Copper staves have been equipped on nearly all of BF （blast furnaces） with volume over than 1000 m3 in China since their introduction from abroad about more than 10 years ago. Because of short application and lack o...Copper staves have been equipped on nearly all of BF （blast furnaces） with volume over than 1000 m3 in China since their introduction from abroad about more than 10 years ago. Because of short application and lack of experience, phenomena of thickened or naked of copper stave happen occasionally which influence production severely. So it is important to study the model of forming-accretion on BF copper stave and realize real-time monitoring of forming-accretion on different copper staves. Therefore, mathematic model of calculating accretion thickness by heat flow of BF is proposed, and the calculated results indicate that accretion thickness could be kept at a reasonable range of around 50 mm by controlling heat flux around 22.0 kW/mz. The monitoring program based on the model was applied to a certain BF in China successfully, and it is found that slip of BF near the inner wall is one of most important reasons that cause fluctuation of accretion thickness. During the period of scheduled maintenance of the certain BF, the thickness of accretion measured through the static pressure holes is in good accordance with the value calculated by the monitoring program, so the results calculated by the monitoring program can be used to guide industrial production展开更多
The temperature of gas flow inside a blast furnace （BF） changes significantly when the blast furnace is under unstable operations, and the temperature and stress distributions of cooling staves （CS） for BF work th...The temperature of gas flow inside a blast furnace （BF） changes significantly when the blast furnace is under unstable operations, and the temperature and stress distributions of cooling staves （CS） for BF work the same pattern. The effect of gas temperature on the temperature, stress, and displacement distributions of the cooling stave were analyzed as the gas temperature inside the blast furnace rose from 1000 to 1600℃ in 900 s. The results show that both the temperature and temperature gradient of the hot side of CS increase when the gas flow temperature inside BF rises. The temperature gradient of the hot side of CS is greater than that of the other area of CS and it can reach 65℃/mm. In the vertical direction of the hot side of CS, closer to the central part of CS, the stress intensity is greater than that of the other area of the hot side of CS, which causes cracks on the hot side of CS in the vertical di- rection. As the gas temperature increases, the stress intensity rate near the fixed pin increases and finally reaches 45 MPa/s. Fatigues near the fixed pin and bolts are caused by great stress intensity rate and the area around the pin can be damaged easily. The edge of CS bends toward the cold side and the central part of CS shifts toward the hot surface.展开更多
A monitoring method that has been designed for the first time for blast furnace wall with copper staves manufactured in China was introduced. Combining the method of ＂inverse problem＂ and the concept ＂non-inverse p...A monitoring method that has been designed for the first time for blast furnace wall with copper staves manufactured in China was introduced. Combining the method of ＂inverse problem＂ and the concept ＂non-inverse problem＂, the monitoring program for blast furnace wall with copper staves has been realized, which can be used to calculate online the accretion thickness and temperature of hot surface of copper staves after obtaining the values of thermocouples of copper staves. The accretion state obtained in the actual investigation has proved that the result of the program is correct. The monitoring program shows that the accretion would easily fluctuate when the accretion layer is extremely thick or thin, thereby the stable and smooth operation of the blast furnace is hindered. By maintaining appropriate accretion thickness, both long campaigns and high productivity of the blast furnace can be achieved; furthermore, it can also optimize the operation of blast furnace and maximize its production. Approximately 30--50 mm in thickness of accretion layer is maintained on the wall of Shougang blast furnace 2, which can meet the requirement for obtaining both long campaign and high productivity.展开更多
The quantificational and normative design is the precondition of improving the design of copper staves for blast furnaces. Based on a 3-dimensional temperature field calculation model, from the view point of heat tran...The quantificational and normative design is the precondition of improving the design of copper staves for blast furnaces. Based on a 3-dimensional temperature field calculation model, from the view point of heat transfer and long campaigns note with the core of forming accretion, the forming-accretion-ability （FAA） and the rib hot surface maximum temperature difference （ATmax） as quantificational indexes to direct and evaluate the design of copper staves for blast furnaces were presented. The application of the two indexes in design essentially embodies the new long campaigns in the stage of design. With the application of the two indexes, good results can be obtained. Firstly, it was suggested that the rib height of a copper stave can be reduced to 15 mm, which is a new method and theory for the reduction of copper staves. Secondly, the influence of insert on FAA and ATmax, is decided by the volume of insert. According to this, the principle of design for the hot surface geometry of copper staves was put forward that the ratio of the rib hot surface to the copper stave hot surface （abbreviated as the ratio of rib to stave） must be maintained in the range of 45% to 55%; for the present copper stave with a 35-40 mm thick rib, the ratio of rib to stave in the range of 50% to 55% can optimize the design of copper staves; for the copper stave with a smaller rib thickness, for example 15 ram, the ratio of rib to stave in the range of 45% to 50% can optimize the design of copper staves. It can be summarized that the thicker the rib thickness, the larger is the ratio of rib to stave. 2008 University of Science and Technology Beijing. All rights reserved.展开更多
Much attention has been paid to copper staves because they have excellentperformance and longevity. The hot test of copper staves was carried out using all-scale staveexperiment system and according to the results, th...Much attention has been paid to copper staves because they have excellentperformance and longevity. The hot test of copper staves was carried out using all-scale staveexperiment system and according to the results, the temperature distribution and heatcharacteristics were studied. The result shows that copper stave possesses outstanding heat transferability, a well-distributed temperature field and low temperature on the hot side. In addition, amodel was established to calculate the cooling water channels' inner face temperature. Thecalculation results indicates that the highest temperature of the inner wall of the channels is 42deg C, and at the same time, the cold side of the stave temperature is 42-43 deg C. That is to say,the temperature in the stave is quite uniform.展开更多
The core of the long-life copper stave was to ensure the stability of the slag layer,and the uniform distribution of the slag layer was beneficial to restrict the generation of the overthick slag layer.A novel model f...The core of the long-life copper stave was to ensure the stability of the slag layer,and the uniform distribution of the slag layer was beneficial to restrict the generation of the overthick slag layer.A novel model for calculating the thickness and distribution of the slag layer in the part of copper stave was established based on the finite element theory through the ANSYS birth-death element technology.The distribution and thickness of the slag layer on the hot surface of copper stave were calculated and analyzed when the gas temperature and slag properties tended to be changed,which was applied to characterize the slag-hanging capability of copper stave with the changes of furnace conditions.It was shown that the thickness of hot surface slag layer in the part of copper stave decreased obviously while the temperature of stave body raised rapidly with increasing gas temperature.When the gas temperature was 1400℃,the inlaid slag layer was gradually melted,and the maximum temperature of the stave body was closed to 120℃.The change of gas temperature was very sensitive to the adherent dross capability of copper stave which would be enhanced by the promotion of slag-hanging temperature.However,when the slag-hanging temperature was 1150℃and the gas temperature was lower than 1250℃,the overlhick slag layer was easily formed on the hot surface of the copper stave,and its stability was poor.The improvement in the thermal conductivity of slag could be conducive to the formation of the uniform and stable slag layer on the hot surface of copper stave,especially in the dovetail groove.When the thermal conductivity of the slag was greater than 1.8 W m^(-2)℃^(-1),the inlaid slag layer in the dovetail groove was not melted,although the gas temperature reached 1500℃.展开更多
The stability and nonlinear dynamic behavior of drilling shaft system in copper stave deep hole drilling were analyzed. The effects of the fluctuation of the cutting force, the mass eccentricity and the hydrodynamic f...The stability and nonlinear dynamic behavior of drilling shaft system in copper stave deep hole drilling were analyzed. The effects of the fluctuation of the cutting force, the mass eccentricity and the hydrodynamic forces of cutting fluid could be taken into consideration in the model of drilling shaft system. Based on the isoparametric finite element method, the variational form of Reynolds equation in hydrodynamic fluid was used to calculate nonlinear hydrodynamic forces and their Jacobian matrices simultaneously. In the stability analysis, a new shooting method for rapidly determining the periodic orbit of the nonlinear drilling shaft system and its period was presented by rebuilding the traditional shooting method and changing the time scale. Through the combination of theories with experiment, the correctness and effectiveness of the above methods are verified by using the Floquet theory. The results show that the mass eccentricity can inhibit the whirling motion of drilling shaft to some extent.展开更多
An experiment of a new type full size copper stave for a real blast furnacewas carried out in a special-designed experimental system. The 3-D temperature distribution insidethe stave including isotherm was obtained ba...An experiment of a new type full size copper stave for a real blast furnacewas carried out in a special-designed experimental system. The 3-D temperature distribution insidethe stave including isotherm was obtained based on the experiment data. And the effects of thetemperature of cooling water and the velocity of the water as well as the temperature of the furnaceon the 3-D temperature distribution were obtained. The experimental and calculation results showthat the highest temperature of the hot surface is lower than 90 deg C which is very good for thesolidified slag formation on the hot surface and protecting the stave.展开更多
A new type of cooling stave with internal ribbed tube was proposed,and the heat transfer performance of the stave was studied by means of thermal test and numerical simulation.The temperature of cooling stave was moni...A new type of cooling stave with internal ribbed tube was proposed,and the heat transfer performance of the stave was studied by means of thermal test and numerical simulation.The temperature of cooling stave was monitored in the conditions of furnace gas temperature of 200-700 C and cooling water velocity of 0.2-1.0 m/s.The thermal test results show that the internal rib structure can form swirl in the water pipe and improve the cooling capacity of the cooling stave.The higher the furnace temperature or the lower the cooling water flow rate,the more obvious the advantage of the cooling stave with internal ribbed tube.The mathematical model of the cooling stave with internal ribbed tube was established by FLUENT software,and the influence of the internal rib structure parameters on the heat transfer performance of the cooling stave was discussed.It is suggested that the parameters of the internal ribbed tube should be 4 ribs,1 mm in height,5-7 mm in width,and 20-30 mm in lead.In the same common working conditions of the cooling stave,the maximum temperature of the newly designed cooling stave with internal ribbed tube is reduced by 5.6%compared with that of common cooling stave with round tube.The water flow rate in the internal ribbed tube only needs 0.9 m/s to reach the cooling effect of 2 m/s in the common tube cooling stave,which can save 55%of water.In case of water shortage accident of cooling stave,the maximum temperature of the cooling stave with internal ribbed tube is decreased by 22.4%compared with that of common round tube,which can effectively reduce the harm of water shortage and protect the cooling stave.展开更多
Key points： PRATO-ACS randomized NSTE-ACS patients to rosuvastatin or control prior to PCI Statin resulted in significant decrease in nephropathy, better short-term outcomes Data needed to elucidate class effects of ...Key points： PRATO-ACS randomized NSTE-ACS patients to rosuvastatin or control prior to PCI Statin resulted in significant decrease in nephropathy, better short-term outcomes Data needed to elucidate class effects of statins, causality展开更多
人类对人体奥秘的探索与了解尚处初级阶段。本文提出的一个问题就让我们感到新奇与愕然。洁齿与口腔卫生有助于抑制糖尿病: Gum(齿龈)disease may even be more important than obesity or age as a factorin the onset of diabetes in ...人类对人体奥秘的探索与了解尚处初级阶段。本文提出的一个问题就让我们感到新奇与愕然。洁齿与口腔卫生有助于抑制糖尿病: Gum(齿龈)disease may even be more important than obesity or age as a factorin the onset of diabetes in adults。 上句可译:就诱发成年人糖尿病的因素而言,齿龈疾病也许比肥胖和年龄这两个因素更为重要。 因此,我们有必要认识:the importance of prevention and early treatment ofgum disease in people who are at risk of developing diabetes。 本文对inflammation([医]炎症,发炎)提出了一个颇有原创性的观点:…heart disease has a substantial inflammatory component。】展开更多
文摘Copper staves have been equipped on nearly all of BF （blast furnaces） with volume over than 1000 m3 in China since their introduction from abroad about more than 10 years ago. Because of short application and lack of experience, phenomena of thickened or naked of copper stave happen occasionally which influence production severely. So it is important to study the model of forming-accretion on BF copper stave and realize real-time monitoring of forming-accretion on different copper staves. Therefore, mathematic model of calculating accretion thickness by heat flow of BF is proposed, and the calculated results indicate that accretion thickness could be kept at a reasonable range of around 50 mm by controlling heat flux around 22.0 kW/mz. The monitoring program based on the model was applied to a certain BF in China successfully, and it is found that slip of BF near the inner wall is one of most important reasons that cause fluctuation of accretion thickness. During the period of scheduled maintenance of the certain BF, the thickness of accretion measured through the static pressure holes is in good accordance with the value calculated by the monitoring program, so the results calculated by the monitoring program can be used to guide industrial production
基金supported by the National Natural Science Foundation of China (No.60672145)
文摘The temperature of gas flow inside a blast furnace （BF） changes significantly when the blast furnace is under unstable operations, and the temperature and stress distributions of cooling staves （CS） for BF work the same pattern. The effect of gas temperature on the temperature, stress, and displacement distributions of the cooling stave were analyzed as the gas temperature inside the blast furnace rose from 1000 to 1600℃ in 900 s. The results show that both the temperature and temperature gradient of the hot side of CS increase when the gas flow temperature inside BF rises. The temperature gradient of the hot side of CS is greater than that of the other area of CS and it can reach 65℃/mm. In the vertical direction of the hot side of CS, closer to the central part of CS, the stress intensity is greater than that of the other area of the hot side of CS, which causes cracks on the hot side of CS in the vertical di- rection. As the gas temperature increases, the stress intensity rate near the fixed pin increases and finally reaches 45 MPa/s. Fatigues near the fixed pin and bolts are caused by great stress intensity rate and the area around the pin can be damaged easily. The edge of CS bends toward the cold side and the central part of CS shifts toward the hot surface.
基金Item Sponsored by National Natural Science Foundation of China(60472095)
文摘A monitoring method that has been designed for the first time for blast furnace wall with copper staves manufactured in China was introduced. Combining the method of ＂inverse problem＂ and the concept ＂non-inverse problem＂, the monitoring program for blast furnace wall with copper staves has been realized, which can be used to calculate online the accretion thickness and temperature of hot surface of copper staves after obtaining the values of thermocouples of copper staves. The accretion state obtained in the actual investigation has proved that the result of the program is correct. The monitoring program shows that the accretion would easily fluctuate when the accretion layer is extremely thick or thin, thereby the stable and smooth operation of the blast furnace is hindered. By maintaining appropriate accretion thickness, both long campaigns and high productivity of the blast furnace can be achieved; furthermore, it can also optimize the operation of blast furnace and maximize its production. Approximately 30--50 mm in thickness of accretion layer is maintained on the wall of Shougang blast furnace 2, which can meet the requirement for obtaining both long campaign and high productivity.
基金the National Natural Science Foundation of China(No.60672145).
文摘The quantificational and normative design is the precondition of improving the design of copper staves for blast furnaces. Based on a 3-dimensional temperature field calculation model, from the view point of heat transfer and long campaigns note with the core of forming accretion, the forming-accretion-ability （FAA） and the rib hot surface maximum temperature difference （ATmax） as quantificational indexes to direct and evaluate the design of copper staves for blast furnaces were presented. The application of the two indexes in design essentially embodies the new long campaigns in the stage of design. With the application of the two indexes, good results can be obtained. Firstly, it was suggested that the rib height of a copper stave can be reduced to 15 mm, which is a new method and theory for the reduction of copper staves. Secondly, the influence of insert on FAA and ATmax, is decided by the volume of insert. According to this, the principle of design for the hot surface geometry of copper staves was put forward that the ratio of the rib hot surface to the copper stave hot surface （abbreviated as the ratio of rib to stave） must be maintained in the range of 45% to 55%; for the present copper stave with a 35-40 mm thick rib, the ratio of rib to stave in the range of 50% to 55% can optimize the design of copper staves; for the copper stave with a smaller rib thickness, for example 15 ram, the ratio of rib to stave in the range of 45% to 50% can optimize the design of copper staves. It can be summarized that the thicker the rib thickness, the larger is the ratio of rib to stave. 2008 University of Science and Technology Beijing. All rights reserved.
文摘Much attention has been paid to copper staves because they have excellentperformance and longevity. The hot test of copper staves was carried out using all-scale staveexperiment system and according to the results, the temperature distribution and heatcharacteristics were studied. The result shows that copper stave possesses outstanding heat transferability, a well-distributed temperature field and low temperature on the hot side. In addition, amodel was established to calculate the cooling water channels' inner face temperature. Thecalculation results indicates that the highest temperature of the inner wall of the channels is 42deg C, and at the same time, the cold side of the stave temperature is 42-43 deg C. That is to say,the temperature in the stave is quite uniform.
基金The authors were especially grateful to the National Natural Science Foundation of China(No.51904063)Fundamental Research Funds for the Central Universities(Nos.N172503016,N172502005,and N172506011)China Postdoctoral Science Foundation(No.2018M640259).
文摘The core of the long-life copper stave was to ensure the stability of the slag layer,and the uniform distribution of the slag layer was beneficial to restrict the generation of the overthick slag layer.A novel model for calculating the thickness and distribution of the slag layer in the part of copper stave was established based on the finite element theory through the ANSYS birth-death element technology.The distribution and thickness of the slag layer on the hot surface of copper stave were calculated and analyzed when the gas temperature and slag properties tended to be changed,which was applied to characterize the slag-hanging capability of copper stave with the changes of furnace conditions.It was shown that the thickness of hot surface slag layer in the part of copper stave decreased obviously while the temperature of stave body raised rapidly with increasing gas temperature.When the gas temperature was 1400℃,the inlaid slag layer was gradually melted,and the maximum temperature of the stave body was closed to 120℃.The change of gas temperature was very sensitive to the adherent dross capability of copper stave which would be enhanced by the promotion of slag-hanging temperature.However,when the slag-hanging temperature was 1150℃and the gas temperature was lower than 1250℃,the overlhick slag layer was easily formed on the hot surface of the copper stave,and its stability was poor.The improvement in the thermal conductivity of slag could be conducive to the formation of the uniform and stable slag layer on the hot surface of copper stave,especially in the dovetail groove.When the thermal conductivity of the slag was greater than 1.8 W m^(-2)℃^(-1),the inlaid slag layer in the dovetail groove was not melted,although the gas temperature reached 1500℃.
基金Project(2007CB707706) supported by the Major State Basic Research Development Program of ChinaProjects(2007E213,2007E203) supported by the Natural Science Foundation of Shaanxi Province,China
文摘The stability and nonlinear dynamic behavior of drilling shaft system in copper stave deep hole drilling were analyzed. The effects of the fluctuation of the cutting force, the mass eccentricity and the hydrodynamic forces of cutting fluid could be taken into consideration in the model of drilling shaft system. Based on the isoparametric finite element method, the variational form of Reynolds equation in hydrodynamic fluid was used to calculate nonlinear hydrodynamic forces and their Jacobian matrices simultaneously. In the stability analysis, a new shooting method for rapidly determining the periodic orbit of the nonlinear drilling shaft system and its period was presented by rebuilding the traditional shooting method and changing the time scale. Through the combination of theories with experiment, the correctness and effectiveness of the above methods are verified by using the Floquet theory. The results show that the mass eccentricity can inhibit the whirling motion of drilling shaft to some extent.
文摘An experiment of a new type full size copper stave for a real blast furnacewas carried out in a special-designed experimental system. The 3-D temperature distribution insidethe stave including isotherm was obtained based on the experiment data. And the effects of thetemperature of cooling water and the velocity of the water as well as the temperature of the furnaceon the 3-D temperature distribution were obtained. The experimental and calculation results showthat the highest temperature of the hot surface is lower than 90 deg C which is very good for thesolidified slag formation on the hot surface and protecting the stave.
基金funded by the National Natural Science Foundation of China(51574179)Nantong Science and Technology Project(JC2019154).
文摘A new type of cooling stave with internal ribbed tube was proposed,and the heat transfer performance of the stave was studied by means of thermal test and numerical simulation.The temperature of cooling stave was monitored in the conditions of furnace gas temperature of 200-700 C and cooling water velocity of 0.2-1.0 m/s.The thermal test results show that the internal rib structure can form swirl in the water pipe and improve the cooling capacity of the cooling stave.The higher the furnace temperature or the lower the cooling water flow rate,the more obvious the advantage of the cooling stave with internal ribbed tube.The mathematical model of the cooling stave with internal ribbed tube was established by FLUENT software,and the influence of the internal rib structure parameters on the heat transfer performance of the cooling stave was discussed.It is suggested that the parameters of the internal ribbed tube should be 4 ribs,1 mm in height,5-7 mm in width,and 20-30 mm in lead.In the same common working conditions of the cooling stave,the maximum temperature of the newly designed cooling stave with internal ribbed tube is reduced by 5.6%compared with that of common cooling stave with round tube.The water flow rate in the internal ribbed tube only needs 0.9 m/s to reach the cooling effect of 2 m/s in the common tube cooling stave,which can save 55%of water.In case of water shortage accident of cooling stave,the maximum temperature of the cooling stave with internal ribbed tube is decreased by 22.4%compared with that of common round tube,which can effectively reduce the harm of water shortage and protect the cooling stave.
文摘Key points： PRATO-ACS randomized NSTE-ACS patients to rosuvastatin or control prior to PCI Statin resulted in significant decrease in nephropathy, better short-term outcomes Data needed to elucidate class effects of statins, causality
文摘人类对人体奥秘的探索与了解尚处初级阶段。本文提出的一个问题就让我们感到新奇与愕然。洁齿与口腔卫生有助于抑制糖尿病: Gum(齿龈)disease may even be more important than obesity or age as a factorin the onset of diabetes in adults。 上句可译:就诱发成年人糖尿病的因素而言,齿龈疾病也许比肥胖和年龄这两个因素更为重要。 因此,我们有必要认识:the importance of prevention and early treatment ofgum disease in people who are at risk of developing diabetes。 本文对inflammation([医]炎症,发炎)提出了一个颇有原创性的观点:…heart disease has a substantial inflammatory component。】
