Thermal Insulation Performance Comparison Using Boil-Off Mass and Boil-Off Rate for Common Bulkhead Structures of Space Launch Vehicles

This study using Boil-Off Mass (BOM) and Boil-Off Rate (BOR) investigates the thermal insulation performance of the common bulkhead structure for propellant tank of launch vehicles. A commercial finite element analysis program, ABAQUS, is used for modelings and transient heat transfer analyses. Using the heat flux in the oxidizer tank, the BOM and BOR are calculated. The BOM of the common bulkhead structure with only foam or the foam core sandwich is derived as 0.263 kg and 0.194 kg, respectively. Therefore, it is investigated that the foam core sandwich common bulkhead structure is effective for thermal insulation. The BOR for the common bulkhead structure with only foam or the foam core sandwich is calculated as 0.161%/hour and 0.119%/hour, respectively, which are lower than the BOR of thermal insulation for Saturn V. The BOR value in this study shows significantly lower results than the previous design criteria of thermal insulation. Therefore, a further research considering heat convection in the oxidizer tank, external heat sources, and structural deformation of common bulkhead will be required in the future.