ICSV 14 Cairns • Australia 9-12 July , 2007 THE INVESTIGATION OF SUBMERGED VERTICAL PUMPS IN A POWER PLANT USING VIBRATION BASED CONDITION MONITORING TECHNIQUE
Condition monitoring has received considerable and wide attentions through most of the industries employing rotating machinery. It is increasingly becoming vital in industry because of the needs to prolong the machine life, increase reliability and decrease possible loss of production due to faulty machines. Vibration monitoring is the most popular technique, given its direct ability to detect and diagnose faults in machinery, which it is typically found in large industries such as oil and gas, petrochemical and power generation plant. This paper presents the field investigations of submerged vertical pumps with suspected cavitation in a power plant. Frequent impeller failures of submerged vertical pumps would potentially result in the total plant shutdown without warning. Vibration analysis was undertaken on the pump of concern in assist plant personnel in making decision on its operations. The predictive condition monitoring for the pump in the investigation include the vibration monitoring and a simple statistical analysis based on monthly overall vibration level, which is useful for reasonably accurate diagnosis in actual commercial pump in power plant. High frequency vibration was shown to be a good indicator of cavitation. It was shown that the investigations implied a wrong setting of the adjusting screw caused the large gap between the impeller and the casing and therefore enabling the seawater to slip back to the pit and hit the impeller and also the pump operating conditions that had resulted to the impeller failures.
Development of a predictive maintenance system for a centrifugal pump
An approach is presented for the development of a predictive maintenance system for rotor‐dynamic pumps, which focuses on the diagnosis of abnormal events related to fluid‐dynamic operating conditions. This methodology is based on an experimental characterization of the dynamic response of the pump under different loads and operation anomalies. The procedure has been put into practice on a medium‐sized centrifugal pump. The results obtained show that a simple spectral analysis of the pressure signals captured at either the inlet or the outlet of the pump can provide sufficient decision criteria to constitute the basis for a diagnostic system. This was not true however when analyzing signals of acceleration at the pump casing.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.