SCI和EI收录∣中国化工学会会刊

Chin.J.Chem.Eng. ›› 2018, Vol. 26 ›› Issue (12): 2420-2430.DOI: 10.1016/j.cjche.2018.03.021

• Fluid Dynamics and Transport Phenomena • Previous Articles     Next Articles

Experimental research on stabilities, thermophysical properties and heat transfer enhancement of nanofluids in heat exchanger systems

Cong Qi, Maoni Liu, Guiqing Wang, Yuhang Pan, Lin Liang   

  1. School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou 221116, China
  • Received:2018-01-11 Revised:2018-03-03 Online:2019-01-09 Published:2018-12-28
  • Contact: Cong Qi
  • Supported by:

    Supported by the National Natural Science Foundation of China (51606214).

Experimental research on stabilities, thermophysical properties and heat transfer enhancement of nanofluids in heat exchanger systems

Cong Qi, Maoni Liu, Guiqing Wang, Yuhang Pan, Lin Liang   

  1. School of Electrical and Power Engineering, China University of Mining and Technology, Xuzhou 221116, China
  • 通讯作者: Cong Qi
  • 作者简介:Maoni Liu,liumaoni@cumt.edu.cn;Guiqing Wang,gqwang@cumt.edu.cn;Yuhang Pan,panyuhang@cumt.edu.cn;Lin Liang,lianglin@cumt.edu.cn.
  • 基金资助:

    Supported by the National Natural Science Foundation of China (51606214).

Abstract: Stable TiO2-water nanofluids are prepared by a two-step method, stabilities of nanofluids are investigated by precipitation method and transmittance method respectively, and thermal conductivities and viscosities are also measured. An experimental system for studying the heat transfer enhancement of nanofluids is established, and heat transfer and flow characteristics of TiO2-water nanofluids in heat exchanger systems with a triangular tube and circular tube are experimentally studied. The effects of nanoparticle mass fractions (ω=0.1 wt%-0.5 wt%) and Reynolds numbers (Re=800-10000) on the heat transfer and flow performances of nanofluids are analyzed. Fitting formulas for Nusselt number and resistance coefficient of nanofluids in a triangular tube are put forward based on the experimental data. The comprehensive performances of nanofluids in a triangular tube are investigated. It is found that nanofluids in a triangular tube can significantly improve the heat transfer performance at the cost of a small increase in resistance coefficient compared with that in a circular tube, especially the resistance coefficients are almost the same between different nanoparticle mass fractions at turbulent flow. It is also found that the comprehensive evaluation index η decreases with Reynolds number at laminar flow but a critical maximum value appears at turbulent flow.

Key words: Heat transfer, Nanoparticles, Turbulent flow, Triangular tube, Comprehensive evaluation index

摘要: Stable TiO2-water nanofluids are prepared by a two-step method, stabilities of nanofluids are investigated by precipitation method and transmittance method respectively, and thermal conductivities and viscosities are also measured. An experimental system for studying the heat transfer enhancement of nanofluids is established, and heat transfer and flow characteristics of TiO2-water nanofluids in heat exchanger systems with a triangular tube and circular tube are experimentally studied. The effects of nanoparticle mass fractions (ω=0.1 wt%-0.5 wt%) and Reynolds numbers (Re=800-10000) on the heat transfer and flow performances of nanofluids are analyzed. Fitting formulas for Nusselt number and resistance coefficient of nanofluids in a triangular tube are put forward based on the experimental data. The comprehensive performances of nanofluids in a triangular tube are investigated. It is found that nanofluids in a triangular tube can significantly improve the heat transfer performance at the cost of a small increase in resistance coefficient compared with that in a circular tube, especially the resistance coefficients are almost the same between different nanoparticle mass fractions at turbulent flow. It is also found that the comprehensive evaluation index η decreases with Reynolds number at laminar flow but a critical maximum value appears at turbulent flow.

关键词: Heat transfer, Nanoparticles, Turbulent flow, Triangular tube, Comprehensive evaluation index