INVESTIGATION OF HEAT TRANSFER ON A HORIZONTAL TUBE USING NANOFLUID AND INSERT BY TAGUCHI METHOD


Thesis Type: Doctorate

Institution Of The Thesis: Erciyes University, Mühendislik Fakültesi, Makina Mühendisliği, Turkey

Approval Date: 2020

Thesis Language: Turkish

Student: TOYGUN DAĞDEVİR

Supervisor: Veysel Özceyhan

Abstract:

Thesis study includes experimental heat transfer augmentation studies on a heat exchanger tube that is heated under a constant heat flux and turbulent flow conditions. Water and water-ethylene glycol mixture were chosen as a base fluid. The experiments are conducted for Reynolds number between 6000 and 23000. Heat transfer augmentation studies are performed by placing twisted tapes with 7 different designs in the tube and 4 different weight ratios (wt) of TiO2 nanoparticles into the base fluids as 0.25%, 0.50%, 0.75% and 1.00%. Twisted tapes are in three main designs which are typically twisted tape, perforated twisted tapes and dimpled twisted tapes. The ratio of the distance between the holes and dimples on the twisted tapes to the twist length (P/y) is designed as 1.00, 0.50 and 0.25. While the amount of nanoparticle increases in the base fluid in the same Reynolds number increases, the Nusselt number increases and the friction factor does not change. Inserting of twisted tape in the tube causes to increase both the Nusselt number and the friction factor. The highest THP value was obtained by using of dimpled twisted tapes (P/y = 0.25) in the tube, the nanoparticle ratio was 1.00% by weight in the use of water-TiO2 and Reynolds number of 6319. The optimum test configuration for the water base fluid is obtained as volumetric flow of 0.25 m3/h, wt=%1.0 and DTT (P/y=0.25) in the pipe. The optimum test configuration for the water-ethylene glycol mixture base fluid is volumetric flow of 1.04 m3/h, wt=%1.0 and smooth pipe.