NUMERICAL INVESTIGATION OF THERMAL AND HYDRAULIC PERFORMANCE A TWISTED TUBE MODIFIED BY USING “CUO/WATER” NANOFLUID

In this study, several numerical simulations were constructed in order to enhance theheat transfer performance by exploiting smooth and twisted tubes with three different pitchlengths was (50mm, 100mm, 250mm). Water was selected as base fluid for analysis, andthe (CuO-Water) nano-fluids effect was tested on the heat transfer through a circular tubein order to improve the thermal and hydraulic performances. The nano-fluid used was asingle-phase of four different volume fractions: 1, 2, 3, and 4%. The analysiswas experimented for Reynolds number values between 6000-40000. Constant uniformheat flux of 50,000 W/m2 was applied to the outer surface of the test tube. Besides; kepsilon standard turbulence model was adopted through the use of CFD (ANSYS)program. The inlet fluid temperature was taken as 293K and a constant hydraulic diameterof 26.9mm was considered. The optimum results (Nu = 443.76, h=12129.98 W/m2, f =0.1582, ∆p = 2782.85 Pa, PEC=2.39) obtained were at pitch length of 50 mm, Reynoldsnumber of 35613 and volume fraction of 4% (CuO-Water) in base fluid.Finally, The results in terms of thermal and hydraulic performances showed decreasingNusselt number, heat transfer coefficient, friction factor and pressure as the number ofpitches length in twisted tube increased. In addition, the thermal and hydrauliccharacteristics increased too when increasing the value of CuO-water nano-fluid fraction.