Thermal-aerodynamic characteristics of staggered mixed tubes bundle composed of circular and drop-shaped tubes
The purpose of this study is to clarify heat transfer and fluid flow behavior across six-row mixed tubes bundles. The tubes bundle is consisting of circular and drop-shaped cross-sections in a staggered arrangement. The Reynolds number Re for the flow is varied from 1.78x103 to 18.72x103. Six cases of the mixed tubes bundle are considered. The results of the mixed tubes bundles are compared with those of the circular (case I) and drop-shaped ones (case II). ANSYS Fluent software package is utilized to predict the flow pattern over the tubes bundles. The results of the numerical simulation showed that the cross-sectional shape of the tubes and their location in the bundle significantly affect the heat transfer and pressure drop in the bundle. Case IV (circular tubes in the 1st,3rd,5th rows, and drop-shaped tubes in the 2nd, 4th, 6th rows) increases the average Nusselt number (Nu) ̅ by about 1.11–8.10% and 47.86–49.04% compared to that of the circular and drop-shaped tubes bundle, respectively. Case VII (drop-shaped tubes in the 1st, 2nd, 4th, 6th rows, and circular tubes in the 3rd, 4th rows) has the lowest friction factor f compared to the other cases of circular and mixed tubes bundles. Moreover, the maximum values of the thermal-hydraulic performance ε are achieved in the case IV at Re =1.78x103 and the case VII at Re>1.78x103, which were about 14.55% and (2.08 – 4.49)%, respectively, higher than those obtained for the drop-shaped tubes bundle. Generalized correlations for (Nu) ̅, f, and ε for the studied mixed tubes bundles were predicted.
Настоящая работа была проведена с целью исследования характеристик теплообмена пучка труб, состоящего из круглого и каплевидного сечений, расположенных в шахматной компоновке. Число Рейнольдса Re варьируется от 1,78x103 до 18,72x103. Рассмотрены шесть случаев смешанного пучка труб. Теплогидродинамические характеристики смешанных пучков труб сравниваются с круглыми (случай I) и каплевидными (случай II). Программный пакет ANSYS Fluent используется для прогнозирования линии тока в пучках труб. Результаты численного моделирования показали, что форма поперечного сечения труб и их расположение в пучке существенно влияют на теплообмен и перепад давления в пучке. Случай IV (круглые трубы в 1-м, 3-м, 5-м рядах и каплевидные трубы во 2-м, 4-м, 6-м рядах) среднее число Нуссельта Nuср увеличивается примерно на 1,11–8,10% и 47,86–49,04% по сравнению с круглым и каплевидным пучком труб, соответственно. Случай VII (каплевидные трубы в 1-м, 2-м, 4-м, 6-м рядах и круглые трубы в 3-м, 4-м рядах) имеет наименьший коэффициент гидродинамического сопротивления f по сравнению с другими случаями круглых и смешанных пучков труб. При этом максимальные значения теплогидрадинамической эффективности ε достигаются в случае IV при Re =1,78x103 и в случае VII при Re>1,78x103, которые были на 14,55 % и (2,08‒4,49) % соответственно выше, чем у пучка каплевидных труб. Предложены зависимости, позволяющие определить Nuср, f и ε для исследованных смешанных пучков труб.
1. Abd Rabbo M.F., Badawy M.T.S., Sakr R.Y., Gomaa A.G., Rashed H. R., Fawaz H.E., “Numerical investigation of cutting edge effect on fluid flow and heat transfer for in-phase trapezoidal air channels,” Alexand. Eng. J., Vol. 57, 2018, pp. 911–926. 2. Zhukauskas A., “Heat transfer from tubes in cross-flow”, Adv. Heat Transf. Vol. 8, 1972, pp. 93–160. 3. Patnana V.K., Bharti R.P., “Two-dimensional unsteady forced convection heat transfer in power-law fluids from a cylinder,” Int. J. Heat Mass Transfer, Vol. 53, No. 19, 2010, pp. 4152–4167. 4. Chatterjee D., Mondal B., “Unsteady mixed convection heat transfer from tandem square cylinders in cross flow at low Reynolds numbers,” Heat Mass Transfer, Vol. 49, 2013, pp. 907–20. 5. Yen S.C., Liu J.H., “Wake flow behind two side-by-side square cylinders,” Int. J. Heat Fluid Flow, Vol. 32, 2011, pp. 41–51. 6. Buyruk E., “Numerical study of heat transfer characteristics on tandem cylinders, inline and staggered tube banks in cross-flow of air,” Int Commun Heat Mass Transfer, Vol. 29, 2002, pp. 355–66. 7. Дееб Р., “Обобщение и анализ результатов последних исследований в области улучшения характеристик теплообмена и гидродинамики при поперечном обтекании гладких труб,” Вестник Тепловые процессы в технике, Том. 13, № 2, 2021. 8. Bahaidarah H.M.S., Anand N.K., Chen H.C., “A numerical study of fluid flow and heat transfer over a bank of flat tubes,” Num. Heat Trans. Part A: Appl. Vol. 48, 2005, pp. 359–385. 9. Yahya M., Saghir M.Z., “Thermal analysis of flow in a porous flat tube in the presence of a nanofluid: Numerical approach,” Int. J. of Thermofluids, Vol. 10, 2021, 100095. 10. Swain A., Das M.K., “Convective heat transfer and pressure drop over elliptical and flattened tube,” Heat Transf- Asian Research, Vol. 45, No. 5, 2016, pp.462-481. 11. Ibrahim T.A., Gomaa A., “Thermal performance criteria of elliptic tube bundle in crossflow,” Int J Therm Sci., Vol. 48, 2009, pp.2148–58. 12. Merker G.P., Hanke H., “Heat transfer and pressure drop on the shell-side of tube banks having oval-shaped tubes,” Int J Heat Mass Transfer, Vol. 29, 1986, pp.1903–9. 13. Brauer H., “Compact heat exchangers,” J. Chem. Process Eng, 1964, pp. 451-460. 14. Rajiva L.M., Abhilas S., Mihir K.D., “Thermal performance of mixed tube bundle composed of circular and elliptical tubes,” Thermal Science and Engineering Progress, Vol. 5, 2018, pp. 492-505. 15. Li Z., Davidson J.H., Mantell S.C., “Numerical simulation of flow field and heat transfer of streamlined cylinders in cross flow,” J. Heat Transfer, Vol. 128, No. 6, 2006, pp.564-570. 16. Bayat H., Lavasani A. M., Maarefdoost T., “Experimental study of thermal–hydraulic performance of cam-shaped tube bundle with staggered arrangement,” Energy Conversion and Management, Vol. 85, 2014, 106748. 17. A Lavasani A. M., Bayat H., “Numerical study of pressure drop and heat transfer from circular and cam-shaped tube bank in cross-flow of nanofluid,” Energy Conversion and Management, Vol.129, 2016, pp. 319–328. 18. Zhukova Yu.V., Terekh A.M., Rudenko A.I, “convective heat transfer and drag of two side-by-side tubes in the narrow channel at different reynolds number,” Doklady of the National Academy of Sciences of Belarus, 2018, vol. 62, no. 6, pp. 756–762 19. Sayed A.S.et al., “Parametric study of air cooling process via water cooled bundle of wing-shaped tubes,” EIJST, 2012 15:3. 20. Deeb R., Sidenkov D.V., “Numerical analysis of heat transfer and fluid flow around circular and non-circular tubes,” IOP Conf. Series J. Phys., 2088, 2021, 012008. 21. Deeb R., “The effect of angle of attack on heat transfer characteristics of drop-shaped tube,” Int. J. Heat Mass Transfer, 183, 2022, 122115. 22. Deeb R., “Experimental and numerical investigation of the effect of angle of attack on air flow characteristics around drop-shaped tube,” Physics of Fluids, 33, 2021, 065110. 23. Дееб Р., “Влияние угла атаки на теплообменные и гидродинамические характеристики шахматного пучка труб каплевидной формы в поперечном обтекании,” Доклады АН ВШ РФ, Том. 48, №. 3 2020, C. 21–36. 24. Дееб Р., “Влияние относительного продольного и поперечного шага на характеристики теплообмена шахматного пучка труб каплевидной формы,” Вестник Тепловые процессы в технике, Том. 14, № 2, 2022, C. 74 – 84. 25. ANSYS Fluent Reference Guide. ANSYS. Inc. Release 16.0. 2015.
