Passive drag reduction of hyperloop pod by ventilation ducts

Abstract

In this paper, the applicability and efficiency of ventilation duct (VD) as a novel passive drag reduction method for Hyperloop pod were investigated using 3-D numerical simulations. Ventilation duct connects the upstream and downstream parts of the pod, increasing the effective cross-sectional area and reducing drag caused by choked flow between the pod walls and the external tube. This study introduces an innovative approach to drag reduction in Hyperloop system by addressing two previously overlooked challenges. First, it overcomes the constraint of allocating central space exclusively to the passenger compartment by redirecting ducts along pod shell’s boundary. Second, it enhances spatial efficiency by implementing a distributed duct configuration. For this purpose, four different design strategies along with six and eight number of ducts were proposed. The accuracy and validity of the solution were established through four distinct phases, including two comparisons with different experimental surveys, numerical research, and an assessment of mesh dependency. Results of the simulations showed that design strategy type 1 has the best performance in drag reduction. Only a minor difference in total drag was observed by changing number of ducts. It was demonstrated that VDs can decrease the total power consumption at all pod speeds with a maximum reduction of 16 % obtained while occupying only 2.5 % of the passenger compartment space. Comparisons of the VD method with compressor revealed that with identical removed frontal area, VDs achieve greater reductions in power consumption with less occupation of pod space.