슬러지유 환경에서 초음파 진동자 혼 선단의 침식특성에 관한 연구

Abstract

Sludge oils were unavoidably produced in ship's operations, therefore it is necessary to manage the sludge oils inside the ship itself with the view to prevent marine oil pollution from ship. The present study deals with the ultrasonic breaking systems that recycle the sludge oil from ships into usable oil to be burnt. Experimental studies were carried out to investigate the homogenizing effect of the marine oils and the erosion aspect of horn disc by repeated vibration of ultrasonic transducer. The matrix structures of the environment of various marine oils were interpreted to analyze the breaking and dispersion effects by cavity. The erosion damages the horn disc SS41 with weight loss rate and the irradiation time to maximum. Erosion rate were simultaneously examined according to the variation of the transducer amplitude, as well as the oil temperature and the immersing depth of horn disc.

The important findings from this study are as follows.

1) According to the depth of horn disk is deep, the variation of organization by cavity is less while the breaking effect of the particles are vitalized according to the increment of oil temperature. In addition, the effects of breaking and dispersion are prominent in proportion as period of experiment increases.

2) The cavitation by the horn of the ultrasonic vibrator is insensitive according as its depth increases in the oil, and the size of the bubble is larger in the high density condition of SLO(sludge lub. oil) than the condition of SFO(sludge fuel oil). Accordingly, the amount and rate of weight loss rate decrease according to the depth of horn, and the degree of loss at SLO condition is bigger than SFO condition.

3) The amount and rate of weight loss rate by the erosion of horn disk inclined to increase at the SFO condition in proportion as a temperature of oil sludge increases while it decreases at the SLO condition.

4) The difference of the maximum erosion rate of the horn disk which has 50㎛ of the amplitude of vibration decreases in proportion as the depth of horn disk gets deep at the both SLO and SFO condition.

5) When the temperature of sludge is going up, the maximum erosion rate of the horn disk which has 50㎛ of the amplitude of vibration inclined to decrease at the SFO condition while it increases at the SLO condition. In addition, the period of the maximum erosion rate at the SLO condition is shorter than the SFO condition

6) With a point of view of the maximum erosion rate according to the amplitude of horn disk, the maximum erosion rate at 50㎛ of the amplitude is more than double compare to the condition of 24㎛.

In view of the results so far achieved we could certificate developmental possibility of the ultrasonic breaking systems to manage the sludge oils inside the ship itself, and the experimental results can be useful to consider a countermeasure for the prevention of erosion damages.