Pumping station at Nghi Son refinery

Detecting a powerful vortex through physical modelling.


Outfall pumping station at the Nghi Son petrochemical complex (Vietnam) - Client: JGCS Consortium
Scale: 1:12

In the context of development of a refinery on the coast of Vietnam 200 km to the south of Hanoi, the consortium commissioned Artelia to perform scale model tests on the sea outfall pumping station in order to validate its hydraulic design.

Purpose of the physical model

The purpose of the model was to confirm or optimise the pumping station design that had been proposed by the Korean consulting engineer, by checking the flow conditions:

  • in the station (screens, distribution chambers)
  • at the intakes of the pumps (pre-rotation, vortices, air entrainment).

The model fully served its purpose, because it revealed that a powerful vortex formed with certain water levels, flow rates and pumping configurations and developed to the extent that it introduced air almost continuously into the intake of one of the pumps. On a life-size structure this constitutes a serious dysfunction, substantially reducing pump efficiency and speeding up the rate of wear, and leading to a high risk of the pump being destroyed within a very short time. Adding a carefully-positioned simple thin concrete wall to guide the water flow eliminated the vortex completely, guaranteeing that the pump would perform satisfactorily in the long term.

Description of the physical model

The model represented the geometry of the station, including the pump sump, the supply weir, the internal baffles and any stoplogs, as well as the three pumps. Each pump was represented by a transparent, instrumented model with a bellmouth geometry identical to that of the original design.



Number of pumps

Total rated capacity

Pump diameter

Operating water depth


30,250 m3/h

 1,900 mm

3.5 - 8.5 m