This study focuses on the design of modifications to the X2 expansion tube to allow for visual access to the fluid flow. It specifically refers to an operation mode proposed and developed by Professor Richard Morgan known as the standing shock in order to study radiating equilibrium shock layers which exist in Re-entry Applications.
The operating conditions for this mode of operation were initially defined through the use of Compressible Flow Shock Relations, Chemical Equilibrium with Applications, a heat transfer approximation, and a Semi-Infinite Solid Heat Transfer Approximation and yielded a maximum internal pressure of approximately 1.96MPa and heat flux of approximately 1.28 MW/m2. This pressure was comparable to the maximum pressure that was measured during a proof of concept test run performed on the operation mode. A major design issue encountered was the presence of such a large heat flux causing thermal shock and possibly rupturing the surface of the transparent material, interfering with the visual access.
In order to select an appropriate material to be used in the design, the material index was utilised coupled with CES Edupack software to identify thermal shock resistant materials. Fused Silica, Polycarbonate and Acrylic were all identified as possible materials however following sourcing issues, Acrylic was utilised due to its abundance on the market. A full design was proposed for the modifications and a static structural FEA analysis was performed with the assistance of Ansys Mechanical Software. The analysis resulted in a peak stress of approximately 41MPa in steel components and 22MPa in the transparent material corresponding to a safety factor of 6.1 and 2.7 respectively