The mechanical properties,microstructure and second phase precipitation behavior of flange forgings for high-pressure hydrogen storage vessels at different tempering temperatures(620–700℃)were studied.The results sh...The mechanical properties,microstructure and second phase precipitation behavior of flange forgings for high-pressure hydrogen storage vessels at different tempering temperatures(620–700℃)were studied.The results showed that when tempered at 620–680°C,the main microstructure of the test steel was tempered sorbite,and the main microstructure of tempered steel changed to martensite at 700℃.At 700℃,the dislocation density increased and some retained austenite existed.With the tempering temperature increasing,the yield strength showed a decreasing trend,the formation of fresh martensite made the tensile strength first decrease and then increase slightly,the impact energy at−40℃increased first and then decreased,and the impact energy at 660℃had the maximum value.The precipitates of MC type were mainly(Mo,V,Ti)C.The test steel had excellent strength and toughness matching at 660℃tempering,the tensile strength at different cross section locations was above 750 MPa,the impact energy was above 200 J at−40℃,and the relative percentage reduction of area(ZH2/ZN2)was above 75%at hydrogen environment of 6.3 MPa.展开更多
Methane,as the main component of natural gas,is a key transitional fuel resource due to its abundance and relatively low carbon emissions,aligning with global carbon neutrality objectives[1].Traditional natural gas st...Methane,as the main component of natural gas,is a key transitional fuel resource due to its abundance and relatively low carbon emissions,aligning with global carbon neutrality objectives[1].Traditional natural gas storage methods,such as liquefied and compressed natural gas,require costly infrastructure and high-pressure conditions.Alternatively,adsorbed natural gas offers a safer,more cost-effective,and environmentally friendly solution by enhancing storage capacity at reduced pressures through the use of methane adsorbents[2].展开更多
Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). ...Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). The pressure fluctuations of the reversible pump turbine at three different water heads(with non-dimensional values being 0.48, 0.71 and 0.90) are measured and compared based on the pressure data recorded in the whole flow passage of the turbine. Furthermore, effects of monitoring points and load variations on the impeller-induced unstable behavior(e.g. blade passing frequency and its harmonics) are quantitatively discussed. Our findings reveal that water head variations play a significant role on the pressure fluctuations and their propagation mechanisms inside the reversible pump turbine.展开更多
基金supported by the National Key research and Development Program of China(No.2022YFB4003001).
文摘The mechanical properties,microstructure and second phase precipitation behavior of flange forgings for high-pressure hydrogen storage vessels at different tempering temperatures(620–700℃)were studied.The results showed that when tempered at 620–680°C,the main microstructure of the test steel was tempered sorbite,and the main microstructure of tempered steel changed to martensite at 700℃.At 700℃,the dislocation density increased and some retained austenite existed.With the tempering temperature increasing,the yield strength showed a decreasing trend,the formation of fresh martensite made the tensile strength first decrease and then increase slightly,the impact energy at−40℃increased first and then decreased,and the impact energy at 660℃had the maximum value.The precipitates of MC type were mainly(Mo,V,Ti)C.The test steel had excellent strength and toughness matching at 660℃tempering,the tensile strength at different cross section locations was above 750 MPa,the impact energy was above 200 J at−40℃,and the relative percentage reduction of area(ZH2/ZN2)was above 75%at hydrogen environment of 6.3 MPa.
文摘Methane,as the main component of natural gas,is a key transitional fuel resource due to its abundance and relatively low carbon emissions,aligning with global carbon neutrality objectives[1].Traditional natural gas storage methods,such as liquefied and compressed natural gas,require costly infrastructure and high-pressure conditions.Alternatively,adsorbed natural gas offers a safer,more cost-effective,and environmentally friendly solution by enhancing storage capacity at reduced pressures through the use of methane adsorbents[2].
基金supported by the National Natural Science Foundation of China(Grant No.51506051)the Fundamental Research Funds for the Central Universities(Grant No.JB2015RCY04)+2 种基金the Open Research Fund Program of Key Laboratory of Fluid and Power Machinery(Xihua University)Ministry of Education(Grant No.szjj-2017-100-1-001)the Open Research Fund Program of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources(Grant No.LAPS16014)
文摘Influences of water head variations on the performances of a prototype reversible pump turbine are experimentally studied in generating mode within a wide range of load conditions(from 25% to 96% of the rated power). The pressure fluctuations of the reversible pump turbine at three different water heads(with non-dimensional values being 0.48, 0.71 and 0.90) are measured and compared based on the pressure data recorded in the whole flow passage of the turbine. Furthermore, effects of monitoring points and load variations on the impeller-induced unstable behavior(e.g. blade passing frequency and its harmonics) are quantitatively discussed. Our findings reveal that water head variations play a significant role on the pressure fluctuations and their propagation mechanisms inside the reversible pump turbine.
