Research On Physically Based Infrared Smoke Screen Simulation

With the rapid development of infrared technology and computer simulation technology,infrared smoke screen simulation has received extensive attention from researchers.Due to the complex geometric characteristics of the infrared smoke screen,it is difficult to simulate the physical shape of the infrared smoke screen using a simple modeling method,The uneven distribution of physical properties such as density,temperature and pressure in space and time make it difficult to calculate the radiation characteristics of infrared smoke screen accurately.Aiming at the problem that infrared smoke screen is difficult to realize quantitative simulation.the infrared smoke screen is simulated based on fundamental principles of fluid mechanics and infrared radiation transmission theory in this thesis.Firstly,the N-S(Navier-Stokes)equations describing low-speed incompressible viscous fluids are used to model the physical shape of the smoke,and the three-dimensional simulation area of smoke screen is divided into uniform cubic grids,each of which contains physical properties such as pressure,density and temperature,the N-S equations are used to convect the different physical properties of each grid,and then the physical model of smoke screen is established.The solving and optimizing methods of each part in the physical model are studied,and then the smoke source initialization method and boundary conditions are presented;Secondly,the infrared radiation model of smoke screen was studied.The infrared radiation characteristics of smoke screen were calculated based on the equivalent molecule blackbody model,and the absorption and scattering effects of the infrared smoke on solar radiation and environmental radiation,as well as the atmospheric effect on the radiation transmission path were comprehensively considered,a complete infrared smoke screen radiation model based on ray casting is built.The high-reality infrared smoke screen simulation was realized by combining the general-purpose computing power and the programmable rendering pipeline of GPU,the problem of slow calculation of N-S equations and ray casting algorithm is effectively solved,and a high fidelity infrared smoke screen simulation is realized.At the end of the thesis,the infrared smoke screen simulation results under different simulation conditions are given,and the simulation results are analyzed and evaluated from three aspects : the display of the infrared smoke screen time series simulation images,the comparison of infrared smoke screen simulation results based on particle system,and the quantitative analysis of infrared radiation distribution,transmittance and coverage of infrared smoke screen.