Vol. 71 No. 4 (2022) http://philstat.org.ph Mathematical Statistician and Engineering Applications ISSN: 2094-0343 2326-9865 6416 Analysis of Flow and Thermal Performance of Sio2- Water Nanofluids with Variable Geometrical and Process Parameters N. Oumer #1* , H. Wan Azmi #1 , Azizuddin Abd Aziz #2 , J. P. Siregar #1 , Aklilu T. Baheta #2 * e-mail: nurye@ump.edu.my Article Info Page Number: 6416-6435 Publication Issue: Vol. 71 No. 4 (2022) Article History Article Received: 25 March 2022 Revised: 30 April 2022 Accepted: 15 June 2022 Abstract This study numerically investigated the thermal-hydraulic performances of a single-phase SiO2-water nanofluid in forced convective turbulent flow in a pipe. The nanoparticle volume concentrations varied from 0-4% by weight. At different Res, bulk temperatures, and particle sizes, simulations were run. The obtained results showed that, in comparison to other input parameters, nanoparticle concentration and inlet velocity considerably affect the heat transfer coefficient (h) and pressure drop (∆). The analysis of thermal and flow performance discovered that increasing the nanoparticle concentration and inflow velocity significantly improves the (∆ and h. Keywords: simulation modelling; heat transfer; nanofluids; CFD; nanoparticles Introduction A nanofluid can be defined as a combination of solid nanoparticles and a liquid base-fluid with at least one of the principal dimensions of the nanoparticles being less than 100 nanometers. They are prepared by the distribution of nanoparticles in a base-fluid. When the nanoparticle is combined with the base-fluid, the thermal conductivity () of the fluid is enhanced and improves its capability of energy exchange. Nanofluids are known for their enhanced thermal properties and can primarily be used as industrial coolants. They can also be used as smart fluids (in the area of cell phones and laptops), and as combustion heat enhancers in diesel engines [1-5]. In the application of such fluids in energy systems, the top priority investigations being done are in the areas of heat exchangers, heat pumps, energy conversion and storage devices [6-7]. For instance, a car cooling system applies the concept of heat transfer; if the heat is not released to the surrounding, the car will overheat and it will damage the car engine and its accessories such as gaskets, sealing of the oil gallery, and water jacket. Hence, a thorough understanding of the enhancement of heat transfer rate using nanofluids is important to ensure that the heat can be released quickly and efficiently. The nanoparticles that are commonly used for nanofluid preparation include Silicon dioxide (SiO2), Titanium dioxide (TiO2), Copper (II) oxide (CuO), Zinc oxide (ZnO), and Aluminium oxide (Al2O3), while the base-fluid can be water, ethylene 1 Faculty of Mechanical and Automotive Engineering Technology, Universiti Malaysia Pahang, 26600, Pekan, Pahang, Malaysia 2 College of Electrical and Mechanical Engineering Department, Sustainable Energy Centre of Excellence, Addis Ababa Science and Technology University, 16417, Addis Ababa, Ethiopia