Erosion in Helico-Axial Pumps

With recent advancements in the petroleum industry, the need for multiphase pumps to transport multiphase products, such as the product of oil, water, and natural gas, arises along with their challenges. A helico-axial multiphase pump should be capable of converting fluid kinetic energy into pressure by avoiding gas-liquid separation and the gas-locking phenomenon, enabling smooth pump operation at higher gas volume fractions. In this paper, erosion on a helico-axial pump is evaluated at different flow conditions using sand particles mixed with water. A very important practical finding of this investigation is that the erosion rate increased when the flow conditions deviated from the design point of 3600 RPM. Operating the pump in off-design conditions not only reduced its hydraulic efficiency but also increased the erosion rates and hence reduces its life. It was observed that at 4800 RPM, the pump efficiency decreased by 11% and the erosion rate increased by 80%. This increase in erosion rate was attributed to the formation of local vortices upstream of the blade leading edge affecting the particle flow path and increasing its impact on the blade surface.