Solution To Cavitation Induced Vibration Problems In Crude Oil Pipeline Pumps

Abstract

An output was increased on the Eat-West crude oil pipeline in Saudi Arabia, increasing shaft seal failures were encountered. These limited the operation of the pipeline. Surveys on site and detailed model tests with flow visualization showed the cause of seal failures to be pressure pulsations generated by collapsing cavitation zones. These cavitation zones occurred on the impeller blades, and also in vortexes shed from the pump inlet features. Particular to this case was that the cavitation erosion was not severe, and was not the limiting factor for pipeline operation. In water, the same cavitation would have limited the impeller life due to cavitation erosion to a few hundred hours only. Through model testing an optimized impeller and casing modifications were developed which greatly extended the operating range of the pipeline. Rough guidelines were developed able to assess the danger of such pulsations in crude oil pumps at the design stage, and to define, in critical cases, the model tests to be performed to ensure roper pump operation.