| The turbomachinery, which is a wide range of applications in National economic,industrial and mining enterprises. In order to ensure the output power and the differentmethods to maintain a higher efficiency when the changes in working conditions ofthe impeller unit change often, for example, the steam turbine usually using partialadmission to adjust the air, while the gas turbine can be used to adjust the guide vaneangle.In this paper, tests and numerical simulation are used to analysis the flow andvibration characteristics of a partial admission and adjustable guide vane turbinecase.This paper use a unsteady calculation to simulate the unsteady flow of turbineunder partial admission, calculate the unsteady characteristics with soft wareNUMECA, analyze aerodynamic performance of turbine at the middle of whole blade,and study the effect of rotate speed, inlet pressure and VAN angle on turbine. In thesame time, calculate the exciting force on rotate blades at different location, and findthere is a large pressure gradient at the junction of blocked part and inlet part, whichcause a sharp change of axial and tangential force. This will demand a increase ofrotate blades’ strength, and the whole force on impel will be asymmetrical, which willcause stronger vibration than full admission.In order to study the vibration of turbine, establish a three-dimensional finiteelement model based on the steam turbine under partial admission, then use FFT toanalyze the exciting force which is calculated by NUMECA. Load the exciting forceon the finite element model, compare the vibration of different test points, providedata for the study of vibration. The study find that vibration strength varies fromdifferent direction of test points, and the vibration of dual inlet turbine is weaker thanthat of single inlet one. But the efficiency of dual inlet turbine is lower than that ofsingle inlet one, which is caused by increase of denounced gas losses. |
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