Numerical study of assisting and opposing mixed convective nanofluid flows in an inclined circular pipe

被引:19
作者
Al-asadi, M. T. [1 ,2 ]
Mohammed, H. A. [3 ]
Kherbeet, A. Sh. [4 ]
Al-aswadi, A. A. [5 ]
机构
[1] Univ Leeds, Sch Mech Engn, Inst Thermofluids, Leeds, W Yorkshire, England
[2] Minist Oil, South Oil Co, Engn Div, Refrigerat Dept, Basra, Iraq
[3] DPU, Tech Coll Engn, Dept Energy Engn, 61 Zakho Rd, Mazi Qr 1006, Duhok Kurdistan, Iraq
[4] KBU Int Coll, Dept Mech Engn, Petaling Jaya 47800, Selangor, Malaysia
[5] Int Univ Technol Twintech, Dept Oil & Gas Engn, Haddeh St, Sanaa, Yemen
关键词
Assisting flow; Opposing flow; Inclined circular pipe; Nanofluids; Heat transfer enhancement; HEAT-TRANSFER; THERMAL-CONDUCTIVITY; TEMPERATURE; PERFORMANCE; SUSPENSIONS; TUBE;
D O I
10.1016/j.icheatmasstransfer.2017.04.015
中图分类号
O414.1 [热力学];
学科分类号
摘要
A numerical investigation of mixed convection is carried out to study the heat transfer and fluid flow characteristics in an inclined circular pipe using the finite volume method. The pipe has L/D of 500 and it was subjected to a uniform heat flux boundary condition. Four types of nanofluids (Al2O3, CuO, SiO2, and TiO2 with H2O) with nanoparticles concentration in the range of 0 <= phi 5% and nanoparticles diameter in the range of 20 s dp 60nm were used. The pipe inclination angle was in the range of 30 <=theta <= 75 degrees using assisting and opposing flow. The influences of Reynolds number in the range of 100 <= Re <= 2000, and Grashof numbers in the range of 6.3 x 10(2) <= Gr <= 8.37 x 10(3) were examined. It is found that the velocity and wall shear stress are increased as Re number increases, while the surface temperature decreases. There is no significant effect of increasing Gr number on thermal and flow fields. The velocity and wall shear stress are increased and the surface temperature is decreased as tp and dp are decreased. It is concluded that the surface temperature is increased as the pipe inclination angle increases from the horizontal position (theta = 0 degrees) to the inclined position (theta = 75 degrees). In addition, it is inferred that the heat transfer is enhanced using SiO2 nanofluid compared with other nanofluids types. Furtheremore, it is enhanced using assisting flow compared to opposing flow.
引用
收藏
页码:81 / 91
页数:11
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