Frothers facilitate the reduction of bubbles size by preventing bubbles coalescence and produce more stable froths.The collision probability of the bubbles and particles substantially increases by decreasing bubble si...Frothers facilitate the reduction of bubbles size by preventing bubbles coalescence and produce more stable froths.The collision probability of the bubbles and particles substantially increases by decreasing bubble size.For the same volume system,fewer bubbles result from a distribution of large-sized bubbles,and more bubbles result from a distribution of small-sized bubbles.In this research,fundamental two-phase frother characterization parameters were aimed to link with three-phase coal and talc flotation behavior.For this purpose,the effect of single and dual frother systems on inhibiting bubble coalescence was investigated with methyl isobutyl carbinol(MIBC),isooctanol(2 ethyl hexanol),pine oil,and Dowfroth 250.Based on the results of single frothers,isooctanol at the lowest critical coalescence concentration(CCC)value of 6×10^(−6) achieved the smallest bubbles with Sauter mean diameter of 0.80 mm.By blending Dowfroth 250 and pine oil,the bubbles size decreased significantly,reaching 0.45 mm.While the highest recoveries in coal flotation were obtained in single and frother blends where the bubbles size was measured as the smallest in two-phase system,and such a relationship was not found for talc flotation.展开更多
The melt stirring in a large copper smelting oxygen bottom-blown furnace is caused by the large amount of gas movement blown in by two rows of oxygen lances.At present,the two rows of oxygen lances provide oxygen of e...The melt stirring in a large copper smelting oxygen bottom-blown furnace is caused by the large amount of gas movement blown in by two rows of oxygen lances.At present,the two rows of oxygen lances provide oxygen of equal strength,and the stirring in the central area of the melt is insufficient,which restricts the efficient progress of the smelting reaction.This study proposes a strong-weak coupling oxygen supply method and establishes an equivalent model based on a large bottom-blown furnace(LBBF)of an enterprise to simulate the bubble characteristics and flow characteristics of the molten pool.The results show that adjusting the flow ratio between the two rows of oxygen lances can create a“strong”and a“weak”coexisting source of disturbance in an LBBF.It is worth noting that when the flow rate ratio of the two rows of oxygen lances is 1.6,the peak velocity generated by the“strong”distur bance source in the molten pool increases by 18.92%,and the disturbance range increases.This method effectively strengthens the stirring in the central area of the molten pool,improves smelting efficiency,and does not produce harmful melt splashes.It provides important guidance for optimizing production practice.展开更多
In this paper,the failure caused by HRAM loads which were generated by high-speed projectile penetration,and protection technology of the fluid-filled structure were explored.A bubble was preset on the projectile traj...In this paper,the failure caused by HRAM loads which were generated by high-speed projectile penetration,and protection technology of the fluid-filled structure were explored.A bubble was preset on the projectile trajectory in a fluid-filled structure.Based on the reflection and transmission phenomena of pressure waves at the gas-liquid interface and the compressibility characteristics of gases,a numerical analysis was conducted on the influence of preset bubble on projectile penetration and structural failure characteristics.The results indicate that the secondary water-entry impact phenomenon occurs when a preset bubble exists on the projectile trajectory,leading to the secondary water entry impact loads.The rarefaction waves reflected on the surface of the preset bubble cause the attenuation ratio of the initial impact pressure peak to reach 68.8%and the total specific impulse attenuation ratio to reach 48.6%.Furthermore,the larger the bubble,the faster the projectile,and the more obvious the attenuation effect.Moreover,due to the compressibility of the bubble,the global deformation attenuation ratio of the front and rear walls can reach over 80%.However,the larger the bubble size,the faster the projectile velocity,the smaller the local deformation attenuation effect of the rear wall,and the more severe the failure at the perforation of the rear wall.展开更多
为了有效解决管道泄漏信号难以从复杂背景噪声中分离以及微小泄漏特征提取困难的问题,提出一种基于VMD和ELM的管道微小泄漏工况识别的方法。首先,利用霜冰优化算法RIME改进VMD的关键参数选取,实现VMD的自适应分解。采用VMD分解产生的各...为了有效解决管道泄漏信号难以从复杂背景噪声中分离以及微小泄漏特征提取困难的问题,提出一种基于VMD和ELM的管道微小泄漏工况识别的方法。首先,利用霜冰优化算法RIME改进VMD的关键参数选取,实现VMD的自适应分解。采用VMD分解产生的各阶本征模态函数之间的互信息熵值作为RIME算法参数优化中的适应度函数值,选择最佳的VMD分解参数,建立基于RIME-VMD的管道泄漏信号去噪方法。在此基础上,计算得到的滤波信号的Bubble熵值,实现对管道微小泄漏特征提取的目的。最终,将特征输入到RIME-ELM模型中进行中,实现了4种不同管道工况的识别。实验结果表明,RIMEVMD方法在滤波效果方面表现优异,其信噪比最高,达23.922 d B,说明其滤波后的重构信号中有效信号的占比最大。同时,该方法的平均绝对误差和均方误差分别为0.187和0.056,均为最小值,表明该方法重构信号中的噪声最少。将得到的故障特征向量输入到RIME-ELM模型后,分类准确率达到了95.71%,相比将故障特征向量直接输入ELM模型提高了37.4%,验证了所提出方法的有效性。展开更多
基金Project(ID42787)supported by the Istanbul Technical University,BAP(Scientific Research Project)Department,Turkey。
文摘Frothers facilitate the reduction of bubbles size by preventing bubbles coalescence and produce more stable froths.The collision probability of the bubbles and particles substantially increases by decreasing bubble size.For the same volume system,fewer bubbles result from a distribution of large-sized bubbles,and more bubbles result from a distribution of small-sized bubbles.In this research,fundamental two-phase frother characterization parameters were aimed to link with three-phase coal and talc flotation behavior.For this purpose,the effect of single and dual frother systems on inhibiting bubble coalescence was investigated with methyl isobutyl carbinol(MIBC),isooctanol(2 ethyl hexanol),pine oil,and Dowfroth 250.Based on the results of single frothers,isooctanol at the lowest critical coalescence concentration(CCC)value of 6×10^(−6) achieved the smallest bubbles with Sauter mean diameter of 0.80 mm.By blending Dowfroth 250 and pine oil,the bubbles size decreased significantly,reaching 0.45 mm.While the highest recoveries in coal flotation were obtained in single and frother blends where the bubbles size was measured as the smallest in two-phase system,and such a relationship was not found for talc flotation.
基金Project(2022YFC3901501)supported by the National Key R&D Program of ChinaProject(U20A20273)supported by the National Natural Science Foundation of China+1 种基金Project(2022JJ10078)supported by the Natural Science Foundation for Distinguished Young Scholars of Hunan Province,ChinaProject(2021RC3005)supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘The melt stirring in a large copper smelting oxygen bottom-blown furnace is caused by the large amount of gas movement blown in by two rows of oxygen lances.At present,the two rows of oxygen lances provide oxygen of equal strength,and the stirring in the central area of the melt is insufficient,which restricts the efficient progress of the smelting reaction.This study proposes a strong-weak coupling oxygen supply method and establishes an equivalent model based on a large bottom-blown furnace(LBBF)of an enterprise to simulate the bubble characteristics and flow characteristics of the molten pool.The results show that adjusting the flow ratio between the two rows of oxygen lances can create a“strong”and a“weak”coexisting source of disturbance in an LBBF.It is worth noting that when the flow rate ratio of the two rows of oxygen lances is 1.6,the peak velocity generated by the“strong”distur bance source in the molten pool increases by 18.92%,and the disturbance range increases.This method effectively strengthens the stirring in the central area of the molten pool,improves smelting efficiency,and does not produce harmful melt splashes.It provides important guidance for optimizing production practice.
文摘In this paper,the failure caused by HRAM loads which were generated by high-speed projectile penetration,and protection technology of the fluid-filled structure were explored.A bubble was preset on the projectile trajectory in a fluid-filled structure.Based on the reflection and transmission phenomena of pressure waves at the gas-liquid interface and the compressibility characteristics of gases,a numerical analysis was conducted on the influence of preset bubble on projectile penetration and structural failure characteristics.The results indicate that the secondary water-entry impact phenomenon occurs when a preset bubble exists on the projectile trajectory,leading to the secondary water entry impact loads.The rarefaction waves reflected on the surface of the preset bubble cause the attenuation ratio of the initial impact pressure peak to reach 68.8%and the total specific impulse attenuation ratio to reach 48.6%.Furthermore,the larger the bubble,the faster the projectile,and the more obvious the attenuation effect.Moreover,due to the compressibility of the bubble,the global deformation attenuation ratio of the front and rear walls can reach over 80%.However,the larger the bubble size,the faster the projectile velocity,the smaller the local deformation attenuation effect of the rear wall,and the more severe the failure at the perforation of the rear wall.
文摘为了有效解决管道泄漏信号难以从复杂背景噪声中分离以及微小泄漏特征提取困难的问题,提出一种基于VMD和ELM的管道微小泄漏工况识别的方法。首先,利用霜冰优化算法RIME改进VMD的关键参数选取,实现VMD的自适应分解。采用VMD分解产生的各阶本征模态函数之间的互信息熵值作为RIME算法参数优化中的适应度函数值,选择最佳的VMD分解参数,建立基于RIME-VMD的管道泄漏信号去噪方法。在此基础上,计算得到的滤波信号的Bubble熵值,实现对管道微小泄漏特征提取的目的。最终,将特征输入到RIME-ELM模型中进行中,实现了4种不同管道工况的识别。实验结果表明,RIMEVMD方法在滤波效果方面表现优异,其信噪比最高,达23.922 d B,说明其滤波后的重构信号中有效信号的占比最大。同时,该方法的平均绝对误差和均方误差分别为0.187和0.056,均为最小值,表明该方法重构信号中的噪声最少。将得到的故障特征向量输入到RIME-ELM模型后,分类准确率达到了95.71%,相比将故障特征向量直接输入ELM模型提高了37.4%,验证了所提出方法的有效性。
