혼-타의 간극 캐비테이션 침식 저감을 위한 형상 개발 연구

Abstract

Cavitation related erosion damages on the surfaces of semi-spade rudder are generally occurred at around leading edge of port-side-lower-face and at behind gap of lower pintle. While the former could be reduced by applying twisted leading edge section, a special shape of gap entrance profile should be introduced to control the erosion damage in the latter case. A new shape of gap entrance profile has been developed by means of extensive model experiments which were carried out in cavitation test facilities at MOERI. Large enough models to investigate the gap flow very closely have been prepared for the tests. In the tests, for the performance comparison between candidates, all the tests at different conditions have been visualized by high speed camera, cavitation inception tests for all models have been performed and also the pressure measurements for the traditional(G rudder) and the developed(F rudder) models have been conducted. The developed model (F rudder) turned out to have very stable pressure distribution along the outer surface to inside the vertical gap and so the cavitation inception speeds within ±5° of rudder angle were delayed approx. 4 knots in average.