Dynamic Behavior of Turbopump Inducer Submerged in Liquid

The dynamic behavior of a turbopump inducer is investigated in this study, with a particular focus on the added mass. Inducers are commonly used in turbopump applications to prevent cavitation. Since inducers have no shroud on the blades, blades of inducers are more prone to vibration. Moreover, it is known that the natural frequencies of the inducer immersed in liquid will decrease due to the added mass effect. Since inducers have complex shapes, there is no analytical formulation to compute natural frequencies. This chapter represent a study that calculates natural frequencies and mode shapes of the inducer immersed in water. Initially, a literature review identified test-verified analytical solutions for natural frequency reductions in simple geometries such as cantilevers and simply supported plates. The ANSYS fluid/structure coupling approach was subsequently used to obtain numerical solutions, which demonstrated good agreement with published results. The techniques derived from this analysis were then applied to the more complex inducer model, and the ANSYS numerical results for both natural frequency and mode shape were obtained. Results of this study reveal that not only natural frequencies but also mode shape of the inducer have changed due to added mass effect. The findings of this study provide valuable insights into the design on the dynamic behavior of turbopump inducer. The results can be utilized by engineers and designers in the optimization to enhance inducer performance, minimize vibration-induced failures, and improve overall system reliability.