The Experts below are selected from a list of 65286 Experts worldwide ranked by ideXlab platform

Mohammadhasan Khaliji Oskouei - One of the best experts on this subject based on the ideXlab platform.

  • efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles
    Renewable Energy, 2020
    Co-Authors: Amir Mohammad Norouzi, Majid Siavashi, Mohammadhasan Khaliji Oskouei
    Abstract:

    Abstract Enhancing the thermal performance of parabolic trough collectors (PTC) is of major interest to maximize solar energy absorption. In common PTCs, solar irradiation is focused on the lower part of the absorber tube which causes high temperatures, thermal stress, and tube deformation. To overcome these problems, it is suggested to rotate the absorber tube with a specified frequency to reduce the high surface temperature and increase the solar energy absorption. In addition, a nanofluid (Al2O3-Therminol) is utilized as the heat-carrying fluid. Effects of various parameters, including the rotational speed, absorber tube Material, Flow Rate, and nanoparticles concentration on the collector efficiency were studied. An approximate 2D-transient model of PTC is proposed and a steady-laminar numerical simulation is conducted for the 3D cases. Results indicate that the aluminum is the best choice among the other Materials used for the absorber tube, providing about 16 K higher output temperature which is nearly 5% higher than that of the steel. Also, a more uniform surface temperature distribution and a higher collector thermal efficiency could be met. Accordingly, an average increase of 15% in the thermal efficiency of the collector and a maximum decrease of 64 K in the absorber tube temperature are reachable.

  • efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles
    Renewable Energy, 2020
    Co-Authors: Amir Mohammad Norouzi, Majid Siavashi, Mohammadhasan Khaliji Oskouei
    Abstract:

    Abstract Enhancing the thermal performance of parabolic trough collectors (PTC) is of major interest to maximize solar energy absorption. In common PTCs, solar irradiation is focused on the lower part of the absorber tube which causes high temperatures, thermal stress, and tube deformation. To overcome these problems, it is suggested to rotate the absorber tube with a specified frequency to reduce the high surface temperature and increase the solar energy absorption. In addition, a nanofluid (Al2O3-Therminol) is utilized as the heat-carrying fluid. Effects of various parameters, including the rotational speed, absorber tube Material, Flow Rate, and nanoparticles concentration on the collector efficiency were studied. An approximate 2D-transient model of PTC is proposed and a steady-laminar numerical simulation is conducted for the 3D cases. Results indicate that the aluminum is the best choice among the other Materials used for the absorber tube, providing about 16 K higher output temperature which is nearly 5% higher than that of the steel. Also, a more uniform surface temperature distribution and a higher collector thermal efficiency could be met. Accordingly, an average increase of 15% in the thermal efficiency of the collector and a maximum decrease of 64 K in the absorber tube temperature are reachable.

Amir Mohammad Norouzi - One of the best experts on this subject based on the ideXlab platform.

  • efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles
    Renewable Energy, 2020
    Co-Authors: Amir Mohammad Norouzi, Majid Siavashi, Mohammadhasan Khaliji Oskouei
    Abstract:

    Abstract Enhancing the thermal performance of parabolic trough collectors (PTC) is of major interest to maximize solar energy absorption. In common PTCs, solar irradiation is focused on the lower part of the absorber tube which causes high temperatures, thermal stress, and tube deformation. To overcome these problems, it is suggested to rotate the absorber tube with a specified frequency to reduce the high surface temperature and increase the solar energy absorption. In addition, a nanofluid (Al2O3-Therminol) is utilized as the heat-carrying fluid. Effects of various parameters, including the rotational speed, absorber tube Material, Flow Rate, and nanoparticles concentration on the collector efficiency were studied. An approximate 2D-transient model of PTC is proposed and a steady-laminar numerical simulation is conducted for the 3D cases. Results indicate that the aluminum is the best choice among the other Materials used for the absorber tube, providing about 16 K higher output temperature which is nearly 5% higher than that of the steel. Also, a more uniform surface temperature distribution and a higher collector thermal efficiency could be met. Accordingly, an average increase of 15% in the thermal efficiency of the collector and a maximum decrease of 64 K in the absorber tube temperature are reachable.

  • efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles
    Renewable Energy, 2020
    Co-Authors: Amir Mohammad Norouzi, Majid Siavashi, Mohammadhasan Khaliji Oskouei
    Abstract:

    Abstract Enhancing the thermal performance of parabolic trough collectors (PTC) is of major interest to maximize solar energy absorption. In common PTCs, solar irradiation is focused on the lower part of the absorber tube which causes high temperatures, thermal stress, and tube deformation. To overcome these problems, it is suggested to rotate the absorber tube with a specified frequency to reduce the high surface temperature and increase the solar energy absorption. In addition, a nanofluid (Al2O3-Therminol) is utilized as the heat-carrying fluid. Effects of various parameters, including the rotational speed, absorber tube Material, Flow Rate, and nanoparticles concentration on the collector efficiency were studied. An approximate 2D-transient model of PTC is proposed and a steady-laminar numerical simulation is conducted for the 3D cases. Results indicate that the aluminum is the best choice among the other Materials used for the absorber tube, providing about 16 K higher output temperature which is nearly 5% higher than that of the steel. Also, a more uniform surface temperature distribution and a higher collector thermal efficiency could be met. Accordingly, an average increase of 15% in the thermal efficiency of the collector and a maximum decrease of 64 K in the absorber tube temperature are reachable.

Majid Siavashi - One of the best experts on this subject based on the ideXlab platform.

  • efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles
    Renewable Energy, 2020
    Co-Authors: Amir Mohammad Norouzi, Majid Siavashi, Mohammadhasan Khaliji Oskouei
    Abstract:

    Abstract Enhancing the thermal performance of parabolic trough collectors (PTC) is of major interest to maximize solar energy absorption. In common PTCs, solar irradiation is focused on the lower part of the absorber tube which causes high temperatures, thermal stress, and tube deformation. To overcome these problems, it is suggested to rotate the absorber tube with a specified frequency to reduce the high surface temperature and increase the solar energy absorption. In addition, a nanofluid (Al2O3-Therminol) is utilized as the heat-carrying fluid. Effects of various parameters, including the rotational speed, absorber tube Material, Flow Rate, and nanoparticles concentration on the collector efficiency were studied. An approximate 2D-transient model of PTC is proposed and a steady-laminar numerical simulation is conducted for the 3D cases. Results indicate that the aluminum is the best choice among the other Materials used for the absorber tube, providing about 16 K higher output temperature which is nearly 5% higher than that of the steel. Also, a more uniform surface temperature distribution and a higher collector thermal efficiency could be met. Accordingly, an average increase of 15% in the thermal efficiency of the collector and a maximum decrease of 64 K in the absorber tube temperature are reachable.

  • efficiency enhancement of the parabolic trough solar collector using the rotating absorber tube and nanoparticles
    Renewable Energy, 2020
    Co-Authors: Amir Mohammad Norouzi, Majid Siavashi, Mohammadhasan Khaliji Oskouei
    Abstract:

    Abstract Enhancing the thermal performance of parabolic trough collectors (PTC) is of major interest to maximize solar energy absorption. In common PTCs, solar irradiation is focused on the lower part of the absorber tube which causes high temperatures, thermal stress, and tube deformation. To overcome these problems, it is suggested to rotate the absorber tube with a specified frequency to reduce the high surface temperature and increase the solar energy absorption. In addition, a nanofluid (Al2O3-Therminol) is utilized as the heat-carrying fluid. Effects of various parameters, including the rotational speed, absorber tube Material, Flow Rate, and nanoparticles concentration on the collector efficiency were studied. An approximate 2D-transient model of PTC is proposed and a steady-laminar numerical simulation is conducted for the 3D cases. Results indicate that the aluminum is the best choice among the other Materials used for the absorber tube, providing about 16 K higher output temperature which is nearly 5% higher than that of the steel. Also, a more uniform surface temperature distribution and a higher collector thermal efficiency could be met. Accordingly, an average increase of 15% in the thermal efficiency of the collector and a maximum decrease of 64 K in the absorber tube temperature are reachable.

O A Koya - One of the best experts on this subject based on the ideXlab platform.

  • numerical analysis of lift based in pipe turbine for predicting hydropower harnessing potential in selected water distribution networks for waterlines optimization
    Engineering Science and Technology an International Journal, 2018
    Co-Authors: Temidayo Lekan Oladosu, O A Koya
    Abstract:

    Abstract The research models and simulates in-pipe turbine hydropower harnessing possibilities in water distribution networks of the sites under investigation considering in-pipe lift-based spherical turbine. The hydrofoil profile of the turbine is geneRated using National Advisory Committee for Aeronautics (NACA) aerofoil generator. Consequently, a Computer-Aided Design (CAD) model of the in-line lift-based spherical turbine is then developed and simulated, based on the peak and lean period of the volumetric discharge Rates using commercial computational fluid dynamics software (Autodesk Simulation CFD®). The time series of power outputs are computed from the time series of discharge variations. A lift-based spherical turbine with NACA 0020 foil cross-section appears appropriate for extraction of energy in the water distribution pipelines. Furthermore, the minimum and maximum percentage head loss due to insertion of the turbine is about 1.94% at lean Flow Rates and 9.70% at the peaks for 250 mm pipelines. The available power was found out to depend on the density of the turbine blades Material, Flow Rate, and the pipe diameter. The estimated lean and the peak electric power are about 415 and 1663 W, respectively, using aluminium foil blades while stainless steel foil produces about 242 and 1080 W in the 250 mm pipe.

  • Numerical analysis of lift-based in-pipe turbine for predicting hydropower harnessing potential in selected water distribution networks for waterlines optimization
    'Elsevier BV', 2018
    Co-Authors: Temidayo Lekan Oladosu, O A Koya
    Abstract:

    The research models and simulates in-pipe turbine hydropower harnessing possibilities in water distribution networks of the sites under investigation considering in-pipe lift-based spherical turbine. The hydrofoil profile of the turbine is geneRated using National Advisory Committee for Aeronautics (NACA) aerofoil generator. Consequently, a Computer-Aided Design (CAD) model of the in-line lift-based spherical turbine is then developed and simulated, based on the peak and lean period of the volumetric discharge Rates using commercial computational fluid dynamics software (Autodesk Simulation CFD®). The time series of power outputs are computed from the time series of discharge variations. A lift-based spherical turbine with NACA 0020 foil cross-section appears appropriate for extraction of energy in the water distribution pipelines. Furthermore, the minimum and maximum percentage head loss due to insertion of the turbine is about 1.94% at lean Flow Rates and 9.70% at the peaks for 250 mm pipelines. The available power was found out to depend on the density of the turbine blades Material, Flow Rate, and the pipe diameter. The estimated lean and the peak electric power are about 415 and 1663 W, respectively, using aluminium foil blades while stainless steel foil produces about 242 and 1080 W in the 250 mm pipe. Keywords: In-pipe, Turbine, Simulation, Optimization, Hydropower, Renewable, Water distribution, Modellin

Schlangen E. - One of the best experts on this subject based on the ideXlab platform.

  • 3D printing of calcined clay-limestone-based cementitious Materials
    'Elsevier BV', 2021
    Co-Authors: Chen Y., Copuroglu Oguzhan, He S., Zhang Y., Wan Z., Schlangen E.
    Abstract:

    This paper aims to investigate the influences of high Portland cement substitutions (>60 wt%) by low-grade calcined clay (CC) and limestone (LF) on 3D concrete printability, stiffness evolution and early-age hydration. Results show that, with the same dosage of admixtures (superplasticizer and viscosity modifier), increasing LF and CC content reduced the slump, Flowability and initial Material Flow Rate, and significantly improved the buildability of fresh mixtures, which can be attributed to the reduced water film thickness (WFT). Furthermore, the stiffness evolution and SSAtotal development up to the first 3 h were acceleRated by increasing CC content, which can also be linked to the change of WFT, and consumption of superplasticizer for the dispersion induced by hydration products. Additionally, the dilution effect on compressive strength and hydration caused by the high cement replacement was observed.Materials and Environmen

  • 3D printing of calcined clay-limestone-based cementitious Materials
    'Elsevier BV', 2021
    Co-Authors: Chen Y., Copuroglu Oguzhan, He S., Zhang Y., Wan Z., Schlangen E.
    Abstract:

    This paper aims to investigate the influences of high Portland cement substitutions (>60 wt%) by low-grade calcined clay (CC) and limestone (LF) on 3D concrete printability, stiffness evolution and early-age hydration. Results show that, with the same dosage of admixtures (superplasticizer and viscosity modifier), increasing LF and CC content reduced the slump, Flowability and initial Material Flow Rate, and significantly improved the buildability of fresh mixtures, which can be attributed to the reduced water film thickness (WFT). Furthermore, the stiffness evolution and SSAtotal development up to the first 3 h were acceleRated by increasing CC content, which can also be linked to the change of WFT, and consumption of superplasticizer for the dispersion induced by hydration products. Additionally, the dilution effect on compressive strength and hydration caused by the high cement replacement was observed.