Performance of a Long Smooth Multiphase Pump Seal in Different Flow Regimes

Demanding for multiphase pumps introduces new challenges to the pump design. To prevent machine failures, the performance of the pump (noncontact) annular seal under multiphase conditions needs to be studied. The air addition into the oil flow not only changes the properties of the fluid but also can change the flow status in the seal clearance. The flow status can significantly affect the performance of the pump seal and thereby impact the pump vibration performance. Within the seal annulus, the axial direction flow is dominated by the pressure drop through the seal and can be considered as a Poiseuille flow. The circumferential direction flow is driven by the rotor rotation and can be considered as a Couette flow. The regime of the flow in the seal is controlled by the axial Reynolds number and the circumferential Reynolds number. Published test results on the boundaries between the laminar, transitional, and turbulent regimes in an annular seal are scant. This article will first draw these boundaries based on the test data for long smooth pump seals. Then, this article will show the performance of the long smooth pump seal in different flow regimes. Predictions will also be presented to compare with test results under different flow conditions.