Large-Eddy Simulation of Turbulent Flow Through Small Gage Gas Appliance Orifices

2009 ◽  
Author(s):  
Emad Y. Tanbour ◽  
Ramin K. Rahmani ◽  
Anahita Ayasoufi
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Compressible Flows ◽  
Incompressible Flows ◽  
Large Diameter ◽  
Flow Characteristics ◽  
Eddy Simulation ◽  
Discrete Equations ◽  
Large Eddy ◽  
Flow Through

Small orifices are widely used in different industries including gas appliances. Although characteristics of orifices such as their coefficient of discharge have been subject of interest for the past several decades, most of the previous studies focus on relatively high Reynolds number flow through relatively large diameter orifices. Moreover, the majority of previous work has focused on incompressible flows. This study focuses on the flow of different compressible gaseous fluids inside small orifices ranging from 1.3 mm to 2.1 mm hydraulic diameters for flow Re numbers of ∼8000 to ∼26000. Large-Eddy Simulation for turbulent flow is employed to solve the second-order discrete equations for compressible and incompressible flows in gas appliance orifices to predict the flow characteristics for relatively low-Re compressible flows in orifices widely used in gas appliance industry. The impacts of fluid material, the orifice hydraulic diameter, and the orifice profile on the characteristics of orifice are studied.

Effect of Pulsation and Acceleration of Liquid Metal Turbulent Flow Through a Horizontal Channel by Large Eddy Simulation

2020 ◽  
Vol 6 (4) ◽  
Author(s):  
N. Satish ◽  
K. Venkatasubbaiah
Keyword(s):  
Heat Transfer ◽  
Liquid Metal ◽  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Horizontal Channel ◽  
Two Dimensional ◽  
Unsteady State ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Flow Through

Abstract Pulsation and acceleration of liquid metal turbulent flow through a horizontal channel has been numerically studied using a large eddy simulation (LES) technique. The effect of inlet pulsation and acceleration on flow and heat transfer characteristics of low Prandtl number liquid metal flow have been investigated and reported here. Results have been presented for different Reynolds numbers, different amplitudes, and frequency with constant bottom wall thickness. The flow field is modeled as unsteady-state two-dimensional incompressible turbulent-forced convection flow. Turbulence is modeled using a LES technique. Two-dimensional unsteady-state heat conduction equation is solved to know the temperature distribution in the solid region. Finite difference method solver is developed for solving the governing equations using sixth-order accuracy of compact schemes. The average Nusselt number shows cyclic variation with respect to time in pulsation flows. The enhancement of heat transfer with pulsation at amplitude 0.4 and frequency 100 Hz is 6.51%. The rate of heat transfer increases in pulsation flow compared to quasi-steady flow. The inlet acceleration shows a significant effect on flow characteristics. The present results are compared with direct numerical simulation (DNS) results available in the literature and matching well with DNS data.

Development of a Spectral Element DNS/LES Method for Turbulent Flow Simulations

2007 ◽  
Author(s):  
Xu Zhang ◽  
Dan Stanescu ◽  
Jonathan W. Naughton
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Turbulent Flows ◽  
Compressible Flows ◽  
Time Integration ◽  
Flow Simulation ◽  
Spectral Element ◽  
Order Of Accuracy ◽  
Eddy Simulation ◽  
Large Eddy

This paper describes a turbulent flow simulation method, which is based on combination of spectral element and large eddy simulation (LES) technique. The robust, high-order discontinuous Galerkin (DG) spectral element method for large-eddy simulation of compressible flows allows for arbitrary order of accuracy and has excellent stability properties. A local spectral discretization in terms of Legendre polynomials is used on each element of the (possibly unstructured) mesh, which allows for high-accurate simulations of turbulent flows. Discontinuities across the interfaces of the elements are resolved using a Riemann solver. An isoparametric representation of the geometry is implemented, with boundaries of the domain discretized to the same order of accuracy as the solution, and explicit low-storage Runge-Kutta methods are used for time integration. Large eddy simulation has proven to be a valuable technique for the calculation of turbulent flows. An element based filtering technique is used in conjunction with the standard Smagorinsky eddy viscosity model to estimate the effect of sub-grid scales stresses in this paper. The recently developed nonlinear model [1] will also be added in the future. The final aim of this project is to use the LES methodology in swirling jet flow simulation. As a first step towards these simulations, simulations of compressible turbulent mixing layer and back-facing step are also performed to evaluate the robust method. Initial results based on both DNS and large eddy simulations are presented in this paper. Future work will be to validate the code.

Large Eddy Simulation of Turbulent Flow Through Submerged Vegetation

2009 ◽  
Vol 78 (3) ◽  
pp. 347-365 ◽  
Author(s):  
Thorsten Stoesser ◽  
Guillermo Palau Salvador ◽  
Wolfgang Rodi ◽  
Panayiotis Diplas
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Submerged Vegetation ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Flow Through
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