A filtered mass density function approach for modeling separated two-phase flows for LES II: Simulation of a droplet laden temporally developing mixing layer

2008 ◽  
Vol 34 (8) ◽  
pp. 748-766 ◽  
Author(s):  
M.D. Carrara ◽  
P.E. DesJardin
Keyword(s):  
Density Function ◽  
Mass Density ◽  
Mixing Layer ◽  
Function Approach ◽  
Two Phase Flows ◽  
Two Phase ◽  
Filtered Mass Density Function

Two-phase filtered mass density function for LES of turbulent reacting flows

2014 ◽  
Vol 760 ◽  
pp. 243-277 ◽  
Author(s):  
Z. Li ◽  
A. Banaeizadeh ◽  
F. A. Jaberi
Keyword(s):  
Density Function ◽  
Stokes Equations ◽  
Liquid Droplet ◽  
Mass Density ◽  
Mixing Layer ◽  
Reacting Flows ◽  
Navier Stokes ◽  
Turbulent Reacting Flows ◽  
Two Phase ◽  
Filtered Mass Density Function

AbstractThis paper describes a new computational model developed based on the filtered mass density function (FMDF) for large-eddy simulation (LES) of two-phase turbulent reacting flows. The model is implemented with a unique Lagrangian–Eulerian–Lagrangian computational methodology. In this methodology, the resolved carrier gas velocity field is obtained by solving the filtered form of the compressible Navier–Stokes equations with high-order finite difference (FD) schemes. The gas scalar (temperature and species mass fractions) field and the liquid (droplet) phase are both obtained by Lagrangian methods. The two-way interactions between the phases and all the Eulerian and Lagrangian fields are included in the new two-phase LES/FMDF methodology. The results generated by LES/FMDF are compared with direct numerical simulation (DNS) data for a spatially developing non-reacting and reacting evaporating mixing layer. Results for two more complex and practical flows (a dump combustor and a double-swirl burner) are also considered. For all flows, it is shown that the two-phase LES/FMDF results are consistent and accurate.

Instability Modes of Two-Phase Flows in a Mixing-Layer Microdevice

2001 ◽  
Author(s):  
Tak For Yu ◽  
Sylvanus Yuk Kwan Lee ◽  
Yitshak Zohar ◽  
Man Wong
Keyword(s):  
Gas Flow ◽  
Mixing Layer ◽  
Fluid Flows ◽  
Two Phase Flows ◽  
Two Phase ◽  
Pressure Distributions ◽  
Instability Modes ◽  
In Series ◽  
Mass Flow Rates ◽  
Flow Through

Abstract Extensive development of biomedical and chemical analytic microdevices involves microscale fluid flows. Merging of fluid streams is expected to be a key feature in such devices. An integrated microsystem consisting of merging microchannels and distributed pressure microsensors has been designed and characterized to study this phenomenon on a microscale. The two narrow, uniform and identical channels merged smoothly into a wide, straight and uniform channel downstream of a splitter plate. All of the devices were fabricated using standard micromachining techniques. Mass flow rates and pressure distributions were measured for single-phase gas flow in order to characterize the device. The experimental results indicated that the flow developed when both inlets were connected together to the gas source could be modeled as gas flow through a straight and uniform microchannel. The flow through a single branch while the other was blocked, however, could be modeled as gas flow through a pair of microchannels in series. Flow visualizations of two-phase flows have been conducted when driving liquid and gas through the inlet channels. Several instability modes of the gas/liquid interface have been observed as a function of the pressure difference between the two streams at the merging location.

A Hybrid Large Eddy Simulation/Filtered Mass Density Function for the Calculation of Strongly Radiating Turbulent Flames

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
Abhilash J. Chandy ◽  
David J. Glaze ◽  
Steven H. Frankel
Keyword(s):  
Density Function ◽  
Soot Formation ◽  
Mass Density ◽  
Combustion Products ◽  
Turbulent Flames ◽  
Finite Rate ◽  
Combustion Chemistry ◽  
Jet Flame ◽  
Large Eddy ◽  
Filtered Mass Density Function

Due to the complex nonlinear coupling of turbulent flow, finite-rate combustion chemistry and thermal radiation from combustion products and soot, modeling, and/or simulation of practical combustors, or even laboratory flames undergoing strong soot formation, remain elusive. Methods based on the determination of the probability density function of the joint thermochemical scalar variables offer a promising approach for handling turbulence-chemistry-radiation interactions in flames. Over the past decade, the development and application of the filtered mass density function (FMDF) approach in the context of large eddy simulations (LES) of turbulent flames have gained considerable ground. The work described here represents the first application of the LES/FMDF approach to flames involving soot formation and luminous radiation. The initial focus here is on the use of a flamelet soot model in an idealized strongly radiating turbulent jet flame, which serves to detail the formulation, highlight the importance of turbulence-radiation interactions, and pave the way for the inclusion of a soot transport and finite-rate kinetics model allowing for quantitative comparisons to laboratory scale sooting flames in the near future.

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