Thermal Analysis on Solid Rocket Motor Casing

A cloud seeding rocket comprises several parts such as the nozzle, propellant, and casing. The CRV7 C-15 rocket motor is the benchmark for current cloud- seeding rockets. A solid rocket motor casing is a hollow cylinder that acts as a combustion chamber for the propellant. This results in thermal and structural loads to the inner wall of the casing. The method to conduct the study was first verified against a Molybdenum casing with a thickness of 5mm and propellant N2H4 and N2O4. Simulation of static stress analysis and steady thermal analysis enables the simulation of overall stress analysis in ANSYS. Solutions were obtained using a steady solver due to the nature of the problem. Constant heat flux and constant pressure load were imposed to the inner wall of the casing for the thermal and structural analyses, respectively. This is to check that the rocket motor casing can withstand the combustion of the propellant. The system requires the safety factor of the rocket motor casing to be at least 1.5 when manipulating the thickness casing of 2.5, 3.5, and 5.0 mm which are CC 2.5, CC 3.5, and CC 5.0. The propellant for this study was solid AP/AL/HTPB propellant. After analysing the overall stress of the three models, the safety factor was calculated. CC 3.5 was undesirable as it had a safety factor of less than 1.5. CC 2.5 had a higher safety factor but was lower than CC 5.0. CC 2.5 was the most suitable casing as it had the smallest thickness, least in weight, and was less costly to fabricate compared to CC 5.0. This study serves as a guideline to indicate the safety factor of any chosen material with any propellant. Disciplinary: Thermal Analysis, Modelling and Simulation, Rocket Analysis. (C)2021 INT TRANS J ENG MANAG SCI TECH.