Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-d...Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun(2D-IB-SPETCG)is presented to describe the process of the ETC launch.Both calculated pressure and projectile muzzle velocity accord well with the experimental results.The feasibility of the 2D-IB-SPETCG model is proved.Depending on the experimental data and initial parameters,detailed distribution of the ballistics parameters can be simulated.With the distribution of pressure and temperature of the gas phase and the propellant,the influence of plasma during the ignition process can be analyzed.Because of the radial flowing plasma,the propellant in the area of the DRPG is ignited within 0.01 ms,while all propellant in the chamber is ignited within 0.09 ms.The radial ignition delay time is much less than the axial delay time.During the ignition process,the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech.The radial ignition uniformity is proved.The temperature of the gas increases from several thousand K(conventional ignition)to several ten thousand K(plasma ignition).Compare the distribution of the density and temperature of the gas,we know that low density and high temperature gas appears near the exits of the DRPG,while high density and low temperature gas appears at the wall near the breech.The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch.The 2D-IB-SPETC model can be used for prediction and improvement of experiments.展开更多
针对复杂管道系统内水流冲击滞留气团现象,采用VOF模型(Volume of Fluid Model)进行了数值模拟计算,并与一维模型进行了比较计算分析,结果表明:系统的最大压力并不总是气团的最大压力,有可能还会叠加水体对管壁的撞击而形成的突然升高...针对复杂管道系统内水流冲击滞留气团现象,采用VOF模型(Volume of Fluid Model)进行了数值模拟计算,并与一维模型进行了比较计算分析,结果表明:系统的最大压力并不总是气团的最大压力,有可能还会叠加水体对管壁的撞击而形成的突然升高压力。与实验实测结果的比较分析表明:采用VOF模型,能够较精细地仿真水流冲击滞留气团现象的气团形态、流场结构以及压力分布等的变化过程,其压力数值计算结果与实验实测基本吻合,其计算误差明显小于现有一维模型的计算误差,是深入研究该复杂瞬变流现象的有效方法。展开更多
文章采用FLOW-3D软件,通过RNGk-ε模型和volume of fluid(VOF)方法相结合,实现了竖井水平旋流泄洪洞水力特性的三维水流流场数值模拟;对开敞式进水口轴线与旋流洞轴线交角不同时起旋室的压强分布、旋流角和紊动能等水力特性进行了对比...文章采用FLOW-3D软件,通过RNGk-ε模型和volume of fluid(VOF)方法相结合,实现了竖井水平旋流泄洪洞水力特性的三维水流流场数值模拟;对开敞式进水口轴线与旋流洞轴线交角不同时起旋室的压强分布、旋流角和紊动能等水力特性进行了对比分析研究,数值模拟能够客观地反映起旋室旋流的流场特性,成果可为旋流溢洪道的研究应用提供参考.展开更多
采用Volume of Fluid(VOF)模型对田山泵站进水池进行了三维流场计算,分析了不同水位及开机组合情况下泵站进水池的水流流态.研究发现:泵站低水位运行时,由于淹没深度较小,进水池水面存在较为剧烈的波动;进水池中水流流态发生恶化,出现...采用Volume of Fluid(VOF)模型对田山泵站进水池进行了三维流场计算,分析了不同水位及开机组合情况下泵站进水池的水流流态.研究发现:泵站低水位运行时,由于淹没深度较小,进水池水面存在较为剧烈的波动;进水池中水流流态发生恶化,出现了水面旋涡和水中旋涡;在附底涡和进水池两侧附壁涡的共同作用下,进水喇叭口正下方存在剧烈的旋涡,对机组的水力性能产生严重的影响.展开更多
针对旋流式催化裂化进料喷嘴进行了实验研究和数值模拟。实验中测量了不同工况下的雾化粒径和喷嘴的雾化角，同时验证了各段的压降分配方案。通过VOF（ volume of fluid）方法对喷嘴气液两相流的流动过程进行了数值模拟，描述了喷嘴中...针对旋流式催化裂化进料喷嘴进行了实验研究和数值模拟。实验中测量了不同工况下的雾化粒径和喷嘴的雾化角，同时验证了各段的压降分配方案。通过VOF（ volume of fluid）方法对喷嘴气液两相流的流动过程进行了数值模拟，描述了喷嘴中两相流的填充过程，得到了喷嘴的压力、速度分布和雾化角，并与实验结果进行了比较，二者吻合较好。对上述结果分析后表明，该型旋流式喷嘴雾化粒径在5360μm，雾化角随气液比或流量的增大而有所增加，采用内外嵌套式旋流器可使射流厚度较为均匀。展开更多
文摘Instead of the capillary plasma generator(CPG),a discharge rod plasma generator(DRPG)is used in the30 mm electrothermal-chemical(ETC)gun to improve the ignition uniformity of the solid propellant.An axisymmetric two-dimensional interior ballistics model of the solid propellant ETC gun(2D-IB-SPETCG)is presented to describe the process of the ETC launch.Both calculated pressure and projectile muzzle velocity accord well with the experimental results.The feasibility of the 2D-IB-SPETCG model is proved.Depending on the experimental data and initial parameters,detailed distribution of the ballistics parameters can be simulated.With the distribution of pressure and temperature of the gas phase and the propellant,the influence of plasma during the ignition process can be analyzed.Because of the radial flowing plasma,the propellant in the area of the DRPG is ignited within 0.01 ms,while all propellant in the chamber is ignited within 0.09 ms.The radial ignition delay time is much less than the axial delay time.During the ignition process,the radial pressure difference is less than 5 MPa at the place 0.025 m away from the breech.The radial ignition uniformity is proved.The temperature of the gas increases from several thousand K(conventional ignition)to several ten thousand K(plasma ignition).Compare the distribution of the density and temperature of the gas,we know that low density and high temperature gas appears near the exits of the DRPG,while high density and low temperature gas appears at the wall near the breech.The simulation of the 2D-IB-SPETCG model is an effective way to investigate the interior ballistics process of the ETC launch.The 2D-IB-SPETC model can be used for prediction and improvement of experiments.
文摘针对复杂管道系统内水流冲击滞留气团现象,采用VOF模型(Volume of Fluid Model)进行了数值模拟计算,并与一维模型进行了比较计算分析,结果表明:系统的最大压力并不总是气团的最大压力,有可能还会叠加水体对管壁的撞击而形成的突然升高压力。与实验实测结果的比较分析表明:采用VOF模型,能够较精细地仿真水流冲击滞留气团现象的气团形态、流场结构以及压力分布等的变化过程,其压力数值计算结果与实验实测基本吻合,其计算误差明显小于现有一维模型的计算误差,是深入研究该复杂瞬变流现象的有效方法。
文摘文章采用FLOW-3D软件,通过RNGk-ε模型和volume of fluid(VOF)方法相结合,实现了竖井水平旋流泄洪洞水力特性的三维水流流场数值模拟;对开敞式进水口轴线与旋流洞轴线交角不同时起旋室的压强分布、旋流角和紊动能等水力特性进行了对比分析研究,数值模拟能够客观地反映起旋室旋流的流场特性,成果可为旋流溢洪道的研究应用提供参考.
文摘采用Volume of Fluid(VOF)模型对田山泵站进水池进行了三维流场计算,分析了不同水位及开机组合情况下泵站进水池的水流流态.研究发现:泵站低水位运行时,由于淹没深度较小,进水池水面存在较为剧烈的波动;进水池中水流流态发生恶化,出现了水面旋涡和水中旋涡;在附底涡和进水池两侧附壁涡的共同作用下,进水喇叭口正下方存在剧烈的旋涡,对机组的水力性能产生严重的影响.
文摘针对旋流式催化裂化进料喷嘴进行了实验研究和数值模拟。实验中测量了不同工况下的雾化粒径和喷嘴的雾化角，同时验证了各段的压降分配方案。通过VOF（ volume of fluid）方法对喷嘴气液两相流的流动过程进行了数值模拟，描述了喷嘴中两相流的填充过程，得到了喷嘴的压力、速度分布和雾化角，并与实验结果进行了比较，二者吻合较好。对上述结果分析后表明，该型旋流式喷嘴雾化粒径在5360μm，雾化角随气液比或流量的增大而有所增加，采用内外嵌套式旋流器可使射流厚度较为均匀。
