Aquecimento aerodinâmico de uma cápsula em reentrada atmosférica

Abstract

Objects reentering the atmosphere travels at hypersonic speeds, a regime where air molecules are subject to the effects of high temperatures, such as: vibration, dissociation, and ionization. In this case, air cannot be treated as a calorically perfect gas. Aerodynamic heating is a predominant phenomenon in this speed regime, resulting from friction between air molecules and the surface of the object in atmospheric reentry. In the 1950s, aerodynamicists engineers studied this phenomenon, to predict the flight behavior of aircraft and rockets. This led to the development of theoretical and experimental methods that subsequently contributed to the beginning of space exploration. In the present work, these methods were used to estimate the aerodynamic heating of a space capsule, with blunt conical geometry, during atmospheric reentry. Seven points of the reentry trajectory were considered. To estimate the heating experienced at the stagnation point of the capsule, the method developed by Fay and Riddell (1958) was used. The method developed by Lees (1956) was used to estimate the heat distribution in the spherical and conical regions of the capsule. To do this, it was necessary to know the geometrical dimensions of the vehicle, the trajectory of the reentry flight, the thermodynamic properties of the atmosphere at the seven points of the trajectory chosen for analysis, normal shock wave relations, and isentropic relations. From this knowledge, it was possible to observe the behavior of thermodynamic properties and how they influenced aerodynamic heating throughout the seven points of the reentry trajectory.