Flow disturbances induced by an orifice plate in a horizontal air-water flow in the slug regime

An experimental study of the flow disturbances induced by an orifice plate in an air-water slug flow is carried on a horizontal test section with 0.026 m and 1009 pipe diameters long. Three orifices with distinct area contraction ratios are tested at three axial positions along the test section. The instantaneous orifice pressure difference as well as the absolute pressure and void fraction along the test section are measured. The data is further processed to get the bubble nose velocities and the slug frequency. The pressure difference at the orifice and the absolute pressure along the test section reveal a pulsatile pressure behavior due the intermittent passage liquid slugs and elongated bubble through the orifice. The spectral analyses disclose a match between the frequency of passage of slugs through the orifice and the frequency of the orifice pressure fluctuations. The orifice disturbances on the void fraction, bubble nose velocity and frequency of passage exhibits a dependency on the orifice size and to the distance from the mixer.