A New Cavitation Test Facility at Centrospazio

The present paper illustrates the result of the trade-offs between operational requirements and practical limitations leading the final design of the CPTF (Cavitating Pump Test Facility), the CPRTF (Cavitating Pump Rotordynamic Test Facility) and the related TCT (Thermal Cavitation Tunnel). The CPTF is an experimental apparatus specifically designed for the performance analysis of turbopumps in fluid dynamic and inertial/thermal cavitation similarity conditions. The apparatus, operating in water up to 90°C, is capable of controlling the pump’s operational conditions and carrying out the measurement of the steady and/or unsteady flow parameters (pressure, velocity, temperature) at the inlet and discharge of full-scale cavitating/noncavitating turbopumps for space propulsion applications. More generally, the CPTF is designed as a flexible, versatile and inexpensive facility that can be readily be adapted to carry out detailed experimental investigations on practically any kind of fluid dynamic phenomena relevant to high performance turbopumps. The CPRTF is currently being completed under ASI (Agenzia Spaziale Italiana) funding and consists in an upgraded version of the CPTF capable of carrying out the measurement of the steady and unsteady rotodynamic forces exerted by the flow on whirling impellers of cavitating/noncavitating turbopumps using an especially designed rotating dynamometer. To this purpose the CPRTF can operate the pump under forced whirl conditions on a circular orbit with assigned eccentricity and angular speed. The TCT is a small-scale water tunnel that can be installed on the suction line of the CPTF, with the specific capability of running tests under thermal cavitation similarity conditions. The main operational requirements and development choices that led to the final configurations of the CPTF, CPRTF and TCT are illustrated and their performance in testing cavitating/noncavitating turbopumps and hydrofoils under fluid dynamic and thermal cavitation similarity are illustrated. Experimental results are presented to document the present capabilities of the facility in a number of typical configurations and operational conditions.