【作者】 蔡旭；

【导师】 吉洪湖；

【作者基本信息】 南京航空航天大学 ， 热能工程， 2006， 硕士

【摘要】 本文从三维数值模拟和实验研究两方面展开了对喷管中安装插入板结构对热喷流红外特征的抑制效果的研究,通过对比安装插入板前后热喷流的温度、高温区的长度、温度场的形面以及红外特征曲线来说明插入板的安装对热喷流红外特征的抑制效果。在数值模拟过程中,研究了轴对称喷管安装十字形插入板前后热喷流的温度场变化,研究结果表明,十字形插入板的安装将热喷流的部分热量转移到喷管壁面,从而降低了热喷流的温度,缩短了其高温区的长度和喷流的宽度,减小了尾向高温区的面积,并且使喷流的等温线发生弯曲,增大了热喷流与环境大气的接触面积。插入板的安装使热喷流温度场产生的这些变化有利于热喷流红外特征的抑制。在实验研究中,通过对轴对称喷管出口附近截面上热喷流温度场的多点测量,得到该截面安装插入板前后的温度场的变化;在对二元喷管的实验研究中,通过总压耙测量喷管出口截面处的总压,得到二元喷管安装插入板前后出口处的总压分布。实验中采集了各个喷管热喷流的热象图,从图中可以明显看出安装插入板结构后各喷管热喷流核心区长度的减小。最后,实验采用傅立叶变换光谱仪采集了各个喷管热喷流的光谱辐射强度,得到了喷管中安装插入板结构对热喷流红外特征的抑制效果曲线。本文的研究结果证明了在喷管中安装插入板结构对热喷流红外特征的抑制效果,对于飞机热喷流红外特征的抑制技术增加了新的内容。更多还原

【Abstract】 The paper reports on 3D numerical and experimental study of the effects on jet’s infrared signature because of the installation of cross-flap in the nozzle channel, it can be recommended from changes of jet’s temperature, length, shapes of temperature field and infrared signature cures before and after fixing cross-flap.In the numerical study, changes of axisymmetric nozzle’s temperature field were studied, and I found that part of jet’s energy was transferred to the nozzle’s wall, temperature was reduced, length was shortened, zone in high temperature was minished, isotherms were cured. These changes make for reducing jet’s infrared signature.In the experimental study of axisymmetric nozzle, temperature field of a section about nozzle’s exit is obtained through thermocouple harrow. In the experimental study of 2D nozzle, pressure field of a section about nozzle’s exit is obtained through total pressure harrow. Heat imaging is adopted to show the length of jet. At last, jet’s infrared spectrum curves are gathered through Fourier transform infrared radiometer (FTIR). All experiments are carried out before and after installation of cross-flap.The investigations of this paper prove the suppression effects of cross-flap on jet’s infrared signature, and offer a new way to reduce jet’s infrared signature.更多还原