Thermal Performance Analysis of Natural Draft Dry Cooling Towers Based on New Theoretical Method

علوم کاربردی و محاسباتی در مکانیک

Article 11, Volume 32, Issue 1 - Serial Number 23, 2021, Pages 191-210   

Document Type: Original Article

DOI: 10.22067/jacsm.2021.56554.0

Authors

Amin Khodakaram-Tafti^* ; Ali-Akbar Golneshan

Department of Thermo-Fluid Engineering, School of Mechanical Engineering, Shiraz University, Shiraz 71936-16548, Iran

Abstract

In present study, the performance of a Heller-type natural draft dry cooling tower in the Fars Combined Cycle Power Plant is investigated under different environmental conditions (ambient temperature and wind velocity), based on a new theoretical method. The data collected from the control center of this power plant confirms the accuracy of the theoretical method; Therefore, a new mathematical model is created for predicting the performance of this cooling tower. This model is only applicable for wind velocities less than critical velocity, which is usually large and uncommon in operational conditions. Using this model for the described Heller cooling tower, it is shown that in high ambient temperatures, as the wind velocity increases, the heat transfer rate in the cooling tower decreases with a lower slope. The results of using the new theoretical method for calculating the performance of three aligned cooling towers in the power plant, along with the measured data, showed that when the wind direction is perpendicular to the towers, the efficiency of each tower is lower than the single tower in the same condition. When the wind is in line with the towers' direction, the efficiency of the rear towers will increase from the tower in the wind attack line.

Keywords

Natural draft dry cooling tower; Heller; Thermal performance; Mathematical model; Aligned cooling towers

References

 

1.    du Preez, A. F., and Kröger, D. G., "Effect of wind on performance of a dry-cooling tower", Heat Recovery Systems and CHP, Vol. 13, pp. 139-146, (1993).

2.    Wei, Q. -d., Zhang, B. -y., Liu, K. -q., Du, X. -d., and Meng, X.-z., "A study of the unfavorable effects of wind on the cooling efficiency of dry cooling towers", Journal of Wind Engineering and Industrial Aerodynamics, Vol. 54-55, pp. 633-643, (1995).

3.    Su, M.D., Tang, G.F., and Fu, S., "Numerical simulation of fluid flow and thermal performance of a dry-cooling tower under cross wind condition", Journal of Wind Engineering and Industrial Aerodynamics, Vol. 79, pp. 289-306, (1999).

4.    Al‐Waked, R., and Behnia, M., "The performance of natural draft dry cooling towers under crosswind: CFD study", International Journal of Energy Research, Vol. 28, pp. 147-161, (2004).

5.    Ghafari, S., Golneshan, A. -A., and Mokhtarpoor, R., "Effect of crosswind and air temperature on the thermal performance of Natural Draft Dry Cooling Tower (NDDCT)", 16th Annual (International) Conference on Mechanical Engineering-ISME, Shahid Bahonar University, Kerman, Iran, (2008).

6.    Ma, H., Si, F., Li, L., Yan, W., and Zhu, K., "Effects of ambient temperature and crosswind on thermo-flow performance of the tower under energy balance of the indirect dry cooling system", Applied Thermal Engineering, Vol. 78, pp. 90-100, (2015).

7.    Ardekani, M. A., Farhani, F., and Mazidi, M., "Effects of cross wind conditions on efficiency of Heller dry cooling tower", Experimental Heat Transfer, Vol. 28, pp. 344-353, (2015).

8.     شمسی‌پور، عباس و گل‌نشان، علی‌اکبر، "بررسی عددی عملکرد رادیاتورهای برج هلر تحت‌تأثیر وزش باد بر ورودی و خروجی برج"، بیست‌وچهارمین همایش سالانه مهندسی مکانیک ایران، یزد، ایران، (۱۳۹۵).

9.    Hooman, K., "Theoretical prediction with numerical and experimental verification to predict crosswind effects on the performance of cooling towers", Heat Transfer Engineering, Vol. 36, pp. 480-487, (2015).

10. Ma, H., Si, F., Kong, Y., Zhu, K., and Yan, W., "A new theoretical method for predicating the part-load performance of natural draft dry cooling towers", Applied Thermal Engineering, Vol. 91, pp. 1106-1115, (2015).

11. Fu, S., and Zhai, Z., "Numerical investigation of the adverse effect of wind on the heat transfer performance of two natural draft cooling towers in tandem arrangement", Acta Mechanica Sinica, Vol. 17, pp. 24-34, (2001).

12.   غفاری‌گوشه، صمد و گل‌نشان، علی‌اکبر، "بررسی عددی سه‌بعدی عملکرد 3برج خنک‌کننده خشک هم‌راستا با مکش طبیعی (NDDCT) تحت وزش باد"، اولین کنفرانس ملی صنعت نیروگاه‌های حرارتی (گازی، سیکل ترکیبی، بخاری)، تهران، ایران، (۱۳۸۸).

13.   آروین‌فر، محمدعلی، "بررسی عددی سه‌بعدی اثر چیدمان مثلثی 3برج خنک‌کننده خشک با مکش طبیعی تحت وزش باد"، پایان‌نامۀ کارشناسی‌ارشد مهندسی مکانیک (تبدیل انرژی)، دانشکدۀ مهندسی مکانیک، دانشگاه شیراز، (1391).

14.   جهانگیری، علی، "بررسی عددی سه‌بعدی اثر تزریق دود خروجی از نیروگاه سیکل ترکیبی به درون 3برج خنک‌کننده خشک هم‌راستا با مکش طبیعی تحت وزش باد"، پایان‌نامۀ کارشناسی‌ارشد مهندسی مکانیک (تبدیل انرژی)، دانشکدۀ مهندسی مکانیک، دانشگاه شیراز، (1388).

15. Iran Power Development Company (I.P.D.C.) Project, "Thermotechnical calculation of main cooling system", Report, Fars Combined Cycle/ Main & Aux. Cooling System, (2005).

16. EGI, "Thermotechnical and aerodynamic design/ calculation/ characteristics of the dry cooling plant system heater", Report Vol. A, Budapest Institute of Engineering, (1985).

17. Incropera, F. P., DeWitt, D. P., Bergman, T. L., and Lavine A. S., "Fundamentals of Heat and Mass Transfer", John Wiley and Sons, Inc., New York, pp. 669-706, (2006).

18.   جهانگیری، علی و گل‌نشان، علی‌اکبر، "بررسی بهبود عملکرد 3برج خنک‌کن هلر هم‌راستا تحت وزش باد با استفاده از تزریق دود اگزوز و دیواره‌های بادشکن"، بیست‌وچهارمین کنفرانس بین‌المللی برق، تهران، ایران، (۱۳۸۸).

19. Zhao, Y. B., Long, G., Sun, F., Li, Y., and Zhang, C., "Numerical study on the cooling performance of dry cooling tower with vertical two-pass column radiators under crosswind", Applied Thermal Engineering, Vol. 75, pp. 1106-1117, (2015).