Effect of Aerodynamic Heating on Separation Mechanism used in Rockets and Need of Thermal Protection for Such Structures

Abstract

During the ascent flight of a rocket, when the vehicle passes through the dense atmosphere, the outer skin of the structure is subjected to aerodynamic heating loads. Due to this heating load, the structure is heated and .the strength of the structure deteriorates rapidly due to temperature rise of the structure. The structure needs to be thermally protected to restrict the temperature rise in order to maintain its structural integrity. However, in certain components of rockets, like in separation mechanism that is heated due to aerodynamic heating loads, the structure also needs thermal protection to minimize the large temperature gradients which if not controlled can result in thermal expansion and jamming of the separation system. Therefore it is very important to thermally protect such structures from aerodynamic heating to minimize the temperature gradients across the structure and avoid a likely mission failure. In this paper, a theoretical study is carried out to study the separation mechanism of a rocket which is subjected to aerodynamic heating. Methodology to estimate the aerodynamic heating using the actual flight trajectory of the rocket is also detailed. A l-D approach is used to estimate the temperature rise of the joint using finite difference schemes. The joint is also idealised using a 2-D finite element mesh to carry out the thermal response analysis of the mechanism. Comparison of the results of the analysis shows that a 2-D approach gives a realistic picture of the temperature distribution across the separation mechanism compared to I-D approach.