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The Importance of Flapping Kinematic Parameters in the Facilitation of the Different Flight Modes of Dragonflies

Journal of Bionic Engineering 2021年第2期18卷 419-427页

作者： Xiaohui Liu Csaba Hefler Wei Shyy huihe qiu Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyHong Kong SARChina

To better understand dragonflies’remarkable flapping wing aerodynamic performance,we measured the kinematic parameters of the wings in two different flight modes(Normal Flight Mode(NFM)and Escape Flight Mode(EFM)).When the specimens switched from normal to escape mode the flapping frequency was invariant,but the stroke plane of the wings was more horizontally *** flapping of both wings was adjusted to be more ventral with a change of the pitching angle that resulted in a larger angle of attack during downstroke and smaller during upstroke to affect the flow directions and the added mass ***,the phasing between the fore and hind pair of wings varies between two flight modes,which affects the wing-wing interaction as well as body *** is found that the momentum stream in the wake of EFM is qualitatively different from that in *** change of the stroke plane angle and the varied pitching angle of the wings diverts the momentum downwards,while the smaller flapping amplitude and less phase difference between the wings compresses the momentum *** seems that in order to achieve greater flight maneuverability a flight vehicle needs to actively control positional angle as well as the pitching angle of the flapping wings.

关键词： wing kinematics flight mode dragonfly flight aerodynamics

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High‐performance and wide relative humidity passive evaporative cooling utilizing atmospheric water

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液滴(英文) 2023年第1期2卷 24-35页

作者： Guang Wang Yang Li huihe qiu He Yan Yanguang Zhou Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyHong KongChina Department of Chemistry The Hong Kong University of Science and TechnologyHong KongChina

Global warming and increased living standards have rapidly increased the demand for cooling *** this demand in less economically developed areas is highly challenging due to a lack of *** this paper,we have demonstrated a high‐performance and wide relative humidity(RH)solar‐driven evaporative cooling strategy that uses only atmospheric *** here for the first time,we designed a metal–organic framework(MOF‐801)based composite with a high‐performance atmospheric water absorption across a wide range of *** as‐synthesized composite can adsorb atmospheric water up to~22%(~80%)of its weight at an RH@28%(~70%).Our demonstration has shown that the corresponding cooling powers range from 136 to 344 W/m2 in a wide range of RH and solar intensities,and the passive cooling temperature is up to 14°C lower than the device's reference *** study thus proposes a solar‐driven cooling coating with high cooling powers across a wide range of RH based on an as‐synthesized composite,which pinpoints a pathway to replace traditional compression‐based cooling systems(e.g.,air conditioners)and which will also have a significant impact in future global energy consumption.

关键词： composite passive performance

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风电制氢微网能量调度策略研究

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能源与节能 2024年第6期 40-43页

作者：黎亚李晓霞邱慧鹤许程崔清华中广核研究院有限公司广东深圳518031 中国广核新能源控股有限公司北京100071

随着国家“双碳”目标的提出,新能源产业备受社会各界重视。氢能作为1种清洁能源,更是得到广泛关注。结合工程实际经验,搭建了风电制氢微网的网络结构,针对风电出力特性和制氢设备运行特性,以平滑波动为目标,制定了详细的风电制氢微网... 详细信息

随着国家“双碳”目标的提出,新能源产业备受社会各界重视。氢能作为1种清洁能源,更是得到广泛关注。结合工程实际经验,搭建了风电制氢微网的网络结构,针对风电出力特性和制氢设备运行特性,以平滑波动为目标,制定了详细的风电制氢微网能量调度策略。

关键词：风电制氢微电网能量调度

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OPTICAL DIAGNOSTICS OF GAS-LIQUID INTERFACIAL FILM IN MICROPIPE FLOWS

OPTICAL DIAGNOSTICS OF GAS-LIQUID INTERFACIAL FILM IN MICROP...

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多相流研究进展国际会议

作者： Xishi Wang huihe qiu Department of Mechanical Engineering The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong SAR China

＜正＞ A novel optical diagnostic technique has been developed to measure the gas-liquid interfacial film thickness in micro capillary two-phase flows. The spatial frequencies from the multi-scattering measured by CCD camera are used to calculate the slug diameter and film thickness. It is found that with optimized optical orientation angle, the spatial frequency method shows a great accuracy in the measurements. To demonstrate the capability of the newly developed method, a validation experiment was conducted in water/air and water-honey-mixture/air two-phase flows. The spatial frequency variations during the microbubble/slug pulsating were measured utilizing the highly accurate signal processing technique and five-point interpolation method. This newly developed method is easy to be implemented and it will be a very useful technique for two-phase flow measurements.

关键词： optical diagnostics two-phase flow micro heatpipe interfacial film thickness

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基于EFDC模型的湿地生物塘水质净化效果模拟与优化设计

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四川环境 2017年第1期36卷 6-10页

作者：赖秋英李一平张文一许益新曾伟峰王鑫华河海大学环境学院南京210098 宁波市城区内河管理处浙江宁波315041 济宁市南四湖人工湿地管理处山东济宁272125

为研究湿地不同生境生物塘水质净化效果,筛选最佳生境的设计方案,以山东省鱼台县惠河湿地项目为背景,基于环境流体力学模型(EFDC模型),建立惠河湿地范围内的水动力、水质数学模型,并根据生物塘水动力、生物特征和物理形态等因素构建目... 详细信息

为研究湿地不同生境生物塘水质净化效果,筛选最佳生境的设计方案,以山东省鱼台县惠河湿地项目为背景,基于环境流体力学模型(EFDC模型),建立惠河湿地范围内的水动力、水质数学模型,并根据生物塘水动力、生物特征和物理形态等因素构建目标函数,进行综合赋分,对湿地中生物塘进行优化设计。结果表明:不同生境生物塘对水质有不同程度的改善作用;水体交换程度适当,生物丰富度大,岸线长,偏离主流的生物塘对水质的净化效果佳。研究筛选出的生物塘生境可为湿地修复与水质改善工程提供参考。

关键词：湿地 EFDC模型生物塘优化设计

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