The Experts below are selected from a list of 121167 Experts worldwide ranked by ideXlab platform
Lan Xiao - One of the best experts on this subject based on the ideXlab platform.
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numerical study on combined free forced convection heat loss of solar cavity receiver under Wind environments
International Journal of Thermal Sciences, 2012Co-Authors: Lan XiaoAbstract:Abstract A numerical study has been carried out to investigate the impact of Wind on combined free-forced convection loss from a fully open solar cavity receiver for high-temperature dish/engine system. Visualization results, i.e., velocity vector field, temperature and velocity contours are provided to reveal the Wind Effect. The variations of combined free-forced convection heat loss with Wind speed, Wind incidence angle as well as the receiver inclinations have been quantitatively analyzed. Results show that, the combined convection heat loss for some Wind cases may not decrease monotonically with increasing inclinations as that of no-Wind cases. Under some certain Wind conditions, the combined convection heat loss may possibly be reduced below the natural convection value, and there exists critical Wind speed that minimizes the combined convection heat loss. Moreover, the combined convection heat loss of receiver at different inclinations becomes more and more indistinguishable as Wind speed increases. Finally, a simple correlation has been proposed to estimate the convection heat loss variation caused by the environmental Wind.
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convection heat loss from cavity receiver in parabolic dish solar thermal power system a review
Solar Energy, 2010Co-Authors: Lan Xiao, Yiding CaoAbstract:The convection heat loss from cavity receiver in parabolic dish solar thermal power system can significantly reduce the efficiency and consequently the cost Effectiveness of the system. It is important to assess this heat loss and subsequently improve the thermal performance of the receiver. This paper aims to present a comprehensive review and systematic summarization of the state of the art in the research and progress in this area. The efforts include the convection heat loss mechanism, experimental and numerical investigations on the cavity receivers with varied shapes that have been considered up to date, and the Nusselt number correlations developed for convection heat loss prediction as well as the Wind Effect. One of the most important features of this paper is that it has covered numerous cavity literatures encountered in various other engineering systems, such as those in electronic cooling devices and buildings. The studies related to those applications may provide valuable information for the solar receiver design, which may otherwise be ignored by a solar system designer. Finally, future development directions and the issues that need to be further investigated are also suggested. It is believed that this comprehensive review will be beneficial to the design, simulation, performance assessment and applications of the solar parabolic dish cavity receivers.
Yiding Cao - One of the best experts on this subject based on the ideXlab platform.
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convection heat loss from cavity receiver in parabolic dish solar thermal power system a review
Solar Energy, 2010Co-Authors: Lan Xiao, Yiding CaoAbstract:The convection heat loss from cavity receiver in parabolic dish solar thermal power system can significantly reduce the efficiency and consequently the cost Effectiveness of the system. It is important to assess this heat loss and subsequently improve the thermal performance of the receiver. This paper aims to present a comprehensive review and systematic summarization of the state of the art in the research and progress in this area. The efforts include the convection heat loss mechanism, experimental and numerical investigations on the cavity receivers with varied shapes that have been considered up to date, and the Nusselt number correlations developed for convection heat loss prediction as well as the Wind Effect. One of the most important features of this paper is that it has covered numerous cavity literatures encountered in various other engineering systems, such as those in electronic cooling devices and buildings. The studies related to those applications may provide valuable information for the solar receiver design, which may otherwise be ignored by a solar system designer. Finally, future development directions and the issues that need to be further investigated are also suggested. It is believed that this comprehensive review will be beneficial to the design, simulation, performance assessment and applications of the solar parabolic dish cavity receivers.
Yanru Yang - One of the best experts on this subject based on the ideXlab platform.
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Wind Effect on the thermo flow performances and its decay characteristics for air cooled condensers in a power plant
International Journal of Thermal Sciences, 2012Co-Authors: L J Yang, Yanru YangAbstract:Abstract Ambient Wind plays important roles in the thermo-flow performances of air-cooled condensers, but the Wind Effect mainly imposes on the upWind and bilateral condenser cells and will decay immediately. It is of benefit to the design and operation optimization of air-cooled condensers in a power plant to investigate the Wind Effect and its decay characteristics. On the basis of a representative 2 × 600 MW direct dry cooling power plant, the physical and mathematical models of the air-side fluid and heat flows for the air-cooled condensers at various ambient Wind speeds and directions are set up. The velocity and temperature fields are presented and the volumetric flow rate, inlet air temperature and heat rejection for different condenser cells are obtained by using CFD simulation. The results show that the reversed flows happened in the upWind condenser cells lead to the high inlet air temperature, worsening the cooling capability of air at high Wind speeds. Due to the combined behavior of hot plume discharge and ambient Wind, the Wind Effect decays rapidly along the Wind direction. At the Wind direction of 90°, the deficiencies of the thermo-flow performances of air-cooled condensers are mainly resulted from the flow rate decrease of the upWind condenser cells, not the hot plume recirculation. The hot plume recirculation flows play adverse roles in deteriorating the performances of air-cooled condensers at the Wind direction of 0°.
Herm Ja Van Wijhe - One of the best experts on this subject based on the ideXlab platform.
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Effects of passing ship with a drift angle on a moored ship
ASME 2014 33rd International Conference on Ocean Offshore and Arctic Engineering, 2014Co-Authors: Minggui Zhou, Zaojia Zou, Dano Roelvink, Herm Ja Van WijheAbstract:When a ship sailing at low speed passes a moored ship with a drift angle due to Wind Effect, the flow field around the ships is very different to the flow field without a drift angle and will cause larger hydrodynamic forces on the moored ship, compared with those without a drift angle. In this paper, a flow model in XBeach is applied to study the Effects of a passing ship at low speed with various drift angles on the moored ship. This method is based on the non-hydrostatic shallow water equations. Simulations are carried out for a 12500 TEU container ship passing a moored Panamax ship by using XBeach. The water level depression, return current and hydrodynamic forces on the moored ship are obtained and compared with the measurement data. Then the results at positive and negative drift angles are compared with the results at zero drift angle, respectively. The influence of the drift angle on the passing ship Effects is analyzed and the most serious situation for the moored ship, when the passing ship has different drift angles, is indicated. Finally, conclusions concerning the Effects of a passing ship with a drift angle on a moored ship are drawn.Copyright © 2014 by ASME
Nattavut Yampikulsakul - One of the best experts on this subject based on the ideXlab platform.
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adaptive learning in time variant processes with application to Wind power systems
IEEE Transactions on Automation Science and Engineering, 2016Co-Authors: Eunshin Byon, Youngjun Choe, Nattavut YampikulsakulAbstract:This study develops new adaptive learning methods for a dynamic system where the dependency among variables changes over time. In general, many statistical methods focus on characterizing a system or process with historical data and predicting future observations based on a developed time-invariant model. However, for a nonstationary process with time-varying input-to-output relationship, a single baseline curve may not accurately characterize the system’s dynamic behavior. This study develops kernel-based nonparametric regression models that allow the baseline curve to evolve over time. Applying the proposed approach to a real Wind power system, we investigate the nonstationary nature of Wind Effect on the turbine response. The results show that the proposed methods can dynamically update the time-varying dependency pattern and can track changes in the operational Wind power system.
