| In recent years,due to the rapid changing of precision-guided weapons researching,and the appearance of dual-mode and multi-mode guidance technology,the traditional aerosol smoke interference technology has been difficult to meet the needs of the modern battlefield.Aqueous foam is a novel medium of PPECM which has advantages of wider jamming band,non-toxic and pollution-free,and safe convenient application.Hence,aqueous foam has a certain prospect in military application.This paper studies the foaming mechanism of aqueous foam and proposes a principle to select foaming agent,foam stabilizer and additive.Based on binary mixed micelle interaction theory,extending to the gas-liquid interface,study the influence of the surfactant combination to the foaming performance and stability of aqueous foam.Then the foaming formulation of aqueous foam is designed and optimized.Result shows that:the foaming solution of total concentration of 0.01 mol/L with SDS-AES preparing as a molar ratio of 7:3,adding PVA of 3g/L as foam stabilizer,is better to achieve the superior foaming performance and stability of aqueous foam.In order to design the suspending foam screen generating plant,this paper studies the preparing principle of aqueous foam and explores the foam suspended technology.Result shows that bubble diameter could be affected by the diameter of air supply port,gas velocity and direction.To further analyze the adhesion of solid particles in the aqueous foam,particle behavior of it in the system has been studied.It is showed that the hydrophobic solid particle increases the viscosity of the foam,and enhances the stability of aqueous foam due to its mechanical support and bridging role to the liquid film.In addition,hydrophobic solid particle has a good stick attached effect in the aqueous foam system,showing up as its adhesion of 88%to the gas-liquid interface even after 40min of dialysate.Based on stress analysis model,Bernoulli's equation and mass conservation of the bubble,the suspending performance of aqueous foam is studied,and is found to have relation with gas pressure and flow of air and helium,and foam number per unit volume.To further explore the extinction property of aqueous foam to broadband,transient light source spectral test systems,laser smoke tester,Fourier transform infrared spectroscopy and uncooled infrared focal plane thermal imager to test the transmittance of aqueous foam to visible light,laser and infrared,respectively;were used RCS testing system,millimeter-wave radiation parameters logger and centimeter wave signal acquisition analyzer to test the attenuation decibels of aqueous foam to millimeter wave and centimeter wave segments;analyze the factors to each band by aqueous foam extinction successively.The results show that the water-based foam plays a good broadband extinction performance.Based on the theories of geometric optics and electromagnetic wave propagation,study the attenuation mechanism of aqueous foam to electromagnetic wave attenuation,and then constructs the attenuation model.The results show that the special polyhedral structure of aqueous foam repeatedly reflecting and refracting to the incident light is an important reason to cause the electromagnetic wave attenuation.Among which,the hollow structure plays a good role of insulation and heat absorption;surface active agent,water and intrinsic absorption group in the liquid membrane system are main absorbing materials for feature band;in addition the scattering effect of additive greatly enhances is an important part of improving and enhancing the extinction property to millimeter wave and centimeter wave by aqueous foam. |
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