The effects of high temperature and pressure on bubble formation under constant flow conditions in N2-H2O

He-H2O and N2-tetradecane were experimentally investigated. The experiment conditions covered orifice velocity from about 0 up to 1500 cm/s

temperature from 293 K up to 393 K

pressure from 0 up to 6 MPa

orifice diameter 1.12 mm up to 2.5 mm. The experiments were carried out in a stainless steel bubble column of 50 mm I.D with three pairs of high strength quartz windows. The bubble flow was visualized and recorded through high speed camera. The results show that bubble diameter decreases and aspect ratio increases with increase of pressure. The effect of temperature is complicated owing to the change of saturated vapor pressure

ratio to system pressure. When the ratio is larger

bubble diameter increases with temperature due to vaporization phenomenon. When the ratio is smaller

bubble diameter decreases with temperature. According to the experimental results

the bubble diameter model proposed by Gaddis was modified

and the saturated vapor pressure contribution was introduced to obtain a new estimation formula for the bubble diameter under high temperature and high pressure conditions.