Visual Experimental Study on Liquid-Nitrogen Cavitating Flow on NACA 66 Hydrofoil

摘要

Cavitation is one of the main causes of failure in rocket engine cryopumps. Based on a visual experimental platformfor liquid-nitrogen (LN_2) cavitating flow over a NACA 66 hydrofoil, morphology evolutions of the cavity cloud fordifferent cavitation numbers are observed with a high-speed camera. The time-averaged pressure distributions in thecavitation zone are also measured, and themaximumtemperature drop is derived from the pressure data by assumingthe thermodynamic equilibrium in the cavitation zone. The attached cavitation length is dependent on the cavitationnumber, and the relationship is investigated by image analysis using the standard-deviation method. The sheddingcharacteristics of the cavitation cloud of LN_2 and room-temperature water are compared, and the mechanism isqualitatively clarified. The research results provide valuable experimental data, which are rare in this field, and helpto understand the influence of cryogenic cavitation.