Sensitivity analysis for the design and operation of a non-contacting mechanical face seal

Detection and diagnosis of failure in non-contacting mechanical face seals may prevent catastrophes in some critical applications. Seal failure due to face contact may occur because of large relative misalignment between the seal rotor and stator faces. The objective of this work is to study the sen sitivity of the relative misalignment to changes in the design and operatio nal parameters of a non-contacting flexibly mounted rotor (FMR) mechanical face seal. These sensitivities can be efficiently exploited to prevent poss ible contact through proper selection of the seal parameters and working po int in both the design and the control stages. Among the design parameters, the seal coning angle is by and large independent of other design requirem ents and should be properly selected to avoid contact. The operational vari ables greatly influencing the relative misalignment are the clearance, the bearing fluid pressure and the shaft speed. Where active control is conside red, the relative misalignment sensitivity to changes in the control parame ters should determine the working point. The sensitivity analysis is demons trated using the data of an existing seal test rig.