Homogeneous nucleation of carbon dioxide by molecular simulation - - PowerPoint PPT Presentation

▶
homogeneous nucleation of carbon dioxide by molecular
SMART_READER_LITE
LIVE PREVIEW

Homogeneous nucleation of carbon dioxide by molecular simulation - - PowerPoint PPT Presentation

Jan 19, 2024 135 likes •305 views

Laboratory of Engineering Thermodynamics (LTD) Prof. Dr.-Ing. H. Hasse Homogeneous nucleation of carbon dioxide by molecular simulation Martin Horsch, Kai Langenbach, Katrin Stbener, Stephan Werth, Zengyong Lin, Thorsten Windmann, Jadran

slide-1
SLIDE 1

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

Homogeneous nucleation of carbon dioxide by molecular simulation

Martin Horsch, Kai Langenbach, Katrin Stöbener, Stephan Werth, Zengyong Lin, Thorsten Windmann, Jadran Vrabec, Hans Hasse Laboratory of Engineering Thermodynamics, University of Kaiserslautern Thermodynamics and Energy Technology, University of Paderborn

  • XIX. Symposium on Thermophysical Properties

Boulder, Colorado, 25th June 2015

slide-2
SLIDE 2

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

2

Molecular modelling of carbon dioxide

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Multicriteria optimization requires characterizing a whole class of models. CO2 (Vrabec et al.) CO2 (Merker et al.) Comparison of literature models density [mol / l] 10 20 temperature [K] 220 240 260 280 300

Merker et al. (2010), JCP 132: 234512.

15 25 5

Merker et al. Vrabec et al. Zhang and Duan Möller and Fischer Harris and Yung

slide-3
SLIDE 3

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

3

Molecular modelling of carbon dioxide

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Multicriteria optimization requires massively-parallel molecular modelling. Pareto set for 2CLJQ models

2CLJQ model by Vrabec et al.

Comparison of literature models density [mol / l] 10 20 temperature [K] 220 240 260 280 300

Merker et al. (2010), JCP 132: 234512.

15 25 5

Merker et al. Vrabec et al. Zhang and Duan Möller and Fischer Harris and Yung

slide-4
SLIDE 4

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

4

Massively-parallel MD on hermit (Stuttgart)

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

large systems “1”: molecular dynamics http://www.ls1-mardyn.de/

CO2 (T = 280 K and ρ = 17.2 mol/l) 100 000 000 interaction sites, 110 592 cores

slide-5
SLIDE 5

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

5

Scale-up to the entire hermit cluster for canonical simulation

  • f cavitation in carbon dioxide.

Evaluation of local density at 180 x 180 x 180 grid points: Liquid phase detected for more than 5 neighbours within a radius

  • f 6.9 Å around the grid point.

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

CO2 (T = 280 K and ρ = 17.2 mol/l) 100 000 000 interaction sites, 110 592 cores

≤ 5 ?

(6 mol/l)

Massively-parallel MD: Cavitation

slide-6
SLIDE 6

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

6

Cavitation in a subsaturated liquid

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Yasuoka-Matsumoto method: Count nuclei exceeding a threshold size ℓ. ℓ = 18 nm3 ℓ = 36 nm3 ℓ = 270 nm3 Three consecutive regimes:

  • relaxation (equilibration)
  • homogeneous cavitation
  • growth and aggregation

N = 2.5 x 107, V = 2.41 x 10-21 m3, T = 280 K

slide-7
SLIDE 7

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

7

Cavitation in a subsaturated liquid

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Yasuoka-Matsumoto method: Count nuclei exceeding a threshold size ℓ. ℓ = 18 nm3 ℓ = 36 nm3 ℓ = 270 nm3 Classical nucleation theory predicts critical cavity sizes from 10 to 30 nm3.

N = 2.5 x 107, V = 2.41 x 10-21 m3, T = 280 K

C N T

slide-8
SLIDE 8

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

8

Cavitation rates from simulation and CNT

Cavities with a volume greater than 250 nm3 are certainly supercritical.

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

C N T ℓ ≥ 250 nm3 T = 280 K For cavitation at high temperatures, CNT is a good approximation. carbon dioxide (3CLJQ)

Diemand et al. (2014), PRE 90: 052407.

L J a n d s i m i l a r 0.4 0.6 0.8 1 T / Tc J = JCNT 100 1020 1010 J / JCNT this work nucleation rate x m3s

slide-9
SLIDE 9

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

9

Nucleation in supersaturated vapours

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

ℓ = 7 5 m

  • l

e c u l e s 2CLJQ Cluster criterion: Stillinger type, single neighbour within radius 1.5 σ + L/4, i.e. 5.1 Å. Critical size predicted by CNT in region of interest: 40 to 60 molecules.

slide-10
SLIDE 10

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

Dichte / Sättigungsdichte 1 2 3 4 Nukleationsrate in m

  • 3s
  • 1

1030 1031 1032 1033 1034 228,4 K 238,4 K 250,2 K 269 K CO2

10

Nucleation in supersaturated vapours

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

supersaturation (in terms of density) nucleation rate / m-3s-1 CNT (nonisothermal) ℓ = 50 molecules ℓ = 75 molecules ℓ = 250 molecules 2CLJQ Cluster criterion: Stillinger type, single neighbour within radius 1.5 σ + L/4, i.e. 5.1 Å.

slide-11
SLIDE 11

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

11

The carrier gas effect on nucleation

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Scenario:

  • Vapour contains k components
  • Liquid phase approximately pure
  • k – 1 components: Carrier gas

Carrier gas effect (Wedekind et al.):

  • Thermalization → J increases
  • Greater pressure → J decreases

Wedekind et al.

slide-12
SLIDE 12

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

12

The air pressure effect on nucleation

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Quaternary system CO2, N2 and O2 (2CLJQ) Ar (LJ) Air components with relative mole fractions as in air. ℓ = 050 ℓ = 100 ℓ = 150 CNT following Wedekind et al.

slide-13
SLIDE 13

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

13

The air pressure effect on nucleation

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Quaternary system CO2, N2 and O2 (2CLJQ) Ar (LJ) Air components with relative mole fractions as in air. ℓ = 050 ℓ = 100 ℓ = 150

slide-14
SLIDE 14

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

14

Is a carrier gas only present in the vapour?

Light boiling compounds (i.e. “carrier gases”) often adsorb at the interface:

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

ΓCO2 = 0 ΓO2 For very small droplets, a bulk-like region (with little air) is absent. The interfacial region contains great amounts of air due to inter- facial enrichment. Droplet growth and decay is domi- nated by heat and mass transfer through the interface. Interfacial enrichment probably influences nucleation in fluid mixtures.

slide-15
SLIDE 15

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

15

Adsorption and surface tension

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse

Even small liquid mole fractions of a carrier gas can reduce γ significantly. Gibbs adsorption equation: dγ = −Σ Γi dμi − ζ dT. xO2 / mol mol-1 ΓO2 / μmol m-2 CO2 + O2 xO2 / mol mol-1 γ / g s-2 adsorption surface tension CO2 + O2 CO2 + O2 CO2 + O2

slide-16
SLIDE 16

Laboratory of Engineering Thermodynamics (LTD)

  • Prof. Dr.-Ing. H. Hasse

16

Conclusion

With optimized and validated molecular models, e.g. from multicriteria

  • ptimization, quantitatively reliable predictions can be made.

Massively parallel MD simulation of large systems makes activated processes like homogeneous nucleation directly accessible. In this way,

  • ver 100 000 cores of a supercomputer can be used efficiently.

For pure carbon dioxide, homogeneous nucleation of bubbles in a metastable liquid and of droplets in a metastable vapour is well described by CNT, without the need for a curvature correction. The influence of a carrier gas cannot be reduced to its presence in the vapour phase, due to the possibility of interfacial enrichment.

25th June 2015

  • M. Horsch, K. Langenbach, K. Stöbener, S. Werth, Z. Lin, T. Windmann, J. Vrabec, and H. Hasse