scholarly journals Monte Carlo simulation for soot dynamics

2012 ◽  
Vol 16 (5) ◽  
pp. 1391-1394 ◽  
Author(s):  
Kun Zhou
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Phase ◽  
Volume Fraction ◽  
Soot Formation ◽  
Bimodal Distribution ◽  
Number Density ◽  
Stochastic Error

A new Monte Carlo method termed Comb-like frame Monte Carlo is developed to simulate the soot dynamics. Detailed stochastic error analysis is provided. Comb-like frame Monte Carlo is coupled with the gas phase solver Chemkin II to simulate soot formation in a 1-D premixed burner stabilized flame. The simulated soot number density, volume fraction, and particle size distribution all agree well with the measurement available in literature. The origin of the bimodal distribution of particle size distribution is revealed with quantitative proof.

Lagrangian particle tracking with new weighted fraction Monte Carlo method for studying the soot particle size distributions in premixed flames

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiao Jiang ◽  
Tat Leung Chan
Keyword(s):  
Particle Size ◽  
Monte Carlo ◽  
Soot Formation ◽  
Particle Size Distributions ◽  
Lagrangian Particle ◽  
Content Type ◽  
Soot Particles ◽  
Stochastic Error ◽  
Formation And Evolution ◽  
Size Interval

Purpose The purpose of this paper is to study the soot formation and evolution by using this newly developed Lagrangian particle tracking with weighted fraction Monte Carlo (LPT-WFMC) method. Design/methodology/approach The weighted soot particles are used in this MC framework and is tracked using Lagrangian approach. A detailed soot model based on the LPT-WFMC method is used to study the soot formation and evolution in ethylene laminar premixed flames. Findings The LPT-WFMC method is validated by both experimental and numerical results of the direct simulation Monte Carlo (DSMC) and Multi-Monte Carlo (MMC) methods. Compared with DSMC and MMC methods, the stochastic error analysis shows this new LPT-WFMC method could further extend the particle size distributions (PSDs) and improve the accuracy for predicting soot PSDs at larger particle size regime. Originality/value Compared with conventional weighted particle schemes, the weight distributions in LPT-WFMC method are adjustable by adopting different fraction functions. As a result, the number of numerical soot particles in each size interval could be also adjustable. The stochastic error of PSDs in larger particle size regime can also be minimized by increasing the number of numerical soot particles at larger size interval.

A Noise Removal Method in Measurement of Particle Size Distribution by the Shifrin-Transform

2014 ◽  
Vol 1058 ◽  
pp. 93-96 ◽  
Author(s):  
Yue Han ◽  
Zong Ling Yang ◽  
Yin Nan Yuan ◽  
Bing Dai
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Large Angle ◽  
Bimodal Distribution ◽  
Noise Removal ◽  
Good Effect ◽  
Actual Measurement ◽  
Original Distribution ◽  
Angle Data

In actual measurement of particle size distribution by the Shifrin-transform, many noises are easily misread as distribution peaks, and bring serious difficulties to the measurement. The purpose of this paper is to find a method of removing these noises to improve existing technology. By analyzing the source of these noises, we found these noises are mainly caused by the serious large angle data loss, and then propose a compensation function in the Shifrin-transform to remove these noises. Simulations explain that the method has a good effect. The method is actually tested for the sample particles of the unimodal and bimodal distribution by experiments. The result shows that the noises disappear but the number and location of original distribution peaks aren’t affected after using the compensate function. So this method can remove effectively noises and restore accurately original distribution in the measurement.

Hall-Petch Relation in a Spheroidized Carbon Steel with Emphasis on the Effect of Intergranular Particles

2016 ◽  
Vol 848 ◽  
pp. 593-606 ◽  
Author(s):  
Jiang Li Ning ◽  
Yun Li Feng ◽  
Jie Li
Keyword(s):  
Particle Size ◽  
Carbon Steel ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Volume Fraction ◽  
Quantitative Relationship ◽  
Medium Carbon Steel ◽  
Orientation Factor ◽  
Triple Junctions ◽  
Petch Relation

The Hall-Petch relation in a spheroidized steel with bimodal cementite particle size distribution has been investigated in this study, with an emphasis on considering the effect of the large particles at ferrite grain boundaries and triple junctions. A medium carbon steel was processed by variable thermomechanical procedures to achieve spheroidized structures with different combinations of microstructrual parameters, but all exhibiting a bimodal particle size distribution, in which large intergranular particles and small intragranular particles coexisted in the ferrite matrix. A quantitative relationship between the Hall-Petch parameter ky and the volume fraction of the intergranular cementite particles is presented, by considering a composite model. The contribution of the large intergranular particles to grain boundary strengthening wa substantiated by the increment of the ky parameter, since the average orientation factor of the composite, is increased. After correction of the ky parameters based on the constants from literatures, the predicted stresses show good agreement with the experimental stresses. A linear fit between the experimental stresses and the reciprocal square root of grain sizes is performed, the slope constant ky derived agrees to within 11 % of the corrected ky parameters based on the constants from literatures.

Simulating Phase Coarsening of Ultra-High Volume Fractions

2010 ◽  
Vol 638-642 ◽  
pp. 3925-3930 ◽  
Author(s):  
K.G. Wang ◽  
X. Ding
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Volume Fraction ◽  
High Volume ◽  
Triple Junctions ◽  
Ginzburg Landau ◽  
Volume Fractions ◽  
Phase Coarsening ◽  
Kinetics Of

The dynamics of phase coarsening at ultra-high volume fractions is studied based on two-dimensional phase-field simulations by numerically solving the time-dependent Ginzburg-Landau and Cahn-Hilliard equations. The kinetics of phase coarsening at ultra-high volume fractions is discovered. The microstructural evolutions for different ultra-high volume fractions are shown. The scaled particle size distribution as functions of the dispersoid volume fraction is presented. The particle size distribution derived from our simulation at ultra-high volume fractions is close to Wagner's particle size distribution due to interface-controlled ripening rather than Hillert's grain size distribution in grain growth. The changes of shapes of particles are carefully studied with increase of volume fraction. It is found that more liquid-filled triple junctions are formed as a result of particle shape accommodation with increase of volume fraction at the regime of ultra-high volume fraction.

scholarly journals NAT-rock formation by mother clouds: a microphysical model study

2002 ◽  
Vol 2 (2) ◽  
pp. 93-98 ◽  
Author(s):  
S. Fueglistaler ◽  
B.P. Luo ◽  
C. Voigt ◽  
K.S. Carslaw ◽  
Th. Peter
Keyword(s):  
Particle Size ◽  
Nitric Acid ◽  
Particle Size Distribution ◽  
Gas Phase ◽  
Cloud Base ◽  
Number Density ◽  
Monodisperse Particle ◽  
Model Study ◽  
Rock Mechanism ◽  
Stratospheric Clouds

Abstract. Polar stratospheric clouds (PSCs) of type 1a or 1a-enh containing high number densities of nitric acid trihydrate (NAT) particles, can act as mother clouds for extremely large NAT particles, termed NAT-rocks, provided the air below the clouds is supersaturated with respect to NAT. Individual NAT particles at the cloud base fall into undepleted gas phase and rapidly accelerate due to a positive feedback between their growth and sedimentation. The resulting reduction in number density is further enhanced by the strong HNO3 depletion within a thin layer below the mother cloud, which delays subsequent particles. This paper introduces the basic microphysical principles behind this mother cloud/NAT-rock mechanism, which produces 10-4 cm-3 NAT-rocks with radii around 10 mm some kilometers below the mother cloud. The mechanism does not require selective nucleation and works even for a monodisperse particle size distribution in the mother cloud.

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