As a means of harvesting solar energy for water treatment,solar-driven vapor generation is becoming more appealing.Due to their entangled fibrous networks and high surface area,fibers can be used as building blocks to...As a means of harvesting solar energy for water treatment,solar-driven vapor generation is becoming more appealing.Due to their entangled fibrous networks and high surface area,fibers can be used as building blocks to generate water vapor.In this paper,using a two-dimensional fiber bundle model,we studied the generation of solar vapor based on the fiber height,distance between fibers,and input sun radiation.The performance of solar absorption system was also evaluated by evaluating thermal and water management.Results showed a constant increase in solar vapor generation with an increasing fiber height and decreasing inter-fiber distance.However,the gain rate of using taller and more densely packed fiber bundles dwindled quickly.On the other hand,a shorter fiber had a higher evaporation rate per fiber height.The distance between fibers had a nonlinear effect on the fiber bundle evaporation rate.A new fiber bundle design was recommended with a fiber height of 15–20 mm and an inter-fiber distance of 1.5 mm.The results of this study can provide guidelines for future fiber bundle designs with increased efficiency,reduced cost,and versatile applications(i.e.,desalination,water purification,and power generation).展开更多
The objective of this study is to systematically assess the influences of the larynopharyneal anatomical details on airflow and particle behaviors during exhalation by means of image-based modeling. A physiologically ...The objective of this study is to systematically assess the influences of the larynopharyneal anatomical details on airflow and particle behaviors during exhalation by means of image-based modeling. A physiologically realistic nose-throat airway was developed with medical images. Individual airway anatomy such as uvula, pharynx, and larynx were then isolated for examination by progressively simplifying this image-based model geometry. Low Reynolds number (LRN) k-w model and Langrangian tracking model were used to simulate the dynamics of airflow and particle transport for a wide range of exhalation conditions (4-45 L/min) and particle sizes (1 nm-1 μm). Results showed that pharyngeal anatomical details exerted a significant impact on breathing resistance and particle profiles. Abrupt pressure drop resulting from the uvula-related airway obstruction was observed. Even though the total deposition rate in the nasal airway is largely unaffected by the upstream effect, the local deposition patterns vary notably. Results of this study also indicate that the pressure drop appears to be an appropriate parameter to characterize the geometric variations for diffusive depositions. Inclusion of pressure drop (D0.5Q-0.62dp0.07) gives an improved correlation than using the conventional diffusion factor (D0.5Q﹣0.28).展开更多
文摘As a means of harvesting solar energy for water treatment,solar-driven vapor generation is becoming more appealing.Due to their entangled fibrous networks and high surface area,fibers can be used as building blocks to generate water vapor.In this paper,using a two-dimensional fiber bundle model,we studied the generation of solar vapor based on the fiber height,distance between fibers,and input sun radiation.The performance of solar absorption system was also evaluated by evaluating thermal and water management.Results showed a constant increase in solar vapor generation with an increasing fiber height and decreasing inter-fiber distance.However,the gain rate of using taller and more densely packed fiber bundles dwindled quickly.On the other hand,a shorter fiber had a higher evaporation rate per fiber height.The distance between fibers had a nonlinear effect on the fiber bundle evaporation rate.A new fiber bundle design was recommended with a fiber height of 15–20 mm and an inter-fiber distance of 1.5 mm.The results of this study can provide guidelines for future fiber bundle designs with increased efficiency,reduced cost,and versatile applications(i.e.,desalination,water purification,and power generation).
文摘The objective of this study is to systematically assess the influences of the larynopharyneal anatomical details on airflow and particle behaviors during exhalation by means of image-based modeling. A physiologically realistic nose-throat airway was developed with medical images. Individual airway anatomy such as uvula, pharynx, and larynx were then isolated for examination by progressively simplifying this image-based model geometry. Low Reynolds number (LRN) k-w model and Langrangian tracking model were used to simulate the dynamics of airflow and particle transport for a wide range of exhalation conditions (4-45 L/min) and particle sizes (1 nm-1 μm). Results showed that pharyngeal anatomical details exerted a significant impact on breathing resistance and particle profiles. Abrupt pressure drop resulting from the uvula-related airway obstruction was observed. Even though the total deposition rate in the nasal airway is largely unaffected by the upstream effect, the local deposition patterns vary notably. Results of this study also indicate that the pressure drop appears to be an appropriate parameter to characterize the geometric variations for diffusive depositions. Inclusion of pressure drop (D0.5Q-0.62dp0.07) gives an improved correlation than using the conventional diffusion factor (D0.5Q﹣0.28).
