CIESC Journal ›› 2022, Vol. 73 ›› Issue (11): 4957-4973.DOI: 10.11949/0438-1157.20221006

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Analysis of flow and heat transfer characteristics of lubricating oil in circular tube with coaxial crossed vortex generators

Zhimin LIN1,2(), Chongzhao WANG1,2, Guozhi QIANG1,2, Shushan LIU1,2, Liangbi WANG1,2   

  1. 1.School of Mechanical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China
    2.Key Laboratory of Railway Vehicle Thermal Engineering, Ministry of Education, Lanzhou 730070, Gansu, China
  • Received:2022-07-19 Revised:2022-08-27 Online:2022-12-06 Published:2022-11-05
  • Contact: Zhimin LIN

润滑油在内插同轴交叉翼型涡产生器管内流动与传热特性分析

林志敏1,2(), 王崇兆1,2, 强国智1,2, 刘树山1,2, 王良璧1,2   

  1. 1.兰州交通大学机电工程学院,甘肃 兰州 730070
    2.铁道车辆热工教育部重点实验室,甘肃 兰州 730070
  • 通讯作者: 林志敏
  • 作者简介:林志敏(1982—),男,博士,教授,linzhimin@mail.lzjtu.cn
  • 基金资助:
    国家自然科学基金项目(51676093);甘肃省杰出青年基金项目(1506RJDA061);兰州交通大学“百名青年优秀人才培养计划”项目

Abstract:

Using lubricating oil as the working fluid, the numerical method was used to simulate the flow and heat transfer in the tube of the coaxial cross isosceles trapezoidal vortex generator inserted in the circular tube. The influence of the different structural parameters of the vortex generators such as twisted ratio (Tr=3, 4, 5, 6), spacing ratio (Ss/W=0.8, 0.9, 1.1, 1.2) and base tape width ratio (Wb/W=0.30, 0.45, 0.60, 0.75) on the characteristics of flow and heat transfer were analyzed. The results show that under the same Re condition, all the averaged Nusselt number Num, secondary flow intensity parameter Se and heat transfer enhancement factor JF are increased with decreasing twisted ratio and spacing ratio, but they have no obvious law with the change of base tape width ratio. However, the friction factor f increases with decreasing twisted ratio and with increasing base tape width ratio, and the spacing ratio has only little effect on friction factor. Given the same geometrical parameters of coaxial crossed isosceles trapezoidal vortex generators, both JF and Se increase with increasing Reynolds number. In the range of Re=50—1000, compared with the smooth round tube, the Num of the coaxial crossed vortex generator with different structural parameters interpolated increased by 32.8%—208.6%, f increased by 3.38—8.92 times, and the maximum JF can reach 1.434. The average Nusselt number Num is related to the secondary flow intensity parameter Se as a power function. The intensity of secondary flow in a circular tube fitted with vortex generator inserts determines its convective heat transfer intensity.

Key words: heat transfer enhancement, secondary flow, coaxial crossed vortex generator, laminar flow, numerical simulation

摘要:

以润滑油为工质,采用数值方法对圆管内插同轴交叉等腰梯形涡产生器的管内流动与传热进行了数值模拟,分析了不同结构参数如扭率(Tr=3,4,5,6)、间距比(Ss/W=0.8,0.9,1.1,1.2)和基带宽度比(Wb/W=0.30,0.45,0.60,0.75)对圆管内插同轴交叉等腰梯形涡产生器的管内流动与传热特性的影响。结果表明:在相同Re下,平均Nusselt数Num、二次流强度Se、强化传热因子JF均随扭率和间距比的减小而增大,而其与基带宽度比的变化没有明显规律,阻力系数f随着扭率的减小和基带宽度比的增大而增大,间距比对f的影响甚微。在相同结构参数下,JFSe均随Re的增大而增大。在Re=50~1000范围内,相比于光滑圆管,内插不同结构参数的同轴交叉涡产生器的Num增加了32.8%~208.6%,f增加了3.38~8.92倍,JF最大可达1.434。NumSe呈幂函数相关,内插同轴交叉翼型涡产生器管内的二次流强度决定了其对流换热强度。

关键词: 强化传热, 二次流, 同轴交叉涡产生器, 层流, 数值模拟

CLC Number: