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CSME 2020/12
Volume 41 No.6
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699-712
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Thermal Analysis on Non-Newtonian Nanofluid in Double Tube Heat Exchanger with Staggered Oval Cross-section Pipe as Inner Pipe
Chen-Hsin Lina, Cha'o-Kuang Chena and Chieh-Li Chenb
aDepartment of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan, ROC.
bDepartment of Aeronautics and Astronautics, National Cheng Kung University, Tainan, Taiwan, ROC.
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Abstract:
In this study, a numerical simulation is used to analyze heat-exchange behaviors of a double tube heat exchanger with a staggered oval cross-section pipe as the inner pipe. In addition, non-Newtonian nanofluid and water are considered to be the working fluid, respectively flowing in the inner tube and outer tube. The non-Newtonian nanofluid is composed of non-Newtonian base fluid and nanoparticle. Besides, a single-phase fluid model was adopted. The purpose of this study is to investigate the heat exchange behavior of non-Newtonian nanofluid concerning different flow behavior index, the inlet velocity and nanoparticle volume fraction. Therefore, the velocity distribution, isotherms contours, synergy angle distribution, the Nusselt number, pressure drop and performance evaluation criterion (PEC) had been studied and calculated. It can be discovered that the heat transfer performance becomes better when the flow behavior index decreases; the inlet velocity of the inner pipe decreases; the inlet velocity of the outer pipe increases and nanoparticle volume fraction decreases.
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Keywords: heat transfer enhancement; staggered oval tube; tubular heat exchanger; non-Newtonian nanofluids; performance evaluation criterion; synergy angle.
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©
2020
CSME , ISSN 0257-9731
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