Integral Pumping Devices for Dual Mechanical Seals: Experiments and Numerical Simulations

An experimental and numerical investigation is carried out to evaluate the performance of alternative pumping ring designs for dual mechanical seals. Both radial-flow and axial-flow pumping rings are considered in the present study. An experimental setup is constructed, and appropriate instrumentation are employed to measure the pressure, temperature, and flow rate of the barrier fluid. A parametric study is carried out to investigate the effect of pump rotational speed, barrier fluid accumulator pressure, and barrier fluid inlet temperature on the performance of the pumping rings. Experiments are also used to evaluate the effect of different geometric parameters such as the radial clearance between the pumping ring and the surrounding gland, and the outlet port orientation. Moreover, a numerical study is conducted to simulate the flow field for the radial pumping ring designs under different operating parameters. The computational fluid dynamics (CFD) model implements a multiple reference frame (MRF) technique, while turbulence is modeled using the standard k-epsilon model. Numerical simulations are also used to visualize the flow of the barrier fluid within the dual seal cavity. Present results indicate that the pump rotational speed and the orientation of the outlet port have a significant effect on the performance of the pumping ring. On the other hand, the effects of barrier fluid accumulator pressure and inlet temperature are minimal on the performance. The study also shows that reducing the radial clearance between the rotating ring and the stationary outer gland would significantly improve the performance of axial pumping rings. Moreover, comparisons between the computational and experimental results show good agreement for pumping ring configurations with tangential outlet (TO) ports and at moderate rotational speeds.