Integrated Modeling and Analysis for a LOX/Methane Expander Cycle Engine: Focusing on Regenerative Cooling Jacket Design

A fully integrated engine analysis methodology was created and employed to study a 25,000 pound-force thrust class expander cycle liquid oxygen/methane engine for Crew Exploration Vehicle applications. All major components for the engine were modeled, including the combustion thermal chemistry, the turbopump assembly, the regenerative cooling jacket and the injector. Significant attention was assigned to the regenerative cooling analysis with respect to varying channel geometry dimensions. Chamber pressures ranging from 500 to 1000 psia, were parametrically studied for varying aspect ratios of 4 to 8, channel widths of 0.020 to 0.080 inches, and 100 to 200 number of channels. Two of the three geometric parameters were held fixed, while trends in the third were studied at constant chamber pressures. The channel cross-section was held constant with respect to axial position in the engine. From the geometry cases studied, the initial baseline channel geometry was determined and chamber pressures were studied in detail from 500 to 1000 psia. A chamber pressure of 850 was determined as most favorable with respect to overall engine performance and design metrics. Using the initial baseline geometry, a constant cross-section and stepped channel design were compared. The performance for the stepped channel configuration is notably superior to the constant cross-section channel case with respect to pressure loss, and chamber mass metrics. Detailed results are presented for all engine components for the most favorable design.