Numerical Simulation for Free Turbulent Reacting Flow by Particle Method

2003 ◽  
Author(s):  
Tomomi Uchiyama ◽  
Naohiro Otsuki
Keyword(s):  
Numerical Simulation ◽  
Chemical Reaction ◽  
Mixing Layer ◽  
Particle Method ◽  
Reacting Flows ◽  
Single Step ◽  
Reacting Flow ◽  
Turbulent Reacting Flows ◽  
Plane Mixing Layer ◽  
Irreversible Chemical Reaction

This paper presents a particle method for free turbulent reacting flows. The vorticity and concentration fields are discretized into the vortex and concentration elements, respectively, and the behavior of the elements is calculated with the Lagrangian method. The chemical reaction is estimated through the Lagrangian calculation for the strength of concentration element. The particle method is applied to simulate a plane mixing layer with a single-step and irreversible chemical reaction of non-premixed reactants so as to discuss the applicability.

The Quenching Characteristics of Gas Deflagration Flame in Narrow Channel

2012 ◽  
Vol 455-456 ◽  
pp. 289-295 ◽  
Author(s):  
Xiao Ping Wen ◽  
Ming Ma ◽  
Wen Ce Sun ◽  
Zhi Chao Liu
Keyword(s):  
Numerical Simulation ◽  
Chemical Reaction ◽  
Fire Retardant ◽  
Narrow Channel ◽  
Single Step ◽  
Combustion Model ◽  
Flame Velocity ◽  
Irreversible Chemical Reaction ◽  
Initial Flame ◽  
Quenching Distance

In order to obtain fire retardant mechanism of gas deflagration flame in narrow channel, a numerical simulation adopting PISO algorithm and self-adapted grids was presented based on the single-step irreversible chemical reaction and the combustion model of EBU-Arrhenius. The numerical dates are well compatible with experimental results and indicate that the initial flame velocity and gap of channel are directly responsible for the quenching distance. And the smaller the flame velocity or gap of channel, the shorter the quenching distance, which means simpler to quench gas deflagration flame.

Reaction in a scalar mixing layer

1991 ◽  
Vol 233 ◽  
pp. 211-242 ◽  
Author(s):  
R. W. Bilger ◽  
L. R. Saetran ◽  
L. V. Krishnamoorthy
Keyword(s):  
Chemical Reaction ◽  
Mixing Layer ◽  
Reacting Flow ◽  
Scalar Mixing ◽  
Scalar Theory ◽  
Thermal Mixing ◽  
Fast Chemistry ◽  
The Mean ◽  
Reactive Scalars ◽  
Made In

Reaction in a scalar mixing layer in grid-generated turbulence is studied experimentally by doping half of the flow with nitric oxide and the other half with ozone. The flow conditions and concentrations are such that the chemical reaction is passive and the flow and chemical timescales are of the same order. Conserved scalar theory for such flows is outlined and further developed; it is used as a basis for presentation of the experimental results. Continuous measurements of concentration are limited in their spatial and temporal resolution but capture sufficient of their spectra for adequate second-order correlations to be made. Two components of velocity have been measured simultaneously with hot-wire anemometry. Conserved scalar mixing results, deduced from reacting and non-reacting measurements of concentration, show the independence of concentration level and concentration ratio expected for passive reacting flow. The results are subject to several limitations due to the necessary experimental compromises, but they agree generally with measurements made in thermal mixing layers. Reactive scalar statistics are consistent with the realizability constraints obtainable from conserved scalar theory where such constraints apply, and otherwise are generally found to lie between the conserved scalar theory limits for frozen and very fast chemistry. It is suggested that Toor's (1969) closure for the mean chemical reaction rate could be improved by interpolating between the frozen and equilibrium values for the covariance. The turbulent fluxes of the reactive scalars are found to approximately obey the gradient model but the value of the diffusivity is found to depend on the Damköhler number.

Diffusion and Mixing in Microchannel Analyzed by the Luminol Chemiluminescence

2013 ◽  
Author(s):  
Ruru Matsuo ◽  
Ryosuke Matsumoto
Keyword(s):  
Numerical Simulation ◽  
Chemical Reaction ◽  
Reaction Rate ◽  
Mixing Layer ◽  
Fluorescence Technique ◽  
Chemiluminescence Intensity ◽  
Luminol Chemiluminescence ◽  
Chemical Reaction Rate ◽  
Pdms Chip ◽  
Reaction Profile

This study focused on the diffusion and mixing phenomena investigated by using luminol chemiluminescence (CL) to estimate the local chemical reaction rate in the T-junction microchannel. Generally, the degree of mixing in microchannel is calculated by the deviation of the obtained concentration profiles from the uniform concentration profile by using fluorescence technique. Thus, the degree of mixing is a macroscopic estimate for the whole microchannel, which is inappropriate for understanding the diffusion and mixing phenomena in the mixing layer. In this study, the luminol CL reaction is applied to visualize the local chemical reaction and to estimate the local diffusion and mixing phenomena at an interface between two liquids in microchannel. Luminol emits blue chemiluminescence when it reacts with the hydrogen peroxide at the mixing layer. Experiments were carried out on the T-junction microchannel with 200 microns in width and 50 microns in depth casted in the PDMS chip. The chemiluminescence intensity profiles clearly show the mixing layer at an interface between two liquids. The experimental results are compared with the results of numerical simulation that involves solving the mass transport equations including the chemical reaction term. By calibrating CL intensity to the chemical reaction rate estimated by the numerical simulation, the local chemical reaction profile can be quantitatively estimated from the CL intensity profile.

Direct numerical simulation of a particle-laden mixing layer with a chemical reaction

2005 ◽  
Vol 31 (7) ◽  
pp. 843-866 ◽  
Author(s):  
Takenobu Michioka ◽  
Ryoichi Kurose ◽  
Kouichi Sada ◽  
Hisao Makino
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Chemical Reaction ◽  
Mixing Layer
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