A FORCED RESPONSE ANALYSIS AND APPLICATION OF IMPACT DAMPERS TO ROTORDYNAMIC VIBRATION SUPPRESSION IN A CRYOGENIC ENVIRONMENT

A high speed damper test rig has been assembled at Texas A&M Universit y to develop rotordynamic dampers for rocket engine turbopumps that op erate at cryogenic temperatures, such as those used in the space shutt le main engines (SSMEs). Damping is difficult to obtain in this class of turbomachinery due to the low temperature and viscosity of the oper ating fluid. An impact damper has been designed and tested as a means to obtain effective damping in a rotorbearing system. The performance and behavior of the impact damper is verified experimentally in a cryo genic test rig at Texas A&M. Analytical investigations indicate a stro ng amplitude dependence on the performance of the impact damper. An op timum operating amplitude exists and is determined both analytically a nd experimentally. In addition, the damper performance is characterize d by an equivalent viscous damping coefficient. The test results prove the impact damper to be a viable means to suppress vibration in a cry ogenic rotorbearing system.