CIESC Journal ›› 2022, Vol. 73 ›› Issue (7): 2924-2932.DOI: 10.11949/0438-1157.20220381

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Experimental study on flow and heat transfer of non-Newtonian fluid in a corrugated double-tube heat exchanger

Wei LU1(),Ran MIAO1,Zhigen WU2(),Changchun WU2,Wei XIE1   

  1. 1.School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
    2.School of Environmental and Scientific Engineering, Tongji University, Shanghai 200092, China
  • Received:2022-03-16 Revised:2022-04-28 Online:2022-08-01 Published:2022-07-05
  • Contact: Zhigen WU

非牛顿流体在波节套管换热器中流动与换热的实验研究

陆威1(),苗冉1,吴志根2(),吴长春2,谢伟1   

  1. 1.上海理工大学能源与动力工程学院,上海 200093
    2.同济大学环境与科学工程学院,上海 200092
  • 通讯作者: 吴志根
  • 作者简介:陆威(1977—),女,博士,副教授,wei.lu@usst.edu.cn
  • 基金资助:
    国家重点研发计划项目(2019YFC1805204);国家自然科学基金青年科学基金项目(51406121);上海理工大学科技发展项目(2019KJFZ196)

Abstract:

This paper investigated the flow and heat transfer of corrugated double-tube heat exchanger with non-Newtonian fluid in the tube side experimentally. The heat transfer and resistance characteristics of non-Newtonian fluid (0.2% Xanthan gum (XG) solution) were studied in double-tube heat exchangers with different corrugated tubes to reveal the effects of geometry of corrugate tube and flow condition on the heat transfer enhancement. The results show that the overall heat transfer coefficient k and pressure difference between inlet and outlet Δp increases with the increase of the Reynolds numberof XG solution ReXG. The corrugated height H and distance S have significant influence on the flow and heat transfer of XG solution in the tube side of the casting heat exchangers. With the increase of corrugate height H, the XG solution is affected more obviously by the vortex effect at the corrugate node, so the interlayer shear force of the fluid increases with higher corrugate node and the viscosity of XG solution decreases, then the degree of turbulence increases to have better heat transfer performance and higher pressure drop, but the comprehensive heat transfer factor keeps increasing. With the increase of corrugate distance S, the number of corrugate nodes per unit length decreases, the disturbance on XG solution slows down and the degree of turbulence decreases. The heat transfer coefficient of XG solution side increases firstly and then decreases with longer node distance, while the flow resistance decreases with longer distance, the comprehensive heat transfer factor increases first and then decreases. The tube with H=3.5 mm, S=30 mm has the highest comprehensive heat transfer factor ηtube, which is 5.11—6.69 times that of smooth tube.

Key words: non-Newtonian fluid, corrugated double-tube heat exchanger, enhanced heat transfer, flow resistance

摘要:

针对非牛顿流体在波节套管换热器管程的流动与换热进行了实验研究。重点研究了0.2%黄原胶溶液(XG)在不同波节套管换热器管程流动时的传热与阻力特性,并分析了强化传热机理。结果表明在相同工况下,随着管程黄原胶溶液Reynolds数ReXG的增大,套管换热器总传热系数k和管程进出口压降Δp逐渐增大;波高H和波距S影响黄原胶溶液在套管换热器管程的流动与换热。随波高H增大,黄原胶溶液受波节处的涡旋效应的影响更明显,流体层间剪切力变大导致黄原胶溶液黏度变小,湍流程度更大,管程传热性能提高,压降也增大,但综合传热性能不断优化;随波距S增大,单位长度波节数量减少,对黄原胶溶液扰动影响降低,湍流程度降低,管程传热系数先增大后减小,流动阻力不断降低,综合传热性能先提高后减弱。当H=3.5 mm、S=30 mm时管程波节管的综合换热因子ηtube达到最大,ηtube是相同条件下圆管的5.11~6.69倍。

关键词: 非牛顿流体, 波节套管换热器, 强化换热, 流动阻力

CLC Number: