Experimental Study On Flow Characteristics Of Slug Flow In The Bending Pipe

Slug flow is a flow of long bubbles and liquid slugs alternating in space and time. In oil-gas mixture transportation, slug flow frequently takes place. Because of instability in flow, it brings many problems for production safety in oil and gas field, such as strong vibration in pipelines, overflow from separator and flow accelerated corrosion in pipeline and so on.The research of Slug flow in horizontal pipelines and relief pipelines, including the mechanism, the calculation model and the characteristics of slug flow characteristic parameters, are available consulted through a considerable amount of literature, but the study of slug flow in bending pipe needs to improve and consummate in these areas. Based on the current research situation of the characteristic parameters of slug flow in a horizontal pipeline and the terrain ups and downs, literature reviews is completed. It makes a summary about the experimental study of the present situation and lays a solid foundation for the experimental study of slug flow in the bending pipe.Relying on equipments and related instruments in multiphase flow lab of the country’s key laboratory in the xi’an Jiaotong university, the test-bed system about this paper is put up successfully. The two phase flow experiment research is finished in pipe diameter for DN32with air and water as medium. The pipe includes horizontal pipeline and four different bending radius and the same length under the big bend curvature level. In order to ensure the reliability of the experimental data, pressure difference is measured and compared with the theoretical value under different superficial gas velocity and superficial fluid velocity in horizontal straight pipe. Relative velocity method is used to analyze and study the characteristic parameters of slug flow in the horizontal pipe bending, including the liquid slug velocity, the liquid slug length and the liquid slug frequency, the influence under different superficial gas velocity, superficial fluid velocity, different curvature radius and the gas inlet pressure on them is analyzed, and the reasons is given. The characteristic of differential pressure of slug flow is analyzed in the horizontal pipe bending. Finally, according to the existing local pressure drop formula, the semi-empirical formula of pressure drop is obtained in bending pipe with large curvature radius.