Objective  As a physical energy storage method characterized by both environmental protection and economic efficiency, gravity energy storage is expected to become an important support for the sustainable development of renewable energy in the future. Nevertheless, it is urgent to solve the problems of large and unstable aerodynamic drag loss during the operation of gravity energy storage equipment.

  Method  This paper employed the numerical simulation method to simulate the whole process of multiple sets of dynamic/static equipment located in different positions in the shaft from the initial movement to the intersection of each other, comprehensively considering factors such as the number, operation state and relative position of the shaft-type gravity energy storage equipment. The influence of key parameter changes on the aerodynamic drag characteristics and the flow field distribution of the shaft during the operation of the equipment was analyzed. Based on this analysis, a streamlined guide cover was designed. The parametric modeling and numerical simulation calculation for the equipment with the guide cover were carried out, and the influence of the guide cover structure on the surface pressure distribution and aerodynamic drag of the equipment was analyzed.

  Result  The research indicates that, for a single set operating conditions, the aerodynamic drag of the car increases due to the influence of dynamic and static intersection in the variable motion stage; for multiple sets operating conditions, the cross-sectional area of the shaft decreases, the airflow is compressed and accelerated, the peak value of the aerodynamic drag of the car increases significantly, and the fluctuation of the aerodynamic drag is more obvious in the uniform speed operation stage after the intersection. After adding the guide cover, the aerodynamic drag of the car is obviously reduced. For a single set operating conditions, the peak aerodynamic drag of the car with the guide cover is 39.8 % of that without the guide cover; for multiple sets operating conditions, the peak aerodynamic drag of the car with the guide cover is 60.2 % of that without the guide cover.

  Conclusion  The dynamic evolution mechanism of the aerodynamic drag of the shaft-type gravity energy storage system is revealed by multi-condition numerical simulation, and the effectiveness of the guide cover design is validated, with a maximum reduction of 60.2 %. This paper provides reference for the structural aerodynamic optimization design of such shaft-type gravity energy storage.