Abstract: Combined coning and waviness mechanical face seal, characterized by circumferential waviness superimposed on coning seal face, works as a non-contacting seal on hydrodynamic and hydrostatic effect. A finite element analysis (FEA) research into sealing film based on the shaft seal of a nuclear reactor coolant pump under laminar flow assumption is presented. The geometric model in this paper enables the decoupling of hydrodynamic effect and hydrostatic effect. The mechanism of combined coning and waviness mechanical face seal working on various conditions is revealed. The results show that hydrodynamic effect and hydrostatic effect do not work simultaneously in a combined coning and waviness mechanical face seal: the former plays a leading role under normal working condition and the latter contributes to the lifting force only when cavitations occur. Due to the hydrodynamic effect, the seal keep non-contact under abnormal working condition such as in low pressure drop situation or thin film situation. Thus the reliability is ensured and the operating life is prolonged.

Key words: Finite element analysis (FEA), Hydrodynamic effect, Combined coning and waviness mechanical face seal