ENHANCING TURBOPUMP EFFICIENCY: ADAPTIVE BEARING COOLING AND LUBRICATION WITH A BACKFLOW DEFLECTOR

This study introduces an innovative approach to enhance the performance and reliability of turbopumps in rocket propulsion systems by integrating a secondary flow path for bearing cooling within the oxidizer pump assembly. Additionally, a comprehensive Computational Fluid Dynamics (CFD) analysis incorporating the Multiple Reference Frame (MRF) method and Conjugate Heat Transfer (CHT) analysis is conducted to evaluate the effectiveness of the secondary flow system in conjunction with the inducer of the oxidizer pump. The proposed design features the incorporation of a backflow deflector pump within the oxidizer pump assembly, enabling both oxidizer pressurization and efficient bearing cooling. Through a dedicated secondary flow path, a portion of the oxidizer is directed towards the bearings, creating a cooling circuit to dissipate heat generated during operation. This integrated approach optimizes system architecture, space utilization, and overall reliability. The thermal behavior of both the fluid and solid components is considered, allowing for a comprehensive assessment of heat transfer mechanisms and reveals favorable flow patterns within the secondary flow path, ensuring efficient cooling of the bearings while minimizing disruptions to the primary function of the oxidizer pump. The inducer's role in directing flow towards the bearings is elucidated, highlighting its contribution to effective heat dissipation and system performance. The CFD analysis provides insightful results about the temperature distribution on bearing balls, pressure distribution in the flow domain, and mass flow rate in the secondary flow path. The results show efficient cooling of the bearings with minimal impact on the primary flow characteristics and identify restrictions caused by the evaporation temperature of liquid oxygen, highlighting potential challenges and opportunities for optimization. In conclusion, the proposed design presents a holistic approach to optimize turbopump performance. This study is assumed to be useful in turbopump design by showing a pioneering CFD approach in the aerospace industry.