Experimental study of gas-lift systems with inclined gas jets

The focus of the present research is on the optical measurements of gas jets in liquid cross flows in vertical pipes. Three distinct injection angles (-45°, 0°, 45°), two orifice diameters (2 and 5 mm) and air and water flow rates varying respectively between 0.57 to 2.15 m3h−1 and 2 to 5 m3h−1 were investigated. To characterize the continuous and dispersed flow phases, shadow sizing and particle image velocimetry (two well-established optical measurement techniques) were employed. Global and local measurements provide data on the bubble diameter distribution, bubble shapes, air jet deflection angles, mean velocity profiles in the continuous phase and pressure distributions. The work compares the different features associated with the three angles of injection to determine the most appropriate geometry for a desired application. The diameter distributions for small bubbles appear to be insensitive to the liquid and gas flow rates and to the diameter and angle of the gas injector. The size distributions of the large bubbles, however, depend strongly on the flow parameters and the geometry of the injector (diameter and angle). The measured mean velocity profiles illustrate the complex interactions between the continuous and dispersed phases and the pipe wall.