Zhurnal Radioelektroniki - Journal of Radio Electronics. eISSN 1684-1719. 2022. 12
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DOI: https://doi.org/10.30898/1684-1719.2022.12.1

 

NUMERICAL Study of molecular gas DYNAMICS

UNDER pulsed laser ablation

 

A.A. Frolova

 

Federal Research Center “Computer Science and Control” of Russian Academy of Sciences

117333, Moscow, Vavilova str., 44(2)

 

The paper was received November 20, 2022.

 

Abstract. The evaporation of a molecular gas with rotational degrees of freedom caused by the action of a pulsed nanosecond laser (pulsed laser ablation) of moderate intensity is considered. Model kinetic equations that account for the exchange of translational and rotational energies using a two-temperature model are used to account for the influence of internal energy on the vapor-gas cloud dynamics. Rykov equations (R-model) are integrated when modeling the flow of a diatomic gas, and a generalization of the Bhatnagar-Gross-Krook (BGK) equation for a molecular gas is used to calculate the flow of nonlinear molecules with a number of rotational degrees of freedom equal to three. Taking into account the influence of internal energy on the gas flow is realized by relaxation terms approximating the collision integral as a sum of elastic and inelastic collisions. Since in the model kinetic equations the collision frequency does not depend on the velocities, and the influence of internal energy is taken into account only due to temperature changes, it is necessary to compare with more realistic approaches, which include, for example, the method of direct simulation Monte Carlo (DSMC). The comparison shows that the change in the average temperature over time and the vapor-gas cloud parameters (density and temperature), obtained by the solution of the kinetic equations and the DSMC method, are close. Calculations of the problem of pulsed laser ablation by direct integration of kinetic equations are carried out by the method of discrete ordinates and are a difficult computational problem, which is associated with discontinuous boundary conditions, the presence of both continuum regions and free molecular flow regions in the solution, as well as the need to calculate the vapor-gas cloud dynamics for a large time interval. To reduce computational costs, grid adaptation in physical and velocity spaces is used.

Key words: model kinetic equations, rotational degrees of freedom, pulsed laser ablation, nonstationary problems.

Corresponding author: Frolova Anna Averkievna, aafrolova@yandex.ru

 

References

1. Itina T.E., Hermann J., Delaporte P., Sentis M. Laser-generated plasma plume expansion: Combined continuous-microscopic modeling. Physical Review E. 2002. V.66. P.066406. https://doi.org/10.1103/PhysRevE.66.066406

2. Bykov N.Y., Bulgakova N.M., Bulgakov A.V., Loukianov G.A. Pulsed laser аblation of metals in vacuum: DSMC study versus experiment. Applied Physics A. 2004. V.79. P.1097. https://doi.org/10.1007/s00339-004-2654-6

3. Morozov A.A., Mironova M.L. Numerical analysis of time-of-flight distributions of neutral particles for pulsed laser ablation of binary substances into vacuum. Applied Physics A. 2017. V.123. 12. P.783. https://doi.org/10.1007/s00339-017-1400-9

4. Morozov A.A. Analysis of time-of-flight distributions under pulsed laser ablation in vacuum based on the DSMC calculations. Applied Physics A. 2013. V.111. P.1107-1111. https://doi.org/10.1007/s00339-012-7325-4

5. Bykov N.Y., Lukuianov G.A. Simulation of pulsed laser ablation of solid material based on a thermal model of the target and direct statistical simulation of vapor dispersion. Teplofisika i aeromehanika. 2003. V.10. №3. P.401-410.

6. Gusarov A.V., Smurov I. Target-vapour interaction and atomic collisions in pulsed laser ablation. Journal of Physics D: Applied Physics. 2001. V.34. P.1147-1156. https://doi.org/10.1088/0022-3727/34/8/304

7. Anisimov S.I., D. Bäuerle D., Luk’yanchuk B.S. Gas dynamics and film profiles in pulsed-laser deposition of materials. Physical Review B. 1993. V.48. P.12076. https://doi.org/10.1103/physrevb.48.12076

8. Anisimov C.I., Luk'yanchuk B.С. Selected problems of laser ablation theory Physics-Uspekhi. 2002. V.45.3. P.293-324. https://doi.org/10.3367/UFNr.0172.200203b.0301

9. Morozov A.A. Dynamics of pulsed expansion of polyatomic gas cloud Internal translational energy transfer contribution. Physics of Fluids. 2007. V.19. 8 P.087101. https://doi.org/10.1063/1.2754347

10. Morozov A.A. Analytical model for polyatomic gas expansion under pulsed. Physics of fluids. 2008. V.20. P.027103. https://doi.org/10.1063/1.2841624

11. Morozov A.A., Frolova A.A., Titarev V.A. On different kinetic approaches for computing planar gas expansion under pulsed evaporation into vacuum. Physics of Fluids. 2020. V.32. 11. P.112005. https://doi.org/ 10.1063/5.0028850

12. Titarev V.A., Morozov A.A. Arbitrary Lagrangian-Eulerian discrete velocity method with application to laser-induced plume expansion. Applied Mathematics and Computation. 2022. V.429 P.127241. https://doi.org/10.1016/j.amc.2022.127241

13. Wang Z., Yan H., Li Q., Xu K. Unified gas-kinetic scheme for diatomic molecular flow with translational, rotational, and vibrational modes. Journal of Computational Physics. 2017. V.350. P.237-259. https://doi.org/10.1016/j.jcp.2017.08.045

14. Andries P., LeTallec P., Perlat J., Perthame B. The Gaussian-BGK model of Boltzmann equation with small Prandtl number. European Journal of Mechanics- B/Fluids. 2000. V.19. P.813-830. https://doi.org/10.1016/s0997-46(00)01103-1

15. Rykov V.A. A Model Kinetic Equation for a Gas with Rotational Degrees of Freedom. Fluids Dynamics. 1975. V.10. P.959-966. https://doi.org/10.1007/BF01023275

16. Titarev V.A., Frolova A.A. Application of Model Kinetic Equations to Calculations of Super-and Hypersonic Molecular Gas Flows. Fluid Dynamics. 2018. V.53. 4. P.536-551. https://doi.org/10.1134/S0015462818040110

For citation:

Frolova A.A. Numerical analysis of molecular gas dynamics under pulsed laser ablation. Zhurnal radioelektroniki [Journal of Radio Electronics] [online]. 2022. №12. https://doi.org/10.30898/1684-1719.2022.12.1 (In Russian)