NUMERICAL INVESTIGATION OF HEAT TRANSFER ENHANCEMENT ON ADDING (TiO2) NANOPARTICALES TO WATER FLOW IN NOZZLES ADDED TOA HORIZONTAL TUBE


Thesis Type: Postgraduate

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

Approval Date: 2017

Thesis Language: English

Student: Natiq Abbas Fadhil AL-AMERI

Supervisor: Veysel Özceyhan

Abstract:

This study presents a quantitative investigation regarding the thermal performance of inserting two types of nozzle; (a) Non-drilled nozzles, (b) Drilled nozzle with three different pitch lengths (126, 180 and 315 mm) through a water-based TiO2 nanofluid flowing into a horizontal tube. The considered nanofluid volume fractions are limited from 0.2% to 2.0%. A uniform constant heat flux of 50 kW/m2was applied onto the outer surface of the tube. The k-ω standard turbulent model was chosen to simulate turbulent flow, and analyses were implemented for the Reynolds number ranging from 4000 to 14,000. The nanofluid flow was modeled using the mixture model as it is more accurate than the single-phase model. The thermophysical properties of nanoparticles and water are considered independent of temperature. The thermophysical properties of the nanofluid were calculated with equations and empirical correlations based on the literature. Thus, as the volume fraction of TiO2 in both the smooth tube and drilled nozzle inserted tube rise, the heat transfer coefficient increases. While increasing pitch length of the nozzles means decreasing the number of nozzles in the tube, yet when using drilled nozzle, it’s higher than the non-drilled nozzle. As such, inserting more nozzles into the tube fosters the heat transfer, but increases the pressure drop penalty. The highest heat transfer coefficient for drilled nozzle is obtained as 72% which is bigger than the non-drilled nozzle, and the heat transfer of non-drilled nozzle is higher than the smooth tube about 54.5% for nanofluid flow through the smooth tube inserted nozzle with a pitch length of 126 and volume fraction of 2.0%, and friction factor increases approximately 5 times more than the smooth tube and less than the non-drilled nozzle approximately 7%.