TURBOPUMP RERATE AND REAPPLICATION WITH BEARING RETROFIT

摘要

CONMEC was contracted to rerate and reapply a surplusrnturbopump (a combined centrifugal compressor pump and steamrnturbine) for a steam turbine application due to the need of ourrncustomer Equilon in California. The turbopump comes from arnNavy shipyard and it was commissioned but never put intornservice. The new application for this unit is to use it as a steamrnturbine running at a higher speed with higher horsepower. Thisrnwould involve hardware changes to the unit, such as removingrnthe pump wheel, change aero design and nozzle blockrnconfiguration, modifying an existing speed governor provided byrnthe customer. The operating condition is significantly differentrnfrom the current rating of the unit due to the new requirement.rnThe horsepower was about four times higher than it was rated.rnThe operating speed was increased by about 30%. Thesernchanges made it a very challenging task to design the rotorrnbearing system to achieve sound rotor dynamics characteristics.rnSeveral bearing design options were studied, including plainrnsleeve bearing with axial grooves, pockets bearings and tiltingrnpad bearing. Since this is a rerate of an existing equipment,rnthere are restrictions in the bearing design to make it fit into thernexisting design envelop. This paper presents a systematic studyrnto find the optimal and most suitable solution to this specificrnapplication.