【作者】 王京；

【导师】 常海萍；

【作者基本信息】 南京航空航天大学 ， 航空宇航推进理论与工程， 2009， 硕士

【摘要】 气溶胶是目前针对飞机发动机喷口的热部件及发动机排出的高温燃气的3～5μm及8～14μm波段的红外辐射抑制的一种有效方法.气溶胶红外遮蔽的实质是利用悬浮的粒子对红外辐射能量的散射和吸收特性,达到抑制高温尾喷流红外辐射传输的效果。为了从机理上研究粒子群衰减特性影响因素及规律,利用Mie理论编写了衰减系数计算程序,分析讨论了颗粒粒径、材料和浓度对衰减系数的影响规律,得出了最佳粒径的结论,并在最佳粒径的情况下计算分析了颗粒材料对衰减系数的影响规律;给出了部分材料在最佳粒径条件下的衰减特性,提出了多分散颗粒材料粒径的选取方法和影响规律,为今后颗粒选材提供了研究手段和参考依据。设计并加工了一套试验系统,完成颗粒浓度、粒径和材料对粒子群衰减系数影响规律的试验研究,通过和计算结果对比,证明本文的计算方法是可行的。以数值模拟研究为主要研究手段,开展了离散颗粒抑制热喷流红外辐射规律研究。其中,颗粒粒径对红外抑制率的影响比较大,本文研究范围内,粒径取1μm左右比较好;颗粒材料对红外抑制率的影响比较显著,所计算的四种材料以SiO₂和Graphite的抑制率较高;随着喷射质量的增加,抑制率显著增加,但这种增加并不随喷射质量的增加呈线性上升;喷射角度和喷射速度对红外抑制率的影响都不是非常显著。本文的研究成果能够为今后气溶胶在红外隐身领域的深入研究提供参考和帮助。更多还原

【Abstract】 Aerosol obscure is one of effectual techniques of I.R. suppression, which has been applied to decrease the I.R. signature of hot air exhausted from aero engine in a few countries. Scattering and absorbing of I.R. energy can be combined together with the small particles suspended in obscure, and the transmission of I.R. will be reduced according to those.In order to study the extinction character of particles, a calculation procedure was prepared by using the Mie theory, the extinction character of particles on particle diameter, material, volume concentration are simulated, come to the conclusion of the best diameter, the extinction character of particles on material was studied in conditions of best diameter. The result of this paper is quite useful to choose particle material and do further research of particle scattering.Based on the infrared suppression of aerosol, this paper designed a test system for the attenuation of the particles. The experiments have been carried out to study the extinction character of particles on particle diameter, material, and volume concentration. Compared to the calculation results, the method of this paper is possible.It was found in investigations that the rule of I.R. signature affected by the diameter of discrete particles was the most complicated. And there existed the best I.R. signature extinction when the diameter of particles was in the range of 1.0μm. The results presented that the I.R. signature is much more sensitive to the complex index. The I.R. signature was decreased greatly in the case of higher mass flow ratio. The I.R. signature was affected by ejection angle and jet velocity faintly. The research result of this paper will provide a valuable research measure for the related topic from now on.更多还原