In order to further investigate how much fuel heat sink could be increased and how much power generation could be obtained by using recooling cycle for a regeneratively cooled scramjet,the energy conversion from heat ...In order to further investigate how much fuel heat sink could be increased and how much power generation could be obtained by using recooling cycle for a regeneratively cooled scramjet,the energy conversion from heat to electricity and the fuel heat sink increase in recooling cycle are experimentally investigated for fuel conversion rate and components of gas cracked fuel products at different fuel temperatures.The results indicate that the total fuel heat sink(i.e.,physical+chemical+recooling) of a recooling cycle is obviously higher than the heat sink of fuel itself,and the maximum heat sink increment is as high as 0.4 MJ/kg throughout the recooling cycle.Furthermore,the cracked fuel mixture has a significant capacity of doing work.The thermodynamic power generation scheme,which adopts the cracked fuel gas mixture as the working fluid,is a potential power generation cycle,and the maximum specific power generation is about 500 kW/kg.Turbine-pump scheme using cracked fuel gas mixture is also a potential fuel feeding cycle.展开更多
The two-stage transcritical CO_(2) refrigeration cycle with dedicated dual-subcooling and mechanical recooling is proposed.The inter-stage pressure is critical for such cycle performances;however,it has not been studi...The two-stage transcritical CO_(2) refrigeration cycle with dedicated dual-subcooling and mechanical recooling is proposed.The inter-stage pressure is critical for such cycle performances;however,it has not been studied exactly.Therefore,the research aim is to disclose the effect of inter-stage pressure on performances of the proposed cycle.The main work consists of four aspects.Firstly,the comparative study is performed to display advantages of the proposed cycle.Secondly,the key temperatures,heat and power consumptions as well as performance indicators for different inter-stage pressures are analyzed in detail,based on the parametric model.Thirdly,the optimal inter-stage pressure for different conditions is obtained by the nonlinear direct search method.Finally,the economic performance is assessed.It is found that the compressor power of the proposed cycle drops by 12%,and the working temperature lower limit is reduced by 11℃.Furthermore,it is considered that the optimal inter-stage pressure is insensitive to the heat source temperature.The novelty lies in illustrating the effect of inter-stage pressure,obtaining trends of the optimal value,and pointing out the system feasibility.The paper is favorable for design and operation optimization of the proposed system.展开更多
Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities,which strongly depends on the measurement situation at hand.The stylus ion trap,formed by two concentric cylinders over a...Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities,which strongly depends on the measurement situation at hand.The stylus ion trap,formed by two concentric cylinders over a ground plane,holds the promise of relatively simple structure and larger solid angle for optical access and fluorescence collection in comparison with the conventional ion traps.Here we report our fabrication and characterization of the first stylus ion trap constructed in China,aiming for studying quantum optics and sensing weak electric fields in the future.We have observed the stable confinement of the ion in the trapping potential for more than two hours and measured the heating rate of the trap to be dε/dt=7.10±0.13 meV/s by the Doppler recooling method.Our work starts a way to building practical quantum sensors with high efficiency of optical collection and with ultimate goal for contributing to future quantum information technology.展开更多
基金supported by the Key Program of the National Natural Science Foundation of China (Grant No. 51076035)
文摘In order to further investigate how much fuel heat sink could be increased and how much power generation could be obtained by using recooling cycle for a regeneratively cooled scramjet,the energy conversion from heat to electricity and the fuel heat sink increase in recooling cycle are experimentally investigated for fuel conversion rate and components of gas cracked fuel products at different fuel temperatures.The results indicate that the total fuel heat sink(i.e.,physical+chemical+recooling) of a recooling cycle is obviously higher than the heat sink of fuel itself,and the maximum heat sink increment is as high as 0.4 MJ/kg throughout the recooling cycle.Furthermore,the cracked fuel mixture has a significant capacity of doing work.The thermodynamic power generation scheme,which adopts the cracked fuel gas mixture as the working fluid,is a potential power generation cycle,and the maximum specific power generation is about 500 kW/kg.Turbine-pump scheme using cracked fuel gas mixture is also a potential fuel feeding cycle.
基金supported by National Foreign Expert Projectunderthecontract No.G2022163009LGuangdong Basic and Applied Basic Research Foundation under the contract No.2023A1515011337+1 种基金Zhuhai Industry-University-Research Cooperation Project under the contract No.ZH22017001210017PWCKey Laboratory of Efficient and Clean Energy Utilization of Guangdong Higher Education Institutes underthecontract No.KLB10004.
文摘The two-stage transcritical CO_(2) refrigeration cycle with dedicated dual-subcooling and mechanical recooling is proposed.The inter-stage pressure is critical for such cycle performances;however,it has not been studied exactly.Therefore,the research aim is to disclose the effect of inter-stage pressure on performances of the proposed cycle.The main work consists of four aspects.Firstly,the comparative study is performed to display advantages of the proposed cycle.Secondly,the key temperatures,heat and power consumptions as well as performance indicators for different inter-stage pressures are analyzed in detail,based on the parametric model.Thirdly,the optimal inter-stage pressure for different conditions is obtained by the nonlinear direct search method.Finally,the economic performance is assessed.It is found that the compressor power of the proposed cycle drops by 12%,and the working temperature lower limit is reduced by 11℃.Furthermore,it is considered that the optimal inter-stage pressure is insensitive to the heat source temperature.The novelty lies in illustrating the effect of inter-stage pressure,obtaining trends of the optimal value,and pointing out the system feasibility.The paper is favorable for design and operation optimization of the proposed system.
基金Project supported by the Special Project for Research and Development in Key Areas of Guangdong Province,China (Grant No.2020B0303300001)the National Natural Science Foundation of China (Grant Nos.U21A20434,12074346,12074390,11835011,11804375,and 11804308)+2 种基金the Fund from the Key Laboratory of Guangzhou for Quantum Precision Measurement (Grant No.202201000010)the Science and Technology Projects in Guangzhou (Grant No.202201011727)the Nansha Senior Leading Talent Team Technology Project (Grant No.2021CXTD02)。
文摘Cold trapped ions can be excellent sensors for ultra-precision detection of physical quantities,which strongly depends on the measurement situation at hand.The stylus ion trap,formed by two concentric cylinders over a ground plane,holds the promise of relatively simple structure and larger solid angle for optical access and fluorescence collection in comparison with the conventional ion traps.Here we report our fabrication and characterization of the first stylus ion trap constructed in China,aiming for studying quantum optics and sensing weak electric fields in the future.We have observed the stable confinement of the ion in the trapping potential for more than two hours and measured the heating rate of the trap to be dε/dt=7.10±0.13 meV/s by the Doppler recooling method.Our work starts a way to building practical quantum sensors with high efficiency of optical collection and with ultimate goal for contributing to future quantum information technology.
