International Scientific Journal


Investigating the pool boiling process in the absorption chiller generator by studying the valid parameters may enhance the chiller’s COP. In the present study, the transient 2-D numerical modelling of LiBr/H2O solution pool boiling in the generator of the absorption chiller was carried out using the two-phase Eulerian-Eulerian approach, extended Rensselaer Polytechnic Institute boiling model and renormalization group k-ε turbulence model. The numerical model was applied on three types of the bare, notched fin, and low fin tubes to investigate the effect of using fin on the boiling heat transfer rate in the generator of the absorption chiller and comparing it with the bare tube. Moreover, the numerical results were compared with the data obtained from the previous experimental studies to validate numerical modelling. A good agreement was achieved between numerical and experimental results. The results showed the evaporation mechanisms in the microlayer, evaporation in the three-phase (liquid-vapor-solid) contact line, and transient conduction the superheat layer for constant thermal heat flux and the three surfaces of the copper tube within a specific period from the boiling point of LiBr/H2O solution. The results also showed that the use of a notched fin-tube and low fin tube increases the non-homogeneous nucleation rate, causes the solution boil earlier than the bare tube, and reduces the required thermal energy in the generator of an absorption chiller.
PAPER REVISED: 1970-01-01
PAPER ACCEPTED: 2020-06-02
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THERMAL SCIENCE YEAR 2021, VOLUME 25, ISSUE Issue 2, PAGES [1599 - 1610]
  1. Labus, J. M., et al., A. Review on Absorption Technology with Emphasis on Small Capacity Absorption Machines, Thermal Science, 17 (2013), 3, pp. 739-762
  2. Misyura, S. Y., Heat Transfer and Evaporation of Salt Solution on a Horizontal Heating Wall, Thermal Science, 24 (2020), 3B, pp. 2171-2179
  3. Kumar, B., et al., Thermodynamic Analysis of a Single Effect Lithium Bromide Water Absorption System Using Waste Heat in Sugar Industry, Thermal Science, 22 (2018), 1B, pp. 507-517
  4. Zhou, J., et al., Simulation Analysis of Performance Optimization of Gas-Driven Ammonia Water Absorption Heat Pump, Thermal Science, 24 (2020), 6B, pp. 4253-4266
  5. Luo, C., et al., Heat Transfer Characteristics of Ammonia-Water Falling Film Reneration Outside a Vertical Tube, Thermal Science, 21 (2017), 3, pp. 1251-1259
  6. Ben, H., et al., Numerical Study of Heat and Mass Transfer Enhancement for Bubble Absorption Process of Ammonia-Water Mixture without and with Nanofluids, Thermal Science, 22 (2018), 6B, pp. 3107-3120
  7. Kunkelmann, C., Stephan, P., The CFD Simulation of Boiling Flow Using the Volume of Fluid Method Within Open Foam, Numerical Heat Transfer, 56 (2009), 8, pp.631-646
  8. Kharangate, C. R., Mudawar, I., Review of Computational S tudies on Boiling and Condensation, International Journal of Heat and Mass Transfer, 108 (2017), Part A, pp. 1164-1196
  9. Mohaghegh, M. R., Rahimi, A. B., Modelling of Nucleate Boiling Heat Transfer of a Stagnation-Point Flow Impinging on a Hot Surface, Thermal Science, 23 (2019), 2A, pp. 695-706
  10. Arshi, B. P. S., Sudharsan, N. M., Experimental Heat and Mass Transfer Studies on Horizontal Falling Film Absorber Using Water-Lithium Bromide, Thermal Science, 24 (2020), 3B, pp. 1923-1934
  11. Jakubowska, B., Mikielewicz, D., An Improved Method for Flow Boiling Heat Transfer with Account of the Reduced Pressure Effect, Thermal Science, 23 (2019), Suppl. 4, pp. S1261-S1272
  12. Misyura, S. Y., Non-Isothermal Desorption and Nucleate Boiling in a Water-Salt Droplet LiBr, Thermal Science, 22 (2018), 1A, pp. 295-300
  13. Nakoryakov, V. E., et al., Non-Isothermal Desorption of Droplets of Complex Compositions, Thermal Science, 16 (2012), 4, pp. 997-1004
  14. Zarzycki, R., Panowski, M., Increase of Thermal Efficiency of Cogeneration Plant by Waste Heat Utilisation with Absorption Heat Pump, Thermal Science, 23 (2019), Suppl. 4, pp. S1101-S1112
  15. Sim, Y.-S., Kim, N.-H., Pool Boiling Performance of Notched Tubes in Lithium Bromide Solution, International Journal of Air-Conditioning and Refrigeration, 23 (2015), 2, 1550013
  16. Lee, J. H., et al., Heat Transfer Characteristics of a Falling Film Generator for Various Configurations of Heating Tubes in an Absorption Chiller, Applied Thermal Engineering, 148 (2019), Feb., pp. 1407-1415
  17. Sim, Y.-S., Kim, N.-H., Pool Boiling Performance of Lithium Bromide Solution on Enhanced Tubes, Journal of Mechanical Science and Technology, 29 (2015), 6, pp. 2555-2563
  18. ***, ANSYS FLUENT, 2019, Available from:
  19. Li, H., et al., Prediction of Boiling and Critical Heat Flux Using an Eulerian Multi-Phase Boiling Model, Proceedings, ASME International Mechanical Engineering Congress & Exposition IMECE, Denver, Col., USA, 2011, pp. 25-35
  20. Nguyen, T. T., et al., A CFD Modelling of Subcooled Pool Boiling, Proceedings, International Conference on Advances in Computational Mechanics, Phu Quoc Island, Vietnam, 2017, pp. 741-758
  21. Ishii, M., et al., Interfacial Area Transport Equation: Model Development and Benchmark Experiments, International Journal of Heat and Mass Transfer, 45 (2002), 5, pp. 3111-3123
  22. Tomiyama, A., Celata, GP., Hosokawa, S., Yoshida, S., Terminal Velocity of Single Bubbles in Surface Tension Force Dominant Regime, International Journal of Multi-Phase Flow, 28 (2002), 9, pp. 1497-1519
  23. Antal, S. P., et al., Analysis of Phase Distribution in Fully Developed Linear Bubbly Two-Phase Flow, Internationa Journal of Multi-Phase Flow, 17 (1991), 5, pp. 635-652
  24. de Bertodano, M. L., Turbulent Bubbly Two-Phase Flow Data in a Triangular Duct, Nuclear Engineering and Design, 146 (1994), 1-3, pp. 43-52
  25. Troshko, A., Hassan, Y. A., A Two-Equation Turbulence Model of Turbulent Bubbly Flow, International Journal of Multi-Phase Flow, 27 (2001), 11, pp. 1956-2000
  26. Ranz, W. E., Marshall, W. R., Evaporation from Drops Chemical Engineering Progress, Chemical Engineering Progress, 48 (1996), 3, pp. 141-146
  27. Tolubinsky, V. I., Kostanchuk, D. M.,Vapor Bubbles Growth Rate and Heat Transfer Intensity at Subcooled Water Boiling, Proceedings, 4th International Heat Transfer Conference, Paris, France, 1970
  28. Cole, R., Bubble Frequencies and Departure Volumes at Sub Atmospheric Pressures, AlChE Journal, 13 (1967), 4, pp. 779-783
  29. Lemmert, M., Chawla, J. M., Influence of Flow Velocity on Surface Boiling Heat Transfer Coefficient, in: Heat Transfer in Boiling, (Eds. E. Hahne and U. Grigull), Academic Press, New York, USA, 1977, pp. 237-247
  30. Varma, H. K., et al., Heat Transfer during Pool Boiling of LiBr-Water Solutions at Sub Atmospheric Pressures, International Communications in Heat and Mass Transfer, 21 (1994), 4, pp. 539-548

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