Experiences on turbopumps, operating in partial cavitating conditions, pointed out the presence of radial loads on the shaft. These are the result of unbalanced hydrodynamic forces on the inducer caused by assymmetric cavitation phenomena on the blades. Since the liquid oxygen turbopump of Ariane 5 VULCAIN engine is requested to operate in these conditions, its inducer was tested in water on a dedicated bench. An instrumented bearing has been used to measure intensity and frequency of radial forces on the shaft. Strain gauges have been fitted on inducer blades to measure amplitude and frequency of vibration. Different tests have been performed to investigate the influence of flow coefficient, rotational speed and water temperature on asymmetric cavitation phenomena. During all the tests the presence of radial loads was observed in certain ranges of pump inlet pressure. The load appears rotating slightly faster than the shaft (supersynchronous condition). Decreasing pump inlet pressure its rotational speed approaches the shaft one. The radial load amplitude has been evaluated. It is maximum when the synchronous condition is reached. Maximum intensity is influenced by flow coefficient.
Experimental investigation on radial loads induced by partial cavitation on liquid oxygen turbopump inducer of the Ariane 5 VULCAIN engine
Experimentelle Untersuchung der durch partielle Kavitation hervorgerufenen radialen Kräfte im Flüssigsauerstoff-Turbopumpenlaufrad des VULCAIN-Antriebes von Ariane 5
1995
8 Seiten, 14 Bilder, 6 Tabellen, 3 Quellen
Aufsatz (Konferenz)
Englisch
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