Design modification in an industrial multistage orifice to avoid cavitation using CFD simulation

Background: Multi-stage orifices (MSOs) are used in many industries such as oil refineries, nuclear power plants, fertilizer plants and chemical plants for pressure reduction applications. This pressure reduction often leads to an outbreak of vapors from liquid water resulting in cavitation. Cavitation imposes many problems, including loss of efficiency, erosion, and vibrations or noise. In order to mitigate the effects of cavitation on the system, it is essential to thoroughly understand the occurring phenomenon. The main objective of this study is to propose a design modification for an industrial multi-stage orifice that inhibits the onset of cavitation. Method: Computational fluid dynamics (CFD) analysis was made to simulate an actual three dimensional setup of a six-stage orifice in which cavitation occurs after the last stage of the orifice. CFD model was validated by comparing the real-time plant data with actual operating conditions.Significant Findings: Various modifications in the geometry were tested with a focus on the orientation of the holes in orifices to eliminate the cavitation problem associated with the existing geometry. Multi-holed geometry having four holes in each orifice plate arranged at alternate positions was observed to be the best performing geometry without any cavitation effects under the same operating conditions.

Automated summary

This study proposes a design modification to prevent cavitation in an industrial multi-stage orifice. Computational fluid dynamics (CFD) analysis is used to simulate the orifice, and it was found that a multi-holed geometry with four holes arranged at alternate positions on each orifice plate performs the best without any cavitation effects under the same operating conditions.