为研究微型冲动式部分进气涡轮机的流场及气动损失特性进而为水下航行器微型涡轮机设计提供参考,建立了2 k W级涡轮机的仿真模型并且通过与公开文献[2]实验结果进行对比验证了所建模型的可靠性,通过改变叶顶间隙、喷管出口与动叶间的轴...为研究微型冲动式部分进气涡轮机的流场及气动损失特性进而为水下航行器微型涡轮机设计提供参考,建立了2 k W级涡轮机的仿真模型并且通过与公开文献[2]实验结果进行对比验证了所建模型的可靠性,通过改变叶顶间隙、喷管出口与动叶间的轴向间隙、喷管扩张角、部分进气度的大小以及轮盘结构,研究了涡轮气动损失。结果表明:微型涡轮具有尺度效应,表现为喷管内声速点移至喉部下游,工作叶片表面的压力变化较为一致;随着上述几何参数的增大,涡轮内效率受叶顶间隙的影响最为明显,而轴向间隙的影响在一定范围内可以忽略,部分进气度为0.35时内效率上升趋于平稳,喷管扩张角为8°时的涡轮内效率高于6°和10°;无叶顶间隙时,除叶片之外的轮盘摩擦损失约为1%。展开更多
Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which ca...Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which can provide different grades of thermal energy with two heat transfer fluids(oil and water),is designed to improve thermal efficiency.In this FPTR-IT,an inner tube and straight fins are employed to respectively lessen heat loss at upper and lower parts of the absorber.Based on the design,a numerical model is developed to investigate its performance.Comparisons with other PTRs indicate that the FPTR-IT can combine the advantages of PTR with inner tube and finned PTR and obtain the best performance.Moreover,performance evaluation under broad ranges of direct normal irradiances(300–1000 W/m^(2)),flow rates(50–250 L/min)and inlet temperatures(400–600 K)of oil as well as flow rates(3.6–10 L/min)and inlet temperatures(298.15–318.15 K)of water is investigated.Compared with conventional PTR,heat loss is reduced by 20.7%–63.2%and total efficiency is improved by 0.03%–4.27%.Furthermore,the proportions of heat gains for water and oil are located in 8.3%–73.9%and-12.0%–64.3%,while their temperature gains are located in 11.6–37.9 K and-1.2–19.6 K,respectively.Thus,the proposed FPTR-IT may have a promising application prospect in remote arid areas or islands to provide different grades of heat for electricity and freshwater production.展开更多
Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to t...Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to the emulsion accumulation.Herein,to address this problem,a material is presented by subtly integrating chemical demulsification and 3D inner-outer asymmetric wettability to a sponge substrate,and thus wettability gradient-driven oil directional transport for achieving unprecedented enormous-volume emulsion wastewater treatment is realized based on a“demulsification-transport”mechanism.The maximum treatment volume realized by the sponge is as large as 3 L(2.08×10^(4) L per cubic meter of the sponge)in one cycle,which is about 100 times of the reported materials.Besides,owing to the large pore size of the sponge,9000 L m^(2)h^(-1)(LMH)separation flux and 99.5%separation efficiency are realized simultaneously,which overcomes the trade-off dilemma.Such a 3D inner-outer asymmetric sponge displaying unprecedented advantage in the treatment volume can promote the development of the oily wastewater treatment field,as well as expand the application prospects of superwetting materials,especially in continuous water treatment.展开更多
文摘为研究微型冲动式部分进气涡轮机的流场及气动损失特性进而为水下航行器微型涡轮机设计提供参考,建立了2 k W级涡轮机的仿真模型并且通过与公开文献[2]实验结果进行对比验证了所建模型的可靠性,通过改变叶顶间隙、喷管出口与动叶间的轴向间隙、喷管扩张角、部分进气度的大小以及轮盘结构,研究了涡轮气动损失。结果表明:微型涡轮具有尺度效应,表现为喷管内声速点移至喉部下游,工作叶片表面的压力变化较为一致;随着上述几何参数的增大,涡轮内效率受叶顶间隙的影响最为明显,而轴向间隙的影响在一定范围内可以忽略,部分进气度为0.35时内效率上升趋于平稳,喷管扩张角为8°时的涡轮内效率高于6°和10°;无叶顶间隙时,除叶片之外的轮盘摩擦损失约为1%。
基金supported by the China Postdoctoral Science Foundation(Grant No.2020M672344)。
文摘Designing highly-efficient parabolic trough receiver(PTR)contributes to promoting solar thermal utilization and alleviating energy crisis and environmental problems.A novel finned PTR with inner tube(FPTR-IT),which can provide different grades of thermal energy with two heat transfer fluids(oil and water),is designed to improve thermal efficiency.In this FPTR-IT,an inner tube and straight fins are employed to respectively lessen heat loss at upper and lower parts of the absorber.Based on the design,a numerical model is developed to investigate its performance.Comparisons with other PTRs indicate that the FPTR-IT can combine the advantages of PTR with inner tube and finned PTR and obtain the best performance.Moreover,performance evaluation under broad ranges of direct normal irradiances(300–1000 W/m^(2)),flow rates(50–250 L/min)and inlet temperatures(400–600 K)of oil as well as flow rates(3.6–10 L/min)and inlet temperatures(298.15–318.15 K)of water is investigated.Compared with conventional PTR,heat loss is reduced by 20.7%–63.2%and total efficiency is improved by 0.03%–4.27%.Furthermore,the proportions of heat gains for water and oil are located in 8.3%–73.9%and-12.0%–64.3%,while their temperature gains are located in 11.6–37.9 K and-1.2–19.6 K,respectively.Thus,the proposed FPTR-IT may have a promising application prospect in remote arid areas or islands to provide different grades of heat for electricity and freshwater production.
基金The authors are grateful for financial support from the National Natural Science Foundation of China(52173111,21788102).
文摘Although oily wastewater treatment realized by superwetting materials has attracted heightened attention in recent years,how to treat enormous-volume emulsion wastewater is still a tough problem,which is ascribed to the emulsion accumulation.Herein,to address this problem,a material is presented by subtly integrating chemical demulsification and 3D inner-outer asymmetric wettability to a sponge substrate,and thus wettability gradient-driven oil directional transport for achieving unprecedented enormous-volume emulsion wastewater treatment is realized based on a“demulsification-transport”mechanism.The maximum treatment volume realized by the sponge is as large as 3 L(2.08×10^(4) L per cubic meter of the sponge)in one cycle,which is about 100 times of the reported materials.Besides,owing to the large pore size of the sponge,9000 L m^(2)h^(-1)(LMH)separation flux and 99.5%separation efficiency are realized simultaneously,which overcomes the trade-off dilemma.Such a 3D inner-outer asymmetric sponge displaying unprecedented advantage in the treatment volume can promote the development of the oily wastewater treatment field,as well as expand the application prospects of superwetting materials,especially in continuous water treatment.
