Research Activities

Computational Fluid Dynamics

1. Numerical simulation of counter-flow diffusion flame with the detailed chemical reaction mechanism

Combustion simulation of counter-flow diffusion flame reported by Sung et al. [1] was performed based on the unstructured finite volume method with the detail chemical reaction mechanism of GRI-Mech 3.0 [2] (left) and San Diego Mechanism [3] (right). Although temporal change in temperature up to steady state was slightly different, spatial temperature distribution at steady state agreed regardless of the reaction mechanisms.

[1] Sung, C. J. et al., Structural response of counterflow diffusion flames to strain rate variations, Combust. Flame, 102(4), 481–492 (1995)
[2] Gregory P. Smith, David M. Golden, Michael Frenklach, Nigel W. Moriarty, Boris Eiteneer, Mikhail Goldenberg, C. Thomas Bowman, Ronald K. Hanson, Soonho Song, William C. Gardiner, Jr., Vitali V. Lissianski, and Zhiwei Qin http://www.me.berkeley.edu/gri_mech/
[3] "Chemical-Kinetic Mechanisms for Combustion Applications", San Diego Mechanism web page, Mechanical and Aerospace Engineering (Combustion Research), University of California at San Diego (http://combustion.ucsd.edu)

2. Large eddy simulation for turbulent flow of co-axial jet with scalar transport

Large eddy simulation for turbulent flow of co-axial jet with scalar transport [1,2] based on unstructured finite volume method was conducted. Turbulent mixing process and external recirculating zone in co-axial jet were well reproduced.

[1] Johnson, B. V. and Bennett, J. C., Mass and momentum transport experiments with confined coaxial jets, NASA Contractor Rep. NASA, CR-165574, UTRC Rep. R81-915540-9 (1981)
[2] Johnson, B. V. and Bennett, J. C., Statistical characteristics of velocity, concentration, mass transport, and momentum transport for coaxial jet mixing in a confined duct, J. Gas Turbines and Power, 106, 121–127 (1984)

3. Large eddy simulation with flamelet/progress variable approach in piloted methane/air jet flame

Large eddy simulation with the flamelet/progress variable approach which is one of the flamelet approach [1–3] was performed for the piloted methane/air jet flame [4–6] known as Sandia Flame D for model problem. Velocity (left), mixture fraction (center), and temperature (right) fields shows the similar trend as the previous work [7] and describes the jet flame stabilized with the pilot burner. This is one of the results of the international collaboration research with Prof. Malalasekera of Loughborough University in United Kingdom.

[1] Peters, N, Laminar diffusion flamelet models in non-premixed turbulent combustion, Prog. Energy Comb., Sci., 10(3), 319–339 (1984)
[2] Peters, N., Laminar flamelet concepts in turbulent combustion, Proc. Combust. Inst., 21(1), 1231–1250 (1986)
[3] Pierce, C. and Moin, P., Progress-variable approach for large-eddy simulation of non-premixed turbulent combustion, JFM, 504, 73–97 (2004)
[4] Barlow, R. S. and Frank, J. H., Effects of turbulence on species mass fractions in methane/air jet flames, Proc. Combust. Inst. 27, 1087–1095 (1998)
[5] Barlow, R. S. et al., Piloted methane/air jet flames: Scalar structure and transport effects, Combust. Flame, 143, 433–449 (2005)
[6] Schneider, Ch. et al., Flow field measurements of stable and locally extinguishing hydrocarbon-fuelled jet flames, Combust. Flame, 135, 185–190 (2003)
[7] Raman, V. and Pitsch, H, A consistent LES/filtered-density function formulation for the simulation of turbulent flames with detailed chemistry, Proc. Combust. Inst., 31(2), 1711–1719 (2007)

4. Numerical investigation for effect of electric field on breakup of liquid column using the volume of fluid method

Based on the volume of fluid method [1], effect of electric field on breakup of liquid column [2] was numerically investigated. Numerical solutions agreed with experimental results [2] in wide range of Reynolds number (not shown here) and liquid column broke up to different droplets in diameter when electric voltage was not applied to the nozzle (top in movie). On the other hand, diameter of droplets generated became uniform with an increase in magnitude of electric voltage (from top to bottom in movie).

[1] C. W. Hirt and B. D. Nichols, Volume of fluid (VOF) method for the dynamics of free boundaries, J. Comput. Phys., 39, 201–225 (1981)
[2] M. Hozawa, T. Tadaki and S. Maeda, The Size of Drops Formed from Single Nozzles in Liquid-Liquid Systems, Chemical engineering, 33, 893–898 (1969)

5. CO2 gasification reaction simulation of highly-resolved coke model

Actual coke was imaged by using the microfocus X-ray CT (Computer Tomography) system and its structure was successfully reproduced with over 0.2 billion voxels. Further, CO2 gasification with mass transfer was numerically analyzed under low- (left) and high- (right) temperature conditions, predicting the different coke reaction processes for different conditions.

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