Numerical simulation of overall heat transfer performance of the rolled curved ribbed tube

Abstract

Abstract: Based on the enhanced heat transfer theory of longitudinal vortex, a novel enhanced heat transfer tube - rolled curved ribs tubes is developed.The influence of its structural parameters including rib width a, lead p, rib deep e and Re on Nu, f and the overall heat transfer performance evaluation criterion(PEC) value is studied numerically in different Re from 500 to 4×10⁴, and the dimensionless correlations of Nu, f are finally obtained.The results show that a strong vortex in the longitudinal direction of the spiral is induced in the near-wall region due to the presence of the ribs, which could break boundary, in turn achieved a heat transfer enhancement.lead p and rib deep e have bigger influence than rib width a in the overall heat transfer performance; the better geometric parameters of the new tube are p=10mm,e=0.6mm,a=1.8mm.When Re<2300, the Nu of the rolled curved ribs tube can be 2.9—7.0 times than that of the smooth circular tube, correspondingly, frictional loss factor is about 1.4—3.6 times than that of the smooth circular tube.When 500< Re <2300, the overall heat transfer performance evaluation criterion (PEC) value can reach up to 2.4—4.6, and when the 2300< Re <40000, it can reach 1.2—2.3.

Key words: enhanced heat transfer, longitudinal vortices, computational fluid dynamics, numerical simulation

摘要： 基于纵向涡强化换热理论提出了新型的强化换热管——弯曲内肋强化换热管。运用数值计算的方法,在Re=500～40000研究了新型强化换热管结构参数肋宽a、导程p、肋深e和Re数对Nu、f及换热性能评价指标PEC的影响,并拟合出换热管Nu、f的量纲为1关联式。结果表明:由于内肋的作用,在换热管的近壁面区域能够有效诱导产生沿纵向的涡旋结构,破坏壁面边界层,实现强化换热;导程p和肋深e对综合换热性能影响较大,肋宽a对综合换热性能影响较小,在Re=500～40000范围内,新型换热管较优的结构参数为p=10mm、e=0.6mm、a=1.8mm;与普通平滑圆管相比,当Re<2300,其换热性能Nu可达到普通圆管的2.9～7.0倍,沿程阻力系数f约为普通圆管的1.4～3.6倍;当500< Re <2300,其综合换热评价指标PEC可以达到2.6～4.6;当2300 <Re <40000时,其PEC可以达到1.2～2.3。

关键词: 强化传热, 纵向涡, 计算流体力学, 数值模拟

CAO Hailiang, HUANG Dan, JIA Baoguang, SU Hang, NIAN Zhiyuan, WANG Dingbiao. Numerical simulation of overall heat transfer performance of the rolled curved ribbed tube[J]. Chemical Industry and Engineering Progree, 2015, 34(s1): 35-42.

曹海亮, 黄丹, 贾宝光, 苏航, 年志远, 王定标. 弯曲内肋换热管综合换热性能的数值模拟[J]. 化工进展, 2015, 34(s1): 35-42.

References

[1] He Yaling, Zhang Yuwen.Advances and outlooks of heat transfer enhancement by longitudinal vortex generators[J]. Advances in Heat Transfer, 2012, 44: 119-185.

[2] Bergles A E.ExHFT for fourth generation heat transfer technology[J].Experimental Thermal and Fluid Science, 2002, 26(2): 335-344.

[3] Huisseune Henk,T'Joen Christophe, De Jaeger Peter, et al.Performance enhancement of a louvered fin heat exchanger by using delta winglet vortex generators[J].International Journal of Heat and Mass Transfer, 2013, 56: 475-487.

[4] Cheng Z D, He Y L, Cui F Q.Numerical study of heat transfer enhancement by unilateral longitudinal vortex generators inside parabolic trough solar receivers[J]. International Journal of Heat and Mass Transfer, 2012, 55(21): 5631-5641.

[5] Kukulka D J, Smith R.Thermal-hydraulic performance of Vipertex 1EHT enhanced heat transfer tubes[J].Applied Thermal Engineering, 2013, 61(1): 60-66.

[6] Chen Y, Fiebig M, Mitra N K.Heat transfer enhancement of a finned oval tubes with staggered punched longitudinal vortex generators[J].International Journal of Heat and Mass Transfer, 2000, 43(3): 417-435

[7] Habchi C, Russeil S, Bougeard D, et al.Enhancing heat transfer in vortex generator-type multifunctional heat exchangers[J].Applied Thermal Engineering, 2012, 38: 14-25.

[8] Caliskan S.Experimental investigation of heat transfer in a channel with new winglet-type vortex generators[J]. International Journal of Heat and Mass Transfer, 2014, 78: 604-614.

[9] 何雅玲, 楚攀, 谢涛.纵向涡发生器在管翅式换热器中的应用及优化[J].化工学报, 2012, 63(3): 746-760.

[10] 楚攀, 何雅玲, 田丽亭, 等.纵向涡强化换热的优化设计及机理分析[J].动力工程, 2009 (12): 1123-1128.

[11] Tian Liting, He Yaling, Tao Yubing, et al.A comparative study on the air-side performance of wavy fin-and-tube heat exchanger with punched delta winglets in staggered and in-line arrangements[J].International Journal of Thermal Sciences, 2009, 48(9): 1765-1776.

[12] 杨泽亮, 吴欣颖.纵向涡强化竖直平板自然对流换热的数值模拟 [J].华南理工大学学报: 自然科学版, 2006, 34(12): 115-119.

[13] Song W M, Meng J A, Li Z X.Numerical study of air-side performance of a finned flat tube heat exchanger with crossed discrete double inclined ribs[J].Applied Thermal Engineering, 2010, 30(13): 1797-1804.

[14] 王令, 陈秋炀, 曾敏, 等.矩形窄通道内带纵向涡发生器的传热强化[J].化工学报, 2007, 58(11): 2549-2553.

[15] 车翠翠, 田茂诚.圆管内置梯形翼片的流场特性PIV实验[J].化工学报, 2013, 64(11): 3976-3984.

[16] 陶文铨.数值传热学 [M].西安:西安交通大学出版社,2003: 347-360.

[17] Meng J A, Liang X G, Chen Z J, et al.Experimental study on convective heat transfer in alternating elliptical axis tubes[J].Experimental Thermal and Fluid Science, 2005, 29(4): 457-465.

[18] 李军.多种强化传热管的强化传热性能与流阻性能研究[D]. 广州: 华南理工大学, 2000.

[19] Webb R L.Principles of Enhanced Heat Transfer[M].New York:John Wiley & Sons, 1994.

[20] Fan J F, Ding W K, Zhang J F, et al.A performance evaluation plot of enhanced heat transfer techniques oriented for energy-saving[J].International Journal of Heat and Mass Transfer, 2009, 52(1): 33-44.