聚能射流侵彻混凝土靶板的工程计算方法研究

详细分析了聚能射流侵彻混凝土介质的整个过程,根据流体模型和流体一弹塑性模型分别推导了侵彻孔深和孔径的计算公式。通过将理论计算值与试验测量值的对比分析.表明该工程计算方法可用于聚能装药对混凝土的侵彻参数计算．有一定的实用价值。     

射流侵彻混凝土介质数值模拟及影响因素研究

利用Ansys/LS-DYNA有限元分析软件,对聚能射流侵彻混凝土介质的全过程进行了数值模拟,模拟结果与实验数据基本吻合。通过数值模拟计算重点分析了药型罩锥角、药型罩厚度、壳体厚度、炸高和装药长度对聚能射流侵彻效能的影响规律。研究结果表明：药型罩锥角、药型罩厚度和炸高对聚能射流的侵彻深度和侵彻孔径影响较大,而壳体厚度和装药长度对侵彻效能影响较小。     

用ALE法实现一种新型聚能罩结构的三维数值模拟

研究分析了一种新型的聚能罩结构——星锥罩结构射流形成的特点,即射流发生了二次碰撞,产生了二次射流。并采用有限元软件LS-DYNA中的多物质ALE算法,成功地实现了星锥罩射流形成过程的三维模拟。计算结果表明：星锥罩形成了高速的二次射流,运用多物质ALE法对星锥聚能装药结构进行模拟是可行有效的。     

气体发生剂高压燃气驱动液体高速喷雾的试验研究

介绍一种气体发生剂高压燃气驱动的高速液体喷洒装置,利用高速摄影和压力测试系统,研究了安装螺旋喷嘴的喷洒装置在不同装药量下的喷射初始速度和液体雾化射流的扩展过程。实验结果表明,气体发生剂装药量大于50 g时,喷洒装置可快速形成稳定的喷雾锥,随着药量的加大,喷嘴的雾化效果也显著提高。并发现气/液界面的Rayleigh-Taylor(RT)不稳定性会对喷嘴的正常工作带来不良影响。     

发射设施热防护研究

热防护是热发射技术主要研究内容之一.提出在发射燃气动力学全三维仿真和相似理论研究的基础上,开展喷流缩比试验工作,通过喷流缩比试验对理论仿真结果和热防护方案进行验证,近似获得结构烧蚀范围和烧蚀程度,以指导热防护设计的工作思路,从而确定了"疏、堵、避、防,快速更换"的设计方法.     

平面夹层炸药对射流干扰的数值模拟

采用三维有限元程序( LS-DYNA)模拟了射流以不同入射角侵彻装有平面夹层炸药的靶板过程,并和无平面夹层炸药情况进行了对比分析,发现平面夹层炸药爆炸后,运动的面板和背板对射流有严重的干扰和切割效应,使射流偏转、弯曲、着靶点分散,导致侵彻能力下降。对于垂直侵彻,干扰不明显。对于斜侵彻情况,平面夹层炸药结构使射流的侵彻能力下降约58%～75%,干扰程度随入射角的增大而呈递增趋势。     

Enhancement of turbulent jet diffusion flame blowout limits by annular counterflow

The effects of a proposed combustion technique, named as annular counterflow, on the enhancement of jet diffusion flame blowout limits were investigated by a series of experiments conducted for the present study. Annular counterflow was formed in a concentric annulus, in which fuel jet was ejected from a nozzle and air was sucked into an outer cylinder encompassing the nozzle. Three fuel nozzles and outer cylinders of different sizes were utilized to perform the experiments. Schlieren technique and normal video filming were employed for the visualization of diverse flame morphologies triggered by the said flow. Gas samplings were taken and scrutinized by the use of a gas chromatograph. Results showed that the blowout limits can be enhanced dramatically by an increase in volume flow rates of air‐suction. Mixing enhancement is achieved with frequent and strong outward ejection of fluids from the cold jet when this technique is applied. The blowout limits are further extended when the diameter of outer cylinders becomes smaller and/or that of the fuel nozzle becomes larger. The base widths of lifted flames were found to be narrower in the interim of annular counterflow application. The rates of increase in flame lift‐off heights and base widths along with an increase in fuel flow velocities become sluggish when the volume flow rates of air are increased. The amount of fuel that was sucked into the outer cylinder was found to be negligible and trivial. A model based on annular and coaxial jet was developed to predict the lifted flame base width and blowout limits. The coincidence between the prediction and experimental results unambiguously validates that the momentum of air‐suction dominates the beneficial effect. Copyright © 2001 John Wiley & Sons, Ltd.     

气粒两相平面湍射流拟序结构的大涡模拟

采用Eulerian/Lagrangian方法,对空间发展的气粒两相平面湍射流的非定常流动过程进行了数值模拟。以Re数为13000的平面不可压缩湍射流流动为例,气相场采用大涡模拟（large-eddy simulaiton,LES）技术,直接求解大尺度涡运动的Navier-Stokes方程,小尺度涡采用标准Smagorinsky亚格子模式模拟。为了示踪两相射流中气相的运动,同时球 解了标志物的浓度输运方程。颗粒相的运动用Lagrangian方法直接求解。大涡模拟结果表明,在平面射流的过渡区及充分发展区存在丰富的拟序结构及其相互作用。对于稀疏两相射流,不同Stokes数的颗粒运动规律和浓度分布取决于颗粒惯性和气相拟序结构的共同作用。对于Stokes数小于10的两相射流,颗粒相的瞬时浓度场分布与拟序结构密切相关,研究颗粒相的扩散应当考虑拟序结构的影响。     

采用射流泵利用城市供水管网的压力节能

介绍射流泵辅助二次加压供水系统的组成、工作过程及节能原理,并对系 统的特点及实际应用效果进行了说明。     

受激液体燃料射流表面波规律初探

利用所设计的实验系统,研究了受激液体燃料射流的表面波特性以及外加激励的幅值、频率及模式对液体射流表面波特性的影响。研究结果表明,大的激励幅值、恰当的激励频率和横向激励模式能够促进液体射流表面波的发展,从而加速液体射流的破碎。