The charge valve is an important element in the charging port of a high-pressure hydrogen storage cylinder(HP-HSC).It is normally closed after the HP-HSC is filled with hydrogen.If the seal of the charge valve is dama...The charge valve is an important element in the charging port of a high-pressure hydrogen storage cylinder(HP-HSC).It is normally closed after the HP-HSC is filled with hydrogen.If the seal of the charge valve is damaged,it will seriously affect the stable operation of the hydrogen supply system and may even cause safety problems.Therefore,the seal performance of the charge valve is important.In this paper,finite element analysis(FEA)is carried out to analyze the seal contact performance of hydrogenated nitrile rubber(HNBR)gaskets in the seal pair of a charge valve.The effects of different pre-compressions,seal widths,and hydrogen pressures on the seal contact performance of the charge valve are analyzed.The contact pressure on the seal surface increases with the increase of pre-compression.With a pre-compression of 2.5 mm,the maximum contact pressure without and with hydrogen pressure are 68.51 and 107.38 MPa,respectively.A contact gap appears in the inner ring of the seal surface with pre-compression below 0.15 mm.The contact gap occurs between the entire seal surface with a seal width of1 mm.The contact pressure on the seal surface and the width of the separation area between the seal surfaces increase with the increase of the seal width.The contact gap between the seal surfaces is zero with a width of 2.5 mm.The width of the separation area between the seal surfaces decreases with the decrease of the hydrogen pressure.The width of the separation area is reduced from 0.5 mm at 35 MPa to 0.17 mm at 15 MPa.This work can be useful for improvement of the seal performance and of the design of the charge valve used in the HP-HSC.展开更多
Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken...Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages: smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.展开更多
Constructing cerium and manganese bimetallic catalysts with excellent catalytic performance for soot combustion is the research frontier at present.In order to find out the key factors for catalytic soot combustion of...Constructing cerium and manganese bimetallic catalysts with excellent catalytic performance for soot combustion is the research frontier at present.In order to find out the key factors for catalytic soot combustion of Ce-Mn-O catalysts,a series of Ce-Mn-O catalysts with different Ce/Mn proportions were prepared by co-precipitation method.The activity test results show that it increases first and then decreases with the increase of Mn content.The best catalytic activity is obtained for Ce_(0.64)Mn_(0.36) catalyst,which shows a maximum rate temperature(T_(m)) at 306℃ for CO_(2) production in TPO curve.Compared with non-catalytic soot combustion,the T_(m) decreases by mo re than 270℃.Syste matical characte rization results suggest that when the adsorbed surface oxygen,lattice oxygen,specific surface area and total reduction amount of the catalysts reach a certain value,the key factors leading to the difference of catalytic activity become the readily reducible and highly dispersed surface manganese oxide species and contact performance of the external surface.The surface manganese oxide species is beneficial to improving the low-temperature reducibility of catalysts and the porous surface is conducive to the contact between catalyst and soot.Furthermore,for the soot combustion reaction containing only O_(2),the promoting effect of Mn^(4+)is not obvious.展开更多
基金supported by the National Natural Science Foundation of China(No.52175067)the Science and Technology Department of Zhejiang Province(No.2021C01021),Chinathe Young Elite Scientist Sponsorship Program by China Association for Science and Technology(No.YESS20200154)。
文摘The charge valve is an important element in the charging port of a high-pressure hydrogen storage cylinder(HP-HSC).It is normally closed after the HP-HSC is filled with hydrogen.If the seal of the charge valve is damaged,it will seriously affect the stable operation of the hydrogen supply system and may even cause safety problems.Therefore,the seal performance of the charge valve is important.In this paper,finite element analysis(FEA)is carried out to analyze the seal contact performance of hydrogenated nitrile rubber(HNBR)gaskets in the seal pair of a charge valve.The effects of different pre-compressions,seal widths,and hydrogen pressures on the seal contact performance of the charge valve are analyzed.The contact pressure on the seal surface increases with the increase of pre-compression.With a pre-compression of 2.5 mm,the maximum contact pressure without and with hydrogen pressure are 68.51 and 107.38 MPa,respectively.A contact gap appears in the inner ring of the seal surface with pre-compression below 0.15 mm.The contact gap occurs between the entire seal surface with a seal width of1 mm.The contact pressure on the seal surface and the width of the separation area between the seal surfaces increase with the increase of the seal width.The contact gap between the seal surfaces is zero with a width of 2.5 mm.The width of the separation area between the seal surfaces decreases with the decrease of the hydrogen pressure.The width of the separation area is reduced from 0.5 mm at 35 MPa to 0.17 mm at 15 MPa.This work can be useful for improvement of the seal performance and of the design of the charge valve used in the HP-HSC.
基金Project (No. 502048) supported by the Natural Science Foundation of Hebei Province, China
文摘Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages: smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.
基金Projects supported by the National Natural Science Foundation of China (21962021)Yunnan Fundamental Research Projects(202001AU070121)。
文摘Constructing cerium and manganese bimetallic catalysts with excellent catalytic performance for soot combustion is the research frontier at present.In order to find out the key factors for catalytic soot combustion of Ce-Mn-O catalysts,a series of Ce-Mn-O catalysts with different Ce/Mn proportions were prepared by co-precipitation method.The activity test results show that it increases first and then decreases with the increase of Mn content.The best catalytic activity is obtained for Ce_(0.64)Mn_(0.36) catalyst,which shows a maximum rate temperature(T_(m)) at 306℃ for CO_(2) production in TPO curve.Compared with non-catalytic soot combustion,the T_(m) decreases by mo re than 270℃.Syste matical characte rization results suggest that when the adsorbed surface oxygen,lattice oxygen,specific surface area and total reduction amount of the catalysts reach a certain value,the key factors leading to the difference of catalytic activity become the readily reducible and highly dispersed surface manganese oxide species and contact performance of the external surface.The surface manganese oxide species is beneficial to improving the low-temperature reducibility of catalysts and the porous surface is conducive to the contact between catalyst and soot.Furthermore,for the soot combustion reaction containing only O_(2),the promoting effect of Mn^(4+)is not obvious.
