Methods for the Simulation of the Aerodynamic Heating Conditions of the Structural Elements of Space Shuttles

摘要

The paper considers the problem of creating and operating products of reusable space-rocket hardware, in particular with respect to ensuring the integrity of structural elements and safe return to Earth under aerodynamic heating conditions. This problem has two aspects, which differ in specificity of the approaches to designing the elements of space shuttle systems (SSS). The first aspect is associated with ensuring the reliable functioning of the most thermally stressed elements of the re-entry glider, which are structures with large angles of attack, such as fuselage nose and leading edge, wing loading edge, elevators and air intake edges. The second aspect mainly concerns ensuring the allowable temperature level of the spacecraft pressure shell on all flight path segments, especially during re-entry in the Earth's atmosphere. In view of this, one of the main goals in creating SSSs is to develop a reliable heat shield having acceptable size and weight parameters, and cost. The successful solution of these problems is determined in many respects by the optimal choice of appropriate classes of materials: special high-temperature alloys, structural ceramics, highmelting-point metallic and polymeric composite materials. For the modern structures of SSSs, the use of structural metallic materials is worth-while in many respects. Rig test procedures are proposed. A complex of gas-dynamic test rigs was used as the basic equipment, whose fundamental design features and methodological solutions ensure the complete rig test cycle for the solution of problems in both directions. The methodological basis of rig tests is a set of specialized procedures for the simulation of thermally stressed states of the material and the intesity of the external action of the environment, which provide the equivalence of material damage processes and the limit state of the structural element under investigation under model and full-scale conditions. The fundamental basis of these approaches is the classical similarity and dimensional theories, the main postulates of which have been transformed and adapted to the problems of the study of the strength of materials and damageability of structural elements under thermal cyclic loading in corrosive environments. The developed procedures and experimental means allowed the modeling of aerodynamic heating processes of the structural elements of space shuttles. It has been shown that the implemented methods enable the evaluation of functional characteristics, determination of a set of properties and refinement of the technology for the formation of structural elements of aerospace vehicles operating under the conditions of aerodynamic heating to extremely high temperatures.