Özet:

In this study, effects of inserting twisted tape into a horizontal tube and adding TiO2 nanoparticle to water on heat transfer enhancement performance and pressure drop penalty are investigated with using CFD program. Analyses are carried out with Reynolds number of in range from 7860 to 15860, and constant heat flux of 50kW/m2K is applied to wall of the tube. To simulate turbulent nanofluid flow k-ω standard turbulent model is applied for all cases. TiO2 particles with diameter of 10 nm dispersed in water with volume fraction of 0.2% - 2.0% are used as the working fluid. To create swirl flow and enhance heat transfer, the twisted tape (constant twist ratio is y/W=3.0) is used in this study. The results show that adding nanoparticle to water causes to get more convective heat transfer coefficient as from 6% (for 0.2% vol. fract.) to 11% (for 2.0% vol. fract.) in a smooth tube. Furthermore, both adding nanoparticle to water and inserting the twisted tape to the smooth tube causes to 1.44 times greater convective heat transfer coefficient than case of smooth tube and water. In addition to heat transfer performance, pressure drop penalty is investigated in this study. Increasing nanoparticles in the water increase pressure drop penalty slightly, but using twisted tape in the smooth tube increases pressure drop penalty as about 6.5 times more.

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