| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 103 === In this paper, the finite element method has been used to analyze vertical pumps with no liquid in chamber which have been manufactured by San Tai machinery manufacturing company for Tam and Tunghsiao power plant. The simulation results are used to determine the vibration characteristics of the pumps which are whether the pump structural natural frequency is close to twenty percent of operation speed frequency or not. In order to verify the accuracy of the simulation, acceleration measurement experiment had been made on the vertical pump and the horizontal pump.
From the simulation results, vertical pumps natural frequencies has similar tendencies because of their similar structure. Tunghsiao vertical pump is weaker than Tam vertical pump because its structure is thinner and longer than Tam. There are three different cases designed in this paper to improve the pump by using the ribs or connecting element between protected pipe and main pipe in different locations. The simulation results show that the pump in case 2 has the best improvement effect. Pump improvement effect in Case1 is better than case 3, because rib connect elements in lower position. In Case 1 and 2, the stiffness of the pump increase and their natural frequencies are successful avoided within the twenty percent of operation frequency. In Case 3, structure natural frequencies increase, but some of them are still close to the operation frequency. Several natural frequencies in acceleration measurement experiment can match to simulation results. Since we can’t have enough power to shake vertical pump structure in impact experiment, only the parts of high frequencies with local vibration can correspond to simulation results
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