The Experts below are selected from a list of 121347 Experts worldwide ranked by ideXlab platform

Yi Min Xia - One of the best experts on this subject based on the ideXlab platform.

  • lifting pipeline buckling under external Pressure Base on imperfect reason
    Advanced Materials Research, 2011
    Co-Authors: Zhi Jin Zhou, Zhao Wang, Yi Min Xia
    Abstract:

    The deep-sea pipe is an important part of mining lifting projects in the ocean floor. The uniqueness of environment conditions and design needs to determine the unforeseeable risks and challenges during the laying of pipeline. Based on extensive studies of loads acted on the pipeline and corresponding possible limit states for each installation method, a series of investigations on load-carrying capacity and buckling response of pipes under different loading combinations and various types defects (such as uniform ovalities)were carried out. In these calculations, the collapse Pressure has been associated with the Pressure maximum of a uniformly deforming long pipe. In experiments in a stiff Pressure lifting pipelines, collapse is always localized as shown in Figures 3 and 4.However,because pipe’s localization takes place after the Pressure maximum, the collapse Pressure yielded by the 2-D analysis suffices for most cases. Exceptions are pipes with local imperfections, in the form of dents. The adequacy of this important conclusion will be demonstrated in the future application, where such predictions are compared to experiments.

F Rovense - One of the best experts on this subject based on the ideXlab platform.

  • optimization of heliostat field in a thermal solar power plant with an unfired closed joule brayton cycle
    Energy Procedia, 2016
    Co-Authors: Mario Amelio, Patrizia Beraldi, Vittorio Ferraro, M Scornaienchi, F Rovense
    Abstract:

    Abstract In the last decades, concentrating solar power (CSP) has been gaining increasing attention as a sustainable technology for producing electricity. Nowadays, in the world, 483.6 MWs are produced by CSP plants of which 457 MW are already in commercial stage, whereas the other 430 MWs are under construction. In this paper, a solar tower with an unfired closed Joule-Brayton cycle of 10 MW peak power, located in Seville, is analyzed. The cycle, that employs only atmospheric air, without fuel consumption, relies on the possibility to vary the mean density of the air flowing in the plant. By using an auxiliary compressor and a bleed valve, a variable mass flow rate can be obtained so to keep the temperature at turbine inlet constant. On the other hand, in the concentrated solar plant, the number of installed heliostats can reflect towards the receiver the nominal thermal power, even with reduced values of the DNI. With the increase of the radiation, when the thermal energy flux achieves the limit tolerable by the receiver, a part of heliostats is defocused. On the contrary, in the presence of transients, due, for example, to clouds or in case of low solar radiation, the mirrors will be all, or in part, oriented towards the receiver face, so to keep constant the receiver outlet air temperature at the design value. Both the above mentioned control systems, without any fuel addition, act with the common goal of maintaining constant the air temperature at turbine inlet. However, they intervene at different times: at rated power, heliostats work, while the air flow rate is kept constant at the maximum value; when the nominal conditions are no longer achievable (the DNI values are insufficient), the adjustment is performed through the modulation of the Pressure Base control system, focusing the entire surface of the mirrors on the receiver. The analysis shows how the interaction between these systems influences the number and size of heliostats to be installed in the solar field. The study of the state of art has demonstrated that, in tower systems currently in operation, without storage, a solar multiple of 1.3 is generally used; our contribution shows how, with the air density control system, this value may be reduced, with consequent benefit on the heliostats cost. The numerical tests have been carried out by using the WINDELSOL software to optimize the heliostat field configuration and the THERMOFLOW, for the thermodynamic analysis.

Zhi Jin Zhou - One of the best experts on this subject based on the ideXlab platform.

  • lifting pipeline buckling under external Pressure Base on imperfect reason
    Advanced Materials Research, 2011
    Co-Authors: Zhi Jin Zhou, Zhao Wang, Yi Min Xia
    Abstract:

    The deep-sea pipe is an important part of mining lifting projects in the ocean floor. The uniqueness of environment conditions and design needs to determine the unforeseeable risks and challenges during the laying of pipeline. Based on extensive studies of loads acted on the pipeline and corresponding possible limit states for each installation method, a series of investigations on load-carrying capacity and buckling response of pipes under different loading combinations and various types defects (such as uniform ovalities)were carried out. In these calculations, the collapse Pressure has been associated with the Pressure maximum of a uniformly deforming long pipe. In experiments in a stiff Pressure lifting pipelines, collapse is always localized as shown in Figures 3 and 4.However,because pipe’s localization takes place after the Pressure maximum, the collapse Pressure yielded by the 2-D analysis suffices for most cases. Exceptions are pipes with local imperfections, in the form of dents. The adequacy of this important conclusion will be demonstrated in the future application, where such predictions are compared to experiments.

Mario Amelio - One of the best experts on this subject based on the ideXlab platform.

  • optimization of heliostat field in a thermal solar power plant with an unfired closed joule brayton cycle
    Energy Procedia, 2016
    Co-Authors: Mario Amelio, Patrizia Beraldi, Vittorio Ferraro, M Scornaienchi, F Rovense
    Abstract:

    Abstract In the last decades, concentrating solar power (CSP) has been gaining increasing attention as a sustainable technology for producing electricity. Nowadays, in the world, 483.6 MWs are produced by CSP plants of which 457 MW are already in commercial stage, whereas the other 430 MWs are under construction. In this paper, a solar tower with an unfired closed Joule-Brayton cycle of 10 MW peak power, located in Seville, is analyzed. The cycle, that employs only atmospheric air, without fuel consumption, relies on the possibility to vary the mean density of the air flowing in the plant. By using an auxiliary compressor and a bleed valve, a variable mass flow rate can be obtained so to keep the temperature at turbine inlet constant. On the other hand, in the concentrated solar plant, the number of installed heliostats can reflect towards the receiver the nominal thermal power, even with reduced values of the DNI. With the increase of the radiation, when the thermal energy flux achieves the limit tolerable by the receiver, a part of heliostats is defocused. On the contrary, in the presence of transients, due, for example, to clouds or in case of low solar radiation, the mirrors will be all, or in part, oriented towards the receiver face, so to keep constant the receiver outlet air temperature at the design value. Both the above mentioned control systems, without any fuel addition, act with the common goal of maintaining constant the air temperature at turbine inlet. However, they intervene at different times: at rated power, heliostats work, while the air flow rate is kept constant at the maximum value; when the nominal conditions are no longer achievable (the DNI values are insufficient), the adjustment is performed through the modulation of the Pressure Base control system, focusing the entire surface of the mirrors on the receiver. The analysis shows how the interaction between these systems influences the number and size of heliostats to be installed in the solar field. The study of the state of art has demonstrated that, in tower systems currently in operation, without storage, a solar multiple of 1.3 is generally used; our contribution shows how, with the air density control system, this value may be reduced, with consequent benefit on the heliostats cost. The numerical tests have been carried out by using the WINDELSOL software to optimize the heliostat field configuration and the THERMOFLOW, for the thermodynamic analysis.

Ming Gu - One of the best experts on this subject based on the ideXlab platform.

  • wind tunnel tests and numerical simulations of wind Pressures on buildings in staggered arrangement
    Journal of Wind Engineering and Industrial Aerodynamics, 2008
    Co-Authors: Aishe Zhang, Ming Gu
    Abstract:

    Abstract This paper presents numerical and experimental investigations of wind-induced interference effects on the Pressure distributions on a building adjacent to another one in staggered arrangement. The wind tunnel tests were carried out in a low-speed boundary layer wind tunnel. Mean and fluctuating Pressure and moment measurements on the principal building with interference from surroundings at different wind directions are obtained. The numerical predictions for Pressure distribution on the principal building are performed by solving the Reynolds-averaged Navier–Stokes (RANS) equations using the renormalization group (RNG) k – e turbulence model and then compared with the measurements. The computational method is Based on a Pressure correction algorithm of the SIMPLEC-type. The simulated Pressure, Base force and Base moment coefficients in different wind directions are generally in good agreement with the corresponding wind tunnel data.