As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currentl...As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currently, thermal performance management of heat exchangers is more importantly issued for long term operation. Therefore, the performance evaluation techniques are required to improve the present method for the integrity evaluation of heat exchangers because of the exclusion of fouling calculation and the uncertainty analysis. This paper describes the developed thermal performance evaluation technique applied to the safety-related heat exchangers such as component cooling heat exchangers in a nuclear power plants.展开更多
The wind energy assessment studies are generally performed referring to neutral stability conditions for the atmosphere; this is considered a good hypothesis because neutral conditions characterize the high wind situa...The wind energy assessment studies are generally performed referring to neutral stability conditions for the atmosphere; this is considered a good hypothesis because neutral conditions characterize the high wind situations. However the increasing size of modem multi megawatt wind turbines allows to produce energy even in low wind regimes and non-neutral conditions can involve significant production period. In such situations the variations of the vertical wind shear can affect the energy production in a sensible way and it could be fundamental to investigate how atmospheric stability and orography can affect the wind profile and the power conversion. In this paper meso-scale numerical data, CFD modeling and remote sensed wind data were used in order to analyze such behavior and to understand how wind shear influences the energy content and the discussion about how to adjust the power curve to the site specific conditions.展开更多
文摘As the operation time of heat exchanger is increased, the thermal performance of them is gradually degraded due to fouling generated by water-borne deposits which are known to reduce the thermal efficiencies. Currently, thermal performance management of heat exchangers is more importantly issued for long term operation. Therefore, the performance evaluation techniques are required to improve the present method for the integrity evaluation of heat exchangers because of the exclusion of fouling calculation and the uncertainty analysis. This paper describes the developed thermal performance evaluation technique applied to the safety-related heat exchangers such as component cooling heat exchangers in a nuclear power plants.
文摘The wind energy assessment studies are generally performed referring to neutral stability conditions for the atmosphere; this is considered a good hypothesis because neutral conditions characterize the high wind situations. However the increasing size of modem multi megawatt wind turbines allows to produce energy even in low wind regimes and non-neutral conditions can involve significant production period. In such situations the variations of the vertical wind shear can affect the energy production in a sensible way and it could be fundamental to investigate how atmospheric stability and orography can affect the wind profile and the power conversion. In this paper meso-scale numerical data, CFD modeling and remote sensed wind data were used in order to analyze such behavior and to understand how wind shear influences the energy content and the discussion about how to adjust the power curve to the site specific conditions.
