Fig. 3 Pressure traces in saturated water-cold water contact experiment
It shows bubble shrinking when the differential e＜0 and expanding when e＞0. Fig.6, typical traces of pressure and differential brightness, indicates that the differential brightness has a large negative peak when high-pressure peak generated in the pressure trace. Therefore, it can be confirmed that a high-pressure peak is caused by rapid bubble growth.
As confined above, the high-pressure peak on high pressure-saturated water-side is caused by rapid bubble growth around the tube surface, and the movement of its water-vapor interface is restricted by mass of the cold water. The rate of bubble growth around the wall surface may be affected not only by its own thermal energy of the high-pressure saturated water, but also by heat supply from the wall on high-pressure saturated water-side. Each run started after one hour keep heating at constant temperature and pressure of the experimental setting on the high-pressure saturated water side using temperature controller (case 1), as above mentioned. The wall temperature of stainless test tube was then almost equilibrium to that of high-pressure saturated water. In order to identify the effect of the heat supply from the tube wall on high-pressure peak, some runs of that the high-pressure saturated water-cold water contact experiment started immediacy after the high-pressure saturated water temperature reached the experimental setting (case 2).
Fig. 4 Image of saturated water-cold water contact
Fig. 7 shows the relationship between initial pressure of high-pressure saturated water PHO and generated pressure peak PHO in cases 1 and 2. As shown in Fig.7, high-pressure peak was generated in runs which the wall surface were sufficiently heated (case 1), and not or weak in runs which the wall surface were not sufficiently heated (case 2).
