Modelling and validation of magnetically suspended turbomolecular pump rotor considering blade structure

The magnetically suspended turbomolecular pumps (MSTMPs) are critical for ultra-high vacuum generation, employing rotors with multistage flexible blades. In experimental and operational observations, the flexibility of these blades induces shaft-blade coupled bending vibrations that risk instability when coinciding with controller bandwidths. To accurately characterize these dynamics and enable vibration control strategies, a comprehensive numerical model is developed and experimentally validated. The effect of the bolted-joint interface contact between the turbo and shaft was modelled as uniformly distributed massless spring units, blade dynamics were discretized using plane beam elements incorporating centrifugal stiffening effects. The model is validated through modal tests and frequency response comparisons demonstrated accurate prediction of shaft-turbo bending modes and turbo-blade coupled modes with natural frequency errors <=10%.