A Simple Method for identifying bubbling/Jetting regimes Transition from large Submerged Orifices using electrical Capacitance Tomography (ECT)

摘要

The bubbling-jetting transition regimes from large orifice submerged in water were investigated for various orifice diameters. A simple and fast way for identifying the regime transition was successfully developed using electrical capacitance tomography (ECT). In all the experiments deionised water was liquid phase and air was gas phase. Orifice gas velocity (V_N) and orifice diameter (d_o) were varied from 0.8 to 186 m/s and 4-21 mm, respectively. It was found that the V_N, trans, strongly depends on the orifice diameter. In the small orifice diameter (d_o < 10 mm), V_N, trans, greatly decreases with the increase of orifice diameter. However, in the large orifice diameter (d_o > 10 mm), the effect of orifice diameter on the transition velocity is insignificant. Finally, the data obtained by ECT compares with other works and the dimensionless orifice Reynolds number (Re_o ～11,000) is preferred to identify the bubbling-jetting transition regimes.