PSI - Issue 24

3

Vincenzo D’Addio et al. / Procedia Structural Integrity 24 (2019) 510–525 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

512

nodal force

f j f 0

shaft operating rotational frequency rotational frequency of the cage

FTF FW

forward

G center of mass G, ̌ gyroscopic matrix, complete and reduced H transfer function I d ,I p diametric and polar moments of inertia k bearing radial stiffness of the bearings Kr global support radial stiffness K, ̌ stiffness matrix, complete and reduced m mass M X ,  M Y components of resultant moment around X and Y directions M, ̌ mass matrix, complete and reduced P X ,  P Y components of resultant load in X and Y directions p, ̌ force vector, complete and reduced P Laplace Transform of p s complex variable u j nodal displacement u, ̌ displacement vector, complete and reduced u m , u s master and slave node displacement vectors ̅ mode shape, eigenvector U Laplace Transform of u x,y components of translation in X and Y directions y participation coefficients Z number of bearing balls  bearing contact angle  j  j  nodal force and displacement phase angles  X ,  Y components of rotation about X and Y axes μ s , μ d static and dynamic friction coefficients  misalignment angle   n  natural angular frequency, eigenvalue Ω  Ω̅  rotational speed, dimensionless rotational speed = Ω  Ω  Ω  operating rotational speed 2. Characteristics of the pump angular frequency, dimensionless angular frequency =  Ω  

The work regards a new product of the company Pierburg Pump Technology; it is an electro-actuated centrifugal automotive pump, called purge pump, aimed at taking the air and gasoline vapor mix from the canister to the intake manifold of combustion chambers, in order to reduce emissions. This paper deals with the mechanical and, in particular, the rotordynamic aspects of the pump, with a focus on the the rotating assembly which is composed by a slender shaft carrying at its ends a magnetic rotor and a bladed impeller (Fig. 1). The shaft is supported by two roller bearings housed in the pump casing. For confidentiality reasons no details can be given on the pump design and dimensions, except for what is shown in Fig. 1, where the small size of the shaft is evidenced.