Pub Date : 2013-05-01DOI: 10.3969/J.ISSN.1006-7043.201206049
Wen-tao Hu, Huajun Wang, Chuan-yao Sun, Yang He, Chunlin Ji, C. Wang, Hongdong Yu
In response to ferric bauxite comprehensive utilization challenge,both the interaction between the ore and soda-lime,and the interaction between soda ash and lime in heat preservation progress were investigated.The study showed,in reduction atmosphere,most Fe2O3 in ore was reduced to iron,only a small part of Al2O3 was converted into sodium aluminate,the others still existed in forms of sodium aluminosilicate or corundum rather than sodium aluminate,leading to low dissolution rate of Na2O and Al2O3.This is because of the low activity of CaO,the Na2O and Al2O3 in sodium aluminosilicate can not be completely displaced.For the dilution effect of low active lime,the relative content of soda ash reduced.So the interaction between ferric bauxite and soda ash was weakened.
{"title":"Reaction mechanism between ferric bauxite and soda lime in reduction atmosphere","authors":"Wen-tao Hu, Huajun Wang, Chuan-yao Sun, Yang He, Chunlin Ji, C. Wang, Hongdong Yu","doi":"10.3969/J.ISSN.1006-7043.201206049","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.201206049","url":null,"abstract":"In response to ferric bauxite comprehensive utilization challenge,both the interaction between the ore and soda-lime,and the interaction between soda ash and lime in heat preservation progress were investigated.The study showed,in reduction atmosphere,most Fe2O3 in ore was reduced to iron,only a small part of Al2O3 was converted into sodium aluminate,the others still existed in forms of sodium aluminosilicate or corundum rather than sodium aluminate,leading to low dissolution rate of Na2O and Al2O3.This is because of the low activity of CaO,the Na2O and Al2O3 in sodium aluminosilicate can not be completely displaced.For the dilution effect of low active lime,the relative content of soda ash reduced.So the interaction between ferric bauxite and soda ash was weakened.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2013-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-06-01DOI: 10.3969/J.ISSN.1006-7043.201107007
Haijun Zhou, Wanyou Li, Binglin Lü, Wenlong Li
According to the vibration problem of a curved beam with elastic support boundary conditions,the in-plane free vibration characteristics of multi-span curved beams were analyzed using an improved Fourier series method.The transverse and tangential displacement functions were sought as a Fourier cosine series,and an auxiliary polynomial function was introduced to take all the relevant discontinuities of the elastic boundaries.The Rayleigh-Ritz method was used to solve Hamilton's equation,which is based on the energy principle,and a standard eigenvalue problem concerning the unknown displacement amplitudes was derived from which the natural frequencies and mode shapes can be solved.The results of single-span and two-span curved beams with free,simple supported,clamped,and elastic supported boundary conditions were obtained and compared with the results acquired from the finite element method(FEM) to validate the correctness of the presented method.Furthermore,the effect of the connecting stiffnesses between two-span curved beams on the first four frequencies was described.
{"title":"In-plane free vibration analysis of multi-span curved beams with elastic support and connecting boundary conditions","authors":"Haijun Zhou, Wanyou Li, Binglin Lü, Wenlong Li","doi":"10.3969/J.ISSN.1006-7043.201107007","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.201107007","url":null,"abstract":"According to the vibration problem of a curved beam with elastic support boundary conditions,the in-plane free vibration characteristics of multi-span curved beams were analyzed using an improved Fourier series method.The transverse and tangential displacement functions were sought as a Fourier cosine series,and an auxiliary polynomial function was introduced to take all the relevant discontinuities of the elastic boundaries.The Rayleigh-Ritz method was used to solve Hamilton's equation,which is based on the energy principle,and a standard eigenvalue problem concerning the unknown displacement amplitudes was derived from which the natural frequencies and mode shapes can be solved.The results of single-span and two-span curved beams with free,simple supported,clamped,and elastic supported boundary conditions were obtained and compared with the results acquired from the finite element method(FEM) to validate the correctness of the presented method.Furthermore,the effect of the connecting stiffnesses between two-span curved beams on the first four frequencies was described.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2011-11-01DOI: 10.3969/J.ISSN.1006-7043.2011.11.005
W. Zheng, Hezhen Yang
The object of this paper is to present a more accurate and useful method for fatigue analysis and life prediction for a stress joint of a deepwater steel catenary riser. The stress joint was used to connect the riser and platform, and it was subjected to ocean environmental loadings and erosion; thus, the fatigue problem is critical. First, global time domain dynamic analysis of the steel catenary riser was performed, and then local analysis was performed for the stress joint. Finally, the fatigue life of the stress joint was evaluated according to the multiaxial fatigue theory, and a preliminary parametric study was also carried out. Results show that taking stress value of the structure as the only criterion is not enough, and fatigue analysis is necessary when the structure is subjected to an alternating load. Compared with uniaxial analysis, multiaxial fatigue analysis can reflect the damage of the structure more realistically. Especially for deepwater steel catenary risers, multiaxial fatigue problems should be given close attention.
{"title":"Multiaxial fatigue analysis of the stress joint for a deepwater steel catenary riser","authors":"W. Zheng, Hezhen Yang","doi":"10.3969/J.ISSN.1006-7043.2011.11.005","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.2011.11.005","url":null,"abstract":"The object of this paper is to present a more accurate and useful method for fatigue analysis and life prediction for a stress joint of a deepwater steel catenary riser. The stress joint was used to connect the riser and platform, and it was subjected to ocean environmental loadings and erosion; thus, the fatigue problem is critical. First, global time domain dynamic analysis of the steel catenary riser was performed, and then local analysis was performed for the stress joint. Finally, the fatigue life of the stress joint was evaluated according to the multiaxial fatigue theory, and a preliminary parametric study was also carried out. Results show that taking stress value of the structure as the only criterion is not enough, and fatigue analysis is necessary when the structure is subjected to an alternating load. Compared with uniaxial analysis, multiaxial fatigue analysis can reflect the damage of the structure more realistically. Especially for deepwater steel catenary risers, multiaxial fatigue problems should be given close attention.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-01-01DOI: 10.3969/J.ISSN.1006-7043.2010.03.010
Hm Wu, W. Chow, Y. Gao
A fire whirl is simply a vortex flow with combustion.To understand the mechanism generating fire whirls,large scale experiments were conducted in a vertical square channel(2.0 m × 2.0 m × 15.0 m) with a lateral seam.They were also simulated with computational fluid dynamics(CFD) using fire dynamics simulator(FDS) version 4.07 which includes a method for large eddy simulation.To investigate the primary characteristics of fire whirls,five cases were simulated,each using a different bottom vent.It was found that when three edges at the bottom of the channel connect with the ambient a fire whirl cannot be produced.The other four cases produced one.In those cases,the distribution rule of temperature and axial velocity of the fire whirl at the channel centerline with the changing of height was presented.Next,the observed shifting of the central axis of the fire whirl from the channel's centerline was analyzed.It was also noted that the positions of the top of the flame in the fire whirl were incontinuous.
火涡就是燃烧时产生的涡流。为了了解火涡的产生机制，在一个垂直的方形通道(2.0 m × 2.0 m × 15.0 m)中进行了大规模的实验。采用计算流体力学(CFD)模拟，采用火焰动力学模拟器(FDS) 4.07版，其中包括大涡模拟方法。为了研究火焰漩涡的主要特征，模拟了五个案例，每个案例使用不同的底部通风口。研究发现，当通道底部的三个边缘与周围环境相连接时，不能产生火涡。其他四个案例产生了一个。在这种情况下，给出了通道中心线处火焰漩涡温度和轴向速度随高度变化的分布规律。其次，分析了观测到的火涡中轴线偏离通道中心线的情况。人们还注意到，火焰顶部在火焰漩涡中的位置是不连续的。
{"title":"The primary characteristics of fire whirls in vertical square channels with a lateral seam","authors":"Hm Wu, W. Chow, Y. Gao","doi":"10.3969/J.ISSN.1006-7043.2010.03.010","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.2010.03.010","url":null,"abstract":"A fire whirl is simply a vortex flow with combustion.To understand the mechanism generating fire whirls,large scale experiments were conducted in a vertical square channel(2.0 m × 2.0 m × 15.0 m) with a lateral seam.They were also simulated with computational fluid dynamics(CFD) using fire dynamics simulator(FDS) version 4.07 which includes a method for large eddy simulation.To investigate the primary characteristics of fire whirls,five cases were simulated,each using a different bottom vent.It was found that when three edges at the bottom of the channel connect with the ambient a fire whirl cannot be produced.The other four cases produced one.In those cases,the distribution rule of temperature and axial velocity of the fire whirl at the channel centerline with the changing of height was presented.Next,the observed shifting of the central axis of the fire whirl from the channel's centerline was analyzed.It was also noted that the positions of the top of the flame in the fire whirl were incontinuous.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.3969/J.ISSN.1006-7043.2009.08.001
Bin Zhang, W. Wu
The heat and mass transfer between liquefied natural gas (LNG) and the environment caused by an LNG vessel leakage underwater was simulated using FLUENT software under different conditions of environment temperature and wind velocity. The VOF was used to define heat and mass source terms, and an experimental average heat exchange velocity value was applied to the environment of the leak. Through numerical simulations, the authors derived distributions of flow, temperature, viscosity, and ice forming mechanisms. A rule was derived for LNG and NG mass changes with time due to boiling. Mechanisms for heat and mass transfer in an LNG vessel's underwater leakage were discussed. On that basis a formula for the effect of environmental temperature and wind velocity on the simulation was proposed. The results show that in high temperature seas there will still be low temperature LNG, but because of violent motion caused by the LNG's rapid phase change, the formation of ice is difficult. When un-boiling LNG reaches the surface of the sea, phase change then forms ice. The higher the environmental temperature and wind velocity, the greater the quantity of heat and mass transferred, the lower the quantity of ice formed.
{"title":"Effects of environmental temperature and wind velocity on underwater LNG vessel leakage","authors":"Bin Zhang, W. Wu","doi":"10.3969/J.ISSN.1006-7043.2009.08.001","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.2009.08.001","url":null,"abstract":"The heat and mass transfer between liquefied natural gas (LNG) and the environment caused by an LNG vessel leakage underwater was simulated using FLUENT software under different conditions of environment temperature and wind velocity. The VOF was used to define heat and mass source terms, and an experimental average heat exchange velocity value was applied to the environment of the leak. Through numerical simulations, the authors derived distributions of flow, temperature, viscosity, and ice forming mechanisms. A rule was derived for LNG and NG mass changes with time due to boiling. Mechanisms for heat and mass transfer in an LNG vessel's underwater leakage were discussed. On that basis a formula for the effect of environmental temperature and wind velocity on the simulation was proposed. The results show that in high temperature seas there will still be low temperature LNG, but because of violent motion caused by the LNG's rapid phase change, the formation of ice is difficult. When un-boiling LNG reaches the surface of the sea, phase change then forms ice. The higher the environmental temperature and wind velocity, the greater the quantity of heat and mass transferred, the lower the quantity of ice formed.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-01-01DOI: 10.3969/J.ISSN.1006-7043.2008.05.017
G. Li, D. Guan, H. Wang, Mingxing Zhang
In order to study how running-in affects surface nanocrystallization of medium carbon steel, running-in and wearing tests were conducted, while under lubrication, using a ring-on-disc tester. Variations in the coefficient of friction and multifractal spectrum parameters of frictional vibration signals were analyzed. Wearing behavior of the surface nanocrystallization of medium carbon steel was investigated by examining wearing surface topography. The results showed that the coefficient of friction and the multifractal spectrum parameters of frictional vibration signals are markedly decreased for specimens showing surface nanocrystallization. High surface activity leads to better adsorption of lubricant-on the condition that the load is below a critical value beyond which oil film formation is inhibited. Our test showed that running-in and wearing properties of medium carbon steel can be improved by means of surface nanocrystallization.
{"title":"Influence of surface nanocrystallization on running-in and wearing properties of medium carbon steel","authors":"G. Li, D. Guan, H. Wang, Mingxing Zhang","doi":"10.3969/J.ISSN.1006-7043.2008.05.017","DOIUrl":"https://doi.org/10.3969/J.ISSN.1006-7043.2008.05.017","url":null,"abstract":"In order to study how running-in affects surface nanocrystallization of medium carbon steel, running-in and wearing tests were conducted, while under lubrication, using a ring-on-disc tester. Variations in the coefficient of friction and multifractal spectrum parameters of frictional vibration signals were analyzed. Wearing behavior of the surface nanocrystallization of medium carbon steel was investigated by examining wearing surface topography. The results showed that the coefficient of friction and the multifractal spectrum parameters of frictional vibration signals are markedly decreased for specimens showing surface nanocrystallization. High surface activity leads to better adsorption of lubricant-on the condition that the load is below a critical value beyond which oil film formation is inhibited. Our test showed that running-in and wearing properties of medium carbon steel can be improved by means of surface nanocrystallization.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70175436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2000-06-28DOI: 10.1109/WCICA.2000.863140
Tan Zhenfan Wang, Bei Xiaoxu
The stability of the restraint loops of a two degree-of-freedom (DOF) gyro has been analyzed by means of the Lyapunov direct method. The state-space model is derived from the technical functions of a 2-DOF gyro, which is a fourth-order system and time varying during the starting process. From the variable gradient method, the Lyapunov function is found, and whereby the stability conditions of the system are obtained. Since the starting process of a gyro is much longer than the time constant of the restraint loops for time-varying systems, it can be stabilized as long as the stability conditions are changed along with the time varying parameters.
{"title":"The Lyapunov stability analysis on restraint loops of a two-degree-of-freedom gyro","authors":"Tan Zhenfan Wang, Bei Xiaoxu","doi":"10.1109/WCICA.2000.863140","DOIUrl":"https://doi.org/10.1109/WCICA.2000.863140","url":null,"abstract":"The stability of the restraint loops of a two degree-of-freedom (DOF) gyro has been analyzed by means of the Lyapunov direct method. The state-space model is derived from the technical functions of a 2-DOF gyro, which is a fourth-order system and time varying during the starting process. From the variable gradient method, the Lyapunov function is found, and whereby the stability conditions of the system are obtained. Since the starting process of a gyro is much longer than the time constant of the restraint loops for time-varying systems, it can be stabilized as long as the stability conditions are changed along with the time varying parameters.","PeriodicalId":35592,"journal":{"name":"哈尔滨工程大学学报","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2000-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1109/WCICA.2000.863140","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"62913774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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