Taking an oxygen enriched side-blown furnace as the prototype,a hydraulic model was established according to the similarity principle.The influence of three factors on the gas-liquid two-phase flow was analyzed,i.e.th...Taking an oxygen enriched side-blown furnace as the prototype,a hydraulic model was established according to the similarity principle.The influence of three factors on the gas-liquid two-phase flow was analyzed,i.e.the airflow speed,the submerged depth and the downward angle of the nozzle.A numerical simulation of the hydraulic model was carried out trying to find the suitable turbulence model which can describe the side-blown two-phase flow correctly by comparing the simulation results with the experimental data.The experiment shows that the airflow speed has a great influence on the flow of the water.The submerged depth of the nozzle has a relatively smaller influence on the penetration depth and the surface fluctuation height in the liquid phase.When the nozzle is at a downward angle of 15°,the penetration depth and the surface fluctuation height are reduced.It is concluded that the numerical results with the realizable k-εturbulence model are the closest to the experiment for the penetration depth,the surface fluctuation height and the bubble scale.展开更多
A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effec...A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effect.Its modeling results were verified with theoretical correlations and experiments,and the nozzle-eroded states in practice were also involved in the analysis.Through comparison,it is confirmed that the thermal expansion effect influences the flow pattern significantly,which may lead to the backward motion of airflow and create a potential risk to production safety.Consequently,the influences of air injection velocity and furnace width on airflow behavior were investigated to provide operating and design guidance.It is found that the thin layer melt,which avoids high-rate oxygen airflow eroding nozzles,shrinks as the injection velocity increases,but safety can be guaranteed when the velocity ranges from 175 to 275 m/s.Moreover,the isoline patterns and heights of thin layers change slightly when the furnace width increases from 2.2 to 2.8 m,indicating that the furnace width shows a limited influence on production safety.展开更多
A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow.Key parameters were extracted,and Spearman correlation analysis was used to quantify the...A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow.Key parameters were extracted,and Spearman correlation analysis was used to quantify the relationships among bubble behavior,circulating flow,and liquid oscillations.The results show that periodic bubble behavior under steady injection drives the circulating flow of the liquid on both sides.The asynchronism of bubble behavior on both sides results in the alternation of circulating intensity,which significantly enhances gas−liquid mixing efficiency at certain liquid levels of 200 and 220 mm.Flow patterns of the double-side-blown process are classified into weak circulation,strong−weak alternating circulation,and strong circulation modes based on the influence of circulating flows on the penetration depth.The penetration depth in the strong−weak alternating circulation mode is generally greater than that in the single-side-blown process.The imbalance of circulating intensities on both sides primarily leads to the stable fluctuation in the injecting direction,which reveals the appearance of periodic oscillations in the molten bath.The effect of control parameters such as liquid level and gas flow rate on the liquid oscillations were discussed.展开更多
To overcome the limited mixing efficiency associated with conventional steady-state side blowing in molten pool smelting,this study proposes a gas injection strategy that combines a swirl lance configuration with sinu...To overcome the limited mixing efficiency associated with conventional steady-state side blowing in molten pool smelting,this study proposes a gas injection strategy that combines a swirl lance configuration with sinusoidal pulsed blowing.Using a volume-of-fluid(VOF)multiphase flow framework coupled with the Realizable k-ε turbulence model,the performance of constant-velocity blowing is systematically compared with sinusoidal pulsed blowing over a range of amplitudes(5,10,and 15 m/s)and frequencies(0.5,1,and 2 Hz).The results demonstrate that sinusoidal pulsed blowing markedly enhances gas-liquid mixing within the melt pool relative to constant-speed injection.Mixing efficiency increases with blowing amplitude,while its dependence on pulse frequency is nonlinear.Within the investigated parameter space,the optimal configuration,an amplitude of 15 m/s and a frequency of 1 Hz,raises the average gas volume fraction by 8%,reduces the mixing dead-zone area by 81%,and expands the active mixing region by 25%.Overall,the imposed sinusoidal pulsing promotes bubble breakup beneath the free surface,leading to more complete bubble collapse,intensified turbulent agitation,and,ultimately,improved gas–liquid mixing.展开更多
基金Project(2018YFC1901606)supported by the National Key R&D Program of China.
文摘Taking an oxygen enriched side-blown furnace as the prototype,a hydraulic model was established according to the similarity principle.The influence of three factors on the gas-liquid two-phase flow was analyzed,i.e.the airflow speed,the submerged depth and the downward angle of the nozzle.A numerical simulation of the hydraulic model was carried out trying to find the suitable turbulence model which can describe the side-blown two-phase flow correctly by comparing the simulation results with the experimental data.The experiment shows that the airflow speed has a great influence on the flow of the water.The submerged depth of the nozzle has a relatively smaller influence on the penetration depth and the surface fluctuation height in the liquid phase.When the nozzle is at a downward angle of 15°,the penetration depth and the surface fluctuation height are reduced.It is concluded that the numerical results with the realizable k-εturbulence model are the closest to the experiment for the penetration depth,the surface fluctuation height and the bubble scale.
基金the support from the National Key R&D Program of China(No.2018YFC1901606).
文摘A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effect.Its modeling results were verified with theoretical correlations and experiments,and the nozzle-eroded states in practice were also involved in the analysis.Through comparison,it is confirmed that the thermal expansion effect influences the flow pattern significantly,which may lead to the backward motion of airflow and create a potential risk to production safety.Consequently,the influences of air injection velocity and furnace width on airflow behavior were investigated to provide operating and design guidance.It is found that the thin layer melt,which avoids high-rate oxygen airflow eroding nozzles,shrinks as the injection velocity increases,but safety can be guaranteed when the velocity ranges from 175 to 275 m/s.Moreover,the isoline patterns and heights of thin layers change slightly when the furnace width increases from 2.2 to 2.8 m,indicating that the furnace width shows a limited influence on production safety.
基金financial support for this research work from the National Key Research and Development Program of China(No.2022YFB3304901)。
文摘A CFD-based numerical model was employed to quantitatively analyze the flow characteristics of double-side-blown gas−liquid flow.Key parameters were extracted,and Spearman correlation analysis was used to quantify the relationships among bubble behavior,circulating flow,and liquid oscillations.The results show that periodic bubble behavior under steady injection drives the circulating flow of the liquid on both sides.The asynchronism of bubble behavior on both sides results in the alternation of circulating intensity,which significantly enhances gas−liquid mixing efficiency at certain liquid levels of 200 and 220 mm.Flow patterns of the double-side-blown process are classified into weak circulation,strong−weak alternating circulation,and strong circulation modes based on the influence of circulating flows on the penetration depth.The penetration depth in the strong−weak alternating circulation mode is generally greater than that in the single-side-blown process.The imbalance of circulating intensities on both sides primarily leads to the stable fluctuation in the injecting direction,which reveals the appearance of periodic oscillations in the molten bath.The effect of control parameters such as liquid level and gas flow rate on the liquid oscillations were discussed.
基金Supported by Yunnan Fundamental Research Projects(202301AT070469,202301AT070275)Supported by Yunnan Provincial Integrated Special Fund for Key Laboratories(Integrated for Provincial and Municipal Levels)(No.202302AN360004).
文摘To overcome the limited mixing efficiency associated with conventional steady-state side blowing in molten pool smelting,this study proposes a gas injection strategy that combines a swirl lance configuration with sinusoidal pulsed blowing.Using a volume-of-fluid(VOF)multiphase flow framework coupled with the Realizable k-ε turbulence model,the performance of constant-velocity blowing is systematically compared with sinusoidal pulsed blowing over a range of amplitudes(5,10,and 15 m/s)and frequencies(0.5,1,and 2 Hz).The results demonstrate that sinusoidal pulsed blowing markedly enhances gas-liquid mixing within the melt pool relative to constant-speed injection.Mixing efficiency increases with blowing amplitude,while its dependence on pulse frequency is nonlinear.Within the investigated parameter space,the optimal configuration,an amplitude of 15 m/s and a frequency of 1 Hz,raises the average gas volume fraction by 8%,reduces the mixing dead-zone area by 81%,and expands the active mixing region by 25%.Overall,the imposed sinusoidal pulsing promotes bubble breakup beneath the free surface,leading to more complete bubble collapse,intensified turbulent agitation,and,ultimately,improved gas–liquid mixing.
