Comparison of rotordynamic fluid forces in axial inducers and centrifugal turbopump impellers

[摘要] The paper illustrates and compares the results of the experimental campaigns carried out in the Cavitating Pump Rotordynamic Test Facility (CPRTF) at Alta, Italy, under ESA funding for the characterization of the lateral rotordynamic fluid forces acting on high-head axial inducers and centrifugal turbopump impellers for space propulsion applications. The configurations presented here refer to a three-bladed tapered-hub, variable-pitch, inducer (DAPROT3) and a single-stage centrifugal pump (VAMPIRE) with vaneless diffuser and single spiral volute. Both the centrifugal pump and the inducer have been designed by means of reduced order models specifically developed by the author and his collaborators for the geometric definition and performance prediction of this kind of hydraulic turbomachinery. Continuous spectra of the rotordynamic forces acting on the impellers as functions of the whirl frequency have been obtained by means of the novel technique recently developed and demonstrated at Alta. The influence of the rotor whirl motion, flow rate, cavitating conditions, and liquid temperature (thermal cavitation effects) on the rotordynamic fluid forces is illustrated and the observed differences in their behavior in axial inducers and centrifugal turbpumps are discussed and interpreted in the light of the outcome of recent cavitation visualization experiments carried out by the Chemical Propulsion Team at Alta.

[发布机构] Dipartimento di Ingegneria Civile Ed Industriale, Università di Pisa, Pisa, Italy^1

[效力级别] 工业技术 [学科分类] 工业工程学

[关键词] Cavitating pump rotordynamic test facility;Experimental campaign;Geometric definition;Hydraulic turbomachineries;Performance prediction;Reduced order models;Single-stage centrifugal pumps;Visualization experiment