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过程工程学报 ›› 2020, Vol. 20 ›› Issue (5): 510-520.DOI: 10.12034/j.issn.1009-606X.219242

• 流动与传递 • 上一篇    下一篇

开口扭曲片圆管强化传热与流动阻力特性模拟

王 娟1,2*, 何星晨1,2, 李 军1,2, 万加亿1,2, 邹 槊1,2, 徐皓晗1,2   

  1. 1. 中国石油大学重质油国家重点实验室,北京 102249 2. 过程流体过滤与分离技术北京市重点实验室,北京 102249
  • 收稿日期:2019-07-02 修回日期:2019-09-02 出版日期:2020-05-22 发布日期:2020-05-18
  • 通讯作者: 王娟
  • 基金资助:
    中国石油化工股份有限公司项目资助

Simulation of heat transfer enhancement and flow resistance characteristics of twisted slice tubes with openings

Juan WANG1,2*, Xingchen HE1,2, Jun LI1,2, Jiayi WAN1,2, Shuo ZOU1,2, Haohan XU1,2   

  1. 1. State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China 2. Beijing Key Laboratory of Process Fluid Filtration and Separation, Beijing 102249, China
  • Received:2019-07-02 Revised:2019-09-02 Online:2020-05-22 Published:2020-05-18
  • Contact: WANG Juan

摘要: 在乙烯裂解管式加热炉的工业应用中,通过在炉管内加入扭曲片内构件,将管内流动由平推流转为旋转流,增大了切向速度的同时加强了流体对管壁的冲刷作用,达到强化传热的目的。在第二代扭曲片的基础上进行结构改进,采用RNG k??湍流模型模拟炉管内部的流动,对比分析了不同扭曲片结构管道内的纵向涡结构、阻力系数、努塞尔数、综合传热系数及速度矢量场与温度梯度场耦合协同情况。结果表明,沿管壁呈“狭缝”状开口的扭曲片结构增大了管内流动的旋流强度,降低了阻力损失;开口长度7 mm、宽度2 mm、间隔2 mm的扭曲片结构局部阻力系数是第一代的93.75%,比第二代增加了8.67%,但综合传热系数比第二代提高了1.56%,是光管的1.29倍,该结构提高了纵向涡的稳定性,强化了管道核心流体与管壁的动量、热量交换;而沿管道中心开口的扭曲片结构增大了局部阻力系数,造成局部损失增加。

关键词: 扭曲片, 数值模拟, 开口结构, 纵向涡, 强化传热, 协同角

Abstract: In the industrial application of ethylene pyrolysis tubular heating furnace, the fluid transferred from horizontal to rotary flow by adding twisted slices internals, which increased the tangential velocity and strengthened the flushing effect on the tube wall, so as to achieve the purpose of enhancing heat transfer. Based on the second generation of twisted slices, the structure was improved, and RNG k?ε turbulence model was used to simulate the flow details inside the furnace tube. The longitudinal vorticity structure, resistance coefficient, Nusselt number Nu, comprehensive heat transfer coefficient PEC and the coupling coordination between velocity vector field and temperature gradient field in different twisted slice structures were compared and analyzed. The results showed that the structure with "slit" openings along the wall can reduce the loss of flow resistance while increased the strength of fluid swirl. The resistance coefficient of twisted slices with opening structure of 7 mm length, 2 mm width and 2 mm interval was 93.75% of the first generation and 8.67% more than the second generation, but the comprehensive heat transfer coefficient was 1.56% higher than that of the second generation and 1.29 times of the smooth tube. It can be considered that the optimized structure improved the stability of longitudinal vortex structure as well as strengthened the coupling between flow and heat transfer. Besides, along the central opening of the slices, the resistance coefficient at the twisted slices increased, resulting in larger local losses.

Key words: twisted slices, numerical simulation, openings structure, longitudinal vortex, heat transfer enhancement, synergy angle