Integral pumping rings for dual mechanical seals: hydraulic performance evaluation using numerical simulations

Abstract

The flow of barrier fluid through an industrial pressurized dual mechanical seal cartridge is investigated and evaluated experimentally and numerically. The cartridge is of the bi-directional type wherein it is radial-flow designed and fitted with a bi-directional integral pumping ring. The standard k–ϵ turbulence model is applied and the multiple frame of reference method is utilized to simulate the motion of the pumping ring. The present study is a continuation of former experimental and numerical companion work conducted in the area of the design and evaluation of integral pumping rings for dual mechanical seals. In the present study, barrier fluid flow is visualized to provide internal insight of the flow behavior leading to a better understanding of the pumping mechanism on both quantitative and qualitative aspects. The flow field is evaluated and a number of design defects are revealed. The simulations show that barrier fluid is being trapped in closed circulation in the inboard-seal region, consequently implying weaker regeneration of barrier fluid in that region in comparison with the outboard-seal region. Moreover, the simulations also reveal the existence of a relatively large separation zone at the outlet port leading to increased losses and reduced flow rate capacity of the device.