Research On Infrared Stealth Technology Of Water Mist And Water Film For Ships

The rapid development of infrared detection technology and infrared guidance technology has made surface ships more and more threatened.Water mist and water film can effectively attenuate and shield the infrared radiation of ships,reduce the probability of being detected by enemys and improve their survival ability.In this thesis,the infrared stealth technology of water mist and water film for ships is deeply studied,the visualization effects of water mist and water film are simulated based on the infrared simulation software of my laboratory,and the problem of calculating the attenuation of radiation energy by water mist and water film in practical application is solved.The main research contents are as follows:aiming at the research of infrared stealth technology of water mist,in order to obtain a water mist system with optimal extinction performance,a technical model for determining the size distribution function of droplets according to optimal extinction particle radius is established.The Mie theory is used to calculate the extinction efficiency factor of droplets,the optimal extinction particle radius is obtained according to the influence of particle radius on the extinction efficiency factor.Based on the principle that the number of particles should be largest in the optimal extinction particle radius,the three parameters of droplet size spectrum distribution function are determined,which solves the problem of difficult selection of relevant parameters in practical application.A simulation experiment is designed to study the influence of water content on the extinction performance of water mist,which provides a certain reference value for improving the stealth effect of water mist in practical application.aiming at the research of infrared stealth technology of water film,in order to reduce the radiation characteristics of target after adding a water film,a technical model for reducing the radiation exitance by lowering the surface temperature of liquid film is established.On the basis of solving the average flow velocity in liquid film and the thickness of liquid film,the energy equation of liquid film is established,and the heat transfer characteristics of liquid film are analyzed,which lays a foundation for further research in the corresponding field.The simulation experiment is designed with the Planck formula,and the effects of Reynolds number Re,the inlet temperature of liquid film,target wall temperature and airflow shear stress on the target radiation exitance are studied.The results show that increasing the Reynolds number Re,decreasing the inlet temperature of liquid film and target wall temperature,decreasing forward shear stress and increasing reverse shear stress can all reduce the target radiation exitance,and effectively improve the stealth effect of water film,which has strong application value.aiming at the research of infrared simulation technology of water mist and water film,in order to improve the simulation effect of water mist,an experimental model based on OSG particle system is established.The water mist model is loaded into the infrared simulation platform,and the optimal parameters of water mist are obtained by analyzing the changes of the simulation effects when changing the particle size,lifetime,number of particles generated per frame,initial particle velocity,gravity and wind speed and direction,which has certain reference significance for the simulation design of related systems.In order to improve the simulation effect of water film,a flow texture generation algorithm based on Perlin noise is proposed.Using a time variable to update the noise texture regularly,simulating the dynamic effect of water film flow,and optimizing the problem that the flow effect is not obvious.