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Cavitation often occurs in inducer pumps of space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. In this study, we carried out cavitation erosion tests using silver plated coatings with different thermodynamic parameter at a constant cavitation number. Then we carried out cavitation erosion tests using some liquid with the same thermodynamic parameter and cavitation number as liquid oxygen condition. Thermodynamic parameter Σ proposed by Brennen was used as a thermodynamic parameter. The fluids used for the cavitation erosion tests were water, ethanol and hexane. We discussed the relation between thermodynamic parameter and mass loss rate, and the relation between acoustic impedance and mass loss rate.

Cavitation often occurs in inducer pumps of space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. In this study, we carried out cavitation erosion tests using silver plated coatings with different thermodynamic parameter at a constant cavitation number. Then we carried out cavitation erosion tests using some liquid with the same thermodynamic parameter and cavitation number as liquid oxygen condition. Thermodynamic parameter ∑ proposed by Brennen was used as a thermodynamic parameter. The fluids used for the cavitation erosion tests were water, ethanol and hexane. We discussed the relation between thermodynamic parameter and mass loss rate, and th e relation between acoustic impedance and mass loss rate.

Cavitation often occurs in inducer pumps used for space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. Therefore, it is important to study about the cavitation erosion resistance for silver plated coating at several operating conditions in the inducer pumps. In this study, the cavitation erosion tests were carried for silver plated coating in deionized water and ethanol at several liquid temperatures (273K–400K) and pressures (0.10MPa–0.48MPa). The mass loss rate is evaluated in terms of thermodynamic parameter Σ proposed by Brennen [9], suppression pressure p–pv (pv: saturated vapor pressure) and acoustic impedance ρc (ρ: density and c: sound speed). Cavitation bubble behaviors depending on the thermodynamic effect and the liquid type were observed by high speed video camera. The mass loss rate is formulated by thermodynamic parameter Σ, suppression pressure p–pv and acoustic impedance ρc.