NUMERICAL STUDY TO INVISTIGATE THE EFFECT OF INLET GAS VELOCITY AND REYNOLDS NUMBER ON BUBBLE FORMATION IN A VISCOUS LIQUID

Abstract

Bubble formation dynamics has great value in mineral recovery and the oil industry. In this paper, a single bubble formation process through an orifice in a rectangle domain is modelled to study the bubble formation characteristics using the volume of fluid (VOF) with the continuum surface force (CSF) method. The effect of gas inlet velocities, Ug ~ 0.1 - 0.3 m/s on bubble formation stages (i.e., expansion, elongation and pinch off), bubble contact angle, dynamics and static pressure, bubble departure diameter etc. was investigated through an orifice diameter of 1 mm. The method was also used to study the effect of Reynolds number, Reμ ~ 1.32 - 120 on bubble formation when all other parameters were kept constant. It is found that a high inlet gas velocity accelerated the reducing of the bubble contact angle from an obtuse angle to an acute angle and the faster development of hemispherical shape of the bubble. It is also found that an increasing of Reynolds number caused speeding up of the bubble pinch-off and formed a smaller bubble neck height due to stronger vortex ring around the bubble neck.

Keywords

Dates

  • Submission Date2014-08-25
  • Revision Date2015-01-18
  • Acceptance Date2015-01-24
  • Online Date2015-02-08

DOI Reference

10.2298/TSCI140825015I

References

  1. Ku, X.K., Li, T., Lovas, T., Eulerian-Lagrangian simulation of a bubbling fluidized bed reactor: assessment of drag force correlations, Thermal Science, 16 (2012), pp. 1442-1445.
  2. Mladenović, M. R., Nemoda, S. D., Komatina, M.S., Dakić, D.V., Numerical simulation of non-conventional liquid fuels feeding in a bubbling fluidized bed combustor, Thermal Science, 17 (2013), pp. 1163-1179.
  3. Kulkarni, A.A., Joshi, J.B., Bubble formation and bubble rise velocity in gas-liquid systems: A review, Industrial & Engineering Chemistry Research, 44 (2005), pp. 5873-931.
  4. Canneto, G., Freda, C., Braccio, G., Numerical simulation of gas-solid flow in an interconnected fluidized bed, Thermal Science, 2014.
  5. Davidson, J., Schüler, B., Bubble formation at an orifice in a viscous liquid, Chemical Engineering Research and Design, 75 (1997), pp. S105-S15.
  6. Zhang, L., Shoji, M., Aperiodic bubble formation from a submerged orifice, Chemical Engineering Science, 56 (2001), pp. 5371-81.
  7. Tsuge, H., Tezuka, Y., Mitsudani M., Bubble formation mechanism from downward nozzle-Effect of nozzle shape and operating parameters, Chemical engineering science, 61 (2006), pp. 3290-8.
  8. Hamad, F.A., Khan, M.K., Pierscionek, B.K., Bruun, H.H., Comparison of experimental results and numerical predictions of drop diameter from a single submerged nozzle in a liquid‐liquid system, Canadian Journal of Chemical Engineering, 79 (2001), pp. 322-8.
  9. Di Bari, S., Lakehal, D., Robinson, A., A numerical study of quasi-static gas injected bubble growth: Some aspects of gravity, International Journal of Heat and Mass Transfer, 64 (2013), pp. 468-82.
  10. Badam, V., Buwa, V., Durst, F., Experimental investigations of regimes of bubble formation on submerged orifices under constant flow condition, Canadian Journal of Chemical Engineering, 85 (2007), pp. 257-67.
  11. Valencia, A., Cordova, M., Ortega, J., Numerical simulation of gas bubbles formation at a submerged orifice in a liquid, International Communications in Heat and Mass Transfer, 29 (2002), pp. 821-30.
  12. Gerlach, D., Alleborn, N., Buwa, V., Durst, F., Numerical simulation of periodic bubble formation at a submerged orifice with constant gas flow rate, Chemical Engineering Science, 62 (2007), pp. 2109-25.
  13. Chakraborty, I., Ray, B., Biswas, G., Durst, F., Sharma, A., Ghoshdastidar, P., Computational investigation on bubble detachment from submerged orifice in quiescent liquid under normal and reduced gravity, Physics of Fluids, 21(2009), pp. 062103.
  14. Brackbill, J., Kothe, D.B., Zemach, C., A continuum method for modeling surface tension, Journal of Computational Physics, 100 (1992), pp. 335-54.
  15. Youngs, D., Time-dependent multi-material flow with large fluid distortion, Numerical Methods for Fluid Dynamics, 24 (1982), pp. 273-85.
  16. Krishna, R., Van Baten, J., Rise characteristics of gas bubbles in a 2D rectangular column: VOF simulations vs experiments, International Communications in Heat and Mass Transfer, 26 (1999), pp. 965-74.
  17. Raymond, F., Rosant, J.M., A numerical and experimental study of the terminal velocity and shape of bubbles in viscous liquids, Chemical Engineering Science, 55 (2000), pp. 943-55.
  18. Hirt, C.W., Nichols, B.D., Volume of fluid (VOF) method for the dynamics of free boundaries, Journal of Computational Physics, 39 (1981), pp. 201-25.
  19. Fluent, I., FLUENT 6.3 user's guide, Fluent documentation, (2006).
  20. Ma, D., Liu, M., Zu, Y., Tang, C., Two-dimensional volume of fluid simulation studies on single bubble formation and dynamics in bubble columns, Chemical Engineering Science, 72 (2012), pp. 61-77.
  21. Kulkarni, A., Ekambara, K., Joshi, J., On the development of flow pattern in a bubble column reactor: experiments and CFD, Chemical Engineering Science, 62 (2007), pp. 1049-72.
  22. Kantarci, N., Borak, F., Ulgen, K.O., Bubble column reactors, Process Biochemistry, 40 (2005), pp. 2263-83.
  23. Krishna, R., Urseanu, M., Van Baten, J., Ellenberger, J., Wall effects on the rise of single gas bubbles in liquids, International Communications in Heat and Mass Transfer, 26 (1999), pp. 781-90.
  24. Kim, I., Kamotani, Y., Ostrach, S., Modeling bubble and drop formation in flowing liquids in microgravity, AIChE Journal, 40 (1994), pp. 19-28.
  25. Bhavaraju, S., Mashelkar, R., Blanch, H., Bubble motion and mass transfer in non‐Newtonian fluids: Part I. Single bubble in power law and Bingham fluids, AIChE Journal, 24 (1978), pp. 1063-70.