In order to research the influence of liquid water content ( LWC ) on blade icing of wind turbine, a numerical simulation method for blade icing was established. The numerical simulation was based on low speed viscous...In order to research the influence of liquid water content ( LWC ) on blade icing of wind turbine, a numerical simulation method for blade icing was established. The numerical simulation was based on low speed viscous N-S equation. The trajectory equation of water droplets was established by Lagrangian method. The mass and energy conservation equations of the water droplets impacting on the surface of the blade were solved based on control body theory. Three sections along blade span wise of a 1.5 MW wind turbine were decided to simulate icing. Five kinds of LWC were selected for simulation including 0.2,0.4,0.6,0.8 and 1.0 g/m^3 under two ambient temperatures of -10 ℃ and -20 ℃. The medium volume droplet diameter ( MVD ) was 30μm. The simulations included icing shape on blade surface, dimensionless icing area and dimensionless maximum stagnation thickness. Furthermore, the flow fields around both the iced blade airfoil and the original one were simulated and analyzed. Accor-ding to the results, the typical icing characteristics of icing shape, icing area and thickness were greatly affected by the difference of LWCs. This study can provide theoretical reference for the research on antiicing and deicing of wind turbine blade.展开更多
Molecular dynamics simulations are performed to observe the evolutions of 512 and 51262 cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 250 K and 230 K. The lifetime...Molecular dynamics simulations are performed to observe the evolutions of 512 and 51262 cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 250 K and 230 K. The lifetimes of these clusters are calculated according to their Lindemann index δ (t) using the criteria of δ≥0.07. For both the filled and empty clusters, we find the dynamics of bulk water determines the lifetimes of cage-like water clusters, and that the lifetime of 512 62 cage-like cluster is the same as that of 512 cage-like cluster. Although the methane molecule indeed makes the filled cage-like cluster more stable than the empty one, the empty cage-like cluster still has chance to be long-lived compared with the filled clusters. These observations support the labile cluster hypothesis on the formation mechanisms of gas hydrates.展开更多
双碳目标驱动下,化学吸收法捕集CO_(2)作为最具有大规模应用前景的碳捕集技术被寄予厚望。但吸收剂的高能耗特性是阻碍其进一步发展的关键因素。新型少水吸收剂由于其在降低能耗方面的巨大潜力引起广泛关注。该文以吸收剂主剂作为分类基...双碳目标驱动下,化学吸收法捕集CO_(2)作为最具有大规模应用前景的碳捕集技术被寄予厚望。但吸收剂的高能耗特性是阻碍其进一步发展的关键因素。新型少水吸收剂由于其在降低能耗方面的巨大潜力引起广泛关注。该文以吸收剂主剂作为分类基准,介绍3大类少水吸收剂(包括均相有机胺类少水吸收剂、两相吸收剂、离子液体、氨基硅油类少水吸收剂以及有机液体吸收剂)国内外研究进展,阐述少水吸收剂关键性能结果如热力学性能、动力学性能、物理特性等,并对不同类少水吸收剂性能进行了横向对比。结果表明,少水吸收剂具有相比乙醇胺(monoethanolamine,MEA)吸收剂更低的再生能耗(平均能耗:2.3 GJ/t CO_(2))。尽管少水吸收剂拥有相比MEA吸收剂更高的富液粘度,但其中均相少水吸收剂相平均粘度仅为10.3 m Pa·S,与目前混合胺吸收剂粘度相当,能够适配现有碳捕集系统中的换热系统,可达到理想换热效果,无需对贫富液换热器等进行额外改造优化。展开更多
基金sponsored by the projects supported by the National Natural Science Foundation of China(NSFC,No.51576037 and 11172314)the National Key Basic Research Program of China (2015CB755800)
文摘In order to research the influence of liquid water content ( LWC ) on blade icing of wind turbine, a numerical simulation method for blade icing was established. The numerical simulation was based on low speed viscous N-S equation. The trajectory equation of water droplets was established by Lagrangian method. The mass and energy conservation equations of the water droplets impacting on the surface of the blade were solved based on control body theory. Three sections along blade span wise of a 1.5 MW wind turbine were decided to simulate icing. Five kinds of LWC were selected for simulation including 0.2,0.4,0.6,0.8 and 1.0 g/m^3 under two ambient temperatures of -10 ℃ and -20 ℃. The medium volume droplet diameter ( MVD ) was 30μm. The simulations included icing shape on blade surface, dimensionless icing area and dimensionless maximum stagnation thickness. Furthermore, the flow fields around both the iced blade airfoil and the original one were simulated and analyzed. Accor-ding to the results, the typical icing characteristics of icing shape, icing area and thickness were greatly affected by the difference of LWCs. This study can provide theoretical reference for the research on antiicing and deicing of wind turbine blade.
基金supported by the National Natural Science Foundation of China(Grant No.40102005 and No.49725205).
文摘Molecular dynamics simulations are performed to observe the evolutions of 512 and 51262 cage-like water clusters filled with or without a methane molecule immersed in bulk liquid water at 250 K and 230 K. The lifetimes of these clusters are calculated according to their Lindemann index δ (t) using the criteria of δ≥0.07. For both the filled and empty clusters, we find the dynamics of bulk water determines the lifetimes of cage-like water clusters, and that the lifetime of 512 62 cage-like cluster is the same as that of 512 cage-like cluster. Although the methane molecule indeed makes the filled cage-like cluster more stable than the empty one, the empty cage-like cluster still has chance to be long-lived compared with the filled clusters. These observations support the labile cluster hypothesis on the formation mechanisms of gas hydrates.
文摘双碳目标驱动下,化学吸收法捕集CO_(2)作为最具有大规模应用前景的碳捕集技术被寄予厚望。但吸收剂的高能耗特性是阻碍其进一步发展的关键因素。新型少水吸收剂由于其在降低能耗方面的巨大潜力引起广泛关注。该文以吸收剂主剂作为分类基准,介绍3大类少水吸收剂(包括均相有机胺类少水吸收剂、两相吸收剂、离子液体、氨基硅油类少水吸收剂以及有机液体吸收剂)国内外研究进展,阐述少水吸收剂关键性能结果如热力学性能、动力学性能、物理特性等,并对不同类少水吸收剂性能进行了横向对比。结果表明,少水吸收剂具有相比乙醇胺(monoethanolamine,MEA)吸收剂更低的再生能耗(平均能耗:2.3 GJ/t CO_(2))。尽管少水吸收剂拥有相比MEA吸收剂更高的富液粘度,但其中均相少水吸收剂相平均粘度仅为10.3 m Pa·S,与目前混合胺吸收剂粘度相当,能够适配现有碳捕集系统中的换热系统,可达到理想换热效果,无需对贫富液换热器等进行额外改造优化。
