Research On The Infrared Radiation Signatures Of Jet Unmanned Aerial Vehicles

Countries around the world are recognising the potential of jet UAV(Unmanned Aerial Vehicle)s in military conflicts and the need to improve their infrared stealth capabilities in order to enhance all aspects of their combat,reconnaissance and support capabilities.In order to reduce the probability of detection of jet UAVs,the infrared radiation characteristics of jet UAVs need to be studied and stealth solutions for them need to be investigated.At present,numerical studies of the infrared radiation characteristics of common aerial targets are relatively adequate,but there are fewer targeted studies for jet UAVs less so.Jet UAVs,on the other hand,differ from manned fighter aircraft in that they are faster and smaller,and therefore require targeted studies of their infrared radiation characteristics.In this thesis,the numerical characteristics of the infrared radiation of a jet UAV during its mission are investigated in the context of its flight state.The research in this thesis is summarised as follows.1.The surface temperature of the UAV is solved.In this thesis,a geometric model of the UAV is established and ansys fluent is used to solve for the surface temperature distribution of the UAV at different flight speeds and flight altitudes.The effect of flight speed and altitude on the surface temperature distribution of the UAV is discussed.2.A method for calculating the infrared radiated power at a specific detection direction and distance was completed.Based on the UAV surface temperature results,the data structure of the alternative simulation surface element was established using a C++ program and the determination of the validity of the surface element structure was completed.The mathematical derivation and programming of the infrared radiation calculation method for a given detection angle and distance were completed,and the infrared radiation in each direction in the plane of the vertical coordinate system was calculated,giving a maximum angle of 120° in the yz plane and a minimum angle of90° in the xz plane,providing a reference for covert manoeuvres.The effect of infrared radiation energy on the detection distance,flight altitude and speed is also investigated.3.The application of infrared radiation simulation calculations for jet UAVs is studied.Firstly,the structure and detection distance of the infrared detection system are investigated,and secondly,the stealth performance of infrared radiation modulating materials and low emissivity materials as well as the radiation heat dissipation effect are calculated and compared.A stealth paint coverage scheme with less stealth paint coverage area and similar stealth effect to full body coverage for a given detection direction is given,approximately one third of the area can be saved compared to covering the whole UAV,and the infrared detection distance of the jet UAV is compared for different cases.