Yazar "Al-Khafaji, Zainab" seçeneğine göre listele

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    Corrosion reduction in steam turbine blades using nano-composite coating
    (Elsevier B.V., 2023) Sattar, Sabaa; Alaiwi, Yaser; Radhi, Nabaa Sattar; Al-Khafaji, Zainab; Al-Hashimi, Osamah; Alzahrani, Hassan; Yaseen, Zaher Mundher
    The current study aims to reduce the hot corrosion issues in steam turbines for Al-Mussaib thermal power stations. To gain the aim of the study, many experimental tests were conducted by taking a sample from an existing broken steam turbine blade to identify the alloy composition and preparing samples with exact composition by powder metallurgy method, then using the electro-deposition method to coat the prepared samples by three different coating composite materials consists of TiO2 in different ratios (5, 10 and 15) g/l and 5 g/l SiO2 added to Watt's solution. To verify the efficiency of coating, several tests were conducted (surface roughness, hardness, wear, and oxidation test). The obtained results indicated that increasing the Ni-5%SiO2-TiO2 (5, 10 and 15) g/l caused an increase in the coating thickness, which is compatible with increasing the surface roughness. Also, the sample hardness increased after coating, which returned to increasing TiO2 amount (5, 10 and 15) g/l. However, wear resistance for the samples after coating by selected coating composite and 10 g/l TiO2 amount records the highest reduction in the wear of the sample.
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    Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency
    (Penerbit Akademia Baru, 2024) Al-Abayechi, Yasir; Alaiwi, Yaser; Al-Khafaji, Zainab
    This research is carried out to investigate and examine the critical benefits and significant contributions of integrating nanoparticles into the ETSC system to enhance the thermal efficiency, thermal performance, temperature out, and energy storage of the ETSC. The Simcenter STAR-CCM+ 2022.1 software package implemented numerical analysis and thermal simulations. Further, a comparative analysis is conducted on two case studies to validate the critical role and contributions of employing the aluminum oxide nanomaterial in the solar collector system to enhance its thermal efficiency and improve its thermal performance and heat transfer, including (1) conventional ETSC and (2) ETSC with Al2O3. According to the numerical analysis and comparative study findings, the results of this research revealed that employing and adding the aluminum oxide nanomaterial into the ETSC system had contributed to several beneficial impacts and significant advantages. In addition, using Al2O3 achieved enhancements in the thermal efficiency, increases in the outlet collector’s temperature, improvements in the rate of heat flux of the pipes, the tube inside the collector, heat transfer of the hot water storage tank, and a rise in the temperature gradient the hot water temperature increased from (between 44.3 and 74.8 ºC) to (between 49.6-80.3 ºC). Besides, the velocity of the water flow inside the solar collector in the second case in which the aluminum oxide nanoparticles are used was higher due to the absorption of further solar radiation and thermal energy, which resulted in a considerable increase in the kinetic energy of water molecules from 0.01 to 0.07 m/s. Also, it was found that the velocity directions and profile were slightly more turbulent in the second case than the conventional solar collector due to more thermal energy absorbed and stored in the ETSC from solar radiation. © 2024, Penerbit Akademia Baru. All rights reserved.
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    INVESTIGATING BACK SURFACE COOLING SYSTEM USING PHASE CHANGE MATERIALS AND HEATSINK ON PHOTOVOLTAIC PERFORMANCE
    (Mustansiriyah University College of Engineering, 2024) Aljumaili, Ahmed; Alaiwi, Yaser; Al-Khafaji, Zainab
    This research aims to improve thermal performance and compare the performance of two common crystalline PV panel types (Mono and poly). Modules with a back-cooling system were designed and numerically analyzed with SolidWorks and ANSYS-Fluent-2021-R2 for the simulation under Baghdad weather at noon. The cooling system used consists of a phase-change material, paraffin wax (RT55), with a thickness of 5 cm and a heatsink with 33 fins with heights of 10, 20, and 30 mm and thicknesses of 2, 4, and 6 mm. to select the best height of the wax 1, 3, 5, 10, 20 cm examined. The result showed that for polycrystals, the panel temperature was reduced by 8.4°C using PCM and 11.9°C using PCM-fins. Also, output power was enhanced to 200.6 W by 10.2 W, and efficiency improved by 5%. Similarly, using PCM and PCM-fins lowered the temperature of the monocrystalline by 8.3 and 12.5°C, respectively. Therefore, the output power is enhanced to 202.4 W by 10.7 W and improves the electrical efficiency by 5.2%. The results of the study showed that mono had better performance than poly. This result is acceptable and is in good agreement with previous studies. © 2024, Mustansiriyah University College of Engineering. All rights reserved.
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    Numerical investigation of nanofluid-based flow behavior and convective heat transfer using helical screw
    (Penerbit Akademia Baru, 2024) Khlewee, Abdulqader Sala; Alaiwi, Yaser; Jasim, Talib Abdulameer; Mahdi, Mohammed Alamin Talib; Hussain, Abdullah Jabar; Al-Khafaji, Zainab
    A multitude of industrial and residential customers have utilized heat transfer devices for heat conversion and recovery. For the last fifty years, engineers have diligently endeavored to refine a heat exchanger design that reduces energy use without compromising efficiency. Most techniques for enhancing heat transfer operate by either augmenting the effective heat transfer surface area or inducing turbulence, hence reducing thermal resistance. This work utilized CFD to model Al2O3 and CuO nanoparticles inside the adsorber tube of a parabolic solar collector with N=1 and N=2 turbulators at Re of 20000, 60000, and 100000, respectively, with a turbulence intensity of 5%. The turbulence intensity was determined to be 5% of the total energy of the particles. The inclusion of nanoparticles in the base fluid enhances heat conduction. Consequently, nanofluids are viable options for alternate heat transmission mechanisms. Torsional turbulator models with N=2 have a higher output temperature (Temp) than those with N=1 due to the elevated practical heat level of the N=2 models. The intake temp is elevated from 35 to 46 degrees Celsius due to the existence of CuO nanoparticles in the adjacent turbulator adsorber tubes. The Reynolds number (Re) consistently increases the Nusselt number (Nu). Furthermore, the Nu indicates a higher quantity of CuO nanoparticle models compared to Al2O3 nanoparticle models. Furthermore, CuO nanoparticles exhibit superior efficacy compared to Al2O3 in pressure reduction. In comparison to the N=2 dual-turbulator mode, the N=1 single-turbulator mode exhibits a 34% increase in conflict. Pressure loss coefficients are higher for devices including two turbulators. Across a broad spectrum of Re, the thermal PEC for N=2 models exceeded that of N=1 models by 12 percentage points. CuO nanofluid receivers have better efficacy compared to Al2O3 receivers in the conversion of solar energy into thermal energy. The two-turbulator model, operating at a Re of 100000 and using CuO nanoparticles, attains optimal thermal efficiency. The factor of friction decreases with increasing Re, with Water N=1 showing higher frictional losses than Water N=2, indicating greater turbulence and resistance.
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    Numerical simulation for effect of composite coating (TIO2+SIO2) thickness on steam turbine blades thermal and stress distribution
    (Editura Politechnica, 2023) Sattar, Sabaa; Alaiwi, Yaser; Radhi, Nabaa Sattar; Al-Khafaji, Zainab
    The steam turbine is the most effective and straightforward method of converting thermal energy into mechanical power. As steam expands, its velocity increases, exerting strong stresses on the turbine blades. The linear motion of the incoming steam with high temp and pressure is converted to rotation of the turbine shaft by the turbine blades. The most important issue in power plants might be corrosion in the turbine blades. Corrosion might cause turbine blade masses to be out of balance, which can cause major vibration issues. The ANSYS software program did a numerical analysis to investigate the impact of coating thickness for the selected coating materials (Ti, TiO2, and SiO2) on the steam turbine. The numerical analysis was done using six coating groups; three of them consist of single materials (Ti, TiO2, and SiO2), and the other three consist of hybrid coating (Ti+ TiO2, Ti+ SiO2, and Ti+TiO2+SiO2) and each group has three coating thickness (0.01, 0.02 and 0.04) μm. Numerical analysis results indicated that the total heat flux and the temp increased after applying the coating. In contrast, total deformation for all selected groups was decreased after applying a coating for all of them; the change in the coating thickness from (0.01 to 0.04) μm has no effective changes on the samples after coating. Using (Ti and TiO2) show a significant increase in max principal stress compared to the uncoated sample. The application of Ti shows the impact of coating thickness on max principal stress, where a change in the coating thickness from 0.01 to 0.04 μm leads to a reduction in the max principal stress value from 1421.9 to 1211.4 MPa.
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    Reducing oil pipes corrosion by (ZN-NI) alloy coating on low carbon steel substrate by sustainable process
    (Taylor's University, 2023) Radhi, Nabaa Sattar; Al-Khafaji, Zainab; Mareai, Basim M.; Radhi, Sabaa; Alsaegh, Ayam M.
    The problem of corrosion is quite risky and costly. There is always the possibility of bridges and buildings collapsing, oil pipelines bursting, chemical plants leaking, and bathroom flooding. Corroded medical implants might result in blood poisoning, corroded electrical connections could start fires and cause other problems, and worldwide air pollution could damage artwork. Corrosion threatens the safe disposal of radioactive waste that should be stored in containers for millennia. This study makes an effort to enhance further the electroplated layer's (Zn-Ni) alloy characteristics. In this study, samples of low-carbon steel are electrodeposited with layers of varying thicknesses of (Zn-Ni) from an alkaline solution throughout various coating times (15, 30, and 60 minutes). The mechanical and corrosion characteristics of the electrodeposits layer are determined using X-ray fluorescence (XRF), which is also utilized to analyse the microhardness and corrosion test results of the (Zn-Ni) deposited layer.
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    Reducing vibration and noise in the oil sector using nanoparticle-reinforced polymers
    (Editura Politechnica, 2024) Al-Abboodi, Taif Mohsin Maeli; Alaiwi, Yaser; Al-Khafaji, Zainab
    Vibration in pumps is a common problem and can lead to various problems that can affect the performance, reliability, and safety of the equipment. When pumps vibrate excessively, it can lead to decreased efficiency, increased wear, and premature failure of pump components. Therefore, it is essential to address pump vibration quickly and effectively. Maintenance personnel can take corrective action by monitoring and diagnosing the cause of pump vibration, which will help ensure reliable and efficient pump operation, reduce downtime, and improve workplace safety. This study conducted experimental work to determine the static specifications, such as tensile and tear strength of specimens manufactured from natural rubber reinforced with materials such as ZnO, MWCNTs, and NaHCO3. Another essential dynamic study was performed on a structure of aluminum sheets resting on flexible rubber foundations. The rubber base around the outer bottom border of the metal plate (Al6061) will be 15 mm wide and in three thicknesses (5, 10, 15) mm. In this work, both computational and experimental methodologies for creating elastomers with confirmed material constants are investigated. The FEA analysis of the seventy-two samples showed results related to the fundamental natural frequencies with a maximum variance value of 3.37%.