Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity grad...Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing electricity.However,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG simultaneously.Herein,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from TSG.It enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam generation.Meanwhile,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity generation.These benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high voltage.Directly interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity supply.It produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.展开更多
A solar steam evaporator provides a sustainable and efficient alternative water purification solution to address the global freshwater shortage.Previous efforts have made significant advances in maximizing its water e...A solar steam evaporator provides a sustainable and efficient alternative water purification solution to address the global freshwater shortage.Previous efforts have made significant advances in maximizing its water evaporation rate,but no single evaporator has all the properties necessary for practical point-of-use application,including a high efficiency for generation of drinkable water,an excellent portability critical for on-site water purification,good washability for mitigating evaporator fouling,and good reusability.We report a strategy to produce a high-performance photothermal material for point-of-use water purification.By simultaneously incorporating graphene and gold particles grown from recycled electronic waste in a mechanically strong sponge,we achieved highly efficient water purification under realistic conditions.In addition to a high evaporation rate(3.55 kg/m^(2)/h under one-sun irradiation)attributed to a control of atomic structure of graphene and the size-dependent surface plasmon resonance of gold nanoparticles,it is portable which can be folded,vacuum compacted,dried and rehydrated without compromising performance.It also allows repeated washing to remove contaminant fouling so that it can be reused.The evaporator transforms various types of contaminated water into drinkable clean water,and can be mounted at any angle to optimize the incident solar irradiation.Furthermore,the assembled steam evaporator device could gain purified water meeting the World Health Organization drinking water standards with a high evaporation rate of 9.36 kg/m^(2)/h under outdoor sunlight.展开更多
Presents the new techniques leading to the improvements in aerodynamics of 200MW steam turbine high pressure cylinder and mid pressure cylinder, discusses the rear loaded profile and blade bowing, and concludes from n...Presents the new techniques leading to the improvements in aerodynamics of 200MW steam turbine high pressure cylinder and mid pressure cylinder, discusses the rear loaded profile and blade bowing, and concludes from numerical simulation and experimental results that the application of rear loaded profile and blade bowing has improved the performance of 200 MW unit.展开更多
构建以新能源为主体的新型电力系统,对燃煤发电机组深度调峰和超低负荷运行提出了越来越严苛的要求,进而对汽轮机组低负荷安全运行提出了越来越严峻的挑战。采用数值模拟方法,基于低负荷工况下汽轮机末级运行性能的深入分析,着重研究探...构建以新能源为主体的新型电力系统,对燃煤发电机组深度调峰和超低负荷运行提出了越来越严苛的要求,进而对汽轮机组低负荷安全运行提出了越来越严峻的挑战。采用数值模拟方法,基于低负荷工况下汽轮机末级运行性能的深入分析,着重研究探索了不同解决方案在超低负荷工况下的工作机理与优化效果。研究发现,当机组从中低负荷下降到超低负荷时,末级叶片附近出现间隙涡、回流涡和分离涡等涡群,其范围随着负荷的减小逐渐扩大。低负荷工况降低机组背压和低压缸切缸运行是弱化汽轮机涡流、提高末级性能的有效途径,二者结合使用效果更佳。例如,在20%热耗率验收(THA)工况条件下,将背压从4.9 k Pa降低到2.5 k Pa,使得末级涡群影响范围明显减小,转子叶片转矩从–38 N·m增加到73N·m,末级运行性能明显改善。在10%THA工况下,采用降低背压和低压缸切缸相结合可使叶顶间隙涡完全消失,回流涡和分离涡的径向长度都减小50%以上;优化后的动叶转矩增加了约130 N·m,末级运行性能改善效果显著。展开更多
基金This work was supported by the National Key Research and Development Program of China(2022YFB4101600,2022YFB4101605)the National Natural Science Foundation of China(52372175,51972040)+1 种基金the Innovation and Technology Fund of Dalian(N2023JJ12GX020,2022JJ12GX023)Liaoning Normal University 2022 Outstanding Research Achievements Cultivation Fund(No.22GDL002).The authors also acknowledge the assistance of the DUT Instrumental Analysis Center.
文摘Solar-driven interfacial water evaporation(SIWE)offers a superb way to leverage concentrated solar heat to minimize energy dissipation during seawater desalination.It also engenders overlapped temperaturesalinity gradient(TSG)between water-air interface and adjacent seawater,affording opportunities of harnessing electricity.However,the efficiency of conventional SIWE technologies is limited by significant challenges,including salt passivation to hinder evaporation and difficulties in exploiting overlapped TSG simultaneously.Herein,we report self-sustaining hybrid SIWE for not only sustainable seawater desalination but also efficient electricity generation from TSG.It enables spontaneous circulation of salt flux upon seawater evaporation,inducing a self-cleaning evaporative interface without salt passivation for stable steam generation.Meanwhile,this design enables spatial separation and simultaneous utilization of overlapped TSG to enhance electricity generation.These benefits render a remarkable efficiency of90.8%in solar energy utilization,manifesting in co-generation of solar steam at a fast rate of 2.01 kg m^(-2)-h^(-1)and electricity power of 1.91 W m^(-2)with high voltage.Directly interfacing the hybrid SIWE with seawater electrolyzer constructs a system for water-electricity-hydrogen co-generation without external electricity supply.It produces hydrogen at a rapid rate of 1.29 L h^(-1)m^(-2)and freshwater with 22 times lower Na+concentration than the World Health Organization(WHO)threshold.
基金supported primarily by the Peacock Team Project(KQTD20210811090112002)the National Natural Science Foundation of China(52188101)+2 种基金the Scientific Research Start-up Funds of Tsinghua SIGS(QD2021026C)the Research Fund from Shenzhen International Graduate School,Tsinghua University(JC2021011)Shenzhen Geim Graphene Center。
文摘A solar steam evaporator provides a sustainable and efficient alternative water purification solution to address the global freshwater shortage.Previous efforts have made significant advances in maximizing its water evaporation rate,but no single evaporator has all the properties necessary for practical point-of-use application,including a high efficiency for generation of drinkable water,an excellent portability critical for on-site water purification,good washability for mitigating evaporator fouling,and good reusability.We report a strategy to produce a high-performance photothermal material for point-of-use water purification.By simultaneously incorporating graphene and gold particles grown from recycled electronic waste in a mechanically strong sponge,we achieved highly efficient water purification under realistic conditions.In addition to a high evaporation rate(3.55 kg/m^(2)/h under one-sun irradiation)attributed to a control of atomic structure of graphene and the size-dependent surface plasmon resonance of gold nanoparticles,it is portable which can be folded,vacuum compacted,dried and rehydrated without compromising performance.It also allows repeated washing to remove contaminant fouling so that it can be reused.The evaporator transforms various types of contaminated water into drinkable clean water,and can be mounted at any angle to optimize the incident solar irradiation.Furthermore,the assembled steam evaporator device could gain purified water meeting the World Health Organization drinking water standards with a high evaporation rate of 9.36 kg/m^(2)/h under outdoor sunlight.
文摘Presents the new techniques leading to the improvements in aerodynamics of 200MW steam turbine high pressure cylinder and mid pressure cylinder, discusses the rear loaded profile and blade bowing, and concludes from numerical simulation and experimental results that the application of rear loaded profile and blade bowing has improved the performance of 200 MW unit.
文摘构建以新能源为主体的新型电力系统,对燃煤发电机组深度调峰和超低负荷运行提出了越来越严苛的要求,进而对汽轮机组低负荷安全运行提出了越来越严峻的挑战。采用数值模拟方法,基于低负荷工况下汽轮机末级运行性能的深入分析,着重研究探索了不同解决方案在超低负荷工况下的工作机理与优化效果。研究发现,当机组从中低负荷下降到超低负荷时,末级叶片附近出现间隙涡、回流涡和分离涡等涡群,其范围随着负荷的减小逐渐扩大。低负荷工况降低机组背压和低压缸切缸运行是弱化汽轮机涡流、提高末级性能的有效途径,二者结合使用效果更佳。例如,在20%热耗率验收(THA)工况条件下,将背压从4.9 k Pa降低到2.5 k Pa,使得末级涡群影响范围明显减小,转子叶片转矩从–38 N·m增加到73N·m,末级运行性能明显改善。在10%THA工况下,采用降低背压和低压缸切缸相结合可使叶顶间隙涡完全消失,回流涡和分离涡的径向长度都减小50%以上;优化后的动叶转矩增加了约130 N·m,末级运行性能改善效果显著。
