Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.28, No.1, 85-92, 1990
라그랑지안 좌표계의 유한요소법을 이용한 비뉴튼성 액체내 구형기포의 수축에 관한 연구
A study on the Collapse of Spherical Bubbles in Non-Newtonian Fluids Using a Finite Element Method in the Lagrangian Frame
본 연구에서는 구형 cavitation bubble이 upper convected Maxwell fluid내에서 수축할 때의 현상을 이론적으로 해석하였다. 수치해법으로는 Lagrangian frame에서 자유표면을 추적하는 완전한 explicit scheme을 개발함으로써 수치해법상의 문제점을 해결한 방법을 이용하였다. 유체의 탄성은 Reynolds 수가 10이하인 경우 수축 초기단계에서는 수축을 가속화하고 후기 단계에서는 감속시키지만, Reynolds수가 10보다 큰 경우는 관성이 지배적이 되어 무시되었다. 후기 단계의 수축의 지연은 정성적으로는 cavitation damage의 감소와 연관이 있을 것으로 예측되었다.
In this research, the collapse of a spherical caviation bubble contained in a large body of upper con-vected Maxwell fluid was studied theoretically. A fully explicit numerical scheme was developed which could track the bubble surface without iteration. It was observed that, when Re was less than 10, fluid elasticity accelerated the collapse in the early stage of collapse while in the later stage it rearded. When Re was larger than 10, however, fluid elasticity was no longer effective in changing the pace of collapse due to the large inertia. The retardation for Re<10 was expected to be related with the reduced cavitation damage in viscoelastic fluids.
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