Research On Thermal Physical Properties Of High Temperature Photonic Crystals Thermal Protection Structure

If the aircrafts fly in a low space by a great velocity, they may be in a very severeaerodynamic heating condition, so the effective thermal protection measures are needed.And so far the laser weapons have been the new danger for satellites and missiles, thehigh energy laser can destroy satellites and missiles in a very short time, so the effectivethermal protection measures are needed as well. Photonic crystals are artificialstructures that consist of different dielectrics periodically. There are photonic band gapsin photonic crystals, the wave of a certain wavelength can’t transmit in these structures.Because the temperature is very high in these two above conditions, the radiative heattransfer is of great importance, and the photonic crystals with photonic band gaps willbe the good thermal protection material.In this thesis, the mainly research is about photonic crystals in thermal protectionarea. At first, a3D geometrical model of aircrafts is established, the distribution oftemperature is calculated in the situation that the ma=5. Then a1D three layers slabmodel is established, the flux is applied on the one side, the distribution of temperatureof slab model has been calculated in two situation that has photonic crystals heatprotection coating or not. So we can get the thermal protection performance of heatprotection coating. Then we discuss the beat weight of laser weapons. Next, we getthermal protection performance of heat protection coating under the condition of lasershock. In addition, the optimum schemes about photonic crystals heat protection coatingare considered. Multilayer structure and adding active cooling channels these twoschemes are taken. By the comparison between the results of these two schemes and theprevious results, we can obtain the effect of optimization. At last, we discuss thephotonic band gaps of photonic crystals by MATLAB. For one-dimensional photoniccrystals, we use transfer matrix method to study the influencing factors of photonic bandgaps, and the influencing factors include periodicity, refractive index, angle of incidenceand thickness; for two-dimensional photonic crystals, we use plane wave expansionmethod to study the influencing factors of photonic band gaps, the influencing factorsinclude cylinder radius and dielectric constant. Through analyzing these influencingfactors, some way to increase the width of band gaps and change the location of theband gaps can be found.