velocity up to the burner exit. The results of velocity profile showed that the high U0 give better swirling flow patterns.

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