Browsing by Author "Togun, Hussein"

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    Experimental investigation of a novel heat exchanger for optimizing heat transfer performance using Al2O3‑water nanofluids
    (Springer, 2023) Hamidatou, Smail; Nadir, M.; Togun, Hussein; Azher, M. Abed; Deghoum, K.; Hadjad, A.; Goodarz, Ahmadi
    This study presents an experimental investigation to determine the heat transfer enhancement in a novel heat exchanger known as the "Helicoidal Square-Shaped Heat Exchanger" with and without using a nanofuid. The experiments were performed for the range of Reynolds numbers from 4400 to 8000, using nanofuid (Al2O3-pure water) at the concentrations 0.1, 0.25, and 0.5%. This experimental investigation found that the heat transfer ratio is improved by increasing the nanofuid concentrations and the fow Reynolds number. The highest value of the heat transfer ratio was at Re = 8000, and 0.5% concentration of nanofuids. The corresponding increment in the heat transfer rate was 13.46 %, the heat transfer coefcient augmented by 9.64 %, and the Nusselt number improved by 10.43% compared to the results obtained experimentally with distilled water. The results obtained for the distilled water were verifed with the Dittus-Boelter equation and numerical simulation. In addition, all obtained experimental data were compared with the CFD simulation. The use of nanofuids for heat transfer enhancement has a wide range of applications. Therefore, the presented results suggest using Al2O3-water nanofuids to improve the efciency of many renewable energy plants, including solar and geothermal energy systems.
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    Numerical simulation on heat transfer augmentation by using innovative hybrid ribs in a forward-facing contracting channel
    (MDPI, 2023) Togun, Hussein; Hamidatou, Smail; Hayder, Ibrahim Mohammed; Azher, M. Abed
    This study aims to investigate the thermal behavior and aerodynamic phenomena in a heated channel with varied rib configurations using computational fluid dynamics (CFD) simulations. Incorporating ribs in such systems enhances heat transfer and increases flow resistance and manufacturing costs. Understanding heat exchanger theory, measurement methods, and numerical calculations are crucial for creating efficient heat exchangers. The current research employs numerical analysis to assess the impact of hybrid ribs on heat transfer enhancement in forward-facing contracting channels (FFS). A two-dimensional forced convection heat transfer simulation under turbulent flow conditions was performed, considering the presence and absence of ribs with dimensions of 1 cm by 1 cm and spaced 11 cm apart. The arrangement of the ribs causes symmetrical temperature and flow distribution after and before each rib. The results demonstrate that the use of hybrid ribs outperforms the use of individual rib configurations in terms of thermal performance. This is due to the distinct flow patterns generated as the fluid passes through each rib. The triangle ribs had a more significant impact on the pressure drop than other rib configurations, while the cross ribs showed a lesser effect. The ribs improve the heat transfer coefficient while increasing the pressure drop, and the values of the Reynolds number were found to be directly proportional to the heat transfer coefficient and the pressure drop. The study concludes with a qualitative and quantitative analysis demonstrating the accuracy and coherence of the obtained computational results