The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminatin...The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminating the influence of the centrifugal force and sediment movement experiments with periodic alternating current. Also included are the experiment-based relationship among sediment concentration, bed shear stress and silt carrying capacity, a proposed erosion-deposition function and bed erosion-deposition calculation together with the results of verification.展开更多
Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The prese...Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The presence of water in the reaction stream results in a significant increase in NH3selectivity.This result is due to water‐induced hydroxylation promoting NH3formation and the competitive adsorption of H2O and NO at the same sites,which inhibits the reactivity of NO reduction by NH3.展开更多
A staggered impulse turbine is proposed for asymmetric air flows in Oscillating Water Column wave energy plants, which is expected to enhance the pneumatic power output in a wave cycle. The setting angle of rotor blad...A staggered impulse turbine is proposed for asymmetric air flows in Oscillating Water Column wave energy plants, which is expected to enhance the pneumatic power output in a wave cycle. The setting angle of rotor blades is set as 5°. The 3D numerical simulations were conducted under steady conditions using MRF and Mixing Plane model based on CFD software Fluent 12.0. Its mean efficiencies under different velocity amplitude ratios are studied using quasi-steady analysis, which derive corresponding data from the numerical simulation. It is found that the staggered turbine shows better performance than the conventional one under the asymmetrical air flows. Furthermore, its mean efficiency and output-work in a wave period are compared with another unsymmetrical twin impulse turbine system. The results show that the staggered turbine shows better output-work performance than the twin turbine system over the high flow coefficient domain(φ>0.7), which provides more choices to future research on turbine's optimization.展开更多
Power generation using small temperature difference such as ocean thermal energy conversion(OTEC)and discharged thermal energy conversion(DTEC)is expected to be the countermeasures against global warming problem.As am...Power generation using small temperature difference such as ocean thermal energy conversion(OTEC)and discharged thermal energy conversion(DTEC)is expected to be the countermeasures against global warming problem.As ammonia and ammonia/water are used in evaporators for OTEC and DTEC as working fluids,the research of their local boiling heat transfer is important for improvement of the power generation efficiency.Measurements of local boiling heat transfer coefficients were performed for ammonia/water mixture(z=0.9-1)on a vertical flat plate heat exchanger in a range of mass flux(7.5-15 kg/m2s),heat flux(15-23 kW/m 2),and pressure(0.7-0.9 MPa).The result shows that in the case of ammonia/water mixture,the local heat transfer coefficients increase with an increase of mass flux and composition of ammonia,and decrease with an increase of heat flux.展开更多
文摘The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminating the influence of the centrifugal force and sediment movement experiments with periodic alternating current. Also included are the experiment-based relationship among sediment concentration, bed shear stress and silt carrying capacity, a proposed erosion-deposition function and bed erosion-deposition calculation together with the results of verification.
基金supported by the National Natural Science Foundation of China (21463015)the Provincial Applied Fundamental Research Program of Yunnan (2014FA045)the National High Technology Research and Development Program of China (863 Program,2015AA034603)~~
文摘Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The presence of water in the reaction stream results in a significant increase in NH3selectivity.This result is due to water‐induced hydroxylation promoting NH3formation and the competitive adsorption of H2O and NO at the same sites,which inhibits the reactivity of NO reduction by NH3.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51279190 and 51311140259)National High Tech Research and Development Program("863"program,Grant No.2011AA050201)
文摘A staggered impulse turbine is proposed for asymmetric air flows in Oscillating Water Column wave energy plants, which is expected to enhance the pneumatic power output in a wave cycle. The setting angle of rotor blades is set as 5°. The 3D numerical simulations were conducted under steady conditions using MRF and Mixing Plane model based on CFD software Fluent 12.0. Its mean efficiencies under different velocity amplitude ratios are studied using quasi-steady analysis, which derive corresponding data from the numerical simulation. It is found that the staggered turbine shows better performance than the conventional one under the asymmetrical air flows. Furthermore, its mean efficiency and output-work in a wave period are compared with another unsymmetrical twin impulse turbine system. The results show that the staggered turbine shows better output-work performance than the twin turbine system over the high flow coefficient domain(φ>0.7), which provides more choices to future research on turbine's optimization.
基金supported by the fund for the 21st Century Center of Excellence program(Advanced Science and Technology for Utilization of Ocean Energy)
文摘Power generation using small temperature difference such as ocean thermal energy conversion(OTEC)and discharged thermal energy conversion(DTEC)is expected to be the countermeasures against global warming problem.As ammonia and ammonia/water are used in evaporators for OTEC and DTEC as working fluids,the research of their local boiling heat transfer is important for improvement of the power generation efficiency.Measurements of local boiling heat transfer coefficients were performed for ammonia/water mixture(z=0.9-1)on a vertical flat plate heat exchanger in a range of mass flux(7.5-15 kg/m2s),heat flux(15-23 kW/m 2),and pressure(0.7-0.9 MPa).The result shows that in the case of ammonia/water mixture,the local heat transfer coefficients increase with an increase of mass flux and composition of ammonia,and decrease with an increase of heat flux.
