This study is on the performance characteristics of bubble pump with vertical pipe of different lengths. For the experimental facilities composed of electrical heater used for providing heat source to generate bubble, a vertical tube with Ø4mm diameter, length of 200mm, 300mm, 400mm and 500mm. Storage tank with capacity was of 40 L containing a heat exchanger. The separator and condenser of the air bubble pump were installed separately. The results obtained from this experiment are as follows: there were a few variations of values of temperatures according to vertical pipe lengths of the bubble pump. The mass flow rate was increased by 0.17g/s when it was short as 200㎜ long pipe. But when vertical pipe length was 500㎜, it reached the normal temperature quickly because the slug flow occurred in this case at initial stage. Consequently, it was found that 500㎜ of the vertical pipe length was optimum for best performance of bubble pump.

해상에 설치된 기초말뚝의 경우 지진의 3가지 성분 즉, 지반의 수평운도, 지반의 연직진동에 의해 발생된 상부구조물과의 피드백 (feedback)에 의한 말뚝의 연직진동, 그리고 지반의 연직진동에 의해 유발된 해진(seaquake)의 진동이 말뚝 기초의 거동에 영향을 미친다. 본 연구에서는 유발된 해진의 진동을 해저면에서 유사화된 sine 정현파 형상의 동수압으로 모델링하였다. 해진(seaquake) 작용중 약 220m 이상의 심해에 설치된 개단 말뚝의 지지력은, 지반내에 유발된 과도한 과잉 간극수압으로 인하여, 심각하게 저감도었으며, 관내토 폐쇄력도 80% 이상 감소되었다. 해진중 관내토 선단 하부에서 발생된 과도한 과잉 간극수압으로 인하여 관내토내에 과도한 상향의 침투력이 유발되어 관내토 폐색이 손상되었다. 약 220m 이하의 천해에 설치된 개단말뚝의 지지력은 해진에 의해 약 10% 감소하였으며, 관내토의 폐쇄력은 5%이하만큼 감소하였다.

In this study, an analytical study on cooling period of vertical pipe cooling method was performed to determine the discontinuance time of pipe cooling.

Vertical pipe cooling method was developed for the thermal cracking control of vertically long and slender mass concrete member. This method was applied to mass concrete wall, and the performance of this method was investigated.