CASE STUDY: SOLVING VIBRATION PROBLEMS IN HIGH SPEED BOILER FEEDWATER PUMPS USING EXPERIMENTAL AND ANALYTICAL TECHNIQUES

摘要

Entergy's Willow Glen Unit 4 main boiler feed pumps experienced high vibration levels and short run times since installation in the 1970's. The two 14,000 horsepower units have been rebuilt many times, with operating life averaging 18 months before vibration levels became excessive. To operate the unit until the next outage, operators had to reduce the running speed of the turbine drivers to control pump vibration and generate less electricity. Vibration and modal analysis testing coupled with lateral rotor dynamic computer models indicated that changing the stiffness of the bearing housing supports and rotor could significantly improve the pump. It was decided to proceed with design changes and as an interim solution fit the pumps with dynamic absorbers to reduce bearing housing vibrations. After the design changes were incorporated the pump operates with vibration levels in the.15 ip/s range.