TY - GEN
T1 - Development of beam-to-beam contact detection algorithms for rotor-stator rubbing applications
AU - Roques, Sébastien
AU - Legrand, Mathias
AU - Stoisser, Carlo Maria
AU - Cartraud, Patrice
AU - Pierre, Christophe
PY - 2008
Y1 - 2008
N2 - In nuclear power plant turbosets, the design-basis accident consists of a blade-off on the low pressure turbine last stage. During the accidental shutdown, a severe rotor-casing interaction may occur at critical speeds due to large shaft line displacements originated by a high unbalance excitation. The contact between the shaft and the stator, also called the diaphragm in this study, induces an important angular deceleration rate and greatly modifies the turbogenerator dynamics including the amplitude of the loads in the bearings. Therefore the main objective is to verify that the designed turbine is capable of going through critical speeds without catastrophic consequences for the shaft line. To this end, a model of a turbogenerator has been developed to compute rotor speed transients by considering the rotating speed of the rotor as an unknown, which allows for the angular deceleration due to rubbing to be calculated in a more realistic fashion. Lagrange multipliers method is applied to compute contact forces. The diaphragm, which is a non-rotating bladed disks assembly, is modeled by curved and straight beams, and different assumptions for the contact detection are studied to find a compromise between CPU time and accuracy. Results of the numerical tool show that the contact forces are sensitive to the retained assumptions only when heavy rub occurs. Nevertheless, the rotating speed and bearing loads are computed with a satisfactory accuracy, even with an approximation on contact detection that saves CPU time.
AB - In nuclear power plant turbosets, the design-basis accident consists of a blade-off on the low pressure turbine last stage. During the accidental shutdown, a severe rotor-casing interaction may occur at critical speeds due to large shaft line displacements originated by a high unbalance excitation. The contact between the shaft and the stator, also called the diaphragm in this study, induces an important angular deceleration rate and greatly modifies the turbogenerator dynamics including the amplitude of the loads in the bearings. Therefore the main objective is to verify that the designed turbine is capable of going through critical speeds without catastrophic consequences for the shaft line. To this end, a model of a turbogenerator has been developed to compute rotor speed transients by considering the rotating speed of the rotor as an unknown, which allows for the angular deceleration due to rubbing to be calculated in a more realistic fashion. Lagrange multipliers method is applied to compute contact forces. The diaphragm, which is a non-rotating bladed disks assembly, is modeled by curved and straight beams, and different assumptions for the contact detection are studied to find a compromise between CPU time and accuracy. Results of the numerical tool show that the contact forces are sensitive to the retained assumptions only when heavy rub occurs. Nevertheless, the rotating speed and bearing loads are computed with a satisfactory accuracy, even with an approximation on contact detection that saves CPU time.
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U2 - 10.1115/DETC2007-34625
DO - 10.1115/DETC2007-34625
M3 - Conference contribution
AN - SCOPUS:44849141374
SN - 0791848027
SN - 9780791848029
SN - 0791848027
SN - 9780791848029
T3 - 2007 Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, DETC2007
SP - 1187
EP - 1194
BT - 2007 Proceedings of the ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, DETC2007
T2 - 21st Biennial Conference on Mechanical Vibration and Noise, presented at - 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2007
Y2 - 4 September 2007 through 7 September 2007
ER -