Increasing the thermal performance of cooling tower by utilizing swirling jets

Year 2020, Volume: 4 Issue: 2, 57 - 63, 15.08.2020

Mustafa Kılıç Mehmet Öztatar Ali Özhan Akyüz Azim Doğuş Tuncer Afşin Güngör

https://doi.org/10.35860/iarej.686816

Abstract

Cooling towers are generally utilized in heating, ventilation, and air conditioning systems, electric power plants and manufacturing applications. The main problem for cooling towers is evaporation loss. The evaporation loss is decreased with utilizing fans, drift eliminators for more water saving. This work is mainly focused numerical analysis of cooling tower for reducing evaporation loss and increase the efficiency of the tower by utilizing two crosswise swirling jets that reduce the inlet hot water temperature in the outlet of the cylindrical channel to the not harmful to ambient conditions temperature. The model is computed for various parameters; air inlet temperatures (10, 22, 32, 40 °C) and Reynolds number for jets inlet velocities (Re= 3900, 5200, 7800, 8500). This model was studied numerically by utilizing ANSYS Fluent CFD software. In this work, it is achieved that increasing Reynolds number causes an increase on evaporation loss. The higher air inlet temperature causes higher evaporation loss. When the air inlet temperatures are reduced from 40 °C to 10 °C, the evaporation loss is decreased as 62% and 81%, respectively. When Reynolds number is decreased from 8500 to 3900, the evaporation loss decreased as 30%. By utilizing this new design, the outlet water temperature could be reduced of 19 °C. Moreover, the numerical findings were validated by some researches available in the literature.

Keywords

Direct contact cooling, effectiveness, evaporation loss, swirling jet

References

• 1. Kloppers, J.C., Kroger, D.G., Cooling Tower Performance: A Critical Evaluation of the Merkel assumptions. R & D Journal, 2004. 20(1): p.24-29.
• 2. Jaber, H., Webb, R.L., Design of Cooling Towers by the Effectiveness-NTU Method. ASME Journal Heat Transfer, 1989. 111(4): p.837–843.
• 3. Kloppers, J.C., Kroger, D.G., Cooling tower performance evaluation: merkel pope and e-NTU methods analysis. Journal of Engineering for Gas Turbines and Power, 2005. 127(1): p. 1-7.
• 4. Kloppers, J.C., Kröger, D.G., A critical investigation into the heat and mass transfer analysis of counter flow wet-cooling towers. International Journal of Heat and Mass Transfer, 2004. 48(3-4): p. 765–777.
• 5. Kloppers, J.C., Kröger, D.G., The Lewis factor and its influence on the performance prediction of wet-cooling towers. Int. J. of Thermal Sciences, 2005. 44(9): p.879–884.
• 6. Wang, Q., Wang, P., Su, Z., An Analytical Model on Thermal Performance Evaluation of Counter Flow. Thermal Science, 2017. 21(6): p.2491-2501.
• 7. Yılmaz, A., Analytical Calculation Of Wet Cooling Tower Performance With Large Cooling Ranges. Journal of Thermal Science and Technology, 2010. 30(2): p.45-56.
• 8. Mansour, M.K., Hassab, M.A., Innovative correlation for calculating thermal performance of counterflow wet-cooling tower. Energy, 2014. 74: p.855-862.
• 9. Deziani, M., Rahmani, K., Mirrezaei Roudaki, S.J., Kordloo, M., Feasibility study for reduce water evaporative loss in a power plant cooling tower by using air to Air heat exchanger with auxiliary Fan. Desalination, 2017. 406: p.119-124.
• 10. Ayoub, A., Gjorgiev, B., Sansavini, G., Cooling towers performance in a changing climate: Techno-economic modeling and design optimization. Energy, 2018. 160: p.1133-1143.
• 11. Smrekar, J., Oman, J., Širok, B., Improving the efficiency of natural draft cooling towers. Energy Convers Management, 2006. 47(9-10): p.1086–1100.
• 12. Fisenko, S.P., Brin, A.A., Petruchik, A.I., Evaporative cooling of water in a mechanical draft cooling tower. Int Journal Heat Mass Transfer, 2004. 47(1): p.165–177.
• 13. Gao, M., Sun, F., Wang, K., Shi, Y., Zhoa, Y., Experimental research of heat transfer performance on natural draft counter flow wet cooling tower under cross-wind conditions. International Journal of Thermal Sciences, 2008. 47(7): p.935–941.
• 14. Hajidavalloo, E., Shakeri, R., Mehrabian, M.A., Thermal performance of cross flow cooling towers in variable wet bulb temperature. Energy Conversion and Management, 2010. 51(6): p.1298–1303.
• 15. Lu, Y., Klimenko, A., Russell, H., Dai, Y., Warner, J., Hooman, K., A conceptual study on air jet-induced swirling plume for performance improvement of natural draft cooling towers. Applied Energy, 2018. 217: p.496–508.
• 16. Rahmati, M., Alavi, S.R., Tavakoli, M.R., Investigation of heat transfer in mechanical draft wet cooling towers using infrared thermal images: An experimental study. International Journal of Refrigeration, 2018. 88: p.229–238.
• 17. Klimanek, A., Cedzich, M., Białecki, R., 3D CFD modeling of natural draft wet-cooling tower with flue gas injection. Applied Thermal Engineering, 2015. 91: p.824-833.
• 18. Li, X., Gurgenci, H., Guan, Z., Sun, Y., Experimental study of cold inflow effect on a small natural draft dry cooling tower. Applied Thermal Engineering, 2018. Vol. 128: p.762–771.
• 19. Imani-Mofrad, P., Heris, S.Z., Shanbedi, M., Experimental investigation of the effect of different nanofluids on the thermal performance of a wet cooling tower using a new method for equalization of ambient conditions. Energy Conversion and Management, 2018. 158: p.23–35.
• 20. Mahmud, T., Kamrul, M., Salam, I., Salam, B., Experimental study of forced draft cross flow wet cooling tower using splash type fill. International Conference on Mechanical Engineering and Renewable Energy, 2013.
• 21. Çengel, Y.A., Boles, M.A., Thermodynamics: an engineering approach. New York, NY: McGraw-Hill Higher Education, 2015.
• 22. Kröger, D.G., Air-Cooled Heat Exchangers and Cooling Towers, Tulsa, Oklahoma, 2004.