شبیه‌سازی دوبُعدی جوشش هسته‌ای استخری و بررسی مکانیزم تغییر فاز در شارهای حرارتی پایین

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده‌ی مهندسی مکانیک، دانشگاه گیلان، رشت، ایران

2 گیلان*مهندسی مکانیک

چکیده

در پژوهش حاضر، جوشش هسته‌ای استخری مبرد R-245fa در شرایط اشباع روی یک لوله‌ی افقی در فشار kPa 8/123 و دمای °C 20 تحت شارهای حرارتی مختلف (بین kW/m2 18 تا 27) به صورت عددی شبیه‌سازی شده و جزئیات جریان در آن مورد بررسی قرار گرفته است. شبیه‌سازی عددی توسط مدل چندفازی حجم سیال با بازسازی هندسی سطح مشترک، بدون ایجاد هسته‌ی حباب‌های اولیه توسط مدل تغییر فاز لی و مدل کشش سطحی نیروی سطحی پیوسته صورت پذیرفته است. اهمیت این مطالعه و ایجاد این مدل عددی، علاوه بر اهمیت صنعتی جوشش استخری در طراحی رآکتورهای هسته‌ای و اواپراتورهای مغروق در سیال، در اعتبارسنجی مدل عددی در پیش‌بینی سهم جوشش در جریان‌های اجباری فیلم‌ریزان یا بالارونده روی لوله یا دسته‌لوله‌ی افقی است. ضریب انتقال حرارت جابه‌جایی مدل عددی ایجادشده در مقایسه با داده‌های تجربی در دو شار حرارتی kW/m218 و 24، حداکثر 67/6% خطا داشته و در مقایسه با رابطه‌ی جوشش کوپر در شارهای حرارتی kW/m218 تا 27، حداکثر 64/8% متفاوت است. علاوه بر این، در این بررسی، روند حباب‌زایی و کنده‌شدن حباب‌ها از دیواره‌ی لوله و مایع مافوق اشباع کناره‌ی آن، دمای مایع و حباب و نحوه‌ی حرکت جریان تحت اثر حباب‌های ایجادشده در اطراف لوله مورد مطالعه قرار گرفته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Two-dimensional simulation of nucleation pool boiling and investigation of phase change mechanism at low heat fluxes

نویسندگان [English]

  • Maryam Hassani 1
  • Ramin Kouhi Kamali 2
1 Faculty of Mechanical Engineering/University of Guilan/Rasht/Iran
چکیده [English]

In the present study, nucleation pool boiling of the saturated refrigerant R-245fa on the horizontal tube at a pressure of 123.8 kPa and temperature of 20°C under different heat fluxes (18-27 kW/m2) has been numerically simulated and the details of the flow are investigated. Numerical simulation is carried out based on the volume of fluid model with a piecewise linear interface construction method, without pre-determined bubbles by Lee phase change model and surface tension model of continuum surface force. The importance of this study and the numerical model, in addition to its industrial applications at nuclear reactors and flooded evaporators, is the model validation at predicting boiling portion of forced falling or climbing flows on horizontal tubes or bundle of tubes. The heat transfer coefficient of the present model, in comparison with the experimental data at two heat fluxes of 18 and 24 kW/m2 and the results of pool boiling Cooper correlation at heat fluxes of 18-27 kW/m2 has the maximum error of 6.67% and 8.64%, respectively. In addition, in this study, bubble nucleation and its departure from the tube wall and superheated liquid beside the wall, liquid and bubble temperature and modality of fluid movement due to the generated bubbles around the tube have been studied.

کلیدواژه‌ها [English]

  • Pool boiling
  • Nucleation
  • Heat transfer coefficient
  • Numerical simulation
  • Volume of fluid model
[1] V.K. Dhir, G.R. Warrier, E. Aktinol, Numerical simulation of pool boiling: a review, Journal of Heat Transfer, Transaction of the ASME, 135(6) (2013) 061502-061517.
[2] D. Gorenflo, E. Baumhogger, T. Windmann, G. Herres, Nucleate pool boiling, film boiling and single-phase free convection at pressures up to the critical state. Part II: Circumferential variation of the wall superheat for a horizontal 25mm copper cylinder, International Journal of Refrigeration, 33 (2010) 1251-1263.
[3] S. Kim, D.E. Kim, S.U. Ryu, S.T. Lee, D.-J. Euh, Experimental investigation on the natural convection flow in pool boiling, Nuclear Engineering and Design, 280 (2014) 349-361.
[4] H.-S. Roh, Heat transfer mechanisms in pool boiling, International Journal of Heat and Mass Transfer, 68 (2014) 332-342.
[5] G. Moreno, B. Kekelia, H. Sitaraman, S. Narumanchi, K. Bennion, Nucleate pool boiling of R-245fa at low saturation temperatures for hydrogen precooling applications, International Journal of Heat and Mass Transfer, 132 (2019) 172-183.
[6] S.S. Kutateladze, V.M. Borishanskii, A Concise Encyclopedia of Heat Transfer, Pergamon Press, New York, NY, USA, 1966.
[7] D.A. Labuntsov, Heat transfer problems with nucleate boiling of liquids, Thermal Engineering 19(9) (1972) 21– 28.
[8] I.L. Pioro, Experimental evaluation of constants for the Rohsenow pool boiling correlation, International Journal of Heat and Mass Transfer, 42 (1999) 2003–2013.
[9] W.M. Rohsenow, A method of correlating heat transfer data for surface boiling of liquids, M.I.T. Division of Industrial Cooporation, 1951.
[10] W.M. Rohsenow, J.P. Hartnett, Y.I. Cho, Handbook of Heat Transfer, 3rd edition ed., New York, NY, USA, 1998.
[11] G.R. Warrier, V.K. Dhir, Heat transfer and wall heat flux partitioning during subcooled flow nucleate boiling—A review, ASME J. Heat Transfer, 128(12) (2006) 1243–1256.
[12] S. Bailey, G.R. Warrier, V.K. Dhir, Wall heat flux partitioning during subcooled flow boiling: part II—model validation, ASME J. Heat Transfer, 127(2) (2005) 141–148.
[13] N. Basu, G.R. Warrier, V.K. Dhir, Wall heat flux partitioning during subcooled flow boiling: part I—model development, ASME J. Heat Transfer, 127(2) (2005) 131–140.
[14] E. Krepper, E.F. Hicken, H. Jaegers, Investigation of natural convection in large pools, Int. J. Heat Fluid Flow, 23 (2002) 359–365.
[15] Y. Liu, T. Olewski, L.N. Vechot, Modeling of a cryogenic liquid pool boiling by CFD simulation, J. Loss Prev. Process. Ind. , 35 (2015) 125–134.
[16] Y. Sato, B. Niceno, Nucleate pool boiling simulations using the interface tracking method: boiling regime from discrete bubble to vapour mushroom region, Int. J. Heat Mass Tran, 105 (2017) 505–524.
[17] Y. Tian, K. Zhang, N. Wang, Z. Cui, L. Cheng, Numerical study of pool boiling heat transfer in a large-scale confined space, Applied Thermal Engineering 118 (2017) 188–198.
[18] W. Lee, A pressure iteration scheme for two-phase flow modeling, Hemisphere Publishing, Washington, DC, 1980.
[19] S.M.A. Noori Rahim Abadia, A. Ahmadpour, J.P. Meyer, Numerical simulation of pool boiling on smooth, vertically aligned tandem tubes, International Journal of Thermal Sciences, 132 (2019) 628–644.
[20] N. Cheng, Y. Guo, C. Peng, A numerical simulation of single bubble growth in subcooled boiling water, Annals of Nuclear Energy, 124 (2019) 179–186.
[21] S.A. Hosseini, R. Kouhikamali, The effect of surface types on bubble dynamic formation during nucleate pool boiling by use of Lee and Tanasawa phase change models, Amirkabir Journal of Mechanical Engineering,  (2019) (In Persian).
[22] W.J. Rider, D.B. Kothe, Reconstructing volume tracking, J Comput Phys 141 (1998) 112-152.
[23] L.-H. Chien, Y.-L. Tsai, An experimental study of pool boiling and falling film vaporization on horizontal tubes in R-245fa, Appl Therm Eng 31 (2011) 4044-4054.
[25] C.R. Kharangate, I. Mudawar, Review of computational studies on boiling and condensation, Int J Heat Mass Tran, 108 (2017) 1164–1196.
[26] J.U. Brackbill, D.B. Kothe, C. Zemach, A continuum method for modeling surface tension, J Comput Phys, 100(2) (1992) 335-354.
[27] S.A. Hosseini, R. Kouhikamali, Simulation of film boiling heat transfer on flat plate and the impact of various phase change models on it, Modares Mechanical Engineering, 16(5) (2016) 169-177 (In Persian).
[28] M.G. Cooper, Saturation nucleate pool boiling - a simple correlation, International Chemical Engineering Symposium, 86 (1984) 785-792.