Numerical characterization of a hyperloop propelling nozzle and its adaption to an experimental wind tunnel.

This article focuses on the numerical analysis and experimental design considerations for the propulsive nozzle system of a hyperloop vehicle, specifically addressing the challenges posed by coaxial jets within a low-pressure tube environment. It investigates the effects of pod front geometry and temperature variations on flow behavior, concluding that these factors have negligible impact on the mixing region downstream of the nozzle, thus allowing simplifications in experimental setups. A key contribution is the development of a modified external duct geometry—a tapered tube section—that compensates for the absence of relative wall motion in wind tunnel tests, effectively replicating the flow and pressure conditions of a moving pod within a stationary tube. The proposed design demonstrates robustness across different nozzle geometries and operating points, providing a practical foundation for future wind tunnel experiments to validate computational fluid dynamics (CFD) predictions in hyperloop propulsion research.