Applied Mathematics and Mechanics (English Edition) ›› 2017, Vol. 38 ›› Issue (4): 585-602.doi: https://doi.org/10.1007/s10483-017-2183-6

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Natural convection of SiO2-water nanofluid in square cavity with thermal square column

Xiaopeng XIONG1, Sheng CHEN1,2,3, Bo YANG1   

  1. 1. State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China;
    2. Institute for Modelling and Simulation in Fluodynamics, Nanoscience and Industrial Mathematics "Gregorio Millan Barbany", Universidad Carlos III de Madrid, Leganes 28911, Spain;
    3. Faculty of Engineering, The University of Nottingham, University Park, Nottingham NG7 2RD, U. K
  • Received:2016-03-30 Revised:2016-06-23 Online:2017-04-01 Published:2017-04-01
  • Contact: Sheng CHEN E-mail:sheng.chen@nottingham.ac.uk
  • Supported by:

    Project supported by the National Natural Science Foundation of China (No. 51176061), the Universidad Carlos III de Madrid, the European Union's Seventh Framework Programme for Research, Technological Development and Demonstration (No. 600371), el Ministerio de Economíay Competitividad (No. COFUND2014-51509), and el Ministerio de Educación, Culturay Deporte (No. CEI-15-17)

Abstract:

A square with a thermal square column is a simple but nontrivial research prototype for nanofluid research. However, until now, the effects of the temperature of the square column on the heat and mass transfer of nanofluids have not been revealed comprehensively, especially on entropy generation. To deepen insight into this important field, the natural convection of the SiO2-water nanofluid in a square cavity with a square thermal column is studied numerically in this study. The effects of the thermal column temperature (T=0.0, 0.5, 1.0, 1.5), the Rayleigh number (ranging from 103 to 106), and the volume fraction of the nanoparticle (varying from 0.01 to 0.04) on the fluid flow, heat transfer, and entropy generation are investigated, respectively. It is found that, no matter at a low or high Rayleigh number, the volume fraction of the nanoparticle shows no considerable effects on the flow field and temperature field for all the temperatures of the thermal column. With an increase in the volume fraction, the mean Nusselt number increases slightly. At the same time, it is found that, with an increase in the temperature of the thermal column, the average Nusselt number gradually decreases at all values of the Rayleigh number. Meanwhile, it is found that, at a high Rayleigh number, the heat transfer mechanism is the main parameter affecting the increase in the total entropy generation rather than the volume fraction. In addition, no matter at a high or low Rayleigh number, when T=0.5, the total entropy generation is the minimum.

Key words: dry friction, Poincar´e map, normal form, periodic solution, torus, Rayleigh number, volume fraction, SiO2-water nanofluid, natural convection, entropy generation

2010 MSC Number: 

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