The study of hypersonic aircraft and their tail flames is an important area of research in the field of aerodynamics. The tail flame of such aircraft is an important characteristic, as it affects the aerodynamic stability of the aircraft and has implications for the safety and efficiency of flight. In order to accurately simulate the tail flame and calculate its spectral radiation characteristics, it is necessary to analyze the scattering characteristics of the ablative particles in detail. This involves studying the changes in optical properties that occur as a result of variations in the proportion of mixed ablation products, specifically B2O3 and SiO2, during the early stages of the reaction. The paper under consideration focuses on the analysis of this process, with particular attention given to the properties of the new modified material ZrB2-SiC. The researchers used MIE scattering theory combined with independent scattering approximation to compare and analyze the process. Their findings indicate that the extinction coefficient decreases with the increase of ablation time during this early transition stage, while the difference in scattering image function is not significant. Therefore, it is suggested that the difference of scattering phase function can be ignored in future studies. The phase function of SiO2 particles is directly taken as the final result. This study is of great significance for the development of more accurate simulation models of flame in the tail of hypersonic aircraft, as it emphasizes the need for a detailed understanding of the scattering properties of ablative particles. By analyzing the optical properties of these particles, we can better understand the situation of tail flame and predict its spectral radiation characteristics more accurately. This information can be used to improve the safety and efficiency of hypersonic aircraft and may have wider applications in the field of aerodynamics.
In non-steady and high-speed flowing high-temperature environments, local thermal non-equilibrium phenomena are widely present. Therefore, if the Boltzmann distribution, which uses a single temperature to describe the energy level distribution of molecules, is adopted, a large error may exist. To solve this problem, a two-temperature / three-temperature model is often used to calculate the spectral radiation characteristics of OH in local thermodynamic non-equilibrium states. In this paper, taking the BSUV-2 aircraft at a flight altitude of 100 km as an example, The OH radiation characteristics in shock waves with a wavelength range of 305nm-315nm were calculated using the two-temperature model. By comparing the relative spectral radiance of experimental spectra and calculated spectra of OH, the optimal calculation range of vibrational temperature was determined to be 2000K-4000K. This method of measuring rotational temperature has significant advantages in low-resolution situations. After determining the rotational temperature, by simulating and calculating the normalized OH spectral radiance corresponding to different vibrational temperatures in the wavelength range of 270nm-340nm, it was found that the maximum intensity peak G1 is not affected by temperature, while the second largest intensity peak G2 has a linear relationship with temperature. Therefore, we can use the ratio of G1 to G2 to invert the range of rotational temperature. This study shows that using a two-temperature thermodynamic non-equilibrium model in local thermodynamic non-equilibrium states can achieve temperature inversion and accurately describe the spectral radiation characteristics of OH molecules, providing an important reference for related research fields.
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