Experimental Study On Flow Characteristics Of Slug Flow In The Variable Diameter Pipe

Slug flow is the alternating flow between liquid plug and long bubbles in space and time,is a common flow in oil-gas transport.And a lot of problems may be caused in the safe production of oil and gas fields by the unstable flow of slug flow,such as pipeline strong vibration,separator overflow and pipeline corrosion acceleration.In order to ensure the optimal design and safe operation of pipeline and downstream oil and gas treatment equipment,it is very important to analyze the flow characteristics of slug flow.In the paper,the experimental platform is built by taking the air and water as the medium,relying on the equipment and related equipment in the multiphase flow laboratory in Xi'an shiyou University.It is very important for improving the study and application on slug flow in the horizontal adjustable pipe to take the experimental study on two-phase flow in the horizontal adjustable tube in large diameter tube diameter of 25 mm,small diameter tube diameter of 50 mm and three different variable cone angle ? are 3.57 °,4.76 ° and 7.13 °.The main research contents and conclusions are as follows: for the gas-liquid two-phase slug flow liquid plug speed in the horizontal variable-diameter tube,large diameter pipe and small diameter pipe show the same law,the liquid plug velocity shows Gaussian distribution,and the change of the gas conversion speed is the main factor affecting the velocity of the liquid plug,the difference is that the small diameter tube is more sensitive to the change of the gas conversion rate,and the increase is more obvious;for the length of the liquid plug,the large diameter pipe and the small diameter tube show the same law,the velocity of the plug shows Gaussian distribution.The change of the length of the liquid plug is mainly affected by the gas conversion rate,and the change of the liquid conversion speed has little effect;for the frequency of liquid plug,the large diameter tube and the small diameter tube all show the Gaussian distribution,and the change of the diameter has obvious influence on the liquid plug frequency;for the liquid holding rate,when the liquid phase conversion rate remains constant,the slug flow rate will decrease with the increase of the gas phase conversion rate;for the different taper angle ? of the variable section,the change tendency of the length of the slug flow,the stopper frequency and the liquid plug speed is same in the large diameter tube and small diameter pipe.If the gas conversion speed and the liquid conversion speed keep constant,the liquid plug speed and liquid plug frequency of slug flow will decrease with the increase of the taper angle ? of the variable-diameter section,but the length of the slug flow plug increases with the taper angle ? of the variable diameter increasing.